flash: Call lock function prior to mapped external read

Mapped read access to external flash may conflict with direct access
through SPI commands, so call a chip-level function to lock access prior
to doing such reads.

BUG=chrome-os-partner:55781
BRANCH=Gru
TEST=Verify 'ver' still works fine on kevin, and vboot hashing completes
successfully.

Change-Id: I009d6d5ee61c83260fb49ad4ee137fa3f4cd625a
Signed-off-by: Shawn Nematbakhsh <shawnn@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/385165
Tested-by: Mulin Chao <mlchao@nuvoton.com>
Reviewed-by: Randall Spangler <rspangler@chromium.org>
Reviewed-by: Mulin Chao <mlchao@nuvoton.com>
(cherry picked from commit a7f3e3fa376731709f4823a0c1d464b4d1deae14)
Reviewed-on: https://chromium-review.googlesource.com/386446
Commit-Ready: Shawn N <shawnn@chromium.org>
Tested-by: Shawn N <shawnn@chromium.org>
Reviewed-by: Shawn N <shawnn@chromium.org>

5 files changed, 37 insertions, 13 deletions

diff --git a/chip/npcx/flash.c b/chip/npcx/flash.c
index 95b4796bb3..ac1a06078d 100644
--- a/chip/npcx/flash.c
+++ b/chip/npcx/flash.c
@@ -777,6 +777,13 @@ int flash_pre_init(void)
 		return EC_SUCCESS;
 }
 
+void flash_lock_mapped_storage(int lock)
+{
+	/*
+	 * TODO(crosbug.com/p/55781): Add mutex to ensure no conflict between
+	 * mapped read and regular flash ops.
+	 */
+}
 /*****************************************************************************/
 /* Console commands */
 
diff --git a/common/flash.c b/common/flash.c
index cdd4219394..05489b7b57 100644
--- a/common/flash.c
+++ b/common/flash.c
@@ -370,9 +370,14 @@ int flash_is_erased(uint32_t offset, int size)
 			  (const char **)&ptr) < 0)
 		return 0;
 
+	flash_lock_mapped_storage(1);
 	for (size /= sizeof(uint32_t); size > 0; size--, ptr++)
-		if (*ptr != CONFIG_FLASH_ERASED_VALUE32)
+		if (*ptr != CONFIG_FLASH_ERASED_VALUE32) {
+			flash_lock_mapped_storage(0);
 			return 0;
+	}
+
+	flash_lock_mapped_storage(0);
 #else
 	/* Read flash a chunk at a time */
 	uint32_t buf[8];
@@ -406,7 +411,9 @@ int flash_read(int offset, int size, char *data)
 	if (flash_dataptr(offset, size, 1, &src) < 0)
 		return EC_ERROR_INVAL;
 
+	flash_lock_mapped_storage(1);
 	memcpy(data, src, size);
+	flash_lock_mapped_storage(0);
 	return EC_SUCCESS;
 #else
 	return flash_physical_read(offset, size, data);
diff --git a/common/system.c b/common/system.c
index 9c1d53b60b..4488f45e66 100644
--- a/common/system.c
+++ b/common/system.c
@@ -407,8 +407,10 @@ int system_get_image_used(enum system_image_copy_t copy)
 	} while (*image != 0xea);
 #else
 	image = (const uint8_t *)(image_offset + CONFIG_MAPPED_STORAGE_BASE);
+	flash_lock_mapped_storage(1);
 	for (size--; size > 0 && image[size] != 0xea; size--)
 		;
+	flash_lock_mapped_storage(0);
 #endif
 
 	return size ? size + 1 : 0;  /* 0xea byte IS part of the image */
@@ -613,12 +615,9 @@ int system_run_image_copy(enum system_image_copy_t copy)
 __attribute__((weak))	   /* Weird chips may need their own implementations */
 const char *system_get_version(enum system_image_copy_t copy)
 {
-#ifndef CONFIG_MAPPED_STORAGE
-	static struct version_struct vdata;
-#endif
+	static struct version_struct v;
 
 	uintptr_t addr;
-	const struct version_struct *v;
 	enum system_image_copy_t active_copy = system_get_image_copy();
 
 	/* Handle version of current image */
@@ -645,21 +644,20 @@ const char *system_get_version(enum system_image_copy_t copy)
 
 #ifdef CONFIG_MAPPED_STORAGE
 	addr += CONFIG_MAPPED_STORAGE_BASE;
-	v = (const struct version_struct *)addr;
+	flash_lock_mapped_storage(1);
+	memcpy(&v, (const void *)addr, sizeof(v));
+	flash_lock_mapped_storage(0);
 #else
-
 	/* Read the version struct from flash into a buffer. */
-	if (flash_read(addr, sizeof(vdata), (char *)&vdata))
+	if (flash_read(addr, sizeof(v), (char *)&v))
 		return "";
-
-	v = &vdata;
 #endif
 
 	/* Make sure the version struct cookies match before returning the
 	 * version string. */
-	if (v->cookie1 == version_data.cookie1 &&
-	    v->cookie2 == version_data.cookie2)
-		return v->version;
+	if (v.cookie1 == version_data.cookie1 &&
+	    v.cookie2 == version_data.cookie2)
+		return v.version;
 
 	return "";
 }
diff --git a/common/vboot_hash.c b/common/vboot_hash.c
index 8de7d8931e..136efe942a 100644
--- a/common/vboot_hash.c
+++ b/common/vboot_hash.c
@@ -117,8 +117,10 @@ static void vboot_hash_next_chunk(void)
 	size = MIN(CHUNK_SIZE, data_size - curr_pos);
 
 #ifdef CONFIG_MAPPED_STORAGE
+	flash_lock_mapped_storage(1);
 	SHA256_update(&ctx, (const uint8_t *)(CONFIG_MAPPED_STORAGE_BASE +
 					      data_offset + curr_pos), size);
+	flash_lock_mapped_storage(0);
 #else
 	if (read_and_hash_chunk(data_offset + curr_pos, size) != EC_SUCCESS)
 		return;
diff --git a/include/flash.h b/include/flash.h
index 03a6e89c25..e0873028f5 100644
--- a/include/flash.h
+++ b/include/flash.h
@@ -261,4 +261,14 @@ const char *flash_read_serial(void);
  */
 int flash_write_serial(const char *serialno);
 
+/**
+ * Lock or unlock HW necessary for mapped storage read.
+ *
+ * @param lock          1 to lock, 0 to unlock.
+ */
+#ifdef CONFIG_EXTERNAL_STORAGE
+void flash_lock_mapped_storage(int lock);
+#else
+static inline void flash_lock_mapped_storage(int lock) { };
+#endif /* CONFIG_EXTERNAL_STORAGE */
 #endif  /* __CROS_EC_FLASH_H */