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>
Reviewed-by: Pratyush Yadav <p.yadav@ti.com>
Reviewed-by: Jagan Teki <jagan@amarulasolutions.com>
diff --git a/drivers/mtd/spi/spi-nor-core.c b/drivers/mtd/spi/spi-nor-core.c
index 9a1801b..3f5f3c8 100644
--- a/drivers/mtd/spi/spi-nor-core.c
+++ b/drivers/mtd/spi/spi-nor-core.c
@@ -2089,6 +2089,36 @@
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
@@ -2262,7 +2292,7 @@
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;
@@ -2588,7 +2618,7 @@
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;