[coreboot-gerrit] [XS] Change in coreboot[main]: soc/amd/common/include/spi: add and use SPI_MISC_CNTRL defines

[Felix Held (Code Review)]

Felix Held has uploaded this change for review. ( https://review.coreboot.org/c/coreboot/+/83773?usp=email )

Change subject: soc/amd/common/include/spi: add and use SPI_MISC_CNTRL defines
......................................................................

soc/amd/common/include/spi: add and use SPI_MISC_CNTRL defines

This register is currently used by the SPI DMA code that sets an
undocumented bit. A following patch will use the
SPI_SEMAPHORE_DRIVER_LOCKED bit definition. Since that one won't affect
the hardware it's marked as reserved in the PPR, but is used as a
semaphore for arbitration of the SPI controller access between SMM code
and non-SMM code like OS drivers in the AGESA reference code.

Signed-off-by: Felix Held 
Change-Id: I48447dcfb3cee07619a9b42434731f0b21458021
---
M src/soc/amd/common/block/include/amdblocks/spi.h
M src/soc/amd/common/block/lpc/spi_dma.c
2 files changed, 7 insertions(+), 2 deletions(-)

git pull ssh://review.coreboot.org:29418/coreboot refs/changes/73/83773/1

diff --git a/src/soc/amd/common/block/include/amdblocks/spi.h b/src/soc/amd/common/block/include/amdblocks/spi.h
index cf91814..d6f35f8 100644
--- a/src/soc/amd/common/block/include/amdblocks/spi.h
+++ b/src/soc/amd/common/block/include/amdblocks/spi.h
@@ -76,6 +76,11 @@
 #define SPI_FIFO_LAST_BYTE		0xc6 /* 0xc7 for Cezanne */
 #define SPI_FIFO_DEPTH			(SPI_FIFO_LAST_BYTE - SPI_FIFO + 1)

+#define SPI_MISC_CNTRL			0xfc
+/* Re-purpose unused SPI controller register bit for semaphore to synchronize
+   SPI access between SMM and non-SMM software/OS driver. */
+#define   SPI_SEMAPHORE_DRIVER_LOCKED	BIT(4)
+
 struct spi_config {
    /*
     * Default values if not overridden by mainboard:
diff --git a/src/soc/amd/common/block/lpc/spi_dma.c b/src/soc/amd/common/block/lpc/spi_dma.c
index 701b61a..9ff9b0e 100644
--- a/src/soc/amd/common/block/lpc/spi_dma.c
+++ b/src/soc/amd/common/block/lpc/spi_dma.c
@@ -277,9 +277,9 @@
 static void spi_dma_fix(void)
 {
    /* Internal only registers */
-	uint8_t val = spi_read8(0xfc);
+	uint8_t val = spi_read8(SPI_MISC_CNTRL);
    val |= BIT(6);
-	spi_write8(0xfc, val);
+	spi_write8(SPI_MISC_CNTRL, val);
 }

void boot_device_init(void)