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From f85e6dacdb7d7a9bc37f33cf8770006ab64286f7 Mon Sep 17 00:00:00 2001
From: John Crispin <blogic@openwrt.org>
Date: Wed, 27 Nov 2013 20:58:16 +0100
Subject: [PATCH 131/133] mtd: add chunked read io to m25p80
Signed-off-by: John Crispin <blogic@openwrt.org>
---
drivers/mtd/devices/m25p80.c | 127 ++++++++++++++++++++++++++++++++++++++++++
1 file changed, 127 insertions(+)
--- a/drivers/mtd/devices/m25p80.c
+++ b/drivers/mtd/devices/m25p80.c
@@ -392,6 +392,57 @@ static int m25p80_read(struct mtd_info *
return 0;
}
+static int m25p80_read_chunked(struct mtd_info *mtd, loff_t from, size_t len,
+ size_t *retlen, u_char *buf)
+{
+ struct m25p *flash = mtd_to_m25p(mtd);
+ struct spi_transfer t[2];
+ struct spi_message m;
+ uint8_t opcode;
+ int idx = 0;
+
+ pr_debug("%s: %s from 0x%08x, len %zd\n", dev_name(&flash->spi->dev),
+ __func__, (u32)from, len);
+
+ spi_message_init(&m);
+ memset(t, 0, (sizeof t));
+
+ t[0].tx_buf = flash->command;
+ t[0].len = m25p_cmdsz(flash);
+ spi_message_add_tail(&t[0], &m);
+ spi_message_add_tail(&t[1], &m);
+
+ while (idx < len) {
+ int rlen = (len - idx > 4) ? (4) : (len - idx);
+
+ t[1].rx_buf = &buf[idx];
+ t[1].len = rlen;
+
+ mutex_lock(&flash->lock);
+
+ /* Wait till previous write/erase is done. */
+ if (wait_till_ready(flash)) {
+ /* REVISIT status return?? */
+ mutex_unlock(&flash->lock);
+ return 1;
+ }
+
+ /* Set up the write data buffer. */
+ opcode = OPCODE_NORM_READ;
+ flash->command[0] = opcode;
+ m25p_addr2cmd(flash, from + idx, flash->command);
+
+ spi_sync(flash->spi, &m);
+
+ *retlen = m.actual_length - m25p_cmdsz(flash) -
+ (flash->fast_read ? 1 : 0);
+
+ mutex_unlock(&flash->lock);
+ idx += rlen;
+ }
+ return 0;
+}
+
/*
* Write an address range to the flash chip. Data must be written in
* FLASH_PAGESIZE chunks. The address range may be any size provided
@@ -479,6 +530,76 @@ static int m25p80_write(struct mtd_info
return 0;
}
+static int m25p80_write_chunked(struct mtd_info *mtd, loff_t to, size_t len,
+ size_t *retlen, const u_char *buf)
+{
+ struct m25p *flash = mtd_to_m25p(mtd);
+ struct spi_transfer t;
+ struct spi_message m;
+ u32 i, page_size;
+ u8 tmp[8];
+
+ pr_debug("%s: %s to 0x%08x, len %zd\n", dev_name(&flash->spi->dev),
+ __func__, (u32)to, len);
+
+ spi_message_init(&m);
+ memset(&t, 0, (sizeof t));
+
+ t.tx_buf = tmp;
+ t.len = 8;
+ spi_message_add_tail(&t, &m);
+
+ mutex_lock(&flash->lock);
+
+ /* Wait until finished previous write command. */
+ if (wait_till_ready(flash)) {
+ mutex_unlock(&flash->lock);
+ return 1;
+ }
+
+ write_enable(flash);
+
+ /* Set up the opcode in the write buffer. */
+ flash->command[0] = OPCODE_PP;
+ m25p_addr2cmd(flash, to, flash->command);
+
+ t.len = 4 + (to & 0x3);
+ if (t.len == 4)
+ t.len = 8;
+ memcpy(tmp, flash->command, 4);
+ memcpy(&tmp[4], buf, t.len - 4);
+ spi_sync(flash->spi, &m);
+ page_size = t.len - 4;
+
+ *retlen = m.actual_length - m25p_cmdsz(flash);
+
+ /* write everything in flash->page_size chunks */
+ for (i = page_size; i < len; i += page_size) {
+ page_size = len - i;
+ if (page_size > 4)
+ page_size = 4;
+
+ /* write the next page to flash */
+ m25p_addr2cmd(flash, to + i, flash->command);
+
+ memcpy(tmp, flash->command, 4);
+ memcpy(&tmp[4], buf + i, page_size);
+ t.len = 4 + page_size;
+
+ wait_till_ready(flash);
+
+ write_enable(flash);
+
+ spi_sync(flash->spi, &m);
+
+ *retlen += m.actual_length - m25p_cmdsz(flash);
+ }
+
+ mutex_unlock(&flash->lock);
+
+ return 0;
+}
+
static int sst_write(struct mtd_info *mtd, loff_t to, size_t len,
size_t *retlen, const u_char *buf)
{
@@ -1058,6 +1179,12 @@ static int m25p_probe(struct spi_device
flash->fast_read = true;
#endif
+ if (np && of_property_read_bool(np, "m25p,chunked-io")) {
+ dev_warn(&spi->dev, "using chunked io\n");
+ flash->mtd._read = m25p80_read_chunked;
+ flash->mtd._write = m25p80_write_chunked;
+ }
+
#ifdef CONFIG_M25PXX_USE_FAST_READ
flash->fast_read = true;
#endif
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