intel/apollolake: Enable SPI properly in bootblock and ramstage

Bootblock:
   - Temporary BAR needs to be assigned for SPI device until PCI
   enumeration is done by ramstage which allocates a new BAR.
   - Call spi_init to allow bootblock/verstage to write/erase on flash.

Ramstage:
   - spi_init needs to run in ramstage to allow write protect to be
   disabled for eventlog and NVRAM updates. This needs to be done pretty
   early so that any init calls(e.g. mainboard_ec_init) writing to flash
   work properly.

Verified with this change that there are no more flash write/erase
errors for ELOG/NVRAM.

BUG=chrome-os-partner:54283

Change-Id: Iff840e055548485e6521889fcf264a10fb5d9491
Signed-off-by: Furquan Shaikh <furquan@google.com>
Reviewed-on: https://review.coreboot.org/15209
Reviewed-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-by: Andrey Petrov <andrey.petrov@intel.com>
Tested-by: build bot (Jenkins)

src/soc/intel/apollolake/Makefile.inc

@@ -15,6 +15,7 @@ bootblock-y += car.c
 bootblock-y += gpio.c
 bootblock-y += lpc_lib.c
 bootblock-y += mmap_boot.c
+bootblock-y += spi.c
 bootblock-y += tsc_freq.c
 bootblock-$(CONFIG_SOC_UART_DEBUG) += uart_early.c
 

src/soc/intel/apollolake/bootblock/bootblock.c

@@ -25,6 +25,7 @@
 #include <soc/northbridge.h>
 #include <soc/pci_devs.h>
 #include <soc/uart.h>
+#include <spi-generic.h>
 #include <timestamp.h>
 
 static const struct pad_config tpm_spi_configs[] = {
@@ -101,6 +102,35 @@ static void cache_bios_region(void)
 	set_var_mtrr(mtrr, 4ULL*GiB - rom_size, rom_size, MTRR_TYPE_WRPROT);
 }
 
+/*
+ * Program temporary BAR for SPI in case any of the stages before ramstage need
+ * to access SPI MMIO regs. Ramstage will assign a new BAR during PCI
+ * enumeration.
+ */
+static void enable_spibar(void)
+{
+	device_t dev = SPI_DEV;
+	uint8_t val;
+
+	/* Disable Bus Master and MMIO space. */
+	val = pci_read_config8(dev, PCI_COMMAND);
+	val &= ~(PCI_COMMAND_MASTER | PCI_COMMAND_MEMORY);
+	pci_write_config8(dev, PCI_COMMAND, val);
+
+	/* Program Temporary BAR for SPI */
+	pci_write_config32(dev, PCI_BASE_ADDRESS_0,
+			   PRERAM_SPI_BASE_ADDRESS |
+			   PCI_BASE_ADDRESS_SPACE_MEMORY);
+
+	/* Enable Bus Master and MMIO Space */
+	val = pci_read_config8(dev, PCI_COMMAND);
+	val |= PCI_COMMAND_MASTER | PCI_COMMAND_MEMORY;
+	pci_write_config8(dev, PCI_COMMAND, val);
+
+	/* Initialize SPI to allow BIOS to write/erase on flash. */
+	spi_init();
+}
+
 void bootblock_soc_early_init(void)
 {
 	/* Prepare UART for serial console. */
@@ -112,5 +142,7 @@ void bootblock_soc_early_init(void)
 
 	enable_pm_timer();
 
+	enable_spibar();
+
 	cache_bios_region();
 }

src/soc/intel/apollolake/chip.c

@@ -31,6 +31,7 @@
 #include <soc/intel/common/vbt.h>
 #include <soc/nvs.h>
 #include <soc/pci_devs.h>
+#include <spi-generic.h>
 
 #include "chip.h"
 
@@ -164,3 +165,16 @@ BOOT_STATE_INIT_ENTRY(BS_PAYLOAD_LOAD, BS_ON_EXIT, fsp_notify_dummy,
 						(void *) READY_TO_BOOT);
 BOOT_STATE_INIT_ENTRY(BS_OS_RESUME, BS_ON_ENTRY, fsp_notify_dummy,
 						(void *) READY_TO_BOOT);
+
+/*
+ * spi_init() needs to run unconditionally on every boot (including resume) to
+ * allow write protect to be disabled for eventlog and nvram updates. This needs
+ * to be done as early as possible in ramstage. Thus, add a callback for entry
+ * into BS_PRE_DEVICE.
+ */
+static void spi_init_cb(void *unused)
+{
+	spi_init();
+}
+
+BOOT_STATE_INIT_ENTRY(BS_PRE_DEVICE, BS_ON_ENTRY, spi_init_cb, NULL);

src/soc/intel/apollolake/include/soc/iomap.h

@@ -30,4 +30,7 @@
 #define PMC_BAR0			0xfe042000
 #define PMC_BAR1			0xfe044000
 
+/* Temporary BAR for SPI until PCI enumeration assigns a BAR in ramstage. */
+#define PRERAM_SPI_BASE_ADDRESS	0xfe010000
+
 #endif /* _SOC_APOLLOLAKE_IOMAP_H_ */