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mtd: spi-nor-core: Implement spi_nor_read_sfdp_dma_unsafe() for sfdp parse 

During sfdp header parse and bfpt parse structures in stack are used
to perform spi_nor_read_sfdp() which expects a dma-safe buffer.

This commit introduces spi_nor_read_sfdp_dma_unsafe() to wrap
spi_nor_read_sfdp() using a kmalloc'ed bounce buffer which is
the same implementation in Linux (drivers/mtd/spi-nor/sfdp.c).

Signed-off-by: Vaishnav Achath <vaishnav.a@ti.com>
This commit is contained in:
Vaishnav Achath 2022-06-08 16:44:45 +05:30 committed by Anand Gadiyar
parent ad3d63b199
commit 1f57340c71
1 changed files with 32 additions and 2 deletions
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34
drivers/mtd/spi/spi-nor-core.c
View File

@ -1940,6 +1940,36 @@ read_err:
return ret;
}
/**
* spi_nor_read_sfdp_dma_unsafe() - read Serial Flash Discoverable Parameters.
* @nor: pointer to a 'struct spi_nor'
* @addr: offset in the SFDP area to start reading data from
* @len: number of bytes to read
* @buf: buffer where the SFDP data are copied into
*
* Wrap spi_nor_read_sfdp() using a kmalloc'ed bounce buffer as @buf is now not
* guaranteed to be dma-safe.
*
* Return: -ENOMEM if kmalloc() fails, the return code of spi_nor_read_sfdp()
* otherwise.
*/
static int spi_nor_read_sfdp_dma_unsafe(struct spi_nor *nor, u32 addr,
size_t len, void *buf)
{
void *dma_safe_buf;
int ret;
dma_safe_buf = kmalloc(len, GFP_KERNEL);
if (!dma_safe_buf)
return -ENOMEM;
ret = spi_nor_read_sfdp(nor, addr, len, dma_safe_buf);
memcpy(buf, dma_safe_buf, len);
kfree(dma_safe_buf);
return ret;
}
/* Fast Read settings. */
static void
@ -2113,7 +2143,7 @@ static int spi_nor_parse_bfpt(struct spi_nor *nor,
bfpt_header->length * sizeof(u32));
addr = SFDP_PARAM_HEADER_PTP(bfpt_header);
memset(&bfpt, 0, sizeof(bfpt));
err = spi_nor_read_sfdp(nor, addr, len, &bfpt);
err = spi_nor_read_sfdp_dma_unsafe(nor, addr, len, &bfpt);
if (err < 0)
return err;
@ -2398,7 +2428,7 @@ static int spi_nor_parse_sfdp(struct spi_nor *nor,
int i, err;
/* Get the SFDP header. */
err = spi_nor_read_sfdp(nor, 0, sizeof(header), &header);
err = spi_nor_read_sfdp_dma_unsafe(nor, 0, sizeof(header), &header);
if (err < 0)
return err;