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 --- drivers/mtd/spi/spi-nor-core.c | 34 ++++++++++++++++++++++++++++++++-- 1 file changed, 32 insertions(+), 2 deletions(-)

diff --git a/drivers/mtd/spi/spi-nor-core.c b/drivers/mtd/spi/spi-nor-core.c index 3b7c817c02..90d05da1d8 100644 --- a/drivers/mtd/spi/spi-nor-core.c +++ b/drivers/mtd/spi/spi-nor-core.c @@ -2022,6 +2022,36 @@ 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 @@ -2195,7 +2225,7 @@ 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;

@@ -2480,7 +2510,7 @@ 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;