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dmaengine: qcom: bam_dma: Avoid writing unavailable register
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Avoid writing unavailable register in BAM-Lite mode.
BAM_DESC_CNT_TRSHLD register is unavailable in BAM-Lite
mode. Its only available in BAM-NDP mode. So only write
this register for clients who is using BAM-NDP.

Signed-off-by: Md Sadre Alam <quic_mdalam@quicinc.com>
Link: https://lore.kernel.org/r/20241220094203.3510335-1-quic_mdalam@quicinc.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>
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Md Sadre Alam authored and Vinod Koul committed Dec 24, 2024
1 parent 3082137 commit 57a7138
Showing 1 changed file with 16 additions and 8 deletions.
24 changes: 16 additions & 8 deletions drivers/dma/qcom/bam_dma.c
Original file line number Diff line number Diff line change
@@ -59,6 +59,9 @@ struct bam_desc_hw {
#define DESC_FLAG_NWD BIT(12)
#define DESC_FLAG_CMD BIT(11)

#define BAM_NDP_REVISION_START 0x20
#define BAM_NDP_REVISION_END 0x27

struct bam_async_desc {
struct virt_dma_desc vd;

@@ -398,6 +401,7 @@ struct bam_device {

/* dma start transaction tasklet */
struct tasklet_struct task;
u32 bam_revision;
};

/**
@@ -441,8 +445,10 @@ static void bam_reset(struct bam_device *bdev)
writel_relaxed(val, bam_addr(bdev, 0, BAM_CTRL));

/* set descriptor threshold, start with 4 bytes */
writel_relaxed(DEFAULT_CNT_THRSHLD,
bam_addr(bdev, 0, BAM_DESC_CNT_TRSHLD));
if (in_range(bdev->bam_revision, BAM_NDP_REVISION_START,
BAM_NDP_REVISION_END))
writel_relaxed(DEFAULT_CNT_THRSHLD,
bam_addr(bdev, 0, BAM_DESC_CNT_TRSHLD));

/* Enable default set of h/w workarounds, ie all except BAM_FULL_PIPE */
writel_relaxed(BAM_CNFG_BITS_DEFAULT, bam_addr(bdev, 0, BAM_CNFG_BITS));
@@ -1000,9 +1006,10 @@ static void bam_apply_new_config(struct bam_chan *bchan,
maxburst = bchan->slave.src_maxburst;
else
maxburst = bchan->slave.dst_maxburst;

writel_relaxed(maxburst,
bam_addr(bdev, 0, BAM_DESC_CNT_TRSHLD));
if (in_range(bdev->bam_revision, BAM_NDP_REVISION_START,
BAM_NDP_REVISION_END))
writel_relaxed(maxburst,
bam_addr(bdev, 0, BAM_DESC_CNT_TRSHLD));
}

bchan->reconfigure = 0;
@@ -1192,10 +1199,11 @@ static int bam_init(struct bam_device *bdev)
u32 val;

/* read revision and configuration information */
if (!bdev->num_ees) {
val = readl_relaxed(bam_addr(bdev, 0, BAM_REVISION));
val = readl_relaxed(bam_addr(bdev, 0, BAM_REVISION));
if (!bdev->num_ees)
bdev->num_ees = (val >> NUM_EES_SHIFT) & NUM_EES_MASK;
}

bdev->bam_revision = val & REVISION_MASK;

/* check that configured EE is within range */
if (bdev->ee >= bdev->num_ees)

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