leandrof/u-boot
1
0
Fork 1
Code Issues Pull Requests Packages Projects Releases Wiki Activity

mtd: spi: Split read transactions per bank

Browse Source 
The patch splits the read transaction into multiple
read transactions which means incase of read requested
across multiple banks, it splits and sends one read per
bank. This can be enabled using new config option
CONFIG_SPI_FLASH_SPLIT_READ.

Signed-off-by: Siva Durga Prasad Paladugu <siva.durga.paladugu@xilinx.com>
Signed-off-by: Michal Simek <michal.simek@xilinx.com>
This commit is contained in:
Siva Durga Prasad Paladugu
2019-05-28 13:03:09 +05:30
committed by Michal Simek
parent b3e44ab427
commit c744e9e6f6
2 changed files with 30 additions and 0 deletions
Download Patch File Download Diff File Expand all files Collapse all files

9
drivers/mtd/spi/Kconfig
View File

@@ -110,6 +110,15 @@ config SPI_FLASH_XMC
endif
config SPI_FLASH_SPLIT_READ
bool "Enable split read transfers"
help
Some flash devices have multiple dies stacked together in it and in
such cases a single read that spans across mutiple dies will not work
So, enabling this config option splits a read that was requested across
multiple banks into one read per bank so that it fixes the issue with
a read across multple banks.
config SPI_FLASH_USE_4K_SECTORS
bool "Use small 4096 B erase sectors"
depends on SPI_FLASH

21
drivers/mtd/spi/spi_flash.c
View File

@@ -749,6 +749,27 @@ int spi_flash_cmd_read_ops(struct spi_flash *flash, u32 offset,
read_len = SPI_FLASH_16MB_BOUN << flash->shift;
else
read_len = len;
#ifdef CONFIG_SPI_FLASH_SPLIT_READ
/*
* Some flash devices like N25Q512 have multiple dies
* in it and one read transaction across multiple dies
* is not possible. So, split a read transaction that
* spans across multiple banks into one read per bank
* to fix these scenarios.
*/
u32 bank_size = (SPI_FLASH_16MB_BOUN << flash->shift);
u8 cur = offset / bank_size;
u8 nxt = (offset + len) / bank_size;
if (cur != nxt) {
remain_len = (bank_size * (cur + 1)) - offset;
if (len < remain_len)
read_len = len;
else
read_len = remain_len;
}
#endif
}
if (spi->max_read_size)