]> git.dujemihanovic.xyz Git - u-boot.git/commitdiff
mtd: mxs_nand: Support EDO mode for imx8mn architecture
authorMichael Trimarchi <michael@amarulasolutions.com>
Tue, 30 Aug 2022 14:48:47 +0000 (16:48 +0200)
committerDario Binacchi <dario.binacchi@amarulasolutions.com>
Sun, 9 Oct 2022 08:42:26 +0000 (10:42 +0200)
Add support for imx8mn architecture in order to run the NAND
in fast edo mode.

Signed-off-by: Michael Trimarchi <michael@amarulasolutions.com>
Reviewed-by: Dario Binacchi <dario.binacchi@amarulasolutions.com>
Signed-off-by: Dario Binacchi <dario.binacchi@amarulasolutions.com>
drivers/mtd/nand/raw/mxs_nand.c
drivers/mtd/nand/raw/mxs_nand_dt.c
include/mxs_nand.h

index 7893e9d7e343a84481a3bfa83426808842505d42..65eab4c8088a43c6b85edd8ed3e38151a0897e3f 100644 (file)
@@ -14,6 +14,7 @@
  */
 
 #include <common.h>
+#include <clk.h>
 #include <cpu_func.h>
 #include <dm.h>
 #include <dm/device_compat.h>
 #include <asm/io.h>
 #include <asm/mach-imx/regs-bch.h>
 #include <asm/mach-imx/regs-gpmi.h>
+#include <linux/delay.h>
 #include <linux/errno.h>
 #include <linux/mtd/rawnand.h>
 #include <linux/sizes.h>
 #include <linux/types.h>
+#include <linux/math64.h>
 
 #define        MXS_NAND_DMA_DESCRIPTOR_COUNT           4
 
 #endif
 
 #define        MXS_NAND_BCH_TIMEOUT                    10000
+#define        USEC_PER_SEC                            1000000
+#define        NSEC_PER_SEC                            1000000000L
+
+#define TO_CYCLES(duration, period) DIV_ROUND_UP_ULL(duration, period)
 
 struct nand_ecclayout fake_ecc_layout;
 
@@ -1344,6 +1351,196 @@ err1:
        return ret;
 }
 
+/*
+ * <1> Firstly, we should know what's the GPMI-clock means.
+ *     The GPMI-clock is the internal clock in the gpmi nand controller.
+ *     If you set 100MHz to gpmi nand controller, the GPMI-clock's period
+ *     is 10ns. Mark the GPMI-clock's period as GPMI-clock-period.
+ *
+ * <2> Secondly, we should know what's the frequency on the nand chip pins.
+ *     The frequency on the nand chip pins is derived from the GPMI-clock.
+ *     We can get it from the following equation:
+ *
+ *         F = G / (DS + DH)
+ *
+ *         F  : the frequency on the nand chip pins.
+ *         G  : the GPMI clock, such as 100MHz.
+ *         DS : GPMI_HW_GPMI_TIMING0:DATA_SETUP
+ *         DH : GPMI_HW_GPMI_TIMING0:DATA_HOLD
+ *
+ * <3> Thirdly, when the frequency on the nand chip pins is above 33MHz,
+ *     the nand EDO(extended Data Out) timing could be applied.
+ *     The GPMI implements a feedback read strobe to sample the read data.
+ *     The feedback read strobe can be delayed to support the nand EDO timing
+ *     where the read strobe may deasserts before the read data is valid, and
+ *     read data is valid for some time after read strobe.
+ *
+ *     The following figure illustrates some aspects of a NAND Flash read:
+ *
+ *                   |<---tREA---->|
+ *                   |             |
+ *                   |         |   |
+ *                   |<--tRP-->|   |
+ *                   |         |   |
+ *                  __          ___|__________________________________
+ *     RDN            \________/   |
+ *                                 |
+ *                                 /---------\
+ *     Read Data    --------------<           >---------
+ *                                 \---------/
+ *                                |     |
+ *                                |<-D->|
+ *     FeedbackRDN  ________             ____________
+ *                          \___________/
+ *
+ *          D stands for delay, set in the HW_GPMI_CTRL1:RDN_DELAY.
+ *
+ *
+ * <4> Now, we begin to describe how to compute the right RDN_DELAY.
+ *
+ *  4.1) From the aspect of the nand chip pins:
+ *        Delay = (tREA + C - tRP)               {1}
+ *
+ *        tREA : the maximum read access time.
+ *        C    : a constant to adjust the delay. default is 4000ps.
+ *        tRP  : the read pulse width, which is exactly:
+ *                   tRP = (GPMI-clock-period) * DATA_SETUP
+ *
+ *  4.2) From the aspect of the GPMI nand controller:
+ *         Delay = RDN_DELAY * 0.125 * RP        {2}
+ *
+ *         RP   : the DLL reference period.
+ *            if (GPMI-clock-period > DLL_THRETHOLD)
+ *                   RP = GPMI-clock-period / 2;
+ *            else
+ *                   RP = GPMI-clock-period;
+ *
+ *            Set the HW_GPMI_CTRL1:HALF_PERIOD if GPMI-clock-period
+ *            is greater DLL_THRETHOLD. In other SOCs, the DLL_THRETHOLD
+ *            is 16000ps, but in mx6q, we use 12000ps.
+ *
+ *  4.3) since {1} equals {2}, we get:
+ *
+ *                     (tREA + 4000 - tRP) * 8
+ *         RDN_DELAY = -----------------------     {3}
+ *                           RP
+ */
+static void mxs_compute_timings(struct nand_chip *chip,
+                               const struct nand_sdr_timings *sdr)
+{
+       struct mxs_nand_info *nand_info = nand_get_controller_data(chip);
+       unsigned long clk_rate;
+       unsigned int dll_wait_time_us;
+       unsigned int dll_threshold_ps = nand_info->max_chain_delay;
+       unsigned int period_ps, reference_period_ps;
+       unsigned int data_setup_cycles, data_hold_cycles, addr_setup_cycles;
+       unsigned int tRP_ps;
+       bool use_half_period;
+       int sample_delay_ps, sample_delay_factor;
+       u16 busy_timeout_cycles;
+       u8 wrn_dly_sel;
+       u32 timing0;
+       u32 timing1;
+       u32 ctrl1n;
+
+       if (sdr->tRC_min >= 30000) {
+               /* ONFI non-EDO modes [0-3] */
+               clk_rate = 22000000;
+               wrn_dly_sel = GPMI_CTRL1_WRN_DLY_SEL_4_TO_8NS;
+       } else if (sdr->tRC_min >= 25000) {
+               /* ONFI EDO mode 4 */
+               clk_rate = 80000000;
+               wrn_dly_sel = GPMI_CTRL1_WRN_DLY_SEL_NO_DELAY;
+               debug("%s, setting ONFI onfi edo 4\n", __func__);
+       } else {
+               /* ONFI EDO mode 5 */
+               clk_rate = 100000000;
+               wrn_dly_sel = GPMI_CTRL1_WRN_DLY_SEL_NO_DELAY;
+               debug("%s, setting ONFI onfi edo 5\n", __func__);
+       }
+
+       /* SDR core timings are given in picoseconds */
+       period_ps = div_u64((u64)NSEC_PER_SEC * 1000, clk_rate);
+
+       addr_setup_cycles = TO_CYCLES(sdr->tALS_min, period_ps);
+       data_setup_cycles = TO_CYCLES(sdr->tDS_min, period_ps);
+       data_hold_cycles = TO_CYCLES(sdr->tDH_min, period_ps);
+       busy_timeout_cycles = TO_CYCLES(sdr->tWB_max + sdr->tR_max, period_ps);
+
+       timing0 = (addr_setup_cycles << GPMI_TIMING0_ADDRESS_SETUP_OFFSET) |
+                     (data_hold_cycles << GPMI_TIMING0_DATA_HOLD_OFFSET) |
+                     (data_setup_cycles << GPMI_TIMING0_DATA_SETUP_OFFSET);
+       timing1 = (busy_timeout_cycles * 4096) << GPMI_TIMING1_DEVICE_BUSY_TIMEOUT_OFFSET;
+
+       /*
+        * Derive NFC ideal delay from {3}:
+        *
+        *                     (tREA + 4000 - tRP) * 8
+        *         RDN_DELAY = -----------------------
+        *                                RP
+        */
+       if (period_ps > dll_threshold_ps) {
+               use_half_period = true;
+               reference_period_ps = period_ps / 2;
+       } else {
+               use_half_period = false;
+               reference_period_ps = period_ps;
+       }
+
+       tRP_ps = data_setup_cycles * period_ps;
+       sample_delay_ps = (sdr->tREA_max + 4000 - tRP_ps) * 8;
+       if (sample_delay_ps > 0)
+               sample_delay_factor = sample_delay_ps / reference_period_ps;
+       else
+               sample_delay_factor = 0;
+
+       ctrl1n = (wrn_dly_sel << GPMI_CTRL1_WRN_DLY_SEL_OFFSET);
+       if (sample_delay_factor)
+               ctrl1n |= (sample_delay_factor << GPMI_CTRL1_RDN_DELAY_OFFSET) |
+                       GPMI_CTRL1_DLL_ENABLE |
+                       (use_half_period ? GPMI_CTRL1_HALF_PERIOD : 0);
+
+       writel(timing0, &nand_info->gpmi_regs->hw_gpmi_timing0);
+       writel(timing1, &nand_info->gpmi_regs->hw_gpmi_timing1);
+
+       /*
+        * Clear several CTRL1 fields, DLL must be disabled when setting
+        * RDN_DELAY or HALF_PERIOD.
+        */
+       writel(GPMI_CTRL1_CLEAR_MASK, &nand_info->gpmi_regs->hw_gpmi_ctrl1_clr);
+       writel(ctrl1n, &nand_info->gpmi_regs->hw_gpmi_ctrl1_set);
+
+       clk_set_rate(nand_info->gpmi_clk, clk_rate);
+
+       /* Wait 64 clock cycles before using the GPMI after enabling the DLL */
+       dll_wait_time_us = USEC_PER_SEC / clk_rate * 64;
+       if (!dll_wait_time_us)
+               dll_wait_time_us = 1;
+
+       /* Wait for the DLL to settle. */
+       udelay(dll_wait_time_us);
+}
+
+static int mxs_nand_setup_interface(struct mtd_info *mtd, int chipnr,
+                                   const struct nand_data_interface *conf)
+{
+       struct nand_chip *chip = mtd_to_nand(mtd);
+       const struct nand_sdr_timings *sdr;
+
+       sdr = nand_get_sdr_timings(conf);
+       if (IS_ERR(sdr))
+               return PTR_ERR(sdr);
+
+       /* Stop here if this call was just a check */
+       if (chipnr < 0)
+               return 0;
+
+       /* Do the actual derivation of the controller timings */
+       mxs_compute_timings(chip, sdr);
+
+       return 0;
+}
+
 int mxs_nand_init_spl(struct nand_chip *nand)
 {
        struct mxs_nand_info *nand_info;
@@ -1432,6 +1629,9 @@ int mxs_nand_init_ctrl(struct mxs_nand_info *nand_info)
        nand->read_buf          = mxs_nand_read_buf;
        nand->write_buf         = mxs_nand_write_buf;
 
+       if (nand_info->gpmi_clk)
+               nand->setup_data_interface = mxs_nand_setup_interface;
+
        /* first scan to find the device and get the page size */
        if (nand_scan_ident(mtd, CONFIG_SYS_MAX_NAND_DEVICE, NULL))
                goto err_free_buffers;
index 94ee7ed9ec83a9d5c5ee0f2f313b665dcbbf828b..a922a22b27302e0c71456183cdb4d10cdee5ad05 100644 (file)
 
 struct mxs_nand_dt_data {
        unsigned int max_ecc_strength_supported;
+       int max_chain_delay; /* See the async EDO mode */
 };
 
 static const struct mxs_nand_dt_data mxs_nand_imx6q_data = {
        .max_ecc_strength_supported = 40,
+       .max_chain_delay = 12000,
 };
 
 static const struct mxs_nand_dt_data mxs_nand_imx6sx_data = {
        .max_ecc_strength_supported = 62,
+       .max_chain_delay = 12000,
 };
 
 static const struct mxs_nand_dt_data mxs_nand_imx7d_data = {
        .max_ecc_strength_supported = 62,
+       .max_chain_delay = 12000,
 };
 
 static const struct mxs_nand_dt_data mxs_nand_imx8qxp_data = {
        .max_ecc_strength_supported = 62,
+       .max_chain_delay = 12000,
 };
 
 static const struct udevice_id mxs_nand_dt_ids[] = {
@@ -72,8 +77,10 @@ static int mxs_nand_dt_probe(struct udevice *dev)
        int ret;
 
        data = (void *)dev_get_driver_data(dev);
-       if (data)
+       if (data) {
                info->max_ecc_strength_supported = data->max_ecc_strength_supported;
+               info->max_chain_delay = data->max_chain_delay;
+       }
 
        info->dev = dev;
 
@@ -92,44 +99,49 @@ static int mxs_nand_dt_probe(struct udevice *dev)
 
        info->use_minimum_ecc = dev_read_bool(dev, "fsl,use-minimum-ecc");
 
-       if (IS_ENABLED(CONFIG_CLK) && IS_ENABLED(CONFIG_IMX8)) {
+       if (IS_ENABLED(CONFIG_CLK) &&
+           (IS_ENABLED(CONFIG_IMX8) || IS_ENABLED(CONFIG_IMX8M))) {
                /* Assigned clock already set clock */
                struct clk gpmi_clk;
 
-               ret = clk_get_by_name(dev, "gpmi_io", &gpmi_clk);
-               if (ret < 0) {
+               info->gpmi_clk = devm_clk_get(dev, "gpmi_io");
+
+               if (IS_ERR(info->gpmi_clk)) {
+                       ret = PTR_ERR(info->gpmi_clk);
                        debug("Can't get gpmi io clk: %d\n", ret);
                        return ret;
                }
 
-               ret = clk_enable(&gpmi_clk);
+               ret = clk_enable(info->gpmi_clk);
                if (ret < 0) {
                        debug("Can't enable gpmi io clk: %d\n", ret);
                        return ret;
                }
 
-               ret = clk_get_by_name(dev, "gpmi_apb", &gpmi_clk);
-               if (ret < 0) {
-                       debug("Can't get gpmi_apb clk: %d\n", ret);
-                       return ret;
-               }
-
-               ret = clk_enable(&gpmi_clk);
-               if (ret < 0) {
-                       debug("Can't enable gpmi_apb clk: %d\n", ret);
-                       return ret;
-               }
-
-               ret = clk_get_by_name(dev, "gpmi_bch", &gpmi_clk);
-               if (ret < 0) {
-                       debug("Can't get gpmi_bch clk: %d\n", ret);
-                       return ret;
-               }
-
-               ret = clk_enable(&gpmi_clk);
-               if (ret < 0) {
-                       debug("Can't enable gpmi_bch clk: %d\n", ret);
-                       return ret;
+               if (IS_ENABLED(CONFIG_IMX8)) {
+                       ret = clk_get_by_name(dev, "gpmi_apb", &gpmi_clk);
+                       if (ret < 0) {
+                               debug("Can't get gpmi_apb clk: %d\n", ret);
+                               return ret;
+                       }
+
+                       ret = clk_enable(&gpmi_clk);
+                       if (ret < 0) {
+                               debug("Can't enable gpmi_apb clk: %d\n", ret);
+                               return ret;
+                       }
+
+                       ret = clk_get_by_name(dev, "gpmi_bch", &gpmi_clk);
+                       if (ret < 0) {
+                               debug("Can't get gpmi_bch clk: %d\n", ret);
+                               return ret;
+                       }
+
+                       ret = clk_enable(&gpmi_clk);
+                       if (ret < 0) {
+                               debug("Can't enable gpmi_bch clk: %d\n", ret);
+                               return ret;
+                       }
                }
 
                ret = clk_get_by_name(dev, "gpmi_bch_apb", &gpmi_clk);
index 741dc8734eae3db8e83c8935a2205984fd1a121d..bb5b84b8c26e252b5a4682d6260ec198308d8ce9 100644 (file)
@@ -12,6 +12,7 @@
 #include <asm/cache.h>
 #include <nand.h>
 #include <asm/mach-imx/dma.h>
+#include <clk.h>
 
 /**
  * @gf_len:                   The length of Galois Field. (e.g., 13 or 14)
@@ -43,6 +44,7 @@ struct mxs_nand_info {
        struct nand_chip chip;
        struct udevice *dev;
        unsigned int    max_ecc_strength_supported;
+       int             max_chain_delay;
        bool            use_minimum_ecc;
        int             cur_chip;
 
@@ -59,6 +61,7 @@ struct mxs_nand_info {
 
        struct mxs_gpmi_regs *gpmi_regs;
        struct mxs_bch_regs *bch_regs;
+       struct clk *gpmi_clk;
 
        /* Functions with altered behaviour */
        int             (*hooked_read_oob)(struct mtd_info *mtd,