[U-Boot] [PATCH] 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>

diff --git a/arch/arm/include/asm/arch-mx28/gpio.h b/arch/arm/include/asm/arch-mx28/gpio.h
index be1c944..36f3be8 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;
}