[U-Boot] [PATCH] M28: Added guarding for reserved bits in GPIO driver

[Robert Deliën]

This patch fixes a small bug that allowed unintended manipulation of non-existing GPIO pins within a pin bank, clobbering reserved bits.

Signed-off-by: Robert Deliën <robert at delien.nl>
diff --git a/arch/arm/include/asm/arch-mx28/iomux.h b/arch/arm/include/asm/arch-mx28/iomux.h
index 7abdf58..829d9a8 100644
--- a/arch/arm/include/asm/arch-mx28/iomux.h
+++ b/arch/arm/include/asm/arch-mx28/iomux.h
@@ -56,6 +56,12 @@ 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 MXS_BANK0_PINS         29
+#define MXS_BANK1_PINS         32
+#define MXS_BANK2_PINS         28
+#define MXS_BANK3_PINS         31
+#define MXS_BANK4_PINS         21
+
 #define PAD_MUXSEL_0           0
 #define PAD_MUXSEL_1           1
 #define PAD_MUXSEL_2           2
diff --git a/drivers/gpio/mxs_gpio.c b/drivers/gpio/mxs_gpio.c
index 539738b..fbc6da3 100644
--- a/drivers/gpio/mxs_gpio.c
+++ b/drivers/gpio/mxs_gpio.c
@@ -120,9 +120,34 @@ int gpio_direction_output(int gp, int value)
 
 int gpio_request(int gp, const char *label)
 {
+       int bank_pins;
+
        if (PAD_BANK(gp) >= PINCTRL_BANKS)
                return -EINVAL;
 
+       switch(PAD_BANK(gp)) {
+       case 0:
+               bank_pins = MXS_BANK0_PINS;
+               break;
+       case 1:
+               bank_pins = MXS_BANK1_PINS;
+               break;
+       case 2:
+               bank_pins = MXS_BANK2_PINS;
+               break;
+       case 3:
+               bank_pins = MXS_BANK3_PINS;
+               break;
+       case 4:
+               bank_pins = MXS_BANK4_PINS;
+               break;
+       default:
+               bank_pins = 0;
+       }
+
+       if (PAD_PIN(gp) >= bank_pins)
+               return -EINVAL;
+
        return 0;
 }