]> git.dujemihanovic.xyz Git - u-boot.git/commitdiff
memory: Add TI GPMC driver
authorRoger Quadros <rogerq@kernel.org>
Thu, 20 Oct 2022 13:30:49 +0000 (16:30 +0300)
committerTom Rini <trini@konsulko.com>
Wed, 26 Oct 2022 19:21:12 +0000 (15:21 -0400)
The GPMC is a unified memory controller dedicated for interfacing
with external memory devices like
 - Asynchronous SRAM-like memories and ASICs
 - Asynchronous, synchronous, and page mode burst NOR flash
 - NAND flash
 - Pseudo-SRAM devices

This driver will take care of setting up the GPMC based on
the settings specified in the Device tree and then
probe its children.

Signed-off-by: Roger Quadros <rogerq@kernel.org>
drivers/memory/Kconfig
drivers/memory/Makefile
drivers/memory/ti-gpmc.c [new file with mode: 0644]
drivers/memory/ti-gpmc.h [new file with mode: 0644]
include/linux/mtd/omap_gpmc.h

index c621f5bba301e335d2f95d2eca4845a9e06b9888..56b89f17be5ce9c7fdafb90e880ea08b1c5abd1f 100644 (file)
@@ -41,4 +41,23 @@ config TI_AEMIF
          of 256M bytes of any of these memories can be accessed at a given
          time via four chip selects with 64M byte access per chip select.
 
+config TI_GPMC
+       bool "Texas Instruments GPMC driver"
+       depends on ARCH_OMAP2PLUS || ARCH_KEYSTONE || ARCH_K3
+       depends on MEMORY && CLK && OF_CONTROL
+       help
+         This driver is for the General Purpose Memory Controller (GPMC)
+          present on Texas Instruments SoCs (e.g. OMAP2+). GPMC allows
+          interfacing to a variety of asynchronous as well as synchronous
+          memory drives like NOR, NAND, OneNAND, SRAM.
+
+if TI_GPMC
+config TI_GPMC_DEBUG
+       bool "Debug Texas Instruments GPMC timings"
+       default n
+       help
+         Enable this to print GPMC timings before and after the GPMC registers
+         are programmed. This should not be left enabled on production systems.
+endif
+
 endmenu
index b27f7018654f3f712e5d4725d9e56a73565fceb7..2b196d78c0bffdd0d96436481c7846edfd4d2689 100644 (file)
@@ -3,3 +3,4 @@ obj-$(CONFIG_MEMORY) += memory-uclass.o
 obj-$(CONFIG_SANDBOX_MEMORY) += memory-sandbox.o
 obj-$(CONFIG_STM32_FMC2_EBI) += stm32-fmc2-ebi.o
 obj-$(CONFIG_TI_AEMIF) += ti-aemif.o
+obj-$(CONFIG_TI_GPMC) += ti-gpmc.o
diff --git a/drivers/memory/ti-gpmc.c b/drivers/memory/ti-gpmc.c
new file mode 100644 (file)
index 0000000..f511a52
--- /dev/null
@@ -0,0 +1,1240 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Texas Instruments GPMC Driver
+ *
+ * Copyright (C) 2021 Texas Instruments Incorporated - http://www.ti.com/
+ */
+
+#include <asm/io.h>
+#include <asm/arch/sys_proto.h>
+#include <clk.h>
+#include <common.h>
+#include <dm.h>
+#include <dm/device-internal.h>
+#include <dm/device_compat.h>
+#include <dm/devres.h>
+#include <dm/lists.h>
+#include <linux/mtd/omap_gpmc.h>
+#include <linux/ioport.h>
+#include <linux/io.h>
+#include "ti-gpmc.h"
+
+enum gpmc_clk_domain {
+       GPMC_CD_FCLK,
+       GPMC_CD_CLK
+};
+
+struct gpmc_cs_data {
+       const char *name;
+#define GPMC_CS_RESERVED       BIT(0)
+       u32 flags;
+};
+
+struct ti_gpmc {
+       void __iomem *base;
+       u32 cs_num;
+       u32 nr_waitpins;
+       struct clk *l3_clk;
+       u32 capability_flags;
+       struct resource data;
+};
+
+static struct gpmc_cs_data gpmc_cs[GPMC_CS_NUM];
+static unsigned int gpmc_cs_num = GPMC_CS_NUM;
+static unsigned int gpmc_nr_waitpins;
+static unsigned int gpmc_capability;
+static void __iomem *gpmc_base;
+static struct clk *gpmc_l3_clk;
+
+/* Public, as required by nand/raw/omap_gpmc.c */
+const struct gpmc *gpmc_cfg;
+
+/*
+ * The first 1MB of GPMC address space is typically mapped to
+ * the internal ROM. Never allocate the first page, to
+ * facilitate bug detection; even if we didn't boot from ROM.
+ * As GPMC minimum partition size is 16MB we can only start from
+ * there.
+ */
+#define GPMC_MEM_START         0x1000000
+#define GPMC_MEM_END           0x3FFFFFFF
+
+static void gpmc_write_reg(int idx, u32 val)
+{
+       writel_relaxed(val, gpmc_base + idx);
+}
+
+static u32 gpmc_read_reg(int idx)
+{
+       return readl_relaxed(gpmc_base + idx);
+}
+
+static void gpmc_cs_write_reg(int cs, int idx, u32 val)
+{
+       void __iomem *reg_addr;
+
+       reg_addr = gpmc_base + GPMC_CS0_OFFSET + (cs * GPMC_CS_SIZE) + idx;
+       writel_relaxed(val, reg_addr);
+}
+
+static u32 gpmc_cs_read_reg(int cs, int idx)
+{
+       void __iomem *reg_addr;
+
+       reg_addr = gpmc_base + GPMC_CS0_OFFSET + (cs * GPMC_CS_SIZE) + idx;
+       return readl_relaxed(reg_addr);
+}
+
+static unsigned long gpmc_get_fclk_period(void)
+{
+       unsigned long rate = clk_get_rate(gpmc_l3_clk);
+
+       rate /= 1000;
+       rate = 1000000000 / rate;       /* In picoseconds */
+
+       return rate;
+}
+
+/**
+ * gpmc_get_clk_period - get period of selected clock domain in ps
+ * @cs: Chip Select Region.
+ * @cd: Clock Domain.
+ *
+ * GPMC_CS_CONFIG1 GPMCFCLKDIVIDER for cs has to be setup
+ * prior to calling this function with GPMC_CD_CLK.
+ */
+static unsigned long gpmc_get_clk_period(int cs, enum gpmc_clk_domain cd)
+{
+       unsigned long tick_ps = gpmc_get_fclk_period();
+       u32 l;
+       int div;
+
+       switch (cd) {
+       case GPMC_CD_CLK:
+               /* get current clk divider */
+               l = gpmc_cs_read_reg(cs, GPMC_CS_CONFIG1);
+               div = (l & 0x03) + 1;
+               /* get GPMC_CLK period */
+               tick_ps *= div;
+               break;
+       case GPMC_CD_FCLK:
+       default:
+               break;
+       }
+
+       return tick_ps;
+}
+
+static unsigned int gpmc_ns_to_clk_ticks(unsigned int time_ns, int cs,
+                                        enum gpmc_clk_domain cd)
+{
+       unsigned long tick_ps;
+
+       /* Calculate in picosecs to yield more exact results */
+       tick_ps = gpmc_get_clk_period(cs, cd);
+
+       return (time_ns * 1000 + tick_ps - 1) / tick_ps;
+}
+
+static unsigned int gpmc_ns_to_ticks(unsigned int time_ns)
+{
+       return gpmc_ns_to_clk_ticks(time_ns, /* any CS */ 0, GPMC_CD_FCLK);
+}
+
+static unsigned int gpmc_ps_to_ticks(unsigned int time_ps)
+{
+       unsigned long tick_ps;
+
+       /* Calculate in picosecs to yield more exact results */
+       tick_ps = gpmc_get_fclk_period();
+
+       return (time_ps + tick_ps - 1) / tick_ps;
+}
+
+static __maybe_unused unsigned int gpmc_clk_ticks_to_ns(unsigned int ticks, int cs,
+                                                       enum gpmc_clk_domain cd)
+{
+       return ticks * gpmc_get_clk_period(cs, cd) / 1000;
+}
+
+static inline void gpmc_cs_modify_reg(int cs, int reg, u32 mask, bool value)
+{
+       u32 l;
+
+       l = gpmc_cs_read_reg(cs, reg);
+       if (value)
+               l |= mask;
+       else
+               l &= ~mask;
+       gpmc_cs_write_reg(cs, reg, l);
+}
+
+static void gpmc_cs_bool_timings(int cs, const struct gpmc_bool_timings *p)
+{
+       gpmc_cs_modify_reg(cs, GPMC_CS_CONFIG1,
+                          GPMC_CONFIG1_TIME_PARA_GRAN,
+                          p->time_para_granularity);
+       gpmc_cs_modify_reg(cs, GPMC_CS_CONFIG2,
+                          GPMC_CONFIG2_CSEXTRADELAY, p->cs_extra_delay);
+       gpmc_cs_modify_reg(cs, GPMC_CS_CONFIG3,
+                          GPMC_CONFIG3_ADVEXTRADELAY, p->adv_extra_delay);
+       gpmc_cs_modify_reg(cs, GPMC_CS_CONFIG4,
+                          GPMC_CONFIG4_OEEXTRADELAY, p->oe_extra_delay);
+       gpmc_cs_modify_reg(cs, GPMC_CS_CONFIG4,
+                          GPMC_CONFIG4_WEEXTRADELAY, p->we_extra_delay);
+       gpmc_cs_modify_reg(cs, GPMC_CS_CONFIG6,
+                          GPMC_CONFIG6_CYCLE2CYCLESAMECSEN,
+                          p->cycle2cyclesamecsen);
+       gpmc_cs_modify_reg(cs, GPMC_CS_CONFIG6,
+                          GPMC_CONFIG6_CYCLE2CYCLEDIFFCSEN,
+                          p->cycle2cyclediffcsen);
+}
+
+#if IS_ENABLED(CONFIG_TI_GPMC_DEBUG)
+/**
+ * get_gpmc_timing_reg - read a timing parameter and print DTS settings for it.
+ * @cs:      Chip Select Region
+ * @reg:     GPMC_CS_CONFIGn register offset.
+ * @st_bit:  Start Bit
+ * @end_bit: End Bit. Must be >= @st_bit.
+ * @max:     Maximum parameter value (before optional @shift).
+ *           If 0, maximum is as high as @st_bit and @end_bit allow.
+ * @name:    DTS node name, w/o "gpmc,"
+ * @cd:      Clock Domain of timing parameter.
+ * @shift:   Parameter value left shifts @shift, which is then printed instead of value.
+ * @raw:     Raw Format Option.
+ *           raw format:  gpmc,name = <value>
+ *           tick format: gpmc,name = <value> /&zwj;* x ns -- y ns; x ticks *&zwj;/
+ *           Where x ns -- y ns result in the same tick value.
+ *           When @max is exceeded, "invalid" is printed inside comment.
+ * @noval:   Parameter values equal to 0 are not printed.
+ * @return:  Specified timing parameter (after optional @shift).
+ *
+ */
+static int get_gpmc_timing_reg(/* timing specifiers */
+       int cs, int reg, int st_bit, int end_bit, int max,
+       const char *name, const enum gpmc_clk_domain cd,
+       /* value transform */
+       int shift,
+       /* format specifiers */
+       bool raw, bool noval)
+{
+       u32 l;
+       int nr_bits;
+       int mask;
+       bool invalid;
+
+       l = gpmc_cs_read_reg(cs, reg);
+       nr_bits = end_bit - st_bit + 1;
+       mask = (1 << nr_bits) - 1;
+       l = (l >> st_bit) & mask;
+       if (!max)
+               max = mask;
+       invalid = l > max;
+       if (shift)
+               l = (shift << l);
+       if (noval && l == 0)
+               return 0;
+       if (!raw) {
+               /* DTS tick format for timings in ns */
+               unsigned int time_ns;
+               unsigned int time_ns_min = 0;
+
+               if (l)
+                       time_ns_min = gpmc_clk_ticks_to_ns(l - 1, cs, cd) + 1;
+               time_ns = gpmc_clk_ticks_to_ns(l, cs, cd);
+               pr_info("gpmc,%s = <%u>; /* %u ns - %u ns; %i ticks%s*/\n",
+                       name, time_ns, time_ns_min, time_ns, l,
+                       invalid ? "; invalid " : " ");
+       } else {
+               /* raw format */
+               pr_info("gpmc,%s = <%u>;%s\n", name, l,
+                       invalid ? " /* invalid */" : "");
+       }
+
+       return l;
+}
+
+#define GPMC_PRINT_CONFIG(cs, config) \
+       pr_info("CS%i %s: 0x%08x\n", cs, #config, \
+               gpmc_cs_read_reg(cs, config))
+#define GPMC_GET_RAW(reg, st, end, field) \
+       get_gpmc_timing_reg(cs, (reg), (st), (end), 0, field, GPMC_CD_FCLK, 0, 1, 0)
+#define GPMC_GET_RAW_MAX(reg, st, end, max, field) \
+       get_gpmc_timing_reg(cs, (reg), (st), (end), (max), field, GPMC_CD_FCLK, 0, 1, 0)
+#define GPMC_GET_RAW_BOOL(reg, st, end, field) \
+       get_gpmc_timing_reg(cs, (reg), (st), (end), 0, field, GPMC_CD_FCLK, 0, 1, 1)
+#define GPMC_GET_RAW_SHIFT_MAX(reg, st, end, shift, max, field) \
+       get_gpmc_timing_reg(cs, (reg), (st), (end), (max), field, GPMC_CD_FCLK, (shift), 1, 1)
+#define GPMC_GET_TICKS(reg, st, end, field) \
+       get_gpmc_timing_reg(cs, (reg), (st), (end), 0, field, GPMC_CD_FCLK, 0, 0, 0)
+#define GPMC_GET_TICKS_CD(reg, st, end, field, cd) \
+       get_gpmc_timing_reg(cs, (reg), (st), (end), 0, field, (cd), 0, 0, 0)
+#define GPMC_GET_TICKS_CD_MAX(reg, st, end, max, field, cd) \
+       get_gpmc_timing_reg(cs, (reg), (st), (end), (max), field, (cd), 0, 0, 0)
+
+static void gpmc_show_regs(int cs, const char *desc)
+{
+       pr_info("gpmc cs%i %s:\n", cs, desc);
+       GPMC_PRINT_CONFIG(cs, GPMC_CS_CONFIG1);
+       GPMC_PRINT_CONFIG(cs, GPMC_CS_CONFIG2);
+       GPMC_PRINT_CONFIG(cs, GPMC_CS_CONFIG3);
+       GPMC_PRINT_CONFIG(cs, GPMC_CS_CONFIG4);
+       GPMC_PRINT_CONFIG(cs, GPMC_CS_CONFIG5);
+       GPMC_PRINT_CONFIG(cs, GPMC_CS_CONFIG6);
+}
+
+/*
+ * Note that gpmc,wait-pin handing wrongly assumes bit 8 is available,
+ * see commit c9fb809.
+ */
+static void gpmc_cs_show_timings(int cs, const char *desc)
+{
+       gpmc_show_regs(cs, desc);
+
+       pr_info("gpmc cs%i access configuration:\n", cs);
+       GPMC_GET_RAW_BOOL(GPMC_CS_CONFIG1,  4,  4, "time-para-granularity");
+       GPMC_GET_RAW(GPMC_CS_CONFIG1,  8,  9, "mux-add-data");
+       GPMC_GET_RAW_SHIFT_MAX(GPMC_CS_CONFIG1, 12, 13, 1,
+                              GPMC_CONFIG1_DEVICESIZE_MAX, "device-width");
+       GPMC_GET_RAW(GPMC_CS_CONFIG1, 16, 17, "wait-pin");
+       GPMC_GET_RAW_BOOL(GPMC_CS_CONFIG1, 21, 21, "wait-on-write");
+       GPMC_GET_RAW_BOOL(GPMC_CS_CONFIG1, 22, 22, "wait-on-read");
+       GPMC_GET_RAW_SHIFT_MAX(GPMC_CS_CONFIG1, 23, 24, 4,
+                              GPMC_CONFIG1_ATTACHEDDEVICEPAGELENGTH_MAX,
+                              "burst-length");
+       GPMC_GET_RAW_BOOL(GPMC_CS_CONFIG1, 27, 27, "sync-write");
+       GPMC_GET_RAW_BOOL(GPMC_CS_CONFIG1, 28, 28, "burst-write");
+       GPMC_GET_RAW_BOOL(GPMC_CS_CONFIG1, 29, 29, "gpmc,sync-read");
+       GPMC_GET_RAW_BOOL(GPMC_CS_CONFIG1, 30, 30, "burst-read");
+       GPMC_GET_RAW_BOOL(GPMC_CS_CONFIG1, 31, 31, "burst-wrap");
+
+       GPMC_GET_RAW_BOOL(GPMC_CS_CONFIG2,  7,  7, "cs-extra-delay");
+
+       GPMC_GET_RAW_BOOL(GPMC_CS_CONFIG3,  7,  7, "adv-extra-delay");
+
+       GPMC_GET_RAW_BOOL(GPMC_CS_CONFIG4, 23, 23, "we-extra-delay");
+       GPMC_GET_RAW_BOOL(GPMC_CS_CONFIG4,  7,  7, "oe-extra-delay");
+
+       GPMC_GET_RAW_BOOL(GPMC_CS_CONFIG6,  7,  7, "cycle2cycle-samecsen");
+       GPMC_GET_RAW_BOOL(GPMC_CS_CONFIG6,  6,  6, "cycle2cycle-diffcsen");
+
+       pr_info("gpmc cs%i timings configuration:\n", cs);
+       GPMC_GET_TICKS(GPMC_CS_CONFIG2,  0,  3, "cs-on-ns");
+       GPMC_GET_TICKS(GPMC_CS_CONFIG2,  8, 12, "cs-rd-off-ns");
+       GPMC_GET_TICKS(GPMC_CS_CONFIG2, 16, 20, "cs-wr-off-ns");
+
+       GPMC_GET_TICKS(GPMC_CS_CONFIG3,  0,  3, "adv-on-ns");
+       GPMC_GET_TICKS(GPMC_CS_CONFIG3,  8, 12, "adv-rd-off-ns");
+       GPMC_GET_TICKS(GPMC_CS_CONFIG3, 16, 20, "adv-wr-off-ns");
+       if (gpmc_capability & GPMC_HAS_MUX_AAD) {
+               GPMC_GET_TICKS(GPMC_CS_CONFIG3, 4, 6, "adv-aad-mux-on-ns");
+               GPMC_GET_TICKS(GPMC_CS_CONFIG3, 24, 26,
+                              "adv-aad-mux-rd-off-ns");
+               GPMC_GET_TICKS(GPMC_CS_CONFIG3, 28, 30,
+                              "adv-aad-mux-wr-off-ns");
+       }
+
+       GPMC_GET_TICKS(GPMC_CS_CONFIG4,  0,  3, "oe-on-ns");
+       GPMC_GET_TICKS(GPMC_CS_CONFIG4,  8, 12, "oe-off-ns");
+       if (gpmc_capability & GPMC_HAS_MUX_AAD) {
+               GPMC_GET_TICKS(GPMC_CS_CONFIG4,  4,  6, "oe-aad-mux-on-ns");
+               GPMC_GET_TICKS(GPMC_CS_CONFIG4, 13, 15, "oe-aad-mux-off-ns");
+       }
+       GPMC_GET_TICKS(GPMC_CS_CONFIG4, 16, 19, "we-on-ns");
+       GPMC_GET_TICKS(GPMC_CS_CONFIG4, 24, 28, "we-off-ns");
+
+       GPMC_GET_TICKS(GPMC_CS_CONFIG5,  0,  4, "rd-cycle-ns");
+       GPMC_GET_TICKS(GPMC_CS_CONFIG5,  8, 12, "wr-cycle-ns");
+       GPMC_GET_TICKS(GPMC_CS_CONFIG5, 16, 20, "access-ns");
+
+       GPMC_GET_TICKS(GPMC_CS_CONFIG5, 24, 27, "page-burst-access-ns");
+
+       GPMC_GET_TICKS(GPMC_CS_CONFIG6, 0, 3, "bus-turnaround-ns");
+       GPMC_GET_TICKS(GPMC_CS_CONFIG6, 8, 11, "cycle2cycle-delay-ns");
+
+       GPMC_GET_TICKS_CD_MAX(GPMC_CS_CONFIG1, 18, 19,
+                             GPMC_CONFIG1_WAITMONITORINGTIME_MAX,
+                             "wait-monitoring-ns", GPMC_CD_CLK);
+       GPMC_GET_TICKS_CD_MAX(GPMC_CS_CONFIG1, 25, 26,
+                             GPMC_CONFIG1_CLKACTIVATIONTIME_MAX,
+                             "clk-activation-ns", GPMC_CD_FCLK);
+
+       GPMC_GET_TICKS(GPMC_CS_CONFIG6, 16, 19, "wr-data-mux-bus-ns");
+       GPMC_GET_TICKS(GPMC_CS_CONFIG6, 24, 28, "wr-access-ns");
+}
+#else
+static inline void gpmc_cs_show_timings(int cs, const char *desc)
+{
+}
+#endif
+
+/**
+ * set_gpmc_timing_reg - set a single timing parameter for Chip Select Region.
+ * Caller is expected to have initialized CONFIG1 GPMCFCLKDIVIDER
+ * prior to calling this function with @cd equal to GPMC_CD_CLK.
+ *
+ * @cs:      Chip Select Region.
+ * @reg:     GPMC_CS_CONFIGn register offset.
+ * @st_bit:  Start Bit
+ * @end_bit: End Bit. Must be >= @st_bit.
+ * @max:     Maximum parameter value.
+ *           If 0, maximum is as high as @st_bit and @end_bit allow.
+ * @time:    Timing parameter in ns.
+ * @cd:      Timing parameter clock domain.
+ * @name:    Timing parameter name.
+ * @return:  0 on success, -1 on error.
+ */
+static int set_gpmc_timing_reg(int cs, int reg, int st_bit, int end_bit, int max,
+                              int time, enum gpmc_clk_domain cd, const char *name)
+{
+       u32 l;
+       int ticks, mask, nr_bits;
+
+       if (time == 0)
+               ticks = 0;
+       else
+               ticks = gpmc_ns_to_clk_ticks(time, cs, cd);
+       nr_bits = end_bit - st_bit + 1;
+       mask = (1 << nr_bits) - 1;
+
+       if (!max)
+               max = mask;
+
+       if (ticks > max) {
+               pr_err("%s: GPMC CS%d: %s %d ns, %d ticks > %d ticks\n",
+                      __func__, cs, name, time, ticks, max);
+
+               return -1;
+       }
+
+       l = gpmc_cs_read_reg(cs, reg);
+       if (IS_ENABLED(CONFIG_TI_GPMC_DEBUG)) {
+               pr_info("GPMC CS%d: %-17s: %3d ticks, %3lu ns (was %3i ticks) %3d ns\n",
+                       cs, name, ticks, gpmc_get_clk_period(cs, cd) * ticks / 1000,
+                               (l >> st_bit) & mask, time);
+       }
+
+       l &= ~(mask << st_bit);
+       l |= ticks << st_bit;
+       gpmc_cs_write_reg(cs, reg, l);
+
+       return 0;
+}
+
+/**
+ * gpmc_calc_waitmonitoring_divider - calculate proper GPMCFCLKDIVIDER based on WAITMONITORINGTIME
+ * WAITMONITORINGTIME will be _at least_ as long as desired, i.e.
+ * read  --> don't sample bus too early
+ * write --> data is longer on bus
+ *
+ * Formula:
+ * gpmc_clk_div + 1 = ceil(ceil(waitmonitoringtime_ns / gpmc_fclk_ns)
+ *                    / waitmonitoring_ticks)
+ * WAITMONITORINGTIME resulting in 0 or 1 tick with div = 1 are caught by
+ * div <= 0 check.
+ *
+ * @wait_monitoring: WAITMONITORINGTIME in ns.
+ * @return:          -1 on failure to scale, else proper divider > 0.
+ */
+static int gpmc_calc_waitmonitoring_divider(unsigned int wait_monitoring)
+{
+       int div = gpmc_ns_to_ticks(wait_monitoring);
+
+       div += GPMC_CONFIG1_WAITMONITORINGTIME_MAX - 1;
+       div /= GPMC_CONFIG1_WAITMONITORINGTIME_MAX;
+
+       if (div > 4)
+               return -1;
+       if (div <= 0)
+               div = 1;
+
+       return div;
+}
+
+/**
+ * gpmc_calc_divider - calculate GPMC_FCLK divider for sync_clk GPMC_CLK period.
+ * @sync_clk: GPMC_CLK period in ps.
+ * @return:   Returns at least 1 if GPMC_FCLK can be divided to GPMC_CLK.
+ *            Else, returns -1.
+ */
+static int gpmc_calc_divider(unsigned int sync_clk)
+{
+       int div = gpmc_ps_to_ticks(sync_clk);
+
+       if (div > 4)
+               return -1;
+       if (div <= 0)
+               div = 1;
+
+       return div;
+}
+
+/**
+ * gpmc_cs_set_timings - program timing parameters for Chip Select Region.
+ * @cs:     Chip Select Region.
+ * @t:      GPMC timing parameters.
+ * @s:      GPMC timing settings.
+ * @return: 0 on success, -1 on error.
+ */
+static int gpmc_cs_set_timings(int cs, const struct gpmc_timings *t,
+                              const struct gpmc_settings *s)
+{
+       int div, ret;
+       u32 l;
+
+       div = gpmc_calc_divider(t->sync_clk);
+       if (div < 0)
+               return -EINVAL;
+
+       /*
+        * See if we need to change the divider for waitmonitoringtime.
+        *
+        * Calculate GPMCFCLKDIVIDER independent of gpmc,sync-clk-ps in DT for
+        * pure asynchronous accesses, i.e. both read and write asynchronous.
+        * However, only do so if WAITMONITORINGTIME is actually used, i.e.
+        * either WAITREADMONITORING or WAITWRITEMONITORING is set.
+        *
+        * This statement must not change div to scale async WAITMONITORINGTIME
+        * to protect mixed synchronous and asynchronous accesses.
+        *
+        * We raise an error later if WAITMONITORINGTIME does not fit.
+        */
+       if (!s->sync_read && !s->sync_write &&
+           (s->wait_on_read || s->wait_on_write)
+          ) {
+               div = gpmc_calc_waitmonitoring_divider(t->wait_monitoring);
+               if (div < 0) {
+                       pr_err("%s: waitmonitoringtime %3d ns too large for greatest gpmcfclkdivider.\n",
+                              __func__,
+                              t->wait_monitoring
+                              );
+                       return -ENXIO;
+               }
+       }
+
+       ret = 0;
+       ret |= set_gpmc_timing_reg(cs, GPMC_CS_CONFIG2, 0, 3, 0, t->cs_on,
+                                  GPMC_CD_FCLK, "cs_on");
+       ret |= set_gpmc_timing_reg(cs, GPMC_CS_CONFIG2, 8, 12, 0, t->cs_rd_off,
+                                  GPMC_CD_FCLK, "cs_rd_off");
+       ret |= set_gpmc_timing_reg(cs, GPMC_CS_CONFIG2, 16, 20, 0, t->cs_wr_off,
+                                  GPMC_CD_FCLK, "cs_wr_off");
+       if (ret)
+               return -ENXIO;
+
+       ret |= set_gpmc_timing_reg(cs, GPMC_CS_CONFIG3, 0, 3, 0, t->adv_on,
+                                  GPMC_CD_FCLK, "adv_on");
+       ret |= set_gpmc_timing_reg(cs, GPMC_CS_CONFIG3, 8, 12, 0, t->adv_rd_off,
+                                  GPMC_CD_FCLK, "adv_rd_off");
+       ret |= set_gpmc_timing_reg(cs, GPMC_CS_CONFIG3, 16, 20, 0, t->adv_wr_off,
+                                  GPMC_CD_FCLK, "adv_wr_off");
+       if (ret)
+               return -ENXIO;
+
+       if (gpmc_capability & GPMC_HAS_MUX_AAD) {
+               ret |= set_gpmc_timing_reg(cs, GPMC_CS_CONFIG3, 4, 6, 0,
+                                          t->adv_aad_mux_on, GPMC_CD_FCLK,
+                                          "adv_aad_mux_on");
+               ret |= set_gpmc_timing_reg(cs, GPMC_CS_CONFIG3, 24, 26, 0,
+                                          t->adv_aad_mux_rd_off, GPMC_CD_FCLK,
+                                          "adv_aad_mux_rd_off");
+               ret |= set_gpmc_timing_reg(cs, GPMC_CS_CONFIG3, 28, 30, 0,
+                                          t->adv_aad_mux_wr_off, GPMC_CD_FCLK,
+                                          "adv_aad_mux_wr_off");
+               if (ret)
+                       return -ENXIO;
+       }
+
+       ret |= set_gpmc_timing_reg(cs, GPMC_CS_CONFIG4, 0, 3, 0, t->oe_on,
+                                  GPMC_CD_FCLK, "oe_on");
+       ret |= set_gpmc_timing_reg(cs, GPMC_CS_CONFIG4, 8, 12, 0, t->oe_off,
+                                  GPMC_CD_FCLK, "oe_off");
+       if (gpmc_capability & GPMC_HAS_MUX_AAD) {
+               ret |= set_gpmc_timing_reg(cs, GPMC_CS_CONFIG4, 4, 6, 0,
+                                          t->oe_aad_mux_on, GPMC_CD_FCLK,
+                                          "oe_aad_mux_on");
+               ret |= set_gpmc_timing_reg(cs, GPMC_CS_CONFIG4, 13, 15, 0,
+                                          t->oe_aad_mux_off, GPMC_CD_FCLK,
+                                          "oe_aad_mux_off");
+       }
+       ret |= set_gpmc_timing_reg(cs, GPMC_CS_CONFIG4, 16, 19, 0, t->we_on,
+                                  GPMC_CD_FCLK, "we_on");
+       ret |= set_gpmc_timing_reg(cs, GPMC_CS_CONFIG4, 24, 28, 0, t->we_off,
+                                  GPMC_CD_FCLK, "we_off");
+       if (ret)
+               return -ENXIO;
+
+       ret |= set_gpmc_timing_reg(cs, GPMC_CS_CONFIG5, 0, 4, 0, t->rd_cycle,
+                                  GPMC_CD_FCLK, "rd_cycle");
+       ret |= set_gpmc_timing_reg(cs, GPMC_CS_CONFIG5, 8, 12, 0, t->wr_cycle,
+                                  GPMC_CD_FCLK, "wr_cycle");
+       ret |= set_gpmc_timing_reg(cs, GPMC_CS_CONFIG5, 16, 20, 0, t->access,
+                                  GPMC_CD_FCLK, "access");
+       ret |= set_gpmc_timing_reg(cs, GPMC_CS_CONFIG5, 24, 27, 0,
+                                  t->page_burst_access, GPMC_CD_FCLK,
+                                  "page_burst_access");
+       if (ret)
+               return -ENXIO;
+
+       ret |= set_gpmc_timing_reg(cs, GPMC_CS_CONFIG6, 0, 3, 0,
+                                  t->bus_turnaround, GPMC_CD_FCLK,
+                                  "bus_turnaround");
+       ret |= set_gpmc_timing_reg(cs, GPMC_CS_CONFIG6, 8, 11, 0,
+                                  t->cycle2cycle_delay, GPMC_CD_FCLK,
+                                  "cycle2cycle_delay");
+       if (ret)
+               return -ENXIO;
+
+       if (gpmc_capability & GPMC_HAS_WR_DATA_MUX_BUS) {
+               ret |= set_gpmc_timing_reg(cs, GPMC_CS_CONFIG6, 16, 19, 0,
+                                          t->wr_data_mux_bus, GPMC_CD_FCLK,
+                                          "wr_data_mux_bus");
+               if (ret)
+                       return -ENXIO;
+       }
+       if (gpmc_capability & GPMC_HAS_WR_ACCESS) {
+               ret |= set_gpmc_timing_reg(cs, GPMC_CS_CONFIG6, 24, 28, 0,
+                                          t->wr_access, GPMC_CD_FCLK,
+                                          "wr_access");
+               if (ret)
+                       return -ENXIO;
+       }
+
+       l = gpmc_cs_read_reg(cs, GPMC_CS_CONFIG1);
+       l &= ~0x03;
+       l |= (div - 1);
+       gpmc_cs_write_reg(cs, GPMC_CS_CONFIG1, l);
+
+       ret = 0;
+       ret |= set_gpmc_timing_reg(cs, GPMC_CS_CONFIG1, 18, 19,
+                                  GPMC_CONFIG1_WAITMONITORINGTIME_MAX,
+                                  t->wait_monitoring, GPMC_CD_CLK,
+                                  "wait_monitoring");
+       ret |= set_gpmc_timing_reg(cs, GPMC_CS_CONFIG1, 25, 26,
+                                  GPMC_CONFIG1_CLKACTIVATIONTIME_MAX,
+                                  t->clk_activation, GPMC_CD_FCLK,
+                                  "clk_activation");
+       if (ret)
+               return -ENXIO;
+
+       if (IS_ENABLED(CONFIG_TI_GPMC_DEBUG)) {
+               pr_info("GPMC CS%d CLK period is %lu ns (div %d)\n",
+                       cs, (div * gpmc_get_fclk_period()) / 1000, div);
+       }
+
+       gpmc_cs_bool_timings(cs, &t->bool_timings);
+       gpmc_cs_show_timings(cs, "after gpmc_set_timings");
+
+       return 0;
+}
+
+static int gpmc_cs_set_memconf(int cs, resource_size_t base, u32 size)
+{
+       u32 l;
+       u32 mask;
+
+       /*
+        * Ensure that base address is aligned on a
+        * boundary equal to or greater than size.
+        */
+       if (base & (size - 1))
+               return -EINVAL;
+
+       base >>= GPMC_CHUNK_SHIFT;
+       mask = (1 << GPMC_SECTION_SHIFT) - size;
+       mask >>= GPMC_CHUNK_SHIFT;
+       mask <<= GPMC_CONFIG7_MASKADDRESS_OFFSET;
+
+       l = gpmc_cs_read_reg(cs, GPMC_CS_CONFIG7);
+       l &= ~GPMC_CONFIG7_MASK;
+       l |= base & GPMC_CONFIG7_BASEADDRESS_MASK;
+       l |= mask & GPMC_CONFIG7_MASKADDRESS_MASK;
+       l |= GPMC_CONFIG7_CSVALID;
+       gpmc_cs_write_reg(cs, GPMC_CS_CONFIG7, l);
+
+       return 0;
+}
+
+static void gpmc_cs_enable_mem(int cs)
+{
+       u32 l;
+
+       l = gpmc_cs_read_reg(cs, GPMC_CS_CONFIG7);
+       l |= GPMC_CONFIG7_CSVALID;
+       gpmc_cs_write_reg(cs, GPMC_CS_CONFIG7, l);
+}
+
+static void gpmc_cs_disable_mem(int cs)
+{
+       u32 l;
+
+       l = gpmc_cs_read_reg(cs, GPMC_CS_CONFIG7);
+       l &= ~GPMC_CONFIG7_CSVALID;
+       gpmc_cs_write_reg(cs, GPMC_CS_CONFIG7, l);
+}
+
+static void gpmc_cs_set_reserved(int cs, int reserved)
+{
+       struct gpmc_cs_data *gpmc = &gpmc_cs[cs];
+
+       gpmc->flags |= GPMC_CS_RESERVED;
+}
+
+static bool gpmc_cs_reserved(int cs)
+{
+       struct gpmc_cs_data *gpmc = &gpmc_cs[cs];
+
+       return gpmc->flags & GPMC_CS_RESERVED;
+}
+
+static unsigned long gpmc_mem_align(unsigned long size)
+{
+       int order;
+
+       size = (size - 1) >> (GPMC_CHUNK_SHIFT - 1);
+       order = GPMC_CHUNK_SHIFT - 1;
+       do {
+               size >>= 1;
+               order++;
+       } while (size);
+       size = 1 << order;
+       return size;
+}
+
+static int gpmc_cs_request(ofnode node, int cs, struct resource *res)
+{
+       int r = -1;
+       u32 size;
+       resource_size_t addr_base = res->start;
+
+       if (cs >= gpmc_cs_num) {
+               pr_err("%s: requested chip-select is disabled\n", __func__);
+               return -ENODEV;
+       }
+
+       size = gpmc_mem_align(resource_size(res));
+       if (size > (1 << GPMC_SECTION_SHIFT))
+               return -ENOMEM;
+
+       if (gpmc_cs_reserved(cs)) {
+               r = -EBUSY;
+               goto out;
+       }
+
+       if (addr_base & (SZ_16M - 1)) {
+               pr_err("CS region should be aligned to 16M boundary\n");
+               goto out;
+       }
+
+       /* Disable CS while changing base address and size mask */
+       gpmc_cs_disable_mem(cs);
+
+       r = gpmc_cs_set_memconf(cs, addr_base, size);
+       if (r < 0)
+               goto out;
+
+       /* Enable CS */
+       gpmc_cs_enable_mem(cs);
+       gpmc_cs_set_reserved(cs, 1);
+out:
+       return r;
+}
+
+static void gpmc_cs_free(int cs)
+{
+       if (cs >= gpmc_cs_num || cs < 0 || !gpmc_cs_reserved(cs)) {
+               pr_warn("Trying to free non-reserved GPMC CS%d\n", cs);
+               return;
+       }
+
+       gpmc_cs_disable_mem(cs);
+       gpmc_cs_set_reserved(cs, 0);
+}
+
+/**
+ * gpmc_configure - write request to configure gpmc
+ * @cmd: command type
+ * @wval: value to write
+ * @return status of the operation
+ */
+static int gpmc_configure(int cmd, int wval)
+{
+       u32 regval;
+
+       switch (cmd) {
+       case GPMC_CONFIG_WP:
+               regval = gpmc_read_reg(GPMC_CONFIG);
+               if (wval)
+                       regval &= ~GPMC_CONFIG_WRITEPROTECT; /* WP is ON */
+               else
+                       regval |= GPMC_CONFIG_WRITEPROTECT;  /* WP is OFF */
+               gpmc_write_reg(GPMC_CONFIG, regval);
+               break;
+
+       default:
+               pr_err("%s: command not supported\n", __func__);
+               return -EINVAL;
+       }
+
+       return 0;
+}
+
+/**
+ * gpmc_cs_program_settings - programs non-timing related settings
+ * @cs:                GPMC chip-select to program
+ * @p:         pointer to GPMC settings structure
+ *
+ * Programs non-timing related settings for a GPMC chip-select, such as
+ * bus-width, burst configuration, etc. Function should be called once
+ * for each chip-select that is being used and must be called before
+ * calling gpmc_cs_set_timings() as timing parameters in the CONFIG1
+ * register will be initialised to zero by this function. Returns 0 on
+ * success and appropriate negative error code on failure.
+ */
+static int gpmc_cs_program_settings(int cs, struct gpmc_settings *p)
+{
+       u32 config1;
+
+       if (!p->device_width || p->device_width > GPMC_DEVWIDTH_16BIT) {
+               pr_err("%s: invalid width %d!", __func__, p->device_width);
+               return -EINVAL;
+       }
+
+       /* Address-data multiplexing not supported for NAND devices */
+       if (p->device_nand && p->mux_add_data) {
+               pr_err("%s: invalid configuration!\n", __func__);
+               return -EINVAL;
+       }
+
+       if (p->mux_add_data > GPMC_MUX_AD ||
+           (p->mux_add_data == GPMC_MUX_AAD &&
+            !(gpmc_capability & GPMC_HAS_MUX_AAD))) {
+               pr_err("%s: invalid multiplex configuration!\n", __func__);
+               return -EINVAL;
+       }
+
+       /* Page/burst mode supports lengths of 4, 8 and 16 bytes */
+       if (p->burst_read || p->burst_write) {
+               switch (p->burst_len) {
+               case GPMC_BURST_4:
+               case GPMC_BURST_8:
+               case GPMC_BURST_16:
+                       break;
+               default:
+                       pr_err("%s: invalid page/burst-length (%d)\n",
+                              __func__, p->burst_len);
+                       return -EINVAL;
+               }
+       }
+
+       if (p->wait_pin > gpmc_nr_waitpins) {
+               pr_err("%s: invalid wait-pin (%d)\n", __func__, p->wait_pin);
+               return -EINVAL;
+       }
+
+       config1 = GPMC_CONFIG1_DEVICESIZE((p->device_width - 1));
+
+       if (p->sync_read)
+               config1 |= GPMC_CONFIG1_READTYPE_SYNC;
+       if (p->sync_write)
+               config1 |= GPMC_CONFIG1_WRITETYPE_SYNC;
+       if (p->wait_on_read)
+               config1 |= GPMC_CONFIG1_WAIT_READ_MON;
+       if (p->wait_on_write)
+               config1 |= GPMC_CONFIG1_WAIT_WRITE_MON;
+       if (p->wait_on_read || p->wait_on_write)
+               config1 |= GPMC_CONFIG1_WAIT_PIN_SEL(p->wait_pin);
+       if (p->device_nand)
+               config1 |= GPMC_CONFIG1_DEVICETYPE(GPMC_DEVICETYPE_NAND);
+       if (p->mux_add_data)
+               config1 |= GPMC_CONFIG1_MUXTYPE(p->mux_add_data);
+       if (p->burst_read)
+               config1 |= GPMC_CONFIG1_READMULTIPLE_SUPP;
+       if (p->burst_write)
+               config1 |= GPMC_CONFIG1_WRITEMULTIPLE_SUPP;
+       if (p->burst_read || p->burst_write) {
+               config1 |= GPMC_CONFIG1_PAGE_LEN(p->burst_len >> 3);
+               config1 |= p->burst_wrap ? GPMC_CONFIG1_WRAPBURST_SUPP : 0;
+       }
+
+       gpmc_cs_write_reg(cs, GPMC_CS_CONFIG1, config1);
+
+       return 0;
+}
+
+static void gpmc_cs_set_name(int cs, const char *name)
+{
+       struct gpmc_cs_data *gpmc = &gpmc_cs[cs];
+
+       gpmc->name = name;
+}
+
+static const char *gpmc_cs_get_name(int cs)
+{
+       struct gpmc_cs_data *gpmc = &gpmc_cs[cs];
+
+       return gpmc->name;
+}
+
+/**
+ * gpmc_read_settings_dt - read gpmc settings from device-tree
+ * @np:                pointer to device-tree node for a gpmc child device
+ * @p:         pointer to gpmc settings structure
+ *
+ * Reads the GPMC settings for a GPMC child device from device-tree and
+ * stores them in the GPMC settings structure passed. The GPMC settings
+ * structure is initialised to zero by this function and so any
+ * previously stored settings will be cleared.
+ */
+static void gpmc_read_settings_dt(ofnode np, struct gpmc_settings *p)
+{
+       memset(p, 0, sizeof(struct gpmc_settings));
+
+       p->sync_read = ofnode_read_bool(np, "gpmc,sync-read");
+       p->sync_write = ofnode_read_bool(np, "gpmc,sync-write");
+       ofnode_read_u32(np, "gpmc,device-width", &p->device_width);
+       ofnode_read_u32(np, "gpmc,mux-add-data", &p->mux_add_data);
+
+       if (!ofnode_read_u32(np, "gpmc,burst-length", &p->burst_len)) {
+               p->burst_wrap = ofnode_read_bool(np, "gpmc,burst-wrap");
+               p->burst_read = ofnode_read_bool(np, "gpmc,burst-read");
+               p->burst_write = ofnode_read_bool(np, "gpmc,burst-write");
+               if (!p->burst_read && !p->burst_write)
+                       pr_warn("%s: page/burst-length set but not used!\n",
+                               __func__);
+       }
+
+       if (!ofnode_read_u32(np, "gpmc,wait-pin", &p->wait_pin)) {
+               p->wait_on_read = ofnode_read_bool(np,
+                                                  "gpmc,wait-on-read");
+               p->wait_on_write = ofnode_read_bool(np,
+                                                   "gpmc,wait-on-write");
+               if (!p->wait_on_read && !p->wait_on_write)
+                       pr_debug("%s: rd/wr wait monitoring not enabled!\n",
+                                __func__);
+       }
+}
+
+static void gpmc_read_timings_dt(ofnode np,
+                                struct gpmc_timings *gpmc_t)
+{
+       struct gpmc_bool_timings *p;
+
+       if (!gpmc_t)
+               return;
+
+       memset(gpmc_t, 0, sizeof(*gpmc_t));
+
+       /* minimum clock period for syncronous mode */
+       ofnode_read_u32(np, "gpmc,sync-clk-ps", &gpmc_t->sync_clk);
+
+       /* chip select timtings */
+       ofnode_read_u32(np, "gpmc,cs-on-ns", &gpmc_t->cs_on);
+       ofnode_read_u32(np, "gpmc,cs-rd-off-ns", &gpmc_t->cs_rd_off);
+       ofnode_read_u32(np, "gpmc,cs-wr-off-ns", &gpmc_t->cs_wr_off);
+
+       /* ADV signal timings */
+       ofnode_read_u32(np, "gpmc,adv-on-ns", &gpmc_t->adv_on);
+       ofnode_read_u32(np, "gpmc,adv-rd-off-ns", &gpmc_t->adv_rd_off);
+       ofnode_read_u32(np, "gpmc,adv-wr-off-ns", &gpmc_t->adv_wr_off);
+       ofnode_read_u32(np, "gpmc,adv-aad-mux-on-ns",
+                       &gpmc_t->adv_aad_mux_on);
+       ofnode_read_u32(np, "gpmc,adv-aad-mux-rd-off-ns",
+                       &gpmc_t->adv_aad_mux_rd_off);
+       ofnode_read_u32(np, "gpmc,adv-aad-mux-wr-off-ns",
+                       &gpmc_t->adv_aad_mux_wr_off);
+
+       /* WE signal timings */
+       ofnode_read_u32(np, "gpmc,we-on-ns", &gpmc_t->we_on);
+       ofnode_read_u32(np, "gpmc,we-off-ns", &gpmc_t->we_off);
+
+       /* OE signal timings */
+       ofnode_read_u32(np, "gpmc,oe-on-ns", &gpmc_t->oe_on);
+       ofnode_read_u32(np, "gpmc,oe-off-ns", &gpmc_t->oe_off);
+       ofnode_read_u32(np, "gpmc,oe-aad-mux-on-ns",
+                       &gpmc_t->oe_aad_mux_on);
+       ofnode_read_u32(np, "gpmc,oe-aad-mux-off-ns",
+                       &gpmc_t->oe_aad_mux_off);
+
+       /* access and cycle timings */
+       ofnode_read_u32(np, "gpmc,page-burst-access-ns",
+                       &gpmc_t->page_burst_access);
+       ofnode_read_u32(np, "gpmc,access-ns", &gpmc_t->access);
+       ofnode_read_u32(np, "gpmc,rd-cycle-ns", &gpmc_t->rd_cycle);
+       ofnode_read_u32(np, "gpmc,wr-cycle-ns", &gpmc_t->wr_cycle);
+       ofnode_read_u32(np, "gpmc,bus-turnaround-ns",
+                       &gpmc_t->bus_turnaround);
+       ofnode_read_u32(np, "gpmc,cycle2cycle-delay-ns",
+                       &gpmc_t->cycle2cycle_delay);
+       ofnode_read_u32(np, "gpmc,wait-monitoring-ns",
+                       &gpmc_t->wait_monitoring);
+       ofnode_read_u32(np, "gpmc,clk-activation-ns",
+                       &gpmc_t->clk_activation);
+
+       /* only applicable to OMAP3+ */
+       ofnode_read_u32(np, "gpmc,wr-access-ns", &gpmc_t->wr_access);
+       ofnode_read_u32(np, "gpmc,wr-data-mux-bus-ns",
+                       &gpmc_t->wr_data_mux_bus);
+
+       /* bool timing parameters */
+       p = &gpmc_t->bool_timings;
+
+       p->cycle2cyclediffcsen =
+               ofnode_read_bool(np, "gpmc,cycle2cycle-diffcsen");
+       p->cycle2cyclesamecsen =
+               ofnode_read_bool(np, "gpmc,cycle2cycle-samecsen");
+       p->we_extra_delay = ofnode_read_bool(np, "gpmc,we-extra-delay");
+       p->oe_extra_delay = ofnode_read_bool(np, "gpmc,oe-extra-delay");
+       p->adv_extra_delay = ofnode_read_bool(np, "gpmc,adv-extra-delay");
+       p->cs_extra_delay = ofnode_read_bool(np, "gpmc,cs-extra-delay");
+       p->time_para_granularity =
+               ofnode_read_bool(np, "gpmc,time-para-granularity");
+}
+
+/**
+ * gpmc_probe_generic_child - configures the gpmc for a child device
+ * @dev:       pointer to gpmc platform device
+ * @child:     pointer to device-tree node for child device
+ *
+ * Allocates and configures a GPMC chip-select for a child device.
+ * Returns 0 on success and appropriate negative error code on failure.
+ */
+static int gpmc_probe_generic_child(struct udevice *dev,
+                                   ofnode child)
+{
+       struct gpmc_settings gpmc_s;
+       struct gpmc_timings gpmc_t;
+       struct resource res;
+       const char *name;
+       int ret;
+       u32 val, cs;
+
+       if (ofnode_read_u32(child, "reg", &cs) < 0) {
+               dev_err(dev, "can't get reg property of child %s\n",
+                       ofnode_get_name(child));
+               return -ENODEV;
+       }
+
+       if (ofnode_read_resource(child, 0, &res) < 0) {
+               dev_err(dev, "%s has malformed 'reg' property\n",
+                       ofnode_get_name(child));
+               return -ENODEV;
+       }
+
+       /*
+        * Check if we have multiple instances of the same device
+        * on a single chip select. If so, use the already initialized
+        * timings.
+        */
+       name = gpmc_cs_get_name(cs);
+       if (name && !strcmp(name, ofnode_get_name(child)))
+               goto no_timings;
+
+       ret = gpmc_cs_request(child, cs, &res);
+       if (ret < 0) {
+               dev_err(dev, "cannot request GPMC CS %d\n", cs);
+               return ret;
+       }
+       gpmc_cs_set_name(cs, ofnode_get_name(child));
+
+       gpmc_read_settings_dt(child, &gpmc_s);
+       gpmc_read_timings_dt(child, &gpmc_t);
+
+       /*
+        * For some GPMC devices we still need to rely on the bootloader
+        * timings because the devices can be connected via FPGA.
+        * REVISIT: Add timing support from slls644g.pdf.
+        */
+       if (!gpmc_t.cs_rd_off) {
+               pr_warn("enable GPMC debug to configure .dts timings for CS%i\n",
+                       cs);
+               gpmc_cs_show_timings(cs,
+                                    "please add GPMC bootloader timings to .dts");
+               goto no_timings;
+       }
+
+       /* CS must be disabled while making changes to gpmc configuration */
+       gpmc_cs_disable_mem(cs);
+
+       if (!ofnode_read_u32(child, "nand-bus-width", &val)) {
+               /* NAND specific setup */
+               ofnode_read_u32(child, "nand-bus-width", &val);
+               switch (val) {
+               case 8:
+                       gpmc_s.device_width = GPMC_DEVWIDTH_8BIT;
+                       break;
+               case 16:
+                       gpmc_s.device_width = GPMC_DEVWIDTH_16BIT;
+                       break;
+               default:
+                       dev_err(dev, "%s: invalid 'nand-bus-width'\n",
+                               ofnode_get_name(child));
+                       ret = -EINVAL;
+                       goto err;
+               }
+
+               /* disable write protect */
+               gpmc_configure(GPMC_CONFIG_WP, 0);
+               gpmc_s.device_nand = true;
+       } else {
+               ret = ofnode_read_u32(child, "bank-width",
+                                     &gpmc_s.device_width);
+               if (ret < 0 && !gpmc_s.device_width) {
+                       dev_err(dev,
+                               "%s has no 'gpmc,device-width' property\n",
+                               ofnode_get_name(child));
+                       goto err;
+               }
+       }
+
+       gpmc_cs_show_timings(cs, "before gpmc_cs_program_settings");
+
+       ret = gpmc_cs_program_settings(cs, &gpmc_s);
+       if (ret < 0)
+               goto err;
+
+       ret = gpmc_cs_set_timings(cs, &gpmc_t, &gpmc_s);
+       if (ret) {
+               dev_err(dev, "failed to set gpmc timings for: %s\n",
+                       ofnode_get_name(child));
+               goto err;
+       }
+
+       /* Clear limited address i.e. enable A26-A11 */
+       val = gpmc_read_reg(GPMC_CONFIG);
+       val &= ~GPMC_CONFIG_LIMITEDADDRESS;
+       gpmc_write_reg(GPMC_CONFIG, val);
+
+       /* Enable CS region */
+       gpmc_cs_enable_mem(cs);
+
+no_timings:
+
+       return 0;
+
+err:
+       gpmc_cs_free(cs);
+
+       return ret;
+}
+
+static void gpmc_probe_dt_children(struct udevice *dev)
+{
+       int ret;
+       ofnode child;
+
+       ofnode_for_each_subnode(child, dev_ofnode(dev)) {
+               ret = gpmc_probe_generic_child(dev, child);
+               if (ret) {
+                       dev_err(dev, "Cannot parse child %s:%d",
+                               ofnode_get_name(child), ret);
+               }
+       }
+}
+
+static int gpmc_parse_dt(struct udevice *dev, struct ti_gpmc *gpmc)
+{
+       int ret;
+       u32 val;
+
+       ret = ofnode_read_u32(dev_ofnode(dev), "gpmc,num-cs",
+                             &val);
+       if (ret < 0) {
+               pr_err("%s: number of chip-selects not defined\n", __func__);
+               return ret;
+       } else if (val < 1) {
+               pr_err("%s: all chip-selects are disabled\n", __func__);
+               return -EINVAL;
+       } else if (val > GPMC_CS_NUM) {
+               pr_err("%s: number of supported chip-selects cannot be > %d\n",
+                      __func__, GPMC_CS_NUM);
+               return -EINVAL;
+       }
+
+       gpmc->cs_num = val;
+       gpmc_cs_num = val;
+
+       ret = ofnode_read_u32(dev_ofnode(dev), "gpmc,num-waitpins",
+                             &gpmc->nr_waitpins);
+       if (ret < 0) {
+               pr_err("%s: number of wait pins not found!\n", __func__);
+               return ret;
+       }
+
+       gpmc_nr_waitpins = gpmc->nr_waitpins;
+
+       return 0;
+}
+
+static int gpmc_probe(struct udevice *dev)
+{
+       struct ti_gpmc *priv = dev_get_priv(dev);
+       int ret;
+       struct resource res;
+
+       ret = dev_read_resource_byname(dev, "cfg", &res);
+       if (ret) {
+               /* Legacy DT */
+               dev_read_resource(dev, 0, &res);
+               priv->base = devm_ioremap(dev, res.start, resource_size(&res));
+
+               priv->data.start = GPMC_MEM_START;
+               priv->data.end = GPMC_MEM_END;
+       } else {
+               priv->base = devm_ioremap(dev, res.start, resource_size(&res));
+               ret = dev_read_resource_byname(dev, "data", &res);
+               if (ret)
+                       return -ENOENT;
+
+               priv->data = res;
+       }
+
+       if (!priv->base)
+               return -ENOMEM;
+
+       gpmc_cfg = (struct gpmc *)priv->base;
+       gpmc_base = priv->base;
+
+       priv->l3_clk = devm_clk_get(dev, "fck");
+       if (IS_ERR(priv->l3_clk))
+               return PTR_ERR(priv->l3_clk);
+
+       if (!clk_get_rate(priv->l3_clk))
+               return -EINVAL;
+
+       gpmc_l3_clk = priv->l3_clk;
+
+       ret = gpmc_parse_dt(dev, priv);
+       if (ret)
+               return ret;
+
+       priv->capability_flags = dev->driver->of_match->data;
+       gpmc_capability = priv->capability_flags;
+
+       gpmc_probe_dt_children(dev);
+
+       return 0;
+}
+
+#define GPMC_DATA_REV2_4 0
+#define GPMC_DATA_REV5 (GPMC_HAS_WR_ACCESS | GPMC_HAS_WR_DATA_MUX_BUS)
+#define GPMC_DATA_REV6 (GPMC_HAS_WR_ACCESS | GPMC_HAS_WR_DATA_MUX_BUS | GPMC_HAS_MUX_AAD)
+
+static const struct udevice_id gpmc_dt_ids[] = {
+       { .compatible = "ti,am64-gpmc", .data = GPMC_DATA_REV6, },
+       { .compatible = "ti,am3352-gpmc", .data = GPMC_DATA_REV5, },
+       { .compatible = "ti,omap2420-gpmc", .data = GPMC_DATA_REV2_4, },
+       { .compatible = "ti,omap2430-gpmc", .data = GPMC_DATA_REV2_4, },
+       { .compatible = "ti,omap3430-gpmc", .data = GPMC_DATA_REV5, },
+       { .compatible = "ti,omap4430-gpmc", .data = GPMC_DATA_REV6, },
+       { } /* sentinel */
+};
+
+U_BOOT_DRIVER(ti_gpmc) = {
+       .name   = "ti-gpmc",
+       .id     = UCLASS_MEMORY,
+       .of_match = gpmc_dt_ids,
+       .probe  = gpmc_probe,
+       .flags  = DM_FLAG_ALLOC_PRIV_DMA,
+};
diff --git a/drivers/memory/ti-gpmc.h b/drivers/memory/ti-gpmc.h
new file mode 100644 (file)
index 0000000..90f8e65
--- /dev/null
@@ -0,0 +1,298 @@
+/* SPDX-License-Identifier: GPL-2.0+ */
+/*
+ * Texas Instruments GPMC Driver
+ *
+ * Copyright (C) 2021 Texas Instruments Incorporated - http://www.ti.com/
+ */
+
+/* GPMC register offsets */
+#define GPMC_REVISION          0x00
+#define GPMC_SYSCONFIG         0x10
+#define GPMC_SYSSTATUS         0x14
+#define GPMC_IRQSTATUS         0x18
+#define GPMC_IRQENABLE         0x1c
+#define GPMC_TIMEOUT_CONTROL   0x40
+#define GPMC_ERR_ADDRESS       0x44
+#define GPMC_ERR_TYPE          0x48
+#define GPMC_CONFIG            0x50
+#define GPMC_STATUS            0x54
+#define GPMC_PREFETCH_CONFIG1  0x1e0
+#define GPMC_PREFETCH_CONFIG2  0x1e4
+#define GPMC_PREFETCH_CONTROL  0x1ec
+#define GPMC_PREFETCH_STATUS   0x1f0
+#define GPMC_ECC_CONFIG                0x1f4
+#define GPMC_ECC_CONTROL       0x1f8
+#define GPMC_ECC_SIZE_CONFIG   0x1fc
+#define GPMC_ECC1_RESULT        0x200
+#define GPMC_ECC_BCH_RESULT_0   0x240   /* not available on OMAP2 */
+#define        GPMC_ECC_BCH_RESULT_1   0x244   /* not available on OMAP2 */
+#define        GPMC_ECC_BCH_RESULT_2   0x248   /* not available on OMAP2 */
+#define        GPMC_ECC_BCH_RESULT_3   0x24c   /* not available on OMAP2 */
+#define        GPMC_ECC_BCH_RESULT_4   0x300   /* not available on OMAP2 */
+#define        GPMC_ECC_BCH_RESULT_5   0x304   /* not available on OMAP2 */
+#define        GPMC_ECC_BCH_RESULT_6   0x308   /* not available on OMAP2 */
+
+/* GPMC ECC control settings */
+#define GPMC_ECC_CTRL_ECCCLEAR         0x100
+#define GPMC_ECC_CTRL_ECCDISABLE       0x000
+#define GPMC_ECC_CTRL_ECCREG1          0x001
+#define GPMC_ECC_CTRL_ECCREG2          0x002
+#define GPMC_ECC_CTRL_ECCREG3          0x003
+#define GPMC_ECC_CTRL_ECCREG4          0x004
+#define GPMC_ECC_CTRL_ECCREG5          0x005
+#define GPMC_ECC_CTRL_ECCREG6          0x006
+#define GPMC_ECC_CTRL_ECCREG7          0x007
+#define GPMC_ECC_CTRL_ECCREG8          0x008
+#define GPMC_ECC_CTRL_ECCREG9          0x009
+
+#define GPMC_CONFIG_LIMITEDADDRESS             BIT(1)
+
+#define GPMC_STATUS_EMPTYWRITEBUFFERSTATUS     BIT(0)
+
+#define        GPMC_CONFIG2_CSEXTRADELAY               BIT(7)
+#define        GPMC_CONFIG3_ADVEXTRADELAY              BIT(7)
+#define        GPMC_CONFIG4_OEEXTRADELAY               BIT(7)
+#define        GPMC_CONFIG4_WEEXTRADELAY               BIT(23)
+#define        GPMC_CONFIG6_CYCLE2CYCLEDIFFCSEN        BIT(6)
+#define        GPMC_CONFIG6_CYCLE2CYCLESAMECSEN        BIT(7)
+
+#define GPMC_CS0_OFFSET                0x60
+#define GPMC_CS_SIZE           0x30
+#define        GPMC_BCH_SIZE           0x10
+
+/*
+ * The first 1MB of GPMC address space is typically mapped to
+ * the internal ROM. Never allocate the first page, to
+ * facilitate bug detection; even if we didn't boot from ROM.
+ * As GPMC minimum partition size is 16MB we can only start from
+ * there.
+ */
+#define GPMC_MEM_START         0x1000000
+#define GPMC_MEM_END           0x3FFFFFFF
+
+#define GPMC_CHUNK_SHIFT       24              /* 16 MB */
+#define GPMC_SECTION_SHIFT     28              /* 128 MB */
+
+#define CS_NUM_SHIFT           24
+#define ENABLE_PREFETCH                (0x1 << 7)
+#define DMA_MPU_MODE           2
+
+#define        GPMC_REVISION_MAJOR(l)          (((l) >> 4) & 0xf)
+#define        GPMC_REVISION_MINOR(l)          ((l) & 0xf)
+
+#define        GPMC_HAS_WR_ACCESS              0x1
+#define        GPMC_HAS_WR_DATA_MUX_BUS        0x2
+#define        GPMC_HAS_MUX_AAD                0x4
+
+#define GPMC_NR_WAITPINS               4
+
+#define GPMC_CS_CONFIG1                0x00
+#define GPMC_CS_CONFIG2                0x04
+#define GPMC_CS_CONFIG3                0x08
+#define GPMC_CS_CONFIG4                0x0c
+#define GPMC_CS_CONFIG5                0x10
+#define GPMC_CS_CONFIG6                0x14
+#define GPMC_CS_CONFIG7                0x18
+#define GPMC_CS_NAND_COMMAND   0x1c
+#define GPMC_CS_NAND_ADDRESS   0x20
+#define GPMC_CS_NAND_DATA      0x24
+
+/* Control Commands */
+#define GPMC_CONFIG_RDY_BSY    0x00000001
+#define GPMC_CONFIG_DEV_SIZE   0x00000002
+#define GPMC_CONFIG_DEV_TYPE   0x00000003
+
+#define GPMC_CONFIG_WP          0x00000005
+
+#define GPMC_CONFIG1_WRAPBURST_SUPP     BIT(31)
+#define GPMC_CONFIG1_READMULTIPLE_SUPP  BIT(30)
+#define GPMC_CONFIG1_READTYPE_ASYNC     (0 << 29)
+#define GPMC_CONFIG1_READTYPE_SYNC      BIT(29)
+#define GPMC_CONFIG1_WRITEMULTIPLE_SUPP BIT(28)
+#define GPMC_CONFIG1_WRITETYPE_ASYNC    (0 << 27)
+#define GPMC_CONFIG1_WRITETYPE_SYNC     BIT(27)
+#define GPMC_CONFIG1_CLKACTIVATIONTIME(val) (((val) & 3) << 25)
+/** CLKACTIVATIONTIME Max Ticks */
+#define GPMC_CONFIG1_CLKACTIVATIONTIME_MAX 2
+#define GPMC_CONFIG1_PAGE_LEN(val)      (((val) & 3) << 23)
+/** ATTACHEDDEVICEPAGELENGTH Max Value */
+#define GPMC_CONFIG1_ATTACHEDDEVICEPAGELENGTH_MAX 2
+#define GPMC_CONFIG1_WAIT_READ_MON      BIT(22)
+#define GPMC_CONFIG1_WAIT_WRITE_MON     BIT(21)
+#define GPMC_CONFIG1_WAIT_MON_TIME(val) (((val) & 3) << 18)
+/** WAITMONITORINGTIME Max Ticks */
+#define GPMC_CONFIG1_WAITMONITORINGTIME_MAX  2
+#define GPMC_CONFIG1_WAIT_PIN_SEL(val)  (((val) & 3) << 16)
+#define GPMC_CONFIG1_DEVICESIZE(val)    (((val) & 3) << 12)
+#define GPMC_CONFIG1_DEVICESIZE_16      GPMC_CONFIG1_DEVICESIZE(1)
+/** DEVICESIZE Max Value */
+#define GPMC_CONFIG1_DEVICESIZE_MAX     1
+#define GPMC_CONFIG1_DEVICETYPE(val)    (((val) & 3) << 10)
+#define GPMC_CONFIG1_DEVICETYPE_NOR     GPMC_CONFIG1_DEVICETYPE(0)
+#define GPMC_CONFIG1_MUXTYPE(val)       (((val) & 3) << 8)
+#define GPMC_CONFIG1_TIME_PARA_GRAN     BIT(4)
+#define GPMC_CONFIG1_FCLK_DIV(val)      ((val) & 3)
+#define GPMC_CONFIG1_FCLK_DIV2          (GPMC_CONFIG1_FCLK_DIV(1))
+#define GPMC_CONFIG1_FCLK_DIV3          (GPMC_CONFIG1_FCLK_DIV(2))
+#define GPMC_CONFIG1_FCLK_DIV4          (GPMC_CONFIG1_FCLK_DIV(3))
+#define GPMC_CONFIG7_CSVALID           BIT(6)
+
+#define GPMC_CONFIG7_BASEADDRESS_MASK  0x3f
+#define GPMC_CONFIG7_CSVALID_MASK      BIT(6)
+#define GPMC_CONFIG7_MASKADDRESS_OFFSET        8
+#define GPMC_CONFIG7_MASKADDRESS_MASK  (0xf << GPMC_CONFIG7_MASKADDRESS_OFFSET)
+/* All CONFIG7 bits except reserved bits */
+#define GPMC_CONFIG7_MASK              (GPMC_CONFIG7_BASEADDRESS_MASK | \
+                                        GPMC_CONFIG7_CSVALID_MASK |     \
+                                        GPMC_CONFIG7_MASKADDRESS_MASK)
+
+#define GPMC_DEVICETYPE_NOR            0
+#define GPMC_DEVICETYPE_NAND           2
+#define GPMC_CONFIG_WRITEPROTECT       0x00000010
+#define WR_RD_PIN_MONITORING           0x00600000
+
+/* ECC commands */
+#define GPMC_ECC_READ          0 /* Reset Hardware ECC for read */
+#define GPMC_ECC_WRITE         1 /* Reset Hardware ECC for write */
+#define GPMC_ECC_READSYN       2 /* Reset before syndrom is read back */
+
+#define        GPMC_NR_NAND_IRQS       2 /* number of NAND specific IRQs */
+
+/* bool type time settings */
+struct gpmc_bool_timings {
+       bool cycle2cyclediffcsen;
+       bool cycle2cyclesamecsen;
+       bool we_extra_delay;
+       bool oe_extra_delay;
+       bool adv_extra_delay;
+       bool cs_extra_delay;
+       bool time_para_granularity;
+};
+
+/*
+ * Note that all values in this struct are in nanoseconds except sync_clk
+ * (which is in picoseconds), while the register values are in gpmc_fck cycles.
+ */
+struct gpmc_timings {
+       /* Minimum clock period for synchronous mode (in picoseconds) */
+       u32 sync_clk;
+
+       /* Chip-select signal timings corresponding to GPMC_CS_CONFIG2 */
+       u32 cs_on;              /* Assertion time */
+       u32 cs_rd_off;          /* Read deassertion time */
+       u32 cs_wr_off;          /* Write deassertion time */
+
+       /* ADV signal timings corresponding to GPMC_CONFIG3 */
+       u32 adv_on;             /* Assertion time */
+       u32 adv_rd_off;         /* Read deassertion time */
+       u32 adv_wr_off;         /* Write deassertion time */
+       u32 adv_aad_mux_on;     /* ADV assertion time for AAD */
+       u32 adv_aad_mux_rd_off; /* ADV read deassertion time for AAD */
+       u32 adv_aad_mux_wr_off; /* ADV write deassertion time for AAD */
+
+       /* WE signals timings corresponding to GPMC_CONFIG4 */
+       u32 we_on;              /* WE assertion time */
+       u32 we_off;             /* WE deassertion time */
+
+       /* OE signals timings corresponding to GPMC_CONFIG4 */
+       u32 oe_on;              /* OE assertion time */
+       u32 oe_off;             /* OE deassertion time */
+       u32 oe_aad_mux_on;      /* OE assertion time for AAD */
+       u32 oe_aad_mux_off;     /* OE deassertion time for AAD */
+
+       /* Access time and cycle time timings corresponding to GPMC_CONFIG5 */
+       u32 page_burst_access;  /* Multiple access word delay */
+       u32 access;             /* Start-cycle to first data valid delay */
+       u32 rd_cycle;           /* Total read cycle time */
+       u32 wr_cycle;           /* Total write cycle time */
+
+       u32 bus_turnaround;
+       u32 cycle2cycle_delay;
+
+       u32 wait_monitoring;
+       u32 clk_activation;
+
+       /* The following are only on OMAP3430 */
+       u32 wr_access;          /* WRACCESSTIME */
+       u32 wr_data_mux_bus;    /* WRDATAONADMUXBUS */
+
+       struct gpmc_bool_timings bool_timings;
+};
+
+/* Device timings in picoseconds */
+struct gpmc_device_timings {
+       u32 t_ceasu;    /* address setup to CS valid */
+       u32 t_avdasu;   /* address setup to ADV valid */
+       /* XXX: try to combine t_avdp_r & t_avdp_w. Issue is
+        * of tusb using these timings even for sync whilst
+        * ideally for adv_rd/(wr)_off it should have considered
+        * t_avdh instead. This indirectly necessitates r/w
+        * variations of t_avdp as it is possible to have one
+        * sync & other async
+        */
+       u32 t_avdp_r;   /* ADV low time (what about t_cer ?) */
+       u32 t_avdp_w;
+       u32 t_aavdh;    /* address hold time */
+       u32 t_oeasu;    /* address setup to OE valid */
+       u32 t_aa;       /* access time from ADV assertion */
+       u32 t_iaa;      /* initial access time */
+       u32 t_oe;       /* access time from OE assertion */
+       u32 t_ce;       /* access time from CS asertion */
+       u32 t_rd_cycle; /* read cycle time */
+       u32 t_cez_r;    /* read CS deassertion to high Z */
+       u32 t_cez_w;    /* write CS deassertion to high Z */
+       u32 t_oez;      /* OE deassertion to high Z */
+       u32 t_weasu;    /* address setup to WE valid */
+       u32 t_wpl;      /* write assertion time */
+       u32 t_wph;      /* write deassertion time */
+       u32 t_wr_cycle; /* write cycle time */
+
+       u32 clk;
+       u32 t_bacc;     /* burst access valid clock to output delay */
+       u32 t_ces;      /* CS setup time to clk */
+       u32 t_avds;     /* ADV setup time to clk */
+       u32 t_avdh;     /* ADV hold time from clk */
+       u32 t_ach;      /* address hold time from clk */
+       u32 t_rdyo;     /* clk to ready valid */
+
+       u32 t_ce_rdyz;  /* XXX: description ?, or use t_cez instead */
+       u32 t_ce_avd;   /* CS on to ADV on delay */
+
+       /* XXX: check the possibility of combining
+        * cyc_aavhd_oe & cyc_aavdh_we
+        */
+       u8 cyc_aavdh_oe;/* read address hold time in cycles */
+       u8 cyc_aavdh_we;/* write address hold time in cycles */
+       u8 cyc_oe;      /* access time from OE assertion in cycles */
+       u8 cyc_wpl;     /* write deassertion time in cycles */
+       u32 cyc_iaa;    /* initial access time in cycles */
+
+       /* extra delays */
+       bool ce_xdelay;
+       bool avd_xdelay;
+       bool oe_xdelay;
+       bool we_xdelay;
+};
+
+#define GPMC_BURST_4                   4       /* 4 word burst */
+#define GPMC_BURST_8                   8       /* 8 word burst */
+#define GPMC_BURST_16                  16      /* 16 word burst */
+#define GPMC_DEVWIDTH_8BIT             1       /* 8-bit device width */
+#define GPMC_DEVWIDTH_16BIT            2       /* 16-bit device width */
+#define GPMC_MUX_AAD                   1       /* Addr-Addr-Data multiplex */
+#define GPMC_MUX_AD                    2       /* Addr-Data multiplex */
+
+struct gpmc_settings {
+       bool burst_wrap;        /* enables wrap bursting */
+       bool burst_read;        /* enables read page/burst mode */
+       bool burst_write;       /* enables write page/burst mode */
+       bool device_nand;       /* device is NAND */
+       bool sync_read;         /* enables synchronous reads */
+       bool sync_write;        /* enables synchronous writes */
+       bool wait_on_read;      /* monitor wait on reads */
+       bool wait_on_write;     /* monitor wait on writes */
+       u32 burst_len;          /* page/burst length */
+       u32 device_width;       /* device bus width (8 or 16 bit) */
+       u32 mux_add_data;       /* multiplex address & data */
+       u32 wait_pin;           /* wait-pin to be used */
+};
index 864b05e432a73b9dfa0ef6744ae95dbc36c83bfc..f08e700a1daf66b65bf1e5b3c8d4d00dbec86f91 100644 (file)
@@ -8,6 +8,9 @@
 #ifndef __ASM_OMAP_GPMC_H
 #define __ASM_OMAP_GPMC_H
 
+/* Maximum Number of Chip Selects */
+#define GPMC_CS_NUM    8
+
 #define GPMC_BUF_EMPTY 0
 #define GPMC_BUF_FULL  1
 #define GPMC_MAX_SECTORS       8