drivers: flash: atmel SAM0 fix flash_write to handle smaller length.

Fix flash_sam0_write to handle byte lengths smaller than FLASH_PAGE_SIZE

Signed-off-by: Daniel Evans <[email protected]>

drivers/flash/flash_sam0.c

@@ -5,6 +5,9 @@
  */
 
 #define DT_DRV_COMPAT atmel_sam0_nvmctrl
+#define SOC_NV_FLASH_NODE DT_INST(0, soc_nv_flash)
+
+#define FLASH_WRITE_BLK_SZ DT_PROP(SOC_NV_FLASH_NODE, write_block_size)
 
 #define LOG_LEVEL CONFIG_FLASH_LOG_LEVEL
 #include <zephyr/logging/log.h>
@@ -67,7 +70,7 @@ static const struct flash_parameters flash_sam0_parameters = {
 #if CONFIG_SOC_FLASH_SAM0_EMULATE_BYTE_PAGES
 	.write_block_size = 1,
 #else
-	.write_block_size = DT_PROP(DT_INST(0, soc_nv_flash), write_block_size),
+	.write_block_size = FLASH_WRITE_BLK_SZ,
 #endif
 	.erase_value = 0xff,
 };
@@ -148,10 +151,9 @@ static int flash_sam0_check_status(off_t offset)
 }
 
 static int flash_sam0_write_page(const struct device *dev, off_t offset,
-				 const void *data)
+				 const void *data, size_t len)
 {
 	const uint32_t *src = data;
-	const uint32_t *end = src + FLASH_PAGE_SIZE / sizeof(*src);
 	uint32_t *dst = FLASH_MEM(offset);
 	int err;
 
@@ -163,10 +165,11 @@ static int flash_sam0_write_page(const struct device *dev, off_t offset,
 	flash_sam0_wait_ready();
 
 	/* Ensure writes happen 32 bits at a time. */
-	for (; src != end; src++, dst++) {
-		*dst = UNALIGNED_GET((uint32_t *)src);
+	for (; len > 0; len -= sizeof(*src)) {
+		*dst++ = UNALIGNED_GET((uint32_t *)src++);
 	}
 
+
 #ifdef NVMCTRL_CTRLA_CMD_WP
 	NVMCTRL->CTRLA.reg = NVMCTRL_CTRLA_CMD_WP | NVMCTRL_CTRLA_CMDEX_KEY;
 #else
@@ -178,7 +181,7 @@ static int flash_sam0_write_page(const struct device *dev, off_t offset,
 		return err;
 	}
 
-	if (memcmp(data, FLASH_MEM(offset), FLASH_PAGE_SIZE) != 0) {
+	if (memcmp(data, FLASH_MEM(offset), len) != 0) {
 		LOG_ERR("verify error at offset 0x%lx", (long)offset);
 		return -EIO;
 	}
@@ -213,7 +216,7 @@ static int flash_sam0_commit(const struct device *dev, off_t base)
 	for (page = 0; page < PAGES_PER_ROW; page++) {
 		err = flash_sam0_write_page(
 			dev, base + page * FLASH_PAGE_SIZE,
-			&ctx->buf[page * FLASH_PAGE_SIZE]);
+			&ctx->buf[page * FLASH_PAGE_SIZE], ROW_SIZE);
 		if (err != 0) {
 			return err;
 		}
@@ -275,24 +278,25 @@ static int flash_sam0_write(const struct device *dev, off_t offset,
 
 #else /* CONFIG_SOC_FLASH_SAM0_EMULATE_BYTE_PAGES */
 
+BUILD_ASSERT((FLASH_WRITE_BLK_SZ % sizeof(uint32_t)) == 0, "unsupported write-block-size");
+
 static int flash_sam0_write(const struct device *dev, off_t offset,
 			    const void *data, size_t len)
 {
 	const uint8_t *pdata = data;
 	int err;
-	size_t idx;
 
 	err = flash_sam0_valid_range(offset, len);
 	if (err != 0) {
 		return err;
 	}
 
-	if ((offset % FLASH_PAGE_SIZE) != 0) {
+	if ((offset % FLASH_WRITE_BLK_SZ) != 0) {
 		LOG_WRN("0x%lx: not on a write block boundary", (long)offset);
 		return -EINVAL;
 	}
 
-	if ((len % FLASH_PAGE_SIZE) != 0) {
+	if ((len % FLASH_WRITE_BLK_SZ) != 0) {
 		LOG_WRN("%zu: not a integer number of write blocks", len);
 		return -EINVAL;
 	}
@@ -301,12 +305,21 @@ static int flash_sam0_write(const struct device *dev, off_t offset,
 
 	err = flash_sam0_write_protection(dev, false);
 	if (err == 0) {
-		for (idx = 0; idx < len; idx += FLASH_PAGE_SIZE) {
-			err = flash_sam0_write_page(dev, offset + idx,
-						    &pdata[idx]);
+		while (len > 0) {
+			size_t eop_len, write_len;
+
+			/* Maximum size without crossing a page */
+			eop_len = -(offset | ~(FLASH_PAGE_SIZE - 1));
+			write_len = MIN(len, eop_len);
+
+			err = flash_sam0_write_page(dev, offset, pdata, write_len);
 			if (err != 0) {
 				break;
 			}
+
+			offset += write_len;
+			pdata += write_len;
+			len -= write_len;
 		}
 	}