gpio: tegra186: Check GPIO pin permission before access.

This change checks if we have the necessary permission to
access the GPIO. For devices that have support for virtualisation
we need to check both the TEGRA186_GPIO_VM_REG and the
TEGRA186_GPIO_SCR_REG registers. For device that do not have
virtualisation support for GPIOs we only need to check the
TEGRA186_GPIO_SCR_REG register.
Signed-off-by: Manish Bhardwaj <mbhardwaj@nvidia.com>
Signed-off-by: Prathamesh Shete <pshete@nvidia.com>
Acked-by: Thierry Reding <treding@nvidia.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Acked-by: Jon Hunter <jonathanh@nvidia.com>
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

drivers/gpio/gpio-tegra186.c

@@ -27,6 +27,22 @@
 
 #define TEGRA186_GPIO_INT_ROUTE_MAPPING(p, x) (0x14 + (p) * 0x20 + (x) * 4)
 
+#define  TEGRA186_GPIO_VM			0x00
+#define  TEGRA186_GPIO_VM_RW_MASK		0x03
+#define  TEGRA186_GPIO_SCR			0x04
+#define  TEGRA186_GPIO_SCR_PIN_SIZE		0x08
+#define  TEGRA186_GPIO_SCR_PORT_SIZE		0x40
+#define  TEGRA186_GPIO_SCR_SEC_WEN		BIT(28)
+#define  TEGRA186_GPIO_SCR_SEC_REN		BIT(27)
+#define  TEGRA186_GPIO_SCR_SEC_G1W		BIT(9)
+#define  TEGRA186_GPIO_SCR_SEC_G1R		BIT(1)
+#define  TEGRA186_GPIO_FULL_ACCESS		(TEGRA186_GPIO_SCR_SEC_WEN | \
+						 TEGRA186_GPIO_SCR_SEC_REN | \
+						 TEGRA186_GPIO_SCR_SEC_G1R | \
+						 TEGRA186_GPIO_SCR_SEC_G1W)
+#define  TEGRA186_GPIO_SCR_SEC_ENABLE		(TEGRA186_GPIO_SCR_SEC_WEN | \
+						 TEGRA186_GPIO_SCR_SEC_REN)
+
 /* control registers */
 #define TEGRA186_GPIO_ENABLE_CONFIG 0x00
 #define  TEGRA186_GPIO_ENABLE_CONFIG_ENABLE BIT(0)
@@ -81,6 +97,7 @@ struct tegra_gpio_soc {
 	unsigned int num_pin_ranges;
 	const char *pinmux;
 	bool has_gte;
+	bool has_vm_support;
 };
 
 struct tegra_gpio {
@@ -130,6 +147,58 @@ static void __iomem *tegra186_gpio_get_base(struct tegra_gpio *gpio,
 	return gpio->base + offset + pin * 0x20;
 }
 
+static void __iomem *tegra186_gpio_get_secure_base(struct tegra_gpio *gpio,
+						   unsigned int pin)
+{
+	const struct tegra_gpio_port *port;
+	unsigned int offset;
+
+	port = tegra186_gpio_get_port(gpio, &pin);
+	if (!port)
+		return NULL;
+
+	offset = port->bank * 0x1000 + port->port * TEGRA186_GPIO_SCR_PORT_SIZE;
+
+	return gpio->secure + offset + pin * TEGRA186_GPIO_SCR_PIN_SIZE;
+}
+
+static inline bool tegra186_gpio_is_accessible(struct tegra_gpio *gpio, unsigned int pin)
+{
+	void __iomem *secure;
+	u32 value;
+
+	secure = tegra186_gpio_get_secure_base(gpio, pin);
+
+	if (gpio->soc->has_vm_support) {
+		value = readl(secure + TEGRA186_GPIO_VM);
+		if ((value & TEGRA186_GPIO_VM_RW_MASK) != TEGRA186_GPIO_VM_RW_MASK)
+			return false;
+	}
+
+	value = __raw_readl(secure + TEGRA186_GPIO_SCR);
+
+	if ((value & TEGRA186_GPIO_SCR_SEC_ENABLE) == 0)
+		return true;
+
+	if ((value & TEGRA186_GPIO_FULL_ACCESS) == TEGRA186_GPIO_FULL_ACCESS)
+		return true;
+
+	return false;
+}
+
+static int tegra186_init_valid_mask(struct gpio_chip *chip,
+				    unsigned long *valid_mask, unsigned int ngpios)
+{
+	struct tegra_gpio *gpio = gpiochip_get_data(chip);
+	unsigned int j;
+
+	for (j = 0; j < ngpios; j++) {
+		if (!tegra186_gpio_is_accessible(gpio, j))
+			clear_bit(j, valid_mask);
+	}
+	return 0;
+}
+
 static int tegra186_gpio_get_direction(struct gpio_chip *chip,
 				       unsigned int offset)
 {
@@ -816,6 +885,7 @@ static int tegra186_gpio_probe(struct platform_device *pdev)
 	gpio->gpio.set = tegra186_gpio_set;
 	gpio->gpio.set_config = tegra186_gpio_set_config;
 	gpio->gpio.add_pin_ranges = tegra186_gpio_add_pin_ranges;
+	gpio->gpio.init_valid_mask = tegra186_init_valid_mask;
 	if (gpio->soc->has_gte) {
 		gpio->gpio.en_hw_timestamp = tegra186_gpio_en_hw_ts;
 		gpio->gpio.dis_hw_timestamp = tegra186_gpio_dis_hw_ts;
@@ -958,6 +1028,7 @@ static const struct tegra_gpio_soc tegra186_main_soc = {
 	.name = "tegra186-gpio",
 	.instance = 0,
 	.num_irqs_per_bank = 1,
+	.has_vm_support = false,
 };
 
 #define TEGRA186_AON_GPIO_PORT(_name, _bank, _port, _pins)	\
@@ -985,6 +1056,7 @@ static const struct tegra_gpio_soc tegra186_aon_soc = {
 	.name = "tegra186-gpio-aon",
 	.instance = 1,
 	.num_irqs_per_bank = 1,
+	.has_vm_support = false,
 };
 
 #define TEGRA194_MAIN_GPIO_PORT(_name, _bank, _port, _pins)	\
@@ -1040,6 +1112,7 @@ static const struct tegra_gpio_soc tegra194_main_soc = {
 	.num_pin_ranges = ARRAY_SIZE(tegra194_main_pin_ranges),
 	.pin_ranges = tegra194_main_pin_ranges,
 	.pinmux = "nvidia,tegra194-pinmux",
+	.has_vm_support = true,
 };
 
 #define TEGRA194_AON_GPIO_PORT(_name, _bank, _port, _pins)	\
@@ -1065,6 +1138,7 @@ static const struct tegra_gpio_soc tegra194_aon_soc = {
 	.instance = 1,
 	.num_irqs_per_bank = 8,
 	.has_gte = true,
+	.has_vm_support = false,
 };
 
 #define TEGRA234_MAIN_GPIO_PORT(_name, _bank, _port, _pins)	\
@@ -1109,6 +1183,7 @@ static const struct tegra_gpio_soc tegra234_main_soc = {
 	.name = "tegra234-gpio",
 	.instance = 0,
 	.num_irqs_per_bank = 8,
+	.has_vm_support = true,
 };
 
 #define TEGRA234_AON_GPIO_PORT(_name, _bank, _port, _pins)	\
@@ -1135,6 +1210,7 @@ static const struct tegra_gpio_soc tegra234_aon_soc = {
 	.instance = 1,
 	.num_irqs_per_bank = 8,
 	.has_gte = true,
+	.has_vm_support = false,
 };
 
 #define TEGRA241_MAIN_GPIO_PORT(_name, _bank, _port, _pins)	\
@@ -1165,6 +1241,7 @@ static const struct tegra_gpio_soc tegra241_main_soc = {
 	.name = "tegra241-gpio",
 	.instance = 0,
 	.num_irqs_per_bank = 8,
+	.has_vm_support = false,
 };
 
 #define TEGRA241_AON_GPIO_PORT(_name, _bank, _port, _pins)	\
@@ -1186,6 +1263,7 @@ static const struct tegra_gpio_soc tegra241_aon_soc = {
 	.name = "tegra241-gpio-aon",
 	.instance = 1,
 	.num_irqs_per_bank = 8,
+	.has_vm_support = false,
 };
 
 static const struct of_device_id tegra186_gpio_of_match[] = {