soc/intel/common: remove mrc cache assumptions

Update the mrc cache implementation to use region_file. Instead
of relying on memory-mapped access and pointer arithmetic
use the region_devices and region_file to obtain the latest
data associated with the region. This removes the need for the
nvm wrapper as the region_devices can be used directly. Thus,
the library is more generic and can be extended to work on
different boot mediums.

BUG=chrome-os-partner:56151

Change-Id: Ic14e2d2f7339e50256b4a3a297fc33991861ca44
Signed-off-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-on: https://review.coreboot.org/17717
Tested-by: build bot (Jenkins)
Reviewed-by: Duncan Laurie <dlaurie@chromium.org>

1 files changed, 26 insertions, 96 deletions

diff --git a/src/soc/intel/common/nvm.c b/src/soc/intel/common/nvm.c
index 99a1fbfb15..b7e0f4e7ac 100644
--- a/src/soc/intel/common/nvm.c
+++ b/src/soc/intel/common/nvm.c
@@ -24,113 +24,43 @@
 #include "nvm.h"
 #include "spi_flash.h"
 
-/* This module assumes the flash is memory mapped just below 4GiB in the
- * address space for reading. Also this module assumes an area it erased
- * when all bytes read as all 0xff's. */
-
-static struct spi_flash *flash;
-
-static int nvm_init(void)
+/* Read flash status register to determine if write protect is active */
+int nvm_is_write_protected(void)
 {
-	if (flash != NULL)
-		return 0;
+	u8 sr1;
+	u8 wp_gpio;
+	u8 wp_spi;
 
-	spi_init();
-	flash = spi_flash_probe(0, 0);
-	if (!flash) {
-		printk(BIOS_DEBUG, "Could not find SPI device\n");
-		return -1;
-	}
-
-	return 0;
-}
+	if (!IS_ENABLED(CONFIG_CHROMEOS))
+		return 0;
 
-/*
- * Convert memory mapped pointer to flash offset.
- *
- * This is weak because not every platforms memory-maps the NVM media in the
- * same manner. This is a stop-gap solution.
- *
- * The root of the problem is that users of this API work in memory space for
- * both reads and writes, but erase and write must be done in flash space. This
- * also only works when the media is memory-mapped, which is no longer
- * universally true. The long-term approach should be to rewrite this and its
- * users to work in flash space, while using rdev_read() instead of rdev_mmap().
- */
-__attribute__((weak))
-uint32_t nvm_mmio_to_flash_offset(void *p)
-{
-	return CONFIG_ROM_SIZE + (uintptr_t)p;
-}
+	if (!IS_ENABLED(CONFIG_BOOT_DEVICE_SPI_FLASH))
+		return 0;
 
-int nvm_is_erased(const void *start, size_t size)
-{
-	const uint8_t *cur = start;
-	const uint8_t erased_value = 0xff;
+	/* Read Write Protect GPIO if available */
+	wp_gpio = get_write_protect_state();
 
-	while (size > 0) {
-		if (*cur != erased_value)
-			return 0;
-		cur++;
-		size--;
+	/* Read Status Register 1 */
+	if (spi_flash_status(boot_device_spi_flash(), &sr1) < 0) {
+		printk(BIOS_ERR, "Failed to read SPI status register 1\n");
+		return -1;
 	}
-	return 1;
-}
+	wp_spi = !!(sr1 & 0x80);
 
-int nvm_erase(void *start, size_t size)
-{
-	if (nvm_init() < 0)
-		return -1;
-	return spi_flash_erase(flash, nvm_mmio_to_flash_offset(start), size);
-}
+	printk(BIOS_DEBUG, "SPI flash protection: WPSW=%d SRP0=%d\n",
+		wp_gpio, wp_spi);
 
-/* Write data to NVM. Returns 0 on success < 0 on error.  */
-int nvm_write(void *start, const void *data, size_t size)
-{
-	if (nvm_init() < 0)
-		return -1;
-	return spi_flash_write(flash, nvm_mmio_to_flash_offset(start), size,
-				data);
+	return wp_gpio && wp_spi;
 }
 
-/* Read flash status register to determine if write protect is active */
-int nvm_is_write_protected(void)
+/* Apply protection to a range of flash */
+int nvm_protect(const struct region *r)
 {
-	if (nvm_init() < 0)
-		return -1;
-
-	if (IS_ENABLED(CONFIG_CHROMEOS)) {
-		u8 sr1;
-		u8 wp_gpio;
-		u8 wp_spi;
-
-		/* Read Write Protect GPIO if available */
-		wp_gpio = get_write_protect_state();
-
-		/* Read Status Register 1 */
-		if (spi_flash_status(flash, &sr1) < 0) {
-			printk(BIOS_ERR,
-				"Failed to read SPI status register 1\n");
-			return -1;
-		}
-		wp_spi = !!(sr1 & 0x80);
-
-		printk(BIOS_DEBUG, "SPI flash protection: WPSW=%d SRP0=%d\n",
-		       wp_gpio, wp_spi);
+	if (!IS_ENABLED(CONFIG_MRC_SETTINGS_PROTECT))
+		return 0;
 
-		return wp_gpio && wp_spi;
-	}
-	return 0;
-}
+	if (!IS_ENABLED(CONFIG_BOOT_DEVICE_SPI_FLASH))
+		return 0;
 
-/* Apply protection to a range of flash */
-int nvm_protect(void *start, size_t size)
-{
-#if IS_ENABLED(CONFIG_MRC_SETTINGS_PROTECT)
-	if (nvm_init() < 0)
-		return -1;
-	return spi_flash_protect(nvm_mmio_to_flash_offset(start), size);
-#else
-	return -1;
-#endif
+	return spi_flash_protect(region_offset(r), region_sz(r));
 }