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bcm53xx: add m25p80 workaround for SPI flash writing problems

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Signed-off-by: Rafał Miłecki <zajec5@gmail.com>

SVN-Revision: 49264
This commit is contained in:
Rafał Miłecki 2016-04-27 21:20:45 +00:00 committed by Jo-Philipp Wich
parent 090b134786
commit cf3b3cfc56
1 changed files with 62 additions and 0 deletions
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target/linux/bcm53xx/patches-4.4/406-mtd-m25p80-use-single-SPI-message-for-writing-data.patch Normal file
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@ -0,0 +1,62 @@
From: =?UTF-8?q?Rafa=C5=82=20Mi=C5=82ecki?= <zajec5@gmail.com>
Subject: [PATCH] mtd: m25p80: use single SPI message for writing data
MIME-Version: 1.0
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On all 3 tested Northstar devices with following flash memories:
mx25l6405d (8192 Kbytes)
mx25l12805d (16384 Kbytes)
mx25l25635e (32768 Kbytes)
I noticed writing to be broken. Not a single bit was changed leaving all
bytes set to 0xff.
This is most likely some problem related to the SPI controller or its
driver. Using a single SPI message seems to workaround this. Of course
it's not perfect solution as copying whole data into a new buffer makes
writing slower.
Signed-off-by: Rafał Miłecki <zajec5@gmail.com>
---
--- a/drivers/mtd/devices/m25p80.c
+++ b/drivers/mtd/devices/m25p80.c
@@ -78,29 +78,30 @@ static void m25p80_write(struct spi_nor *nor, loff_t to, size_t len,
{
struct m25p *flash = nor->priv;
struct spi_device *spi = flash->spi;
+ u8 *command = kzalloc(MAX_CMD_SIZE + len, GFP_KERNEL);
struct spi_transfer t[2] = {};
struct spi_message m;
int cmd_sz = m25p_cmdsz(nor);
+ int i;
spi_message_init(&m);
if (nor->program_opcode == SPINOR_OP_AAI_WP && nor->sst_write_second)
cmd_sz = 1;
- flash->command[0] = nor->program_opcode;
- m25p_addr2cmd(nor, to, flash->command);
+ command[0] = nor->program_opcode;
+ m25p_addr2cmd(nor, to, command);
+ memcpy(&command[cmd_sz], buf, len);
- t[0].tx_buf = flash->command;
- t[0].len = cmd_sz;
+ t[0].tx_buf = command;
+ t[0].len = cmd_sz + len;
spi_message_add_tail(&t[0], &m);
- t[1].tx_buf = buf;
- t[1].len = len;
- spi_message_add_tail(&t[1], &m);
-
spi_sync(spi, &m);
*retlen += m.actual_length - cmd_sz;
+
+ kfree(command);
}
static inline unsigned int m25p80_rx_nbits(struct spi_nor *nor)