soc/intel/alderlake: provide a list of D-states to enter LPM

Implement sub-function 1 (Get Device Constraints)
of the Low Power S0 Idle Device-Specific Method (_DSM).
This provides a way in which to describe various devices required
D-states to enter LPM (S0ix).  The information can be used to help
in diagnostics and understanding of S0ix entry failure.

Values were derived from Intel document 595644 (rev 0.45) and
the ADL FSP sample ASL.

This implementation adds support for ADL.  Other SoC's could be
ported to be included as well.  If they aren't, they will default
to the existing behavior of a single hardcoded device to ensure
compatibility with Windows.

TEST=Built and tested on brya by verifying SSDT contents

Change-Id: Ibe46a0583c522a8adf0a015cd3a698f694482437
Signed-off-by: Tarun Tuli <taruntuli@google.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/63969
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Tim Wawrzynczak <twawrzynczak@chromium.org>
Reviewed-by: Lance Zhao

2 files changed, 175 insertions, 2 deletions

diff --git a/src/soc/intel/alderlake/acpi.c b/src/soc/intel/alderlake/acpi.c
index 159553465a..b6c5699d78 100644
--- a/src/soc/intel/alderlake/acpi.c
+++ b/src/soc/intel/alderlake/acpi.c
@@ -18,8 +18,16 @@
 #include <soc/pm.h>
 #include <soc/soc_chip.h>
 #include <soc/systemagent.h>
+#include <cpu/cpu.h>
 #include <types.h>
 
+
+#define DEFAULT_CPU_D_STATE	D0
+#define LPI_STATES_ALL		0xff
+#define LPI_REVISION		0
+#define LPI_ENABLED		1
+
+
 /*
  * List of supported C-states in this processor.
  */
@@ -110,6 +118,14 @@ static int cstate_set_s0ix[] = {
 	C_STATE_C10
 };
 
+enum dev_sleep_states {
+	D0,  /* 0 */
+	D1,  /* 1 */
+	D2,  /* 2 */
+	D3,  /* 3 */
+	NONE
+};
+
 const acpi_cstate_t *soc_get_cstate_map(size_t *entries)
 {
 	static acpi_cstate_t map[MAX(ARRAY_SIZE(cstate_set_s0ix),
@@ -164,6 +180,162 @@ void soc_fill_fadt(acpi_fadt_t *fadt)
 		fadt->flags |= ACPI_FADT_LOW_PWR_IDLE_S0;
 }
 
+static const struct {
+	uint8_t pci_dev;
+	enum dev_sleep_states min_sleep_state;
+} min_pci_sleep_states[] = {
+	{ SA_DEVFN_ROOT,	D3 },
+	{ SA_DEVFN_CPU_PCIE1_0,	D3 },
+	{ SA_DEVFN_IGD,		D3 },
+	{ SA_DEVFN_DPTF,	D3 },
+	{ SA_DEVFN_IPU,		D3 },
+	{ SA_DEVFN_CPU_PCIE6_0,	D3 },
+	{ SA_DEVFN_CPU_PCIE6_2,	D3 },
+	{ SA_DEVFN_TBT0,	D3 },
+	{ SA_DEVFN_TBT1,	D3 },
+	{ SA_DEVFN_TBT2,	D3 },
+	{ SA_DEVFN_TBT3,	D3 },
+	{ SA_DEVFN_GNA,		D3 },
+	{ SA_DEVFN_TCSS_XHCI,	D3 },
+	{ SA_DEVFN_TCSS_XDCI,	D3 },
+	{ SA_DEVFN_TCSS_DMA0,	D3 },
+	{ SA_DEVFN_TCSS_DMA1,	D3 },
+	{ SA_DEVFN_VMD,		D3 },
+	{ PCH_DEVFN_I2C6,	D3 },
+	{ PCH_DEVFN_I2C7,	D3 },
+	{ PCH_DEVFN_THC0,	D3 },
+	{ PCH_DEVFN_THC1,	D3 },
+	{ PCH_DEVFN_XHCI,	D3 },
+	{ PCH_DEVFN_USBOTG,	D3 },
+	{ PCH_DEVFN_SRAM,	D3 },
+	{ PCH_DEVFN_CNVI_WIFI,	D3 },
+	{ PCH_DEVFN_I2C0,	D3 },
+	{ PCH_DEVFN_I2C1,	D3 },
+	{ PCH_DEVFN_I2C2,	D3 },
+	{ PCH_DEVFN_I2C3,	D3 },
+	{ PCH_DEVFN_CSE,	D0 },
+	{ PCH_DEVFN_SATA,	D3 },
+	{ PCH_DEVFN_I2C4,	D3 },
+	{ PCH_DEVFN_I2C5,	D3 },
+	{ PCH_DEVFN_UART2,	D3 },
+	{ PCH_DEVFN_PCIE1,	D0 },
+	{ PCH_DEVFN_PCIE2,	D0 },
+	{ PCH_DEVFN_PCIE3,	D0 },
+	{ PCH_DEVFN_PCIE4,	D0 },
+	{ PCH_DEVFN_PCIE5,	D0 },
+	{ PCH_DEVFN_PCIE6,	D0 },
+	{ PCH_DEVFN_PCIE7,	D0 },
+	{ PCH_DEVFN_PCIE8,	D0 },
+	{ PCH_DEVFN_PCIE9,	D0 },
+	{ PCH_DEVFN_PCIE10,	D0 },
+	{ PCH_DEVFN_PCIE11,	D0 },
+	{ PCH_DEVFN_PCIE12,	D0 },
+	{ PCH_DEVFN_UART0,	D3 },
+	{ PCH_DEVFN_UART1,	D3 },
+	{ PCH_DEVFN_GSPI0,	D3 },
+	{ PCH_DEVFN_GSPI1,	D3 },
+	{ PCH_DEVFN_ESPI,	D0 },
+	{ PCH_DEVFN_PMC,	D0 },
+	{ PCH_DEVFN_HDA,	D0 },
+	{ PCH_DEVFN_SPI,	D3 },
+	{ PCH_DEVFN_GBE,	D3 },
+};
+
+static enum dev_sleep_states get_min_sleep_state(const struct device *dev)
+{
+	if (!is_dev_enabled(dev))
+		return NONE;
+
+	switch (dev->path.type) {
+	case DEVICE_PATH_APIC:
+		return DEFAULT_CPU_D_STATE;
+
+	case DEVICE_PATH_PCI:
+		for (size_t i = 0; i < ARRAY_SIZE(min_pci_sleep_states); i++)
+			if (min_pci_sleep_states[i].pci_dev == dev->path.pci.devfn)
+				return min_pci_sleep_states[i].min_sleep_state;
+		printk(BIOS_WARNING, "Unknown min d_state for %x\n", dev->path.pci.devfn);
+		return NONE;
+
+	default:
+		return NONE;
+	}
+}
+
+/* Generate the LPI constraint table and return the number of devices included */
+void soc_lpi_get_constraints(void *unused)
+{
+	unsigned int num_entries;
+	const struct device *dev;
+	enum dev_sleep_states min_sleep_state;
+
+	num_entries = 0;
+
+	for (dev = all_devices; dev; dev = dev->next) {
+		if (get_min_sleep_state(dev) != NONE)
+			num_entries++;
+	}
+
+	acpigen_emit_byte(RETURN_OP);
+	acpigen_write_package(num_entries);
+
+	for (dev = all_devices; dev; dev = dev->next) {
+		min_sleep_state = get_min_sleep_state(dev);
+		if (min_sleep_state == NONE)
+			continue;
+
+		acpigen_write_package(3);
+		{
+			/* Emit the device path */
+			switch (dev->path.type) {
+			case DEVICE_PATH_PCI:
+				acpigen_emit_namestring(acpi_device_path(dev));
+				break;
+
+			case DEVICE_PATH_APIC:
+				char path[32];
+
+				/* Lookup CPU id */
+				for (size_t i = 0; i < CONFIG_MAX_CPUS; i++) {
+					if (cpu_get_apic_id(i) == dev->path.apic.apic_id) {
+						snprintf(path, sizeof(path),
+							CONFIG_ACPI_CPU_STRING, i);
+						break;
+					}
+				}
+
+				acpigen_emit_namestring(path);
+				break;
+
+			default:
+				/* Unhandled */
+				printk(BIOS_WARNING,
+					"Unhandled device path type %d\n", dev->path.type);
+				acpigen_emit_namestring(NULL);
+				break;
+			}
+
+			acpigen_write_integer(LPI_ENABLED);
+			acpigen_write_package(2);
+			{
+				acpigen_write_integer(LPI_REVISION);
+				acpigen_write_package(2);	/* no optional device info */
+				{
+					/* Assume constraints apply to all entries */
+					acpigen_write_integer(LPI_STATES_ALL);
+					acpigen_write_integer(min_sleep_state); /* min D-state */
+				}
+				acpigen_write_package_end();
+			}
+			acpigen_write_package_end();
+		}
+		acpigen_write_package_end();
+	}
+
+	acpigen_write_package_end();
+	printk(BIOS_INFO, "Returning SoC specific constraint package for %d devices\n", num_entries);
+}
+
 uint32_t soc_read_sci_irq_select(void)
 {
 	return read32p(soc_read_pmc_base() + IRQ_REG);
diff --git a/src/soc/intel/common/block/acpi/pep.c b/src/soc/intel/common/block/acpi/pep.c
index 8028b8147c..21e3d35753 100644
--- a/src/soc/intel/common/block/acpi/pep.c
+++ b/src/soc/intel/common/block/acpi/pep.c
@@ -77,9 +77,10 @@ static void read_pmc_lpm_requirements(const struct soc_pmc_lpm *lpm,
  * device, one that is known to exist, i.e.  ACPI_CPU_STRING.  expects at least
  * one device and crashes without it with a bluescreen.
  */
-static void lpi_get_constraints(void *unused)
+__weak void soc_lpi_get_constraints(void *unused)
 {
 	char path[16];
+	printk(BIOS_INFO, "Returning default LPI constraint package\n");
 
 	/*
 	 * Return (Package() {
@@ -183,7 +184,7 @@ static void lpi_display_off(void *unused)
 
 static void (*lpi_s0_helpers[])(void *) = {
 	NULL,			/* enumerate functions (autogenerated) */
-	lpi_get_constraints,	/* get device constraints */
+	soc_lpi_get_constraints,/* get device constraints */
 	NULL,			/* get crash dump device */
 	lpi_display_off,	/* display off notify */
 	lpi_display_on,		/* display on notify */