Patch set updated for coreboot: soc/intel/apollolake: add option for SLP_S3_L assertion width

[Aaron Durbin]

Aaron Durbin ([e-mail]) just uploaded a new patch set to gerrit, which you can find at https://review.coreboot.org/16326

-gerrit

commit 10d71eaa23289692c759e74f70ec490640e4e3b1
Author: Aaron Durbin 
Date:   Thu Aug 25 15:42:04 2016 -0500

soc/intel/apollolake: add option for SLP_S3_L assertion width

In order to provide time for the S0 rails to discharge one needs
    to be able to set the SLP_S3_L assertion width. The hardware default
    is 60 microcseconds which is not slow enough on most boards. Therefore
    provide a devicetree option for the mainboard to set accordingly
    for its needs. An unset value in devicetree results in a conservative
    2 second SLP_S3_L duration.

BUG=chrome-os-partner:56581

Change-Id: I6c6df2f7a181746708ab7897249ae82109c55f50
    Signed-off-by: Aaron Durbin 
---
 src/soc/intel/apollolake/chip.h           |  3 ++
 src/soc/intel/apollolake/include/soc/pm.h |  6 ++++
 src/soc/intel/apollolake/pmc.c            | 59 +++++++++++++++++++++++++++++++
 3 files changed, 68 insertions(+)

diff --git a/src/soc/intel/apollolake/chip.h b/src/soc/intel/apollolake/chip.h
index 16c3aeb..22217a4 100644
--- a/src/soc/intel/apollolake/chip.h
+++ b/src/soc/intel/apollolake/chip.h
@@ -106,6 +106,9 @@ struct soc_intel_apollolake_config {

/* Enable DPTF support */
    int dptf_enable;
+
+	/* SLP S3 minimum assertion width. */
+	int slp_s3_assertion_width_usecs;
 };

#endif	/* _SOC_APOLLOLAKE_CHIP_H_ */
diff --git a/src/soc/intel/apollolake/include/soc/pm.h b/src/soc/intel/apollolake/include/soc/pm.h
index 5641e54..f17ed54 100644
--- a/src/soc/intel/apollolake/include/soc/pm.h
+++ b/src/soc/intel/apollolake/include/soc/pm.h
@@ -129,6 +129,12 @@
 #define GEN_PMCON2		0x1024
 #       define RPS		(1 <<  2)
 #define GEN_PMCON3		0x1028
+#       define SLP_S3_ASSERT_WIDTH_SHIFT	10
+#       define SLP_S3_ASSERT_MASK	(0x3 << SLP_S3_ASSERT_WIDTH_SHIFT)
+#       define SLP_S3_ASSERT_60_USEC	0x0
+#       define SLP_S3_ASSERT_1_MSEC	0x1
+#       define SLP_S3_ASSERT_50_MSEC	0x2
+#       define SLP_S3_ASSERT_2_SEC	0x3
 #define ETR			0x1048
 #       define CF9_LOCK         (1 << 31)
 #       define CF9_GLB_RST      (1 << 20)
diff --git a/src/soc/intel/apollolake/pmc.c b/src/soc/intel/apollolake/pmc.c
index 92a150d..81505e2 100644
--- a/src/soc/intel/apollolake/pmc.c
+++ b/src/soc/intel/apollolake/pmc.c
@@ -25,6 +25,7 @@
 #include <soc/gpio.h>
 #include <soc/pci_devs.h>
 #include <soc/pm.h>
+#include <timer.h>
 #include "chip.h"

/*
@@ -132,11 +133,69 @@ static void pch_set_acpi_mode(void)
    }
 }

+static int choose_slp_s3_assertion_width(int width_usecs)
+{
+	int i;
+	static const struct {
+		int max_width;
+		int value;
+	} slp_s3_settings[] = {
+		{
+			.max_width = 60,
+			.value = SLP_S3_ASSERT_60_USEC,
+		},
+		{
+			.max_width = 1 * USECS_PER_MSEC,
+			.value = SLP_S3_ASSERT_1_MSEC,
+		},
+		{
+			.max_width = 50 * USECS_PER_MSEC,
+			.value = SLP_S3_ASSERT_50_MSEC,
+		},
+		{
+			.max_width =  2 * USECS_PER_SEC,
+			.value = SLP_S3_ASSERT_2_SEC,
+		},
+	};
+
+	for (i = 0; i < ARRAY_SIZE(slp_s3_settings); i++) {
+		if (width_usecs <= slp_s3_settings[i].max_width)
+			break;
+	}
+
+	/* Provide conservative default if nothing set in devicetree
+	 * or requested assertion width too large. */
+	if (width_usecs <= 0 || i == ARRAY_SIZE(slp_s3_settings))
+		i = ARRAY_SIZE(slp_s3_settings) - 1;
+
+	printk(BIOS_DEBUG, "SLP S3 assertion width: %d usecs\n",
+		slp_s3_settings[i].max_width);
+
+	return slp_s3_settings[i].value;
+}
+
+static void set_slp_s3_assertion_width(int width_usecs)
+{
+	uint32_t reg;
+	uintptr_t gen_pmcon3 = get_pmc_mmio_bar() + GEN_PMCON3;
+	int setting = choose_slp_s3_assertion_width(width_usecs);
+
+	reg = read32((void *)gen_pmcon3);
+	reg &= ~SLP_S3_ASSERT_MASK;
+	reg |= setting << SLP_S3_ASSERT_WIDTH_SHIFT;
+	write32((void *)gen_pmcon3, reg);
+}
+
 static void pmc_init(struct device *dev)
 {
+	const struct soc_intel_apollolake_config *cfg = dev->chip_info;
+
    /* Set up GPE configuration */
    pmc_gpe_init();
    pch_set_acpi_mode();
+
+	if (cfg != NULL)
+		set_slp_s3_assertion_width(cfg->slp_s3_assertion_width_usecs);
 }

static const struct device_operations device_ops = {