[alsa-devel] Applied "ASoC: wm_adsp: Fix dma-unsafe read of scratch registers" to the asoc tree

[Mark Brown]

The patch

   ASoC: wm_adsp: Fix dma-unsafe read of scratch registers

has been applied to the asoc tree at

   https://git.kernel.org/pub/scm/linux/kernel/git/broonie/sound.git 

All being well this means that it will be integrated into the linux-next
tree (usually sometime in the next 24 hours) and sent to Linus during
the next merge window (or sooner if it is a bug fix), however if
problems are discovered then the patch may be dropped or reverted.  

You may get further e-mails resulting from automated or manual testing
and review of the tree, please engage with people reporting problems and
send followup patches addressing any issues that are reported if needed.

If any updates are required or you are submitting further changes they
should be sent as incremental updates against current git, existing
patches will not be replaced.

Please add any relevant lists and maintainers to the CCs when replying
to this mail.

Thanks,
Mark

>From 20e00db2f59bdddf8a8e241473ef8be94631d3ae Mon Sep 17 00:00:00 2001
From: Richard Fitzgerald <rf at opensource.cirrus.com>
Date: Mon, 12 Nov 2018 13:36:38 +0000
Subject: [PATCH] ASoC: wm_adsp: Fix dma-unsafe read of scratch registers

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 at opensource.cirrus.com>
Signed-off-by: Mark Brown <broonie at 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 a53dc174bbf0..66501b8dc46f 100644
--- a/sound/soc/codecs/wm_adsp.c
+++ b/sound/soc/codecs/wm_adsp.c
@@ -765,38 +765,41 @@ 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,
-- 
2.19.1