spi_flash: Add option to verify all writes by reading back data

Helpful when debugging SPI flash hardware related issues.

TW15203

components/spi_flash/Kconfig

@@ -1,5 +1,22 @@
 menu "SPI Flash driver"
 
+config SPI_FLASH_VERIFY_WRITE
+    bool "Verify SPI flash writes"
+    default n
+    help
+        If this option is enabled, any time SPI flash is written then the data will be read
+        back and verified. This can catch hardware problems with SPI flash, or flash which
+        was not erased before verification.
+
+config SPI_FLASH_LOG_FAILED_WRITE
+    bool "Log errors if verification fails"
+    depends on SPI_FLASH_VERIFY_WRITE
+    default n
+    help
+        If this option is enabled, if SPI flash write verification fails then a log error line
+        will be written with the address, expected & actual values. This can be useful when
+        debugging hardware SPI flash problems.
+
 config SPI_FLASH_ENABLE_COUNTERS
     bool "Enable operation counters"
     default 0

components/spi_flash/flash_ops.c

@@ -44,8 +44,9 @@
 #define MAX_WRITE_CHUNK 8192
 #define MAX_READ_CHUNK 16384
 
+static const char *TAG __attribute__((unused)) = "spi_flash";
+
 #if CONFIG_SPI_FLASH_ENABLE_COUNTERS
-static const char *TAG = "spi_flash";
 static spi_flash_counters_t s_flash_stats;
 
 #define COUNTER_START()     uint32_t ts_begin = xthal_get_ccount()
@@ -233,6 +234,66 @@ esp_err_t IRAM_ATTR spi_flash_erase_range(uint32_t start_addr, uint32_t size)
     return spi_flash_translate_rc(rc);
 }
 
+/* Wrapper around esp_rom_spiflash_write() that verifies data as written if CONFIG_SPI_FLASH_VERIFY_WRITE is set.
+
+   If CONFIG_SPI_FLASH_VERIFY_WRITE is not set, this is esp_rom_spiflash_write().
+*/
+static IRAM_ATTR esp_rom_spiflash_result_t spi_flash_write_inner(uint32_t target, const uint32_t *src_addr, int32_t len)
+{
+#ifndef CONFIG_SPI_FLASH_VERIFY_WRITE
+    return esp_rom_spiflash_write(target, src_addr, len);
+#else // CONFIG_SPI_FLASH_VERIFY_WRITE
+    esp_rom_spiflash_result_t res = ESP_ROM_SPIFLASH_RESULT_OK;
+    assert(len % sizeof(uint32_t) == 0);
+
+    uint32_t before_buf[ESP_ROM_SPIFLASH_BUFF_BYTE_READ_NUM / sizeof(uint32_t)];
+    uint32_t after_buf[ESP_ROM_SPIFLASH_BUFF_BYTE_READ_NUM / sizeof(uint32_t)];
+    int32_t remaining = len;
+    for(int i = 0; i < len; i += sizeof(before_buf)) {
+        int i_w = i / sizeof(uint32_t); // index in words (i is an index in bytes)
+
+        int32_t read_len = MIN(sizeof(before_buf), remaining);
+
+        // Read "before" contents from flash
+        res = esp_rom_spiflash_read(target + i, before_buf, read_len);
+        if (res != ESP_ROM_SPIFLASH_RESULT_OK) {
+            break;
+        }
+
+        res = esp_rom_spiflash_write(target + i, &src_addr[i_w], read_len);
+        if (res != ESP_ROM_SPIFLASH_RESULT_OK) {
+            break;
+        }
+
+        res = esp_rom_spiflash_read(target + i, after_buf, read_len);
+        if (res != ESP_ROM_SPIFLASH_RESULT_OK) {
+            break;
+        }
+
+        for (int r = 0; r < read_len; r += sizeof(uint32_t)) {
+            int r_w = r / sizeof(uint32_t); // index in words (r is index in bytes)
+
+            uint32_t expected = src_addr[i_w + r_w] & before_buf[r_w];
+            uint32_t actual = after_buf[r_w];
+            if (expected != actual) {
+#ifdef CONFIG_SPI_FLASH_LOG_FAILED_WRITE
+                spi_flash_guard_end();
+                ESP_LOGE(TAG, "Bad write at offset 0x%x expected 0x%08x readback 0x%08x", target + i + r, expected, actual);
+                spi_flash_guard_start();
+#endif
+                res = ESP_ROM_SPIFLASH_RESULT_ERR;
+            }
+        }
+        if (res != ESP_ROM_SPIFLASH_RESULT_OK) {
+            break;
+        }
+        remaining -= read_len;
+    }
+    return res;
+#endif // CONFIG_SPI_FLASH_VERIFY_WRITE
+}
+
+
 esp_err_t IRAM_ATTR spi_flash_write(size_t dst, const void *srcv, size_t size)
 {
     CHECK_WRITE_ADDRESS(dst, size);
@@ -269,7 +330,7 @@ esp_err_t IRAM_ATTR spi_flash_write(size_t dst, const void *srcv, size_t size)
         uint32_t t = 0xffffffff;
         memcpy(((uint8_t *) &t) + (dst - left_off), srcc, left_size);
         spi_flash_guard_start();
-        rc = esp_rom_spiflash_write(left_off, &t, 4);
+        rc = spi_flash_write_inner(left_off, &t, 4);
         spi_flash_guard_end();
         if (rc != ESP_ROM_SPIFLASH_RESULT_OK) {
             goto out;
@@ -296,7 +357,7 @@ esp_err_t IRAM_ATTR spi_flash_write(size_t dst, const void *srcv, size_t size)
                 write_src = (const uint8_t *)write_buf;
             }
             spi_flash_guard_start();
-            rc = esp_rom_spiflash_write(dst + mid_off, (const uint32_t *) write_src, write_size);
+            rc = spi_flash_write_inner(dst + mid_off, (const uint32_t *) write_src, write_size);
             spi_flash_guard_end();
             COUNTER_ADD_BYTES(write, write_size);
             mid_size -= write_size;
@@ -311,7 +372,7 @@ esp_err_t IRAM_ATTR spi_flash_write(size_t dst, const void *srcv, size_t size)
         uint32_t t = 0xffffffff;
         memcpy(&t, srcc + right_off, right_size);
         spi_flash_guard_start();
-        rc = esp_rom_spiflash_write(dst + right_off, &t, 4);
+        rc = spi_flash_write_inner(dst + right_off, &t, 4);
         spi_flash_guard_end();
         if (rc != ESP_ROM_SPIFLASH_RESULT_OK) {
             goto out;