spi: Clean up SPI flash driver interface

RW flag was added to spi_slave structure to get around a requirement on
some AMD flash controllers that need to group together all spi volatile
operations (write/erase). This rw flag is not a property or attribute of
the SPI slave or controller. Thus, instead of saving it in spi_slave
structure, clean up the SPI flash driver interface. This allows
chipsets/mainboards (that require volatile operations to be grouped) to
indicate beginning and end of such grouped operations.

New user APIs are added to allow users to perform probe, read, write,
erase, volatile group begin and end operations. Callbacks defined in
spi_flash structure are expected to be used only by the SPI flash
driver. Any chipset that requires grouping of volatile operations can
select the newly added Kconfig option SPI_FLASH_HAS_VOLATILE_GROUP and
define callbacks for chipset_volatile_group_{begin,end}.

spi_claim_bus/spi_release_bus calls have been removed from the SPI flash
chip drivers which end up calling do_spi_flash_cmd since it already has
required calls for claiming and releasing SPI bus before performing a
read/write operation.

BUG=None
BRANCH=None
TEST=Compiles successfully.

Change-Id: Idfc052e82ec15b6c9fa874cee7a61bd06e923fbf
Signed-off-by: Furquan Shaikh <furquan@chromium.org>
Reviewed-on: https://review.coreboot.org/17462
Tested-by: build bot (Jenkins)
Reviewed-by: Aaron Durbin <adurbin@chromium.org>

2 files changed, 22 insertions, 25 deletions

diff --git a/src/southbridge/amd/cimx/sb800/Kconfig b/src/southbridge/amd/cimx/sb800/Kconfig
index a48b93a67c..07232f1a74 100644
--- a/src/southbridge/amd/cimx/sb800/Kconfig
+++ b/src/southbridge/amd/cimx/sb800/Kconfig
@@ -123,6 +123,7 @@ endif
 config SB800_IMC_FWM
 	bool "Add IMC firmware"
 	default n
+	select SPI_FLASH_HAS_VOLATILE_GROUP if SPI_FLASH
 	help
 	  Add SB800 / Hudson 1 IMC Firmware to support the onboard fan control.
 
diff --git a/src/southbridge/amd/cimx/sb800/spi.c b/src/southbridge/amd/cimx/sb800/spi.c
index f6898926e3..726d8e0129 100644
--- a/src/southbridge/amd/cimx/sb800/spi.c
+++ b/src/southbridge/amd/cimx/sb800/spi.c
@@ -17,18 +17,15 @@
 #include <string.h>
 #include <arch/io.h>
 #include <console/console.h>
+#include <spi_flash.h>
 #include <spi-generic.h>
 #include <device/device.h>
 #include <device/pci.h>
 #include <device/pci_ops.h>
 
-#if IS_ENABLED (CONFIG_SB800_IMC_FWM)
 #include "SBPLATFORM.h"
 #include <vendorcode/amd/cimx/sb800/ECfan.h>
 
-static int bus_claimed = 0;
-#endif
-
 #define AMD_SB_SPI_TX_LEN	8
 
 static uintptr_t spibar;
@@ -114,8 +111,6 @@ int spi_xfer(struct spi_slave *slave, const void *dout,
 	return 0;
 }
 
-#if IS_ENABLED (CONFIG_SB800_IMC_FWM)
-
 static void ImcSleep(void)
 {
 	u8	cmd_val = 0x96;		/* Kick off IMC Mailbox command 96 */
@@ -142,34 +137,35 @@ static void ImcWakeup(void)
 
 	WaitForEcLDN9MailboxCmdAck();
 }
-#endif
 
 int spi_claim_bus(struct spi_slave *slave)
 {
-#if IS_ENABLED (CONFIG_SB800_IMC_FWM)
+	/* Nothing is required. */
+	return 0;
+}
 
-	if (slave->rw == SPI_WRITE_FLAG) {
-		bus_claimed++;
-		if (bus_claimed == 1)
-			ImcSleep();
-	}
-#endif
+void spi_release_bus(struct spi_slave *slave)
+{
+	/* Nothing is required. */
+	return;
+}
+
+int chipset_volatile_group_begin(const struct spi_flash *flash)
+{
+	if (!IS_ENABLED(CONFIG_SB800_IMC_FWM))
+		return 0;
 
+	ImcSleep();
 	return 0;
 }
 
-void spi_release_bus(struct spi_slave *slave)
+int chipset_volatile_group_end(const struct spi_flash *flash)
 {
-#if IS_ENABLED (CONFIG_SB800_IMC_FWM)
-
-	if (slave->rw == SPI_WRITE_FLAG)  {
-		bus_claimed--;
-		if (bus_claimed <= 0) {
-			bus_claimed = 0;
-			ImcWakeup();
-		}
-	}
-#endif
+	if (!IS_ENABLED(CONFIG_SB800_IMC_FWM))
+		return 0;
+
+	ImcWakeup();
+	return 0;
 }
 
 struct spi_slave *spi_setup_slave(unsigned int bus, unsigned int cs)