[U-Boot] [PATCH v2] M28: GPIO pin validity check added

[Robert Deliën]

This patch adds a validity check for GPIO pins to prevent clobbering reserved bit or even registers, per suggestion of Marek Vasut.

Please note:
1. gpio_request no longer checks validity. Pin validity must be checked explicitly use gpio_invalid prior to request and hence use. Previous validity check in gpio_request was incomplete anyway.
2. MX233 is not supported yet. Until it is, macros defining the number of pins for each bank reside in arch/arm/include/asm/arch-mx28/iomux.h

Signed-off-by: Robert Deliën <robert at delien.nl<http://delien.nl/>>

diff --git a/arch/arm/include/asm/arch-mx28/gpio.h b/arch/arm/include/asm/arch-mx28/gpio.h
index be1c944..5abd7b1 100644
--- a/arch/arm/include/asm/arch-mx28/gpio.h
+++ b/arch/arm/include/asm/arch-mx28/gpio.h
@@ -25,6 +25,10 @@

 #ifdef CONFIG_MXS_GPIO
 void mxs_gpio_init(void);
+
+extern int gpio_invalid(int gp);
+#define gpio_invalid(gpio) gpio_invalid(gpio)
+
 #else
 inline void mxs_gpio_init(void) {}
 #endif
diff --git a/arch/arm/include/asm/arch-mx28/iomux.h b/arch/arm/include/asm/arch-mx28/iomux.h
index 7abdf58..2326fdb 100644
--- a/arch/arm/include/asm/arch-mx28/iomux.h
+++ b/arch/arm/include/asm/arch-mx28/iomux.h
@@ -56,6 +56,16 @@ typedef u32 iomux_cfg_t;
 #define MXS_PAD_PULL_VALID_SHIFT 16
 #define MXS_PAD_PULL_VALID_MASK ((iomux_cfg_t)0x1 << MXS_PAD_PULL_VALID_SHIFT)

+#define MX28_BANK0_PINS 29
+#define MX28_BANK1_PINS 32
+#define MX28_BANK2_PINS 28
+#define MX28_BANK3_PINS 31
+#define MX28_BANK4_PINS 21
+
+#define MX23_BANK0_PINS 32
+#define MX23_BANK1_PINS 31
+#define MX23_BANK2_PINS 32
+
 #define PAD_MUXSEL_0 0
 #define PAD_MUXSEL_1 1
 #define PAD_MUXSEL_2 2
diff --git a/common/cmd_gpio.c b/common/cmd_gpio.c
index 9cc790a..f81c7d8 100644
--- a/common/cmd_gpio.c
+++ b/common/cmd_gpio.c
@@ -15,6 +15,10 @@
 #define name_to_gpio(name) simple_strtoul(name, NULL, 10)
 #endif

+#ifndef gpio_invalid
+#define gpio_invalid(gpio) (0)
+#endif
+
 enum gpio_cmd {
  GPIO_INPUT,
  GPIO_SET,
@@ -56,6 +60,12 @@ static int do_gpio(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
  if (gpio < 0)
  goto show_usage;

+ /* check bank and pin number for validity */
+ if (gpio_invalid(gpio)) {
+ printf("gpio: invalid pin %u\n", gpio);
+ return (-1);
+ }
+
  /* grab the pin before we tweak it */
  if (gpio_request(gpio, "cmd_gpio")) {
  printf("gpio: requesting pin %u failed\n", gpio);
diff --git a/drivers/gpio/mxs_gpio.c b/drivers/gpio/mxs_gpio.c
index b7e9591..d2e9bac 100644
--- a/drivers/gpio/mxs_gpio.c
+++ b/drivers/gpio/mxs_gpio.c
@@ -31,7 +31,6 @@
 #include <asm/arch/imx-regs.h>

 #if defined(CONFIG_MX23)
-#define PINCTRL_BANKS 3
 #define PINCTRL_DOUT(n) (0x0500 + ((n) * 0x10))
 #define PINCTRL_DIN(n) (0x0600 + ((n) * 0x10))
 #define PINCTRL_DOE(n) (0x0700 + ((n) * 0x10))
@@ -39,7 +38,6 @@
 #define PINCTRL_IRQEN(n) (0x0900 + ((n) * 0x10))
 #define PINCTRL_IRQSTAT(n) (0x0c00 + ((n) * 0x10))
 #elif defined(CONFIG_MX28)
-#define PINCTRL_BANKS 5
 #define PINCTRL_DOUT(n) (0x0700 + ((n) * 0x10))
 #define PINCTRL_DIN(n) (0x0900 + ((n) * 0x10))
 #define PINCTRL_DOE(n) (0x0b00 + ((n) * 0x10))
@@ -57,11 +55,25 @@
 #define GPIO_INT_LEV_MASK (1 << 0)
 #define GPIO_INT_POL_MASK (1 << 1)

+static const int mxs_bank_pins[] = {
+#if defined(CONFIG_MX23)
+ MX23_BANK0_PINS,
+ MX23_BANK1_PINS,
+ MX23_BANK2_PINS
+#elif defined(CONFIG_MX28)
+ MX28_BANK0_PINS,
+ MX28_BANK1_PINS,
+ MX28_BANK2_PINS,
+ MX28_BANK3_PINS,
+ MX28_BANK4_PINS
+#endif
+};
+
 void mxs_gpio_init(void)
 {
  int i;

- for (i = 0; i < PINCTRL_BANKS; i++) {
+ for (i = 0; i < ARRAY_SIZE(mxs_bank_pins); i++) {
  writel(0, MXS_PINCTRL_BASE + PINCTRL_PIN2IRQ(i));
  writel(0, MXS_PINCTRL_BASE + PINCTRL_IRQEN(i));
  /* Use SCT address here to clear the IRQSTAT bits */
@@ -69,6 +81,16 @@ void mxs_gpio_init(void)
  }
 }

+int gpio_invalid(int gp)
+{
+ if ( (gp & ~(MXS_PAD_BANK_MASK | MXS_PAD_PIN_MASK)) ||
+     (PAD_BANK(gp) >= ARRAY_SIZE(mxs_bank_pins)) ||
+     (PAD_PIN(gp) >= mxs_bank_pins[PAD_BANK(gp)]) )
+ return (-EINVAL);
+
+ return (0);
+}
+
 int gpio_get_value(int gp)
 {
  uint32_t bank = PAD_BANK(gp);
@@ -120,9 +142,6 @@ int gpio_direction_output(int gp, int value)

 int gpio_request(int gp, const char *label)
 {
- if (PAD_BANK(gp) > PINCTRL_BANKS)
- return -EINVAL;
-
  return 0;
 }