baytrail: add support for S3 resume

Previously the only path through memory init and coreboot was
hardcoding S5. Therefore all S3 paths would not be taken. Allow
for S3 resume to work by enabling the proper control paths in
romstage.

BUG=chrome-os-partner:22867
BRANCH=None
TEST=While in kernel 'echo mem > /sys/power/state'. Board went
     into S3. Power button press resumed back into kernel.

Change-Id: I3cbae73223f0d71c74eb3d6b7c25d1b32318ab3e
Signed-off-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/175940
Reviewed-by: Duncan Laurie <dlaurie@chromium.org>
Reviewed-on: http://review.coreboot.org/4943
Tested-by: build bot (Jenkins)
Reviewed-by: Kyösti Mälkki <kyosti.malkki@gmail.com>

3 files changed, 77 insertions, 6 deletions

diff --git a/src/soc/intel/baytrail/baytrail/pmc.h b/src/soc/intel/baytrail/baytrail/pmc.h
index 92edb6ef64..1a7588cc20 100644
--- a/src/soc/intel/baytrail/baytrail/pmc.h
+++ b/src/soc/intel/baytrail/baytrail/pmc.h
@@ -24,9 +24,11 @@
 #define IOCOM1		0x3f8
 
 /* Memory mapped IO registers behind PMC_BASE_ADDRESS */
-#define GEN_PMCONF1	0x20
+#define GEN_PMCON1	0x20
 #	define AFTERG3_EN	(1 <<  0)
 #	define UART_EN		(1 << 24)
+#	define PWR_FLR		(1 << 16)
+#	define SUS_PWR_FLR	(1 << 14)
 #define ETR			0x48
 #	define CF9LOCK		(1 << 31)
 #	define LTR_DEF		(1 << 22)
@@ -86,7 +88,8 @@
 #define   TMROF_EN	(1 << 0)
 #define PM1_CNT			0x04
 #define   SLP_EN	(1 << 13)
-#define   SLP_TYP	(7 << 10)
+#define   SLP_TYP_SHIFT	10
+#define   SLP_TYP	(7 << SLP_TYP_SHIFT)
 #define    SLP_TYP_S0	0
 #define    SLP_TYP_S1	1
 #define    SLP_TYP_S3	5
diff --git a/src/soc/intel/baytrail/romstage/raminit.c b/src/soc/intel/baytrail/romstage/raminit.c
index 98d389eb2c..017f37d3ef 100644
--- a/src/soc/intel/baytrail/romstage/raminit.c
+++ b/src/soc/intel/baytrail/romstage/raminit.c
@@ -18,7 +18,9 @@
  */
 
 #include <stddef.h>
+#include <arch/hlt.h>
 #include <arch/io.h>
+#include <bootmode.h>
 #include <cbfs.h>
 #include <cbmem.h>
 #include <console/console.h>
@@ -28,8 +30,14 @@
 #include <baytrail/iomap.h>
 #include <baytrail/iosf.h>
 #include <baytrail/pci_devs.h>
+#include <baytrail/reset.h>
 #include <baytrail/romstage.h>
 
+static void reset_system(void)
+{
+	warm_reset();
+	while(1) { hlt(); }
+}
 
 static void enable_smbus(void)
 {
@@ -111,9 +119,16 @@ void raminit(struct mrc_params *mp, int prev_sleep_state)
 	mp->console_out = &send_to_console;
 	mp->prev_sleep_state = prev_sleep_state;
 
-	if (!mrc_cache_get_current(&cache)) {
+	if (recovery_mode_enabled()) {
+		printk(BIOS_DEBUG, "Recovery mode: not using MRC cache.\n");
+	} else if (!mrc_cache_get_current(&cache)) {
 		mp->saved_data_size = cache->size;
 		mp->saved_data = &cache->data[0];
+	} else if (prev_sleep_state == 3) {
+		/* If waking from S3 and no cache then. */
+		printk(BIOS_DEBUG, "No MRC cache found in S3 resume path.\n");
+		post_code(POST_RESUME_FAILURE);
+		reset_system();
 	} else {
 		printk(BIOS_DEBUG, "No MRC cache found.\n");
 	}
@@ -132,7 +147,15 @@ void raminit(struct mrc_params *mp, int prev_sleep_state)
 
 	print_dram_info();
 
-	cbmem_initialize_empty();
+	if (prev_sleep_state != 3) {
+		cbmem_initialize_empty();
+	} else if (cbmem_initialize()) {
+	#if CONFIG_HAVE_ACPI_RESUME
+		printk(BIOS_DEBUG, "Failed to recover CBMEM in S3 resume.\n");
+		/* Failed S3 resume, reset to come up cleanly */
+		reset_system();
+	#endif
+	}
 
 	printk(BIOS_DEBUG, "MRC Wrapper returned %d\n", ret);
 	printk(BIOS_DEBUG, "MRC data at %p %d bytes\n", mp->data_to_save,
diff --git a/src/soc/intel/baytrail/romstage/romstage.c b/src/soc/intel/baytrail/romstage/romstage.c
index 5af9bf4566..969e8487f9 100644
--- a/src/soc/intel/baytrail/romstage/romstage.c
+++ b/src/soc/intel/baytrail/romstage/romstage.c
@@ -36,6 +36,7 @@
 #include <baytrail/iomap.h>
 #include <baytrail/lpc.h>
 #include <baytrail/pci_devs.h>
+#include <baytrail/pmc.h>
 #include <baytrail/reset.h>
 #include <baytrail/romstage.h>
 #include <baytrail/smm.h>
@@ -139,10 +140,50 @@ void * asmlinkage romstage_main(unsigned long bist,
 	return setup_stack_and_mttrs();
 }
 
+/* Return 0, 3, or 5 to indicate the previous sleep state. */
+static int chipset_prev_sleep_state(void)
+{
+	uint16_t pm1_sts;
+	uint32_t pm1_cnt;
+	uint32_t gen_pmcon1;
+	/* Default to S0. */
+	int prev_sleep_state = 0;
+
+	pm1_sts = inw(ACPI_BASE_ADDRESS + PM1_STS);
+	pm1_cnt = inl(ACPI_BASE_ADDRESS + PM1_CNT);
+
+	if (pm1_sts & WAK_STS) {
+		switch ((pm1_cnt & SLP_TYP) >> SLP_TYP_SHIFT) {
+	#if CONFIG_HAVE_ACPI_RESUME
+		case SLP_TYP_S3:
+			prev_sleep_state = 3;
+			break;
+	#endif
+		case SLP_TYP_S5:
+			prev_sleep_state = 5;
+		}
+		/* Clear SLP_TYP. */
+		outl(pm1_cnt & ~(SLP_TYP), ACPI_BASE_ADDRESS + PM1_CNT);
+	}
+
+	gen_pmcon1 = read32(PMC_BASE_ADDRESS + GEN_PMCON1);
+	if (gen_pmcon1 & (PWR_FLR | SUS_PWR_FLR)) {
+		/* Clear power failure bits. */
+		write32(PMC_BASE_ADDRESS + GEN_PMCON1, gen_pmcon1);
+		prev_sleep_state = 5;
+	}
+
+	printk(BIOS_DEBUG, "pm1_sts = %04x pm1_cnt = %08x gen_pmcon1 = %08x\n",
+	       pm1_sts, pm1_cnt, gen_pmcon1);
+
+	return prev_sleep_state;
+}
+
 /* Entry from the mainboard. */
 void romstage_common(struct romstage_params *params)
 {
 	struct romstage_handoff *handoff;
+	int prev_sleep_state;
 
 	mark_ts(params, timestamp_get());
 
@@ -150,14 +191,18 @@ void romstage_common(struct romstage_params *params)
 	boot_count_increment();
 #endif
 
+	prev_sleep_state = chipset_prev_sleep_state();
+
+	printk(BIOS_DEBUG, "prev_sleep_state = S%d\n", prev_sleep_state);
+
 	/* Initialize RAM */
-	raminit(params->mrc_params, 5);
+	raminit(params->mrc_params, prev_sleep_state);
 
 	mark_ts(params, timestamp_get());
 
 	handoff = romstage_handoff_find_or_add();
 	if (handoff != NULL)
-		handoff->s3_resume = 0;
+		handoff->s3_resume = (prev_sleep_state == 3);
 	else
 		printk(BIOS_DEBUG, "Romstage handoff structure not added!\n");