Re: [PATCH v2 2/3] dma: arm-dma350: add support for shared interrupt mode

Robin Murphy
2025-12-16T12:51:07Z

On 2025-12-16 12:30 pm, Jun Guo wrote:
> The arm dma350 controller's hardware implementation varies: some
> designs dedicate a separate interrupt line for each channel, while
> others have all channels sharing a single interrupt.This patch adds
> support for the hardware design where all DMA channels share a
> single interrupt.
>
> Signed-off-by: Jun Guo <jun.guo@cixtech.com>
> ---
> drivers/dma/arm-dma350.c | 124 +++++++++++++++++++++++++++++++++++----
> 1 file changed, 114 insertions(+), 10 deletions(-)
>
> diff --git a/drivers/dma/arm-dma350.c b/drivers/dma/arm-dma350.c
> index 9efe2ca7d5ec..6bea18521edd 100644
> --- a/drivers/dma/arm-dma350.c
> +++ b/drivers/dma/arm-dma350.c
> @@ -14,6 +14,7 @@
> #include "virt-dma.h"
>
> #define DMAINFO 0x0f00
> +#define DRIVER_NAME "arm-dma350"
>
> #define DMA_BUILDCFG0 0xb0
> #define DMA_CFG_DATA_WIDTH GENMASK(18, 16)
> @@ -142,6 +143,9 @@
> #define LINK_LINKADDR BIT(30)
> #define LINK_LINKADDRHI BIT(31)
>
> +/* DMA NONSECURE CONTROL REGISTER */
> +#define DMANSECCTRL 0x20c
> +#define INTREN_ANYCHINTR_EN BIT(0)
>
> enum ch_ctrl_donetype {
> CH_CTRL_DONETYPE_NONE = 0,
> @@ -192,11 +196,16 @@ struct d350_chan {
>
> struct d350 {
> struct dma_device dma;
> + void __iomem *base;
> int nchan;
> int nreq;
> struct d350_chan channels[] __counted_by(nchan);
> };
>
> +struct d350_driver_data {
> + bool combined_irq;
> +};
> +
> static inline struct d350_chan *to_d350_chan(struct dma_chan *chan)
> {
> return container_of(chan, struct d350_chan, vc.chan);
> @@ -461,7 +470,61 @@ static void d350_issue_pending(struct dma_chan *chan)
> spin_unlock_irqrestore(&dch->vc.lock, flags);
> }
>
> -static irqreturn_t d350_irq(int irq, void *data)
> +static irqreturn_t d350_global_irq(int irq, void *data)
> +{
> + struct d350 *dmac = (struct d350 *)data;
> + struct device *dev = dmac->dma.dev;
> + irqreturn_t ret = IRQ_NONE;
> + int i;
> +
> + for (i = 0; i < dmac->nchan; i++) {
> + struct d350_chan *dch = &dmac->channels[i];
> + u32 ch_status;
> +
> + ch_status = readl(dch->base + CH_STATUS);
> + if (!ch_status)
> + continue;
> +
> + ret = IRQ_HANDLED;
> +
> + if (ch_status & CH_STAT_INTR_ERR) {
> + struct virt_dma_desc *vd = &dch->desc->vd;
> + u32 errinfo = readl_relaxed(dch->base + CH_ERRINFO);
> +
> + if (errinfo &
> + (CH_ERRINFO_AXIRDPOISERR | CH_ERRINFO_AXIRDRESPERR))
> + vd->tx_result.result = DMA_TRANS_READ_FAILED;
> + else if (errinfo & CH_ERRINFO_AXIWRRESPERR)
> + vd->tx_result.result = DMA_TRANS_WRITE_FAILED;
> + else
> + vd->tx_result.result = DMA_TRANS_ABORTED;
> +
> + vd->tx_result.residue = d350_get_residue(dch);
> + } else if (!(ch_status & CH_STAT_INTR_DONE)) {
> + dev_warn(dev, "Channel %d unexpected IRQ: 0x%08x\n", i,
> + ch_status);
> + }
> +
> + writel_relaxed(ch_status, dch->base + CH_STATUS);
> +
> + spin_lock(&dch->vc.lock);
> + if (ch_status & CH_STAT_INTR_DONE) {
> + vchan_cookie_complete(&dch->desc->vd);
> + dch->status = DMA_COMPLETE;
> + dch->residue = 0;
> + d350_start_next(dch);
> + } else if (ch_status & CH_STAT_INTR_ERR) {
> + vchan_cookie_complete(&dch->desc->vd);
> + dch->status = DMA_ERROR;
> + dch->residue = dch->desc->vd.tx_result.residue;
> + }
> + spin_unlock(&dch->vc.lock);
> + }
> +
> + return ret;
> +}
> +
> +static irqreturn_t d350_channel_irq(int irq, void *data)
> {
> struct d350_chan *dch = data;
> struct device *dev = dch->vc.chan.device->dev;
> @@ -506,10 +569,18 @@ static irqreturn_t d350_irq(int irq, void *data)
> static int d350_alloc_chan_resources(struct dma_chan *chan)
> {
> struct d350_chan *dch = to_d350_chan(chan);
> - int ret = request_irq(dch->irq, d350_irq, IRQF_SHARED,
> - dev_name(&dch->vc.chan.dev->device), dch);
> - if (!ret)
> - writel_relaxed(CH_INTREN_DONE | CH_INTREN_ERR, dch->base + CH_INTREN);
> + int ret = 0;
> +
> + if (dch->irq) {
> + ret = request_irq(dch->irq, d350_channel_irq, IRQF_SHARED,
> + dev_name(&dch->vc.chan.dev->device), dch);
> + if (ret) {
> + dev_err(chan->device->dev, "Failed to request IRQ %d\n", dch->irq);
> + return ret;
> + }
> + }
> +
> + writel_relaxed(CH_INTREN_DONE | CH_INTREN_ERR, dch->base + CH_INTREN);
>
> return ret;
> }
> @@ -526,7 +597,8 @@ static void d350_free_chan_resources(struct dma_chan *chan)
> static int d350_probe(struct platform_device *pdev)
> {
> struct device *dev = &pdev->dev;
> - struct d350 *dmac;
> + struct d350 *dmac = NULL;
> + const struct d350_driver_data *data;
> void __iomem *base;
> u32 reg;
> int ret, nchan, dw, aw, r, p;
> @@ -556,6 +628,7 @@ static int d350_probe(struct platform_device *pdev)
> return -ENOMEM;
>
> dmac->nchan = nchan;
> + dmac->base = base;
>
> reg = readl_relaxed(base + DMAINFO + DMA_BUILDCFG1);
> dmac->nreq = FIELD_GET(DMA_CFG_NUM_TRIGGER_IN, reg);
> @@ -582,6 +655,27 @@ static int d350_probe(struct platform_device *pdev)
> dmac->dma.device_issue_pending = d350_issue_pending;
> INIT_LIST_HEAD(&dmac->dma.channels);
>
> + data = device_get_match_data(dev);
> + /* Cix Sky1 has a common host IRQ for all its channels. */
> + if (data && data->combined_irq) {
> + int host_irq = platform_get_irq(pdev, 0);
> +
> + if (host_irq < 0)
> + return dev_err_probe(dev, host_irq,
> + "Failed to get IRQ\n");
> +
> + ret = devm_request_irq(&pdev->dev, host_irq, d350_global_irq,
> + IRQF_SHARED, DRIVER_NAME, dmac);
> + if (ret)
> + return dev_err_probe(
> + dev, ret,
> + "Failed to request the combined IRQ %d\n",
> + host_irq);
> + }
> +
> + /* Combined Non-Secure Channel Interrupt Enable */
> + writel_relaxed(INTREN_ANYCHINTR_EN, dmac->base + DMANSECCTRL);

This one line is all that should be needed - all the rest is pointless
overcomplication and churn. And either way, copy-pasting the entire IRQ
handler is not OK.

Thanks,
Robin.

> +
> /* Would be nice to have per-channel caps for this... */
> memset = true;
> for (int i = 0; i < nchan; i++) {
> @@ -595,10 +689,15 @@ static int d350_probe(struct platform_device *pdev)
> dev_warn(dev, "No command link support on channel %d\n", i);
> continue;
> }
> - dch->irq = platform_get_irq(pdev, i);
> - if (dch->irq < 0)
> - return dev_err_probe(dev, dch->irq,
> - "Failed to get IRQ for channel %d\n", i);
> +
> + if (!data) {
> + dch->irq = platform_get_irq(pdev, i);
> + if (dch->irq < 0)
> + return dev_err_probe(
> + dev, dch->irq,
> + "Failed to get IRQ for channel %d\n",
> + i);
> + }
>
> dch->has_wrap = FIELD_GET(CH_CFG_HAS_WRAP, reg);
> dch->has_trig = FIELD_GET(CH_CFG_HAS_TRIGIN, reg) &
> @@ -639,7 +738,12 @@ static void d350_remove(struct platform_device *pdev)
> dma_async_device_unregister(&dmac->dma);
> }
>
> +static const struct d350_driver_data sky1_dma350_data = {
> + .combined_irq = true,
> +};
> +
> static const struct of_device_id d350_of_match[] __maybe_unused = {
> + { .compatible = "cix,sky1-dma-350", .data = &sky1_dma350_data },
> { .compatible = "arm,dma-350" },
> {}
> };