arm: mvebu: Add support for specifying VHV_Enable GPIO

VHV_Enable GPIO is required to enable during eFuse programming on Armada
SoCs not from 3700 family. Add support for enabling and disabling VHV pin
via GPIO during eFuse programming, when specified.

All details are in Marvell AN-389: ARMADA VHV Power document
(Doc. No. MV-S302545-00 Rev. C, August 2, 2016).

Note that due to HW Errata 3.6 eFuse erroneous burning (Ref #: HWE-3718342)
VHV power must be disabled while core voltage is off to prevent erroneous
eFuse programming.

This is specified in Marvell ARMADA 380/385/388 Functional Errata,
Guidelines, and Restrictions document
(Doc. No. MV-S501377-00 Rev. D, December 1, 2016).

Signed-off-by: Pali Rohár <pali@kernel.org>

diff --git a/arch/arm/mach-mvebu/Kconfig b/arch/arm/mach-mvebu/Kconfig
index 2ebe341ed1b742c292f677f5dbeccd18da3981c9..fe6b785d0bdc7ae82193eef2ff6ed774a8dd770d 100644 (file)
--- a/arch/arm/mach-mvebu/Kconfig
+++ b/arch/arm/mach-mvebu/Kconfig
@@ -348,6 +348,21 @@ config MVEBU_EFUSE_FAKE
          from a memory block.
          This is can be used for testing prog scripts.
 
+config MVEBU_EFUSE_VHV_GPIO
+       string "VHV_Enable GPIO name for eFuse programming"
+       depends on MVEBU_EFUSE && !ARMADA_3700
+       help
+         The eFuse programing (burning) phase requires supplying 1.8V to the
+         device on the VHV power pin, while for normal operation the VHV power
+         rail must be left unconnected. See Marvell AN-389: ARMADA VHV Power
+         document (Doc. No. MV-S302545-00 Rev. C, August 2, 2016) for details.
+         .
+         This specify VHV_Enable GPIO name used in U-Boot for enabling VHV power.
+
+config MVEBU_EFUSE_VHV_GPIO_ACTIVE_LOW
+       bool "VHV_Enable GPIO is Active Low"
+       depends on MVEBU_EFUSE_VHV_GPIO != ""
+
 config SECURED_MODE_IMAGE
        bool "Build image for trusted boot"
        default false

diff --git a/arch/arm/mach-mvebu/efuse.c b/arch/arm/mach-mvebu/efuse.c
index 4b04337821710aaa75394ec4d91b403d8506cd6f..be5dc0e07d9bcab8707efb4631e1fc22b80bad7c 100644 (file)
--- a/arch/arm/mach-mvebu/efuse.c
+++ b/arch/arm/mach-mvebu/efuse.c
@@ -10,6 +10,7 @@
 #include <asm/arch/cpu.h>
 #include <asm/arch/efuse.h>
 #include <asm/arch/soc.h>
+#include <asm/gpio.h>
 #include <linux/bitops.h>
 #include <linux/delay.h>
 #include <linux/mbus.h>
@@ -56,17 +57,48 @@ static struct mvebu_hd_efuse *get_efuse_line(int nr)
        return efuses + nr;
 }
 
-static void enable_efuse_program(void)
+#ifndef DRY_RUN
+static int vhv_gpio;
+#endif
+
+static int enable_efuse_program(void)
 {
 #ifndef DRY_RUN
+       if (CONFIG_MVEBU_EFUSE_VHV_GPIO[0]) {
+               if (gpio_lookup_name(CONFIG_MVEBU_EFUSE_VHV_GPIO, NULL, NULL, &vhv_gpio)) {
+                       printf("Error: VHV gpio lookup failed\n");
+                       return -EOPNOTSUPP;
+               }
+               if (gpio_request(vhv_gpio, CONFIG_MVEBU_EFUSE_VHV_GPIO)) {
+                       printf("Error: VHV gpio request failed\n");
+                       return -EOPNOTSUPP;
+               }
+               if (gpio_direction_output(vhv_gpio,
+                   IS_ENABLED(CONFIG_MVEBU_EFUSE_VHV_GPIO_ACTIVE_LOW) ? 0 : 1)) {
+                       printf("Error: VHV gpio enable failed\n");
+                       return -EINVAL;
+               }
+               mdelay(5); /* Wait for the VHV power to stabilize */
+       }
+
        setbits_le32(MVEBU_EFUSE_CONTROL, MVEBU_EFUSE_CTRL_PROGRAM_ENABLE);
 #endif
+
+       return 0;
 }
 
 static void disable_efuse_program(void)
 {
 #ifndef DRY_RUN
        clrbits_le32(MVEBU_EFUSE_CONTROL, MVEBU_EFUSE_CTRL_PROGRAM_ENABLE);
+
+       if (CONFIG_MVEBU_EFUSE_VHV_GPIO[0]) {
+               if (gpio_direction_output(vhv_gpio,
+                   IS_ENABLED(CONFIG_MVEBU_EFUSE_VHV_GPIO_ACTIVE_LOW) ? 1 : 0))
+                       printf("Error: VHV gpio disable failed\n");
+               gpio_free(vhv_gpio);
+               vhv_gpio = 0;
+       }
 #endif
 }
 
@@ -123,7 +155,9 @@ static int prog_efuse(int nr, struct efuse_val *new_val, u32 mask0, u32 mask1)
        if (!new_val->dwords.d[0] && !new_val->dwords.d[1] && (mask0 | mask1))
                return 0;
 
-       enable_efuse_program();
+       res = enable_efuse_program();
+       if (res)
+               return res;
 
        res = do_prog_efuse(efuse, new_val, mask0, mask1);
 
@@ -155,7 +189,9 @@ int mvebu_prog_ld_efuse(int ld1, u32 word, u32 val)
        if (val == (line[word] & val))
                return 0;
 
-       enable_efuse_program();
+       res = enable_efuse_program();
+       if (res)
+               return res;
 
        mvebu_read_ld_efuse(ld1, line);
        line[word] |= val;