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- From ccc38234fdc70120be79e7fb2df5c27ca5cd4c8a Mon Sep 17 00:00:00 2001
- From: =?UTF-8?q?Rafa=C5=82=20Mi=C5=82ecki?= <rafal@milecki.pl>
- Date: Wed, 8 Feb 2017 23:53:44 +0100
- Subject: [PATCH] mtd: bcm47xxsflash: support reading flash out of mapping
- window
- MIME-Version: 1.0
- Content-Type: text/plain; charset=UTF-8
- Content-Transfer-Encoding: 8bit
- For reading flash content we use MMIO but it's possible to read only
- first 16 MiB this way. It's simply an arch design/limitation.
- To support flash sizes bigger than 16 MiB implement indirect access
- using ChipCommon registers.
- This has been tested using MX25L25635F.
- Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
- Acked-by: Marek Vasut <marek.vasut@gmail.com>
- Signed-off-by: Brian Norris <computersforpeace@gmail.com>
- ---
- drivers/mtd/devices/bcm47xxsflash.c | 24 +++++++++++++++++++++---
- drivers/mtd/devices/bcm47xxsflash.h | 3 +++
- 2 files changed, 24 insertions(+), 3 deletions(-)
- --- a/drivers/mtd/devices/bcm47xxsflash.c
- +++ b/drivers/mtd/devices/bcm47xxsflash.c
- @@ -105,15 +105,33 @@ static int bcm47xxsflash_read(struct mtd
- size_t *retlen, u_char *buf)
- {
- struct bcm47xxsflash *b47s = mtd->priv;
- + size_t orig_len = len;
-
- /* Check address range */
- if ((from + len) > mtd->size)
- return -EINVAL;
-
- - memcpy_fromio(buf, b47s->window + from, len);
- - *retlen = len;
- + /* Read as much as possible using fast MMIO window */
- + if (from < BCM47XXSFLASH_WINDOW_SZ) {
- + size_t memcpy_len;
-
- - return len;
- + memcpy_len = min(len, (size_t)(BCM47XXSFLASH_WINDOW_SZ - from));
- + memcpy_fromio(buf, b47s->window + from, memcpy_len);
- + from += memcpy_len;
- + len -= memcpy_len;
- + buf += memcpy_len;
- + }
- +
- + /* Use indirect access for content out of the window */
- + for (; len; len--) {
- + b47s->cc_write(b47s, BCMA_CC_FLASHADDR, from++);
- + bcm47xxsflash_cmd(b47s, OPCODE_ST_READ4B);
- + *buf++ = b47s->cc_read(b47s, BCMA_CC_FLASHDATA);
- + }
- +
- + *retlen = orig_len;
- +
- + return orig_len;
- }
-
- static int bcm47xxsflash_write_st(struct mtd_info *mtd, u32 offset, size_t len,
- --- a/drivers/mtd/devices/bcm47xxsflash.h
- +++ b/drivers/mtd/devices/bcm47xxsflash.h
- @@ -3,6 +3,8 @@
-
- #include <linux/mtd/mtd.h>
-
- +#define BCM47XXSFLASH_WINDOW_SZ SZ_16M
- +
- /* Used for ST flashes only. */
- #define OPCODE_ST_WREN 0x0006 /* Write Enable */
- #define OPCODE_ST_WRDIS 0x0004 /* Write Disable */
- @@ -16,6 +18,7 @@
- #define OPCODE_ST_RES 0x03ab /* Read Electronic Signature */
- #define OPCODE_ST_CSA 0x1000 /* Keep chip select asserted */
- #define OPCODE_ST_SSE 0x0220 /* Sub-sector Erase */
- +#define OPCODE_ST_READ4B 0x6313 /* Read Data Bytes in 4Byte addressing mode */
-
- /* Used for Atmel flashes only. */
- #define OPCODE_AT_READ 0x07e8
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