gpio: tegra186: Support multiple interrupts per bank

Tegra194 and later support more than a single interrupt per bank. This
is primarily useful for virtualization but can also be helpful for more
fine-grained CPU affinity control. To keep things simple for now, route
all pins to the first interrupt.

For backwards-compatibility, support old device trees that specify only
one interrupt per bank by counting the interrupts at probe time.

Signed-off-by: Thierry Reding <treding@nvidia.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Bartosz Golaszewski <brgl@bgdev.pl>

diff --git a/drivers/gpio/gpio-tegra186.c b/drivers/gpio/gpio-tegra186.c
index 1bc4152e0275caf28a07368186af45333b0dcca6..c026e7141e4ea570996b5d2d2c9ac6b5d7d1c15e 100644 (file)
--- a/drivers/gpio/gpio-tegra186.c
+++ b/drivers/gpio/gpio-tegra186.c
@@ -69,6 +69,8 @@ struct tegra_gpio_soc {
        const char *name;
        unsigned int instance;
 
+       unsigned int num_irqs_per_bank;
+
        const struct tegra186_pin_range *pin_ranges;
        unsigned int num_pin_ranges;
        const char *pinmux;
@@ -452,7 +454,7 @@ static void tegra186_gpio_irq(struct irq_desc *desc)
        struct irq_domain *domain = gpio->gpio.irq.domain;
        struct irq_chip *chip = irq_desc_get_chip(desc);
        unsigned int parent = irq_desc_get_irq(desc);
-       unsigned int i, offset = 0;
+       unsigned int i, j, offset = 0;
 
        chained_irq_enter(chip, desc);
 
@@ -465,7 +467,12 @@ static void tegra186_gpio_irq(struct irq_desc *desc)
                base = gpio->base + port->bank * 0x1000 + port->port * 0x200;
 
                /* skip ports that are not associated with this bank */
-               if (parent != gpio->irq[port->bank])
+               for (j = 0; j < gpio->num_irqs_per_bank; j++) {
+                       if (parent == gpio->irq[port->bank * gpio->num_irqs_per_bank + j])
+                               break;
+               }
+
+               if (j == gpio->num_irqs_per_bank)
                        goto skip;
 
                value = readl(base + TEGRA186_GPIO_INTERRUPT_STATUS(1));
@@ -567,6 +574,7 @@ static const struct of_device_id tegra186_pmc_of_match[] = {
 
 static void tegra186_gpio_init_route_mapping(struct tegra_gpio *gpio)
 {
+       struct device *dev = gpio->gpio.parent;
        unsigned int i, j;
        u32 value;
 
@@ -585,12 +593,30 @@ static void tegra186_gpio_init_route_mapping(struct tegra_gpio *gpio)
                 */
                if ((value & TEGRA186_GPIO_CTL_SCR_SEC_REN) == 0 &&
                    (value & TEGRA186_GPIO_CTL_SCR_SEC_WEN) == 0) {
-                       for (j = 0; j < 8; j++) {
+                       /*
+                        * On Tegra194 and later, each pin can be routed to one or more
+                        * interrupts.
+                        */
+                       for (j = 0; j < gpio->num_irqs_per_bank; j++) {
+                               dev_dbg(dev, "programming default interrupt routing for port %s\n",
+                                       port->name);
+
                                offset = TEGRA186_GPIO_INT_ROUTE_MAPPING(p, j);
 
-                               value = readl(base + offset);
-                               value = BIT(port->pins) - 1;
-                               writel(value, base + offset);
+                               /*
+                                * By default we only want to route GPIO pins to IRQ 0. This works
+                                * only under the assumption that we're running as the host kernel
+                                * and hence all GPIO pins are owned by Linux.
+                                *
+                                * For cases where Linux is the guest OS, the hypervisor will have
+                                * to configure the interrupt routing and pass only the valid
+                                * interrupts via device tree.
+                                */
+                               if (j == 0) {
+                                       value = readl(base + offset);
+                                       value = BIT(port->pins) - 1;
+                                       writel(value, base + offset);
+                               }
                        }
                }
        }
@@ -610,6 +636,9 @@ static unsigned int tegra186_gpio_irqs_per_bank(struct tegra_gpio *gpio)
 
        gpio->num_irqs_per_bank = gpio->num_irq / gpio->num_banks;
 
+       if (gpio->num_irqs_per_bank > gpio->soc->num_irqs_per_bank)
+               goto error;
+
        return 0;
 
 error:
@@ -766,7 +795,8 @@ static int tegra186_gpio_probe(struct platform_device *pdev)
                irq->parents = gpio->irq;
        }
 
-       tegra186_gpio_init_route_mapping(gpio);
+       if (gpio->soc->num_irqs_per_bank > 1)
+               tegra186_gpio_init_route_mapping(gpio);
 
        np = of_find_matching_node(NULL, tegra186_pmc_of_match);
        if (np) {
@@ -833,6 +863,7 @@ static const struct tegra_gpio_soc tegra186_main_soc = {
        .ports = tegra186_main_ports,
        .name = "tegra186-gpio",
        .instance = 0,
+       .num_irqs_per_bank = 1,
 };
 
 #define TEGRA186_AON_GPIO_PORT(_name, _bank, _port, _pins)     \
@@ -859,6 +890,7 @@ static const struct tegra_gpio_soc tegra186_aon_soc = {
        .ports = tegra186_aon_ports,
        .name = "tegra186-gpio-aon",
        .instance = 1,
+       .num_irqs_per_bank = 1,
 };
 
 #define TEGRA194_MAIN_GPIO_PORT(_name, _bank, _port, _pins)    \
@@ -910,6 +942,7 @@ static const struct tegra_gpio_soc tegra194_main_soc = {
        .ports = tegra194_main_ports,
        .name = "tegra194-gpio",
        .instance = 0,
+       .num_irqs_per_bank = 8,
        .num_pin_ranges = ARRAY_SIZE(tegra194_main_pin_ranges),
        .pin_ranges = tegra194_main_pin_ranges,
        .pinmux = "nvidia,tegra194-pinmux",
@@ -936,6 +969,7 @@ static const struct tegra_gpio_soc tegra194_aon_soc = {
        .ports = tegra194_aon_ports,
        .name = "tegra194-gpio-aon",
        .instance = 1,
+       .num_irqs_per_bank = 8,
 };
 
 static const struct of_device_id tegra186_gpio_of_match[] = {