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