[PATCH AUTOSEL 4.14 11/69] ASoC: wm_adsp: Fix dma-unsafe read of scratch registers

Sasha Levin
2018-12-05T09:44:05Z

From: Richard Fitzgerald <rf@opensource.cirrus.com>

[ Upstream commit 20e00db2f59bdddf8a8e241473ef8be94631d3ae ]

Stack memory isn't DMA-safe so it isn't safe to use either
regmap_raw_read or regmap_bulk_read to read into stack memory.

The two functions to read the scratch registers were using
stack memory and regmap_raw_read. It's not worth allocating
memory just for this trivial read, and it isn't time-critical.
A simple regmap_read for each register is sufficient.

Signed-off-by: Richard Fitzgerald <rf@opensource.cirrus.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
sound/soc/codecs/wm_adsp.c | 37 ++++++++++++++++++++-----------------
1 file changed, 20 insertions(+), 17 deletions(-)

diff --git a/sound/soc/codecs/wm_adsp.c b/sound/soc/codecs/wm_adsp.c
index 989d093abda7..67330b6ab204 100644
--- a/sound/soc/codecs/wm_adsp.c
+++ b/sound/soc/codecs/wm_adsp.c
@@ -787,38 +787,41 @@ static unsigned int wm_adsp_region_to_reg(struct wm_adsp_region const *mem,

static void wm_adsp2_show_fw_status(struct wm_adsp *dsp)
{
- u16 scratch[4];
+ unsigned int scratch[4];
+ unsigned int addr = dsp->base + ADSP2_SCRATCH0;
+ unsigned int i;
int ret;

- ret = regmap_raw_read(dsp->regmap, dsp->base + ADSP2_SCRATCH0,
- scratch, sizeof(scratch));
- if (ret) {
- adsp_err(dsp, "Failed to read SCRATCH regs: %d\n", ret);
- return;
+ for (i = 0; i < ARRAY_SIZE(scratch); ++i) {
+ ret = regmap_read(dsp->regmap, addr + i, &scratch[i]);
+ if (ret) {
+ adsp_err(dsp, "Failed to read SCRATCH%u: %d\n", i, ret);
+ return;
+ }
}

adsp_dbg(dsp, "FW SCRATCH 0:0x%x 1:0x%x 2:0x%x 3:0x%x\n",
- be16_to_cpu(scratch[0]),
- be16_to_cpu(scratch[1]),
- be16_to_cpu(scratch[2]),
- be16_to_cpu(scratch[3]));
+ scratch[0], scratch[1], scratch[2], scratch[3]);
}

static void wm_adsp2v2_show_fw_status(struct wm_adsp *dsp)
{
- u32 scratch[2];
+ unsigned int scratch[2];
int ret;

- ret = regmap_raw_read(dsp->regmap, dsp->base + ADSP2V2_SCRATCH0_1,
- scratch, sizeof(scratch));
-
+ ret = regmap_read(dsp->regmap, dsp->base + ADSP2V2_SCRATCH0_1,
+ &scratch[0]);
if (ret) {
- adsp_err(dsp, "Failed to read SCRATCH regs: %d\n", ret);
+ adsp_err(dsp, "Failed to read SCRATCH0_1: %d\n", ret);
return;
}

- scratch[0] = be32_to_cpu(scratch[0]);
- scratch[1] = be32_to_cpu(scratch[1]);
+ ret = regmap_read(dsp->regmap, dsp->base + ADSP2V2_SCRATCH2_3,
+ &scratch[1]);
+ if (ret) {
+ adsp_err(dsp, "Failed to read SCRATCH2_3: %d\n", ret);
+ return;
+ }

adsp_dbg(dsp, "FW SCRATCH 0:0x%x 1:0x%x 2:0x%x 3:0x%x\n",
scratch[0] & 0xFFFF,
--
2.17.1