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>

1 files changed, 93 insertions, 12 deletions

diff --git a/src/drivers/spi/spi_flash.c b/src/drivers/spi/spi_flash.c
index 60064208d2..7ca6822ba1 100644
--- a/src/drivers/spi/spi_flash.c
+++ b/src/drivers/spi/spi_flash.c
@@ -7,6 +7,8 @@
  * Licensed under the GPL-2 or later.
  */
 
+#include <arch/early_variables.h>
+#include <assert.h>
 #include <boot_device.h>
 #include <cbfs.h>
 #include <cpu/x86/smm.h>
@@ -142,8 +144,8 @@ static int spi_flash_cmd_read_array(struct spi_slave *spi, u8 *cmd,
 	return len != 0;
 }
 
-int spi_flash_cmd_read_fast(struct spi_flash *flash, u32 offset,
-		size_t len, void *data)
+int spi_flash_cmd_read_fast(const struct spi_flash *flash, u32 offset,
+			size_t len, void *data)
 {
 	u8 cmd[5];
 
@@ -154,8 +156,8 @@ int spi_flash_cmd_read_fast(struct spi_flash *flash, u32 offset,
 					offset, len, data);
 }
 
-int spi_flash_cmd_read_slow(struct spi_flash *flash, u32 offset,
-			    size_t len, void *data)
+int spi_flash_cmd_read_slow(const struct spi_flash *flash, u32 offset,
+			size_t len, void *data)
 {
 	u8 cmd[4];
 
@@ -164,7 +166,7 @@ int spi_flash_cmd_read_slow(struct spi_flash *flash, u32 offset,
 					offset, len, data);
 }
 
-int spi_flash_cmd_poll_bit(struct spi_flash *flash, unsigned long timeout,
+int spi_flash_cmd_poll_bit(const struct spi_flash *flash, unsigned long timeout,
 			   u8 cmd, u8 poll_bit)
 {
 	struct spi_slave *spi = flash->spi;
@@ -189,13 +191,14 @@ int spi_flash_cmd_poll_bit(struct spi_flash *flash, unsigned long timeout,
 	return -1;
 }
 
-int spi_flash_cmd_wait_ready(struct spi_flash *flash, unsigned long timeout)
+int spi_flash_cmd_wait_ready(const struct spi_flash *flash,
+			unsigned long timeout)
 {
 	return spi_flash_cmd_poll_bit(flash, timeout,
 		CMD_READ_STATUS, STATUS_WIP);
 }
 
-int spi_flash_cmd_erase(struct spi_flash *flash, u32 offset, size_t len)
+int spi_flash_cmd_erase(const struct spi_flash *flash, u32 offset, size_t len)
 {
 	u32 start, end, erase_size;
 	int ret;
@@ -207,8 +210,6 @@ int spi_flash_cmd_erase(struct spi_flash *flash, u32 offset, size_t len)
 		return -1;
 	}
 
-	flash->spi->rw = SPI_WRITE_FLAG;
-
 	cmd[0] = flash->erase_cmd;
 	start = offset;
 	end = start + len;
@@ -240,7 +241,7 @@ out:
 	return ret;
 }
 
-int spi_flash_cmd_status(struct spi_flash *flash, u8 *reg)
+int spi_flash_cmd_status(const struct spi_flash *flash, u8 *reg)
 {
 	return spi_flash_cmd(flash->spi, flash->status_cmd, reg, sizeof(*reg));
 }
@@ -312,6 +313,8 @@ static struct {
 };
 #define IDCODE_LEN (IDCODE_CONT_LEN + IDCODE_PART_LEN)
 
+
+/* Public API implementations. */
 struct spi_flash *spi_flash_probe(unsigned int bus, unsigned int cs)
 {
 	struct spi_slave *spi;
@@ -325,8 +328,6 @@ struct spi_flash *spi_flash_probe(unsigned int bus, unsigned int cs)
 		return NULL;
 	}
 
-	spi->rw = SPI_READ_FLAG;
-
 	if (spi->force_programmer_specific && spi->programmer_specific_probe) {
 		flash = spi->programmer_specific_probe (spi);
 		if (!flash)
@@ -388,6 +389,86 @@ err_read_id:
 	return NULL;
 }
 
+int spi_flash_read(const struct spi_flash *flash, u32 offset, size_t len,
+		void *buf)
+{
+	return flash->internal_read(flash, offset, len, buf);
+}
+
+int spi_flash_write(const struct spi_flash *flash, u32 offset, size_t len,
+		const void *buf)
+{
+	int ret;
+
+	if (spi_flash_volatile_group_begin(flash))
+		return -1;
+
+	ret = flash->internal_write(flash, offset, len, buf);
+
+	if (spi_flash_volatile_group_end(flash))
+		return -1;
+
+	return ret;
+}
+
+int spi_flash_erase(const struct spi_flash *flash, u32 offset, size_t len)
+{
+	int ret;
+
+	if (spi_flash_volatile_group_begin(flash))
+		return -1;
+
+	ret = flash->internal_erase(flash, offset, len);
+
+	if (spi_flash_volatile_group_end(flash))
+		return -1;
+
+	return ret;
+}
+
+int spi_flash_status(const struct spi_flash *flash, u8 *reg)
+{
+	return flash->internal_status(flash, reg);
+}
+
+static uint32_t volatile_group_count CAR_GLOBAL;
+
+int spi_flash_volatile_group_begin(const struct spi_flash *flash)
+{
+	uint32_t count;
+	int ret = 0;
+
+	if (!IS_ENABLED(CONFIG_SPI_FLASH_HAS_VOLATILE_GROUP))
+		return ret;
+
+	count = car_get_var(volatile_group_count);
+	if (count == 0)
+		ret = chipset_volatile_group_begin(flash);
+
+	count++;
+	car_set_var(volatile_group_count, count);
+	return ret;
+}
+
+int spi_flash_volatile_group_end(const struct spi_flash *flash)
+{
+	uint32_t count;
+	int ret = 0;
+
+	if (!IS_ENABLED(CONFIG_SPI_FLASH_HAS_VOLATILE_GROUP))
+		return ret;
+
+	count = car_get_var(volatile_group_count);
+	assert(count == 0);
+	count--;
+	car_set_var(volatile_group_count, count);
+
+	if (count == 0)
+		ret = chipset_volatile_group_end(flash);
+
+	return ret;
+}
+
 void lb_spi_flash(struct lb_header *header)
 {
 	struct lb_spi_flash *flash;