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misc: rp1-pio: release DMA channel outside pio->lock #7519

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misc: rp1-pio: release DMA channel outside pio->lock #7519

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9137c1b
misc: rp1-pio: Ensure transfers are configured
pelwell Jun 16, 2026
7c84b83
misc: rp1-pio: release DMA channel outside pio->lock
nbuchwitz Jul 21, 2026
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35 changes: 25 additions & 10 deletions drivers/misc/rp1-pio.c
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Original file line number Diff line number Diff line change
Expand Up @@ -609,11 +609,12 @@ static int rp1_pio_sm_config_xfer_internal(struct rp1_pio_client *client, uint s
struct rp1_pio_sm_set_dmactrl_args set_dmactrl_args;
struct rp1_pio_device *pio = client->pio;
struct platform_device *pdev = pio->pdev;
struct device *dev = &pdev->dev;
struct dma_slave_config config = {};
struct device *dev = &pdev->dev;
struct dma_slave_caps dma_caps;
struct dma_info *dma = NULL;
bool reconfigure = false;
phys_addr_t fifo_addr;
struct dma_info *dma;
uint32_t dma_mask;
char chan_name[4];
int ret = 0;
Expand All @@ -627,14 +628,21 @@ static int rp1_pio_sm_config_xfer_internal(struct rp1_pio_client *client, uint s

dma_mask = 1 << (sm * 2 + dir);

dma = &pio->dma_configs[sm][dir];

spin_lock(&pio->lock);
if (pio->claimed_dmas & dma_mask)
rp1_pio_sm_dma_free(dev, dma);
pio->claimed_dmas |= dma_mask;
client->claimed_dmas |= dma_mask;
if (!(pio->claimed_dmas & dma_mask & ~client->claimed_dmas)) {
dma = &pio->dma_configs[sm][dir];
if (client->claimed_dmas & dma_mask)
reconfigure = true;
pio->claimed_dmas |= dma_mask;
client->claimed_dmas |= dma_mask;
}
spin_unlock(&pio->lock);
if (!dma)
return -EBUSY;

/* dma_release_channel() sleeps, so free the old channel outside the lock. */
if (reconfigure)
rp1_pio_sm_dma_free(dev, dma);

dma->buf_size = buf_size;
/* Round up the allocations */
Expand Down Expand Up @@ -873,13 +881,20 @@ static int rp1_pio_sm_xfer_data32_user(struct rp1_pio_client *client, void *para
{
struct rp1_pio_sm_xfer_data32_args *args = param;
struct rp1_pio_device *pio = client->pio;
struct dma_info *dma;
struct dma_info *dma = NULL;
uint32_t dma_mask;

if (args->sm >= RP1_PIO_SMS_COUNT || args->dir >= RP1_PIO_DIR_COUNT ||
!args->data_bytes || !args->data)
return -EINVAL;

dma = &pio->dma_configs[args->sm][args->dir];
dma_mask = 1 << (args->sm * 2 + args->dir);
spin_lock(&pio->lock);
if (client->claimed_dmas & dma_mask)
dma = &pio->dma_configs[args->sm][args->dir];
spin_unlock(&pio->lock);
if (!dma)
return -EINVAL;

if (args->dir == RP1_PIO_DIR_TO_SM)
return rp1_pio_sm_tx_user(pio, dma, args->data, args->data_bytes);
Expand Down
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