[PATCH 6.18 189/752] spi: spi-mem: Protect dirmap_create() with spi_mem_access_start/end

Sasha Levin
2026-02-28T17:50:49Z

From: Chin-Ting Kuo <chin-ting_kuo@aspeedtech.com>

[ Upstream commit 53f826ff5e0e3ecb279862ca7cce1491b94bb017 ]

spi_mem_dirmap_create() may reconfigure controller-wide settings,
which can interfere with concurrent transfers to other devices
sharing the same SPI controller but using different chip selects.

Wrap the ->dirmap_create() callback with spi_mem_access_start() and
spi_mem_access_end() to serialize access and prevent cross-CS
interference during dirmap creation.

This patch has been verified on a setup where a SPI TPM is connected
to CS0 of a SPI controller, while a SPI NOR flash is connected to CS1
of the same controller. Without this patch, spi_mem_dirmap_create()
for the SPI NOR flash interferes with ongoing SPI TPM data transfers,
resulting in failure to create the TPM device. This was tested on an
ASPEED AST2700 EVB.

Signed-off-by: Chin-Ting Kuo <chin-ting_kuo@aspeedtech.com>
Reviewed-by: Paul Menzel <pmenzel@molgen.mpg.de>
Link: https://patch.msgid.link/20260120123005.1392071-2-chin-ting_kuo@aspeedtech.com
Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/spi/spi-mem.c | 11 ++++++++++-
1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/drivers/spi/spi-mem.c b/drivers/spi/spi-mem.c
index 71e3eaf59df97..db9467535416d 100644
--- a/drivers/spi/spi-mem.c
+++ b/drivers/spi/spi-mem.c
@@ -714,9 +714,18 @@ spi_mem_dirmap_create(struct spi_mem *mem,

desc->mem = mem;
desc->info = *info;
- if (ctlr->mem_ops && ctlr->mem_ops->dirmap_create)
+ if (ctlr->mem_ops && ctlr->mem_ops->dirmap_create) {
+ ret = spi_mem_access_start(mem);
+ if (ret) {
+ kfree(desc);
+ return ERR_PTR(ret);
+ }
+
ret = ctlr->mem_ops->dirmap_create(desc);

+ spi_mem_access_end(mem);
+ }
+
if (ret) {
desc->nodirmap = true;
if (!spi_mem_supports_op(desc->mem, &desc->info.op_tmpl))
--
2.51.0