soc/intel/cannonlake: Add PchPmPwrCycDur to chip options

Add PchPmPwrCycDur to chip options to control the UPD FSPS PchPmPwrCycDur
from devicetree. The UPD determines the minimum time a platform will stay
in reset during host partition reset with power cycle or global reset.
This patch also ensures configured PchPmPwrCycDur value doesn't violate
the PCH EDS specification.

TEST=Verified on Hatch and Puff boards

Signed-off-by: Sridhar Siricilla <sridhar.siricilla@intel.com>
Change-Id: I55e836c78fab34e34d57b04428a1498b7dc7174b
Reviewed-on: https://review.coreboot.org/c/coreboot/+/42440
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Edward O'Callaghan <quasisec@chromium.org>

src/soc/intel/cannonlake/chip.h

@@ -314,6 +314,23 @@ struct soc_intel_cannonlake_config {
 	 */
 	uint8_t PchPmSlpAMinAssert;
 
+	/*
+	 * PCH PM Reset Power Cycle Duration
+	 *  0 = 4s
+	 *  1 = 1s
+	 *  2 = 2s
+	 *  3 = 3s
+	 *  4 = 4s (default)
+	 *
+	 * NOTE: Duration programmed in the PchPmPwrCycDur should never be smaller than the
+	 * stretch duration programmed in the following registers -
+	 *  - GEN_PMCON_A.SLP_S3_MIN_ASST_WDTH (PchPmSlpS3MinAssert)
+	 *  - GEN_PMCON_A.S4MAW (PchPmSlpS4MinAssert)
+	 *  - PM_CFG.SLP_A_MIN_ASST_WDTH (PchPmSlpAMinAssert)
+	 *  - PM_CFG.SLP_LAN_MIN_ASST_WDTH
+	 */
+	uint8_t PchPmPwrCycDur;
+
 	/*
 	 * SerialIO device mode selection:
 	 *

src/soc/intel/cannonlake/fsp_params.c

@@ -32,6 +32,39 @@ static const pci_devfn_t serial_io_dev[] = {
 	PCH_DEVFN_UART2
 };
 
+/* List of Minimum Assertion durations in microseconds */
+enum min_assrt_dur {
+	MinAssrtDur0s		= 0,
+	MinAssrtDur60us		= 60,
+	MinAssrtDur1ms		= 1000,
+	MinAssrtDur50ms		= 50000,
+	MinAssrtDur98ms		= 98000,
+	MinAssrtDur500ms	= 500000,
+	MinAssrtDur1s		= 1000000,
+	MinAssrtDur2s		= 2000000,
+	MinAssrtDur3s		= 3000000,
+	MinAssrtDur4s		= 4000000,
+};
+
+
+/* Signal Assertion duration values */
+struct cfg_assrt_dur {
+	/* Minimum assertion duration of SLP_A signal */
+	enum min_assrt_dur slp_a;
+
+	/* Minimum assertion duration of SLP_4 signal */
+	enum min_assrt_dur slp_s4;
+
+	/* Minimum assertion duration of SLP_3 signal */
+	enum min_assrt_dur slp_s3;
+
+	/* PCH PM Power Cycle duration */
+	enum min_assrt_dur pm_pwr_cyc_dur;
+};
+
+/* Default value of PchPmPwrCycDur */
+#define PCH_PM_PWR_CYC_DUR	4
+
 /*
  * Given an enum for PCH_SERIAL_IO_MODE, 1 needs to be subtracted to get the FSP
  * UPD expected value for Serial IO since valid enum index starts from 1.
@@ -57,6 +90,93 @@ static uint8_t get_param_value(const config_t *config, uint32_t dev_offset)
 }
 
 #if CONFIG(SOC_INTEL_COMETLAKE)
+static enum min_assrt_dur get_high_asst_width(const struct cfg_assrt_dur *cfg_assrt_dur)
+{
+	enum min_assrt_dur max_assert_dur = cfg_assrt_dur->slp_s4;
+
+	if (max_assert_dur < cfg_assrt_dur->slp_s3)
+		max_assert_dur = cfg_assrt_dur->slp_s3;
+
+	if (max_assert_dur < cfg_assrt_dur->slp_a)
+		max_assert_dur = cfg_assrt_dur->slp_a;
+
+	return max_assert_dur;
+}
+
+static void get_min_assrt_dur(uint8_t slp_s4_min_asst, uint8_t slp_s3_min_asst,
+		uint8_t slp_a_min_asst, uint8_t pm_pwr_cyc_dur,
+		struct cfg_assrt_dur *cfg_assrt_dur)
+{
+	/*
+	 * Ensure slp_x_dur_list[] elements are in sync with devicetree config to FSP encoded
+	 * values.
+	 * slp_s4_asst_dur_list : 1s, 1s, 2s, 3s, 4s(Default)
+	 */
+	const enum min_assrt_dur slp_s4_asst_dur_list[] = {
+		MinAssrtDur1s, MinAssrtDur1s, MinAssrtDur2s, MinAssrtDur3s, MinAssrtDur4s
+	};
+
+	/* slp_s3_asst_dur_list: 50ms, 60us, 50ms (Default), 2s */
+	const enum min_assrt_dur slp_s3_asst_dur_list[] = {
+		MinAssrtDur50ms, MinAssrtDur60us, MinAssrtDur50ms, MinAssrtDur2s
+	};
+
+	/* slp_a_asst_dur_list: 2s, 0s, 4s, 98ms, 2s(Default) */
+	const enum min_assrt_dur slp_a_asst_dur_list[] = {
+		MinAssrtDur2s, MinAssrtDur0s, MinAssrtDur4s, MinAssrtDur98ms, MinAssrtDur2s
+	};
+
+	/* pm_pwr_cyc_dur_list: 4s(Default), 1s, 2s, 3s, 4s */
+	const enum min_assrt_dur pm_pwr_cyc_dur_list[] = {
+		MinAssrtDur4s, MinAssrtDur1s, MinAssrtDur2s, MinAssrtDur3s, MinAssrtDur4s
+	};
+
+	/* Get signal assertion width */
+	if (slp_s4_min_asst < ARRAY_SIZE(slp_s4_asst_dur_list))
+		cfg_assrt_dur->slp_s4 = slp_s4_asst_dur_list[slp_s4_min_asst];
+
+	if (slp_s3_min_asst < ARRAY_SIZE(slp_s3_asst_dur_list))
+		cfg_assrt_dur->slp_s3 = slp_s3_asst_dur_list[slp_s3_min_asst];
+
+	if (slp_a_min_asst < ARRAY_SIZE(slp_a_asst_dur_list))
+		cfg_assrt_dur->slp_a = slp_a_asst_dur_list[slp_a_min_asst];
+
+	if (pm_pwr_cyc_dur < ARRAY_SIZE(pm_pwr_cyc_dur_list))
+		cfg_assrt_dur->pm_pwr_cyc_dur = pm_pwr_cyc_dur_list[pm_pwr_cyc_dur];
+}
+
+
+static uint8_t get_pm_pwr_cyc_dur(uint8_t slp_s4_min_asst, uint8_t slp_s3_min_asst,
+		uint8_t slp_a_min_asst, uint8_t pm_pwr_cyc_dur)
+{
+	/* Sets default minimum asserton duration values */
+	struct cfg_assrt_dur cfg_assrt_dur = {
+		.slp_a		= MinAssrtDur2s,
+		.slp_s4		= MinAssrtDur4s,
+		.slp_s3		= MinAssrtDur50ms,
+		.pm_pwr_cyc_dur	= MinAssrtDur4s
+	};
+
+	enum min_assrt_dur high_asst_width;
+
+	/* Convert assertion durations from register-encoded to microseconds */
+	get_min_assrt_dur(slp_s4_min_asst, slp_s3_min_asst, slp_a_min_asst, pm_pwr_cyc_dur,
+			&cfg_assrt_dur);
+
+	/* Get the higher assertion duration among PCH EDS specified signals for pwr_cyc_dur */
+	high_asst_width = get_high_asst_width(&cfg_assrt_dur);
+
+	if (cfg_assrt_dur.pm_pwr_cyc_dur >= high_asst_width)
+		return pm_pwr_cyc_dur;
+
+	printk(BIOS_DEBUG,
+			"Set PmPwrCycDur to 4s as configured PmPwrCycDur(%d) violates PCH EDS "
+			"spec\n", pm_pwr_cyc_dur);
+
+	return PCH_PM_PWR_CYC_DUR;
+}
+
+
 static void parse_devicetree_param(const config_t *config, FSP_S_CONFIG *params)
 {
 	uint32_t dev_offset = 0;
@@ -412,6 +532,13 @@ void platform_fsp_silicon_init_params_cb(FSPS_UPD *supd)
 	if (config->PchPmSlpAMinAssert)
 		params->PchPmSlpAMinAssert = config->PchPmSlpAMinAssert;
 
+#if CONFIG(SOC_INTEL_COMETLAKE)
+	if (config->PchPmPwrCycDur)
+		params->PchPmPwrCycDur = get_pm_pwr_cyc_dur(config->PchPmSlpS4MinAssert,
+				config->PchPmSlpS3MinAssert, config->PchPmSlpAMinAssert,
+				config->PchPmPwrCycDur);
+#endif
+
 	/* Set TccActivationOffset */
 	tconfig->TccActivationOffset = config->tcc_offset;