lib: utils/gpio: Add minimal SiFive GPIO driver

We add a minimal SiFive GPIO driver so that we can do GPIO based
system power-off and reset.

Signed-off-by: Green Wan <green.wan@sifive.com>
Signed-off-by: Anup Patel <anup.patel@wdc.com>
Reviewed-by: Atish Patra <atish.patra@wdc.com>

diff --git a/lib/utils/gpio/fdt_gpio.c b/lib/utils/gpio/fdt_gpio.c
index bff391f..297b248 100644 (file)
--- a/lib/utils/gpio/fdt_gpio.c
+++ b/lib/utils/gpio/fdt_gpio.c
@@ -12,7 +12,10 @@
 #include <sbi_utils/fdt/fdt_helper.h>
 #include <sbi_utils/gpio/fdt_gpio.h>
 
+extern struct fdt_gpio fdt_gpio_sifive;
+
 static struct fdt_gpio *gpio_drivers[] = {
+       &fdt_gpio_sifive
 };
 
 static struct fdt_gpio *fdt_gpio_driver(struct gpio_chip *chip)

diff --git a/lib/utils/gpio/fdt_gpio_sifive.c b/lib/utils/gpio/fdt_gpio_sifive.c
new file mode 100644 (file)
index 0000000..abc9d72
--- /dev/null
+++ b/lib/utils/gpio/fdt_gpio_sifive.c
@@ -0,0 +1,105 @@
+/*
+ * SPDX-License-Identifier: BSD-2-Clause
+ *
+ * Copyright (c) 2021 SiFive
+ *
+ * Authors:
+ *   Green Wan <green.wan@sifive.com>
+ */
+
+#include <sbi/riscv_io.h>
+#include <sbi/sbi_error.h>
+#include <sbi_utils/fdt/fdt_helper.h>
+#include <sbi_utils/gpio/fdt_gpio.h>
+
+#define SIFIVE_GPIO_CHIP_MAX   2
+
+#define SIFIVE_GPIO_PINS_MIN   1
+#define SIFIVE_GPIO_PINS_MAX   32
+#define SIFIVE_GPIO_PINS_DEF   16
+
+#define SIFIVE_GPIO_OUTEN      0x8
+#define SIFIVE_GPIO_OUTVAL     0xc
+#define SIFIVE_GPIO_BIT(b)     (1U << (b))
+
+struct sifive_gpio_chip {
+       unsigned long addr;
+       struct gpio_chip chip;
+};
+
+static unsigned int sifive_gpio_chip_count;
+static struct sifive_gpio_chip sifive_gpio_chip_array[SIFIVE_GPIO_CHIP_MAX];
+
+static int sifive_gpio_direction_output(struct gpio_pin *gp, int value)
+{
+       unsigned int v;
+       struct sifive_gpio_chip *chip =
+               container_of(gp->chip, struct sifive_gpio_chip, chip);
+
+       v = readl((volatile void *)(chip->addr + SIFIVE_GPIO_OUTEN));
+       v |= SIFIVE_GPIO_BIT(gp->offset);
+       writel(v, (volatile void *)(chip->addr + SIFIVE_GPIO_OUTEN));
+
+       v = readl((volatile void *)(chip->addr + SIFIVE_GPIO_OUTVAL));
+       if (!value)
+               v &= ~SIFIVE_GPIO_BIT(gp->offset);
+       else
+               v |= SIFIVE_GPIO_BIT(gp->offset);
+       writel(v, (volatile void *)(chip->addr + SIFIVE_GPIO_OUTVAL));
+
+       return 0;
+}
+
+static void sifive_gpio_set(struct gpio_pin *gp, int value)
+{
+       unsigned int v;
+       struct sifive_gpio_chip *chip =
+               container_of(gp->chip, struct sifive_gpio_chip, chip);
+
+       v = readl((volatile void *)(chip->addr + SIFIVE_GPIO_OUTVAL));
+       if (!value)
+               v &= ~SIFIVE_GPIO_BIT(gp->offset);
+       else
+               v |= SIFIVE_GPIO_BIT(gp->offset);
+       writel(v, (volatile void *)(chip->addr + SIFIVE_GPIO_OUTVAL));
+}
+
+extern struct fdt_gpio fdt_gpio_sifive;
+
+static int sifive_gpio_init(void *fdt, int nodeoff, u32 phandle,
+                           const struct fdt_match *match)
+{
+       int rc;
+       struct sifive_gpio_chip *chip;
+
+       if (SIFIVE_GPIO_CHIP_MAX <= sifive_gpio_chip_count)
+               return SBI_ENOSPC;
+       chip = &sifive_gpio_chip_array[sifive_gpio_chip_count];
+
+       rc = fdt_get_node_addr_size(fdt, nodeoff, &chip->addr, NULL);
+       if (rc)
+               return rc;
+
+       chip->chip.driver = &fdt_gpio_sifive;
+       chip->chip.id = phandle;
+       chip->chip.ngpio = SIFIVE_GPIO_PINS_DEF;
+       chip->chip.direction_output = sifive_gpio_direction_output;
+       chip->chip.set = sifive_gpio_set;
+       rc = gpio_chip_add(&chip->chip);
+       if (rc)
+               return rc;
+
+       sifive_gpio_chip_count++;
+       return 0;
+}
+
+static const struct fdt_match sifive_gpio_match[] = {
+       { .compatible = "sifive,gpio0" },
+       { },
+};
+
+struct fdt_gpio fdt_gpio_sifive = {
+       .match_table = sifive_gpio_match,
+       .xlate = fdt_gpio_simple_xlate,
+       .init = sifive_gpio_init,
+};

diff --git a/lib/utils/gpio/objects.mk b/lib/utils/gpio/objects.mk
index dade45e..8eb7736 100644 (file)
--- a/lib/utils/gpio/objects.mk
+++ b/lib/utils/gpio/objects.mk
@@ -8,4 +8,5 @@
 #
 
 libsbiutils-objs-y += gpio/fdt_gpio.o
+libsbiutils-objs-y += gpio/fdt_gpio_sifive.o
 libsbiutils-objs-y += gpio/gpio.o