soc/amd/common: add gpio subsystem event reporting

In order to log gpio events for wake purposes the state
of the gpio subsystem should be snapshotted. Add the ability
to capture state of gpio subystem as well as saving up to 16
gpios that indicate their wake status.

Likewise, provide the eventlog additions based on state.

BUG=b:159947207

Signed-off-by: Aaron Durbin <adurbin@chromium.org>
Change-Id: I49fca56c87543aa8aad0eb7da5c5cb570c4349d5
Reviewed-on: https://review.coreboot.org/c/coreboot/+/44534
Reviewed-by: Furquan Shaikh <furquan@google.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

src/soc/amd/common/block/gpio_banks/gpio.c

@@ -3,12 +3,14 @@
 #include <device/mmio.h>
 #include <device/device.h>
 #include <console/console.h>
+#include <elog.h>
 #include <gpio.h>
 #include <amdblocks/acpimmio.h>
 #include <amdblocks/gpio_banks.h>
 #include <soc/gpio.h>
 #include <soc/smi.h>
 #include <assert.h>
+#include <string.h>
 
 static int get_gpio_gevent(uint8_t gpio, const struct soc_amd_event *table,
 				size_t items)
@@ -298,3 +300,72 @@ void gpio_configure_pads_with_override(const struct soc_amd_gpio *base_cfg,
 		program_gpios(c, 1);
 	}
 }
+
+static void check_and_add_wake_gpio(int begin, int end, struct gpio_wake_state *state)
+{
+	int i;
+	uint32_t reg;
+
+	for (i = begin; i < end; i++) {
+		reg = gpio_read32(i);
+		if (!(reg & GPIO_WAKE_STATUS))
+			continue;
+		printk(BIOS_INFO, "GPIO %d woke system.\n", i);
+		if (state->num_valid_wake_gpios >= ARRAY_SIZE(state->wake_gpios))
+			continue;
+		state->wake_gpios[state->num_valid_wake_gpios++] = i;
+	}
+}
+
+static void check_gpios(uint32_t wake_stat, int bit_limit, int gpio_base,
+			struct gpio_wake_state *state)
+{
+	int i;
+	int begin;
+	int end;
+
+	for (i = 0; i < bit_limit; i++) {
+		if (!(wake_stat & BIT(i)))
+			continue;
+		begin = gpio_base + i * 4;
+		end = begin + 4;
+		/* There is no gpio 63. */
+		if (begin == 60)
+			end = 63;
+		check_and_add_wake_gpio(begin, end, state);
+	}
+}
+
+void gpio_fill_wake_state(struct gpio_wake_state *state)
+{
+	/* Turn the wake registers into "gpio" index to conform to existing API. */
+	const uint8_t stat0 = GPIO_WAKE_STAT_0 / sizeof(uint32_t);
+	const uint8_t stat1 = GPIO_WAKE_STAT_1 / sizeof(uint32_t);
+	const uint8_t control_switch = GPIO_MASTER_SWITCH / sizeof(uint32_t);
+
+	/* Register fields and gpio availability need to be confirmed on other chipsets. */
+	if (!CONFIG(SOC_AMD_PICASSO))
+		dead_code();
+
+	memset(state, 0, sizeof(*state));
+
+	state->control_switch = gpio_read32(control_switch);
+	state->wake_stat[0] = gpio_read32(stat0);
+	state->wake_stat[1] = gpio_read32(stat1);
+
+	printk(BIOS_INFO, "GPIO Control Switch: 0x%08x, Wake Stat 0: 0x%08x, Wake Stat 1: 0x%08x\n",
+		state->control_switch, state->wake_stat[0], state->wake_stat[1]);
+
+	check_gpios(state->wake_stat[0], 32, 0, state);
+	check_gpios(state->wake_stat[1], 14, 128, state);
+}
+
+void gpio_add_events(const struct gpio_wake_state *state)
+{
+	int i;
+	int end;
+
+	end = MIN(state->num_valid_wake_gpios, ARRAY_SIZE(state->wake_gpios));
+	for (i = 0; i < end; i++)
+		elog_add_event_wake(ELOG_WAKE_SOURCE_GPIO, state->wake_gpios[i]);
+}

src/soc/amd/common/block/include/amdblocks/gpio_banks.h

@@ -20,6 +20,23 @@ struct soc_amd_event {
 #define GPIO_MASTER_SWITCH	0xFC
 #define   GPIO_MASK_STS_EN	BIT(28)
 #define   GPIO_INTERRUPT_EN	BIT(30)
+#define   GPIO_WAKE_EN		BIT(31)
+
+#define GPIO_WAKE_STAT_0	0x2F0
+#define GPIO_WAKE_STAT_1	0x2F4
+struct gpio_wake_state {
+	uint32_t control_switch;
+	uint32_t wake_stat[2];
+	/* Number of wake_gpio with a valid setting. */
+	uint32_t num_valid_wake_gpios;
+	/* GPIO index number that caused a wake. */
+	uint8_t wake_gpios[16];
+};
+
+/* Fill gpio_wake_state object for future event reporting. */
+void gpio_fill_wake_state(struct gpio_wake_state *state);
+/* Add gpio events to the eventlog. */
+void gpio_add_events(const struct gpio_wake_state *state);
 
 #define GPIO_PIN_IN		(1 << 0)	/* for byte access */
 #define GPIO_PIN_OUT		(1 << 6)	/* for byte access */