baytrail: Switch from ACPI mode to PCI mode for legacy support

Most Baytrail based devices MMIO registers are reported in ACPI
space and the device's PCI config space is disabled. The PCI config
space is required for many "legacy" OSs that don't have the ACPI
driver loading mechanism. Depthcharge signals the legacy boot
path via the SMI 0xCC and the coreboot SMI handler can switch the
device specific registers to re-enable PCI config space.

BUG=chrome-os-partner:30836
BRANCH=None
TEST=Build and boot Rambi SeaBIOS.

Change-Id: I87248936e2a7e026f38c147bdf0df378e605e370
Signed-off-by: Stefan Reinauer <reinauer@chromium.org>
Original-Commit-Id: dbb9205ee22ffce44e965be51ae0bc62d4ca5dd4
Original-Change-Id: Ia5e54f4330eda10a01ce3de5aa4d86779d6e1bf9
Original-Signed-off-by: Marc Jones <marc.jones@se-eng.com>
Original-Reviewed-on: https://chromium-review.googlesource.com/219801
Original-Reviewed-by: Aaron Durbin <adurbin@chromium.org>
Original-Reviewed-by: Mike Loptien <mike.loptien@se-eng.com>
Original-Tested-by: Mike Loptien <mike.loptien@se-eng.com>
Reviewed-on: http://review.coreboot.org/9459
Tested-by: build bot (Jenkins)
Reviewed-by: Patrick Georgi <pgeorgi@google.com>

3 files changed, 61 insertions, 0 deletions

diff --git a/src/include/cpu/x86/smm.h b/src/include/cpu/x86/smm.h
index c16a6c50d2..adaf74b7ae 100644
--- a/src/include/cpu/x86/smm.h
+++ b/src/include/cpu/x86/smm.h
@@ -460,6 +460,7 @@ typedef struct {
 #define APM_CNT_MBI_UPDATE	0xeb
 #define APM_CNT_GNVS_UPDATE	0xea
 #define APM_CNT_FINALIZE	0xcb
+#define APM_CNT_LEGACY		0xcc
 #define APM_STS		0xb3
 
 /* SMI handler function prototypes */
diff --git a/src/soc/intel/baytrail/Makefile.inc b/src/soc/intel/baytrail/Makefile.inc
index 67ad00bebb..6d28c78684 100644
--- a/src/soc/intel/baytrail/Makefile.inc
+++ b/src/soc/intel/baytrail/Makefile.inc
@@ -20,6 +20,7 @@ ramstage-y += chip.c
 ramstage-y += gfx.c
 ramstage-y += iosf.c
 romstage-y += iosf.c
+smm-y += iosf.c
 ramstage-y += northcluster.c
 ramstage-y += ramstage.c
 ramstage-y += gpio.c
diff --git a/src/soc/intel/baytrail/smihandler.c b/src/soc/intel/baytrail/smihandler.c
index 03842b2fba..3fac525069 100644
--- a/src/soc/intel/baytrail/smihandler.c
+++ b/src/soc/intel/baytrail/smihandler.c
@@ -28,6 +28,7 @@
 #include <halt.h>
 #include <spi-generic.h>
 
+#include <soc/iosf.h>
 #include <soc/pci_devs.h>
 #include <soc/pmc.h>
 #include <soc/nvs.h>
@@ -250,6 +251,60 @@ static void finalize(void)
 #endif
 }
 
+/*
+ * soc_legacy: A payload (Depthcharge) has indicated that the
+ *   legacy payload (SeaBIOS) is being loaded. Switch devices that are
+ *   in ACPI mode to PCI mode so that non-ACPI drivers may work.
+ *
+ */
+static void soc_legacy(void)
+{
+	u32 reg32;
+
+	/* LPE Device */
+	 if (gnvs->dev.lpe_en) {
+		reg32 = iosf_port58_read(LPE_PCICFGCTR1);
+		reg32 &=
+		~(LPE_PCICFGCTR1_PCI_CFG_DIS | LPE_PCICFGCTR1_ACPI_INT_EN);
+		iosf_port58_write(LPE_PCICFGCTR1, reg32);
+	}
+
+	/* SCC Devices */
+#define SCC_ACPI_MODE_DISABLE(name_) \
+	do { if (gnvs->dev.scc_en[SCC_NVS_ ## name_]) { \
+		reg32 = iosf_scc_read(SCC_ ## name_ ## _CTL); \
+		reg32 &= ~(SCC_CTL_PCI_CFG_DIS | SCC_CTL_ACPI_INT_EN); \
+		iosf_scc_write(SCC_ ## name_ ## _CTL, reg32); \
+	} } while (0)
+
+	SCC_ACPI_MODE_DISABLE(MMC);
+	SCC_ACPI_MODE_DISABLE(SD);
+	SCC_ACPI_MODE_DISABLE(SDIO);
+
+	 /* LPSS Devices */
+#define LPSS_ACPI_MODE_DISABLE(name_) \
+	do { if (gnvs->dev.lpss_en[LPSS_NVS_ ## name_]) { \
+		reg32 = iosf_lpss_read(LPSS_ ## name_ ## _CTL); \
+		reg32 &= ~LPSS_CTL_PCI_CFG_DIS | ~LPSS_CTL_ACPI_INT_EN; \
+		iosf_lpss_write(LPSS_ ## name_ ## _CTL, reg32); \
+	} } while (0)
+
+	LPSS_ACPI_MODE_DISABLE(SIO_DMA1);
+	LPSS_ACPI_MODE_DISABLE(I2C1);
+	LPSS_ACPI_MODE_DISABLE(I2C2);
+	LPSS_ACPI_MODE_DISABLE(I2C3);
+	LPSS_ACPI_MODE_DISABLE(I2C4);
+	LPSS_ACPI_MODE_DISABLE(I2C5);
+	LPSS_ACPI_MODE_DISABLE(I2C6);
+	LPSS_ACPI_MODE_DISABLE(I2C7);
+	LPSS_ACPI_MODE_DISABLE(SIO_DMA2);
+	LPSS_ACPI_MODE_DISABLE(PWM1);
+	LPSS_ACPI_MODE_DISABLE(PWM2);
+	LPSS_ACPI_MODE_DISABLE(HSUART1);
+	LPSS_ACPI_MODE_DISABLE(HSUART2);
+	LPSS_ACPI_MODE_DISABLE(SPI);
+}
+
 static void southbridge_smi_apmc(void)
 {
 	uint8_t reg8;
@@ -303,6 +358,10 @@ static void southbridge_smi_apmc(void)
 	case APM_CNT_FINALIZE:
 		finalize();
 		break;
+
+	case APM_CNT_LEGACY:
+		soc_legacy();
+		break;
 	}
 
 	mainboard_smi_apmc(reg8);