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author | Chuah, Kim Tatt <kim.tatt.chuah@intel.com> | 2016-06-15 13:44:11 +0800 |
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committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2016-06-25 14:30:42 -0700 |
commit | c6f82787a5a193a5c4c49ddaeb362d320efa5fba (patch) | |
tree | 55da1b24d1b63bcb073e11ae49249887e297006e /drivers/dma/hsu | |
parent | d03516df837587368fc6e75591f6329c072b9eb5 (diff) | |
download | linux-c6f82787a5a193a5c4c49ddaeb362d320efa5fba.tar.gz linux-c6f82787a5a193a5c4c49ddaeb362d320efa5fba.tar.bz2 linux-c6f82787a5a193a5c4c49ddaeb362d320efa5fba.zip |
dmaengine: hsu: Export hsu_dma_get_status()
To allow other code to safely read DMA Channel Status Register (where
the register attribute for Channel Error, Descriptor Time Out &
Descriptor Done fields are read-clear), export hsu_dma_get_status().
hsu_dma_irq() is renamed to hsu_dma_do_irq() and requires Status
Register value to be passed in.
Signed-off-by: Chuah, Kim Tatt <kim.tatt.chuah@intel.com>
Acked-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/dma/hsu')
-rw-r--r-- | drivers/dma/hsu/hsu.c | 90 | ||||
-rw-r--r-- | drivers/dma/hsu/pci.c | 11 |
2 files changed, 78 insertions, 23 deletions
diff --git a/drivers/dma/hsu/hsu.c b/drivers/dma/hsu/hsu.c index f8c5cd53307c..c5f21efd6090 100644 --- a/drivers/dma/hsu/hsu.c +++ b/drivers/dma/hsu/hsu.c @@ -126,28 +126,33 @@ static void hsu_dma_start_transfer(struct hsu_dma_chan *hsuc) hsu_dma_start_channel(hsuc); } -static u32 hsu_dma_chan_get_sr(struct hsu_dma_chan *hsuc) -{ - unsigned long flags; - u32 sr; - - spin_lock_irqsave(&hsuc->vchan.lock, flags); - sr = hsu_chan_readl(hsuc, HSU_CH_SR); - spin_unlock_irqrestore(&hsuc->vchan.lock, flags); - - return sr & ~(HSU_CH_SR_DESCE_ANY | HSU_CH_SR_CDESC_ANY); -} - -irqreturn_t hsu_dma_irq(struct hsu_dma_chip *chip, unsigned short nr) +/* + * hsu_dma_get_status() - get DMA channel status + * @chip: HSUART DMA chip + * @nr: DMA channel number + * @status: pointer for DMA Channel Status Register value + * + * Description: + * The function reads and clears the DMA Channel Status Register, checks + * if it was a timeout interrupt and returns a corresponding value. + * + * Caller should provide a valid pointer for the DMA Channel Status + * Register value that will be returned in @status. + * + * Return: + * 1 for DMA timeout status, 0 for other DMA status, or error code for + * invalid parameters or no interrupt pending. + */ +int hsu_dma_get_status(struct hsu_dma_chip *chip, unsigned short nr, + u32 *status) { struct hsu_dma_chan *hsuc; - struct hsu_dma_desc *desc; unsigned long flags; u32 sr; /* Sanity check */ if (nr >= chip->hsu->nr_channels) - return IRQ_NONE; + return -EINVAL; hsuc = &chip->hsu->chan[nr]; @@ -155,22 +160,65 @@ irqreturn_t hsu_dma_irq(struct hsu_dma_chip *chip, unsigned short nr) * No matter what situation, need read clear the IRQ status * There is a bug, see Errata 5, HSD 2900918 */ - sr = hsu_dma_chan_get_sr(hsuc); + spin_lock_irqsave(&hsuc->vchan.lock, flags); + sr = hsu_chan_readl(hsuc, HSU_CH_SR); + spin_unlock_irqrestore(&hsuc->vchan.lock, flags); + + /* Check if any interrupt is pending */ + sr &= ~(HSU_CH_SR_DESCE_ANY | HSU_CH_SR_CDESC_ANY); if (!sr) - return IRQ_NONE; + return -EIO; /* Timeout IRQ, need wait some time, see Errata 2 */ if (sr & HSU_CH_SR_DESCTO_ANY) udelay(2); + /* + * At this point, at least one of Descriptor Time Out, Channel Error + * or Descriptor Done bits must be set. Clear the Descriptor Time Out + * bits and if sr is still non-zero, it must be channel error or + * descriptor done which are higher priority than timeout and handled + * in hsu_dma_do_irq(). Else, it must be a timeout. + */ sr &= ~HSU_CH_SR_DESCTO_ANY; - if (!sr) - return IRQ_HANDLED; + + *status = sr; + + return sr ? 0 : 1; +} +EXPORT_SYMBOL_GPL(hsu_dma_get_status); + +/* + * hsu_dma_do_irq() - DMA interrupt handler + * @chip: HSUART DMA chip + * @nr: DMA channel number + * @status: Channel Status Register value + * + * Description: + * This function handles Channel Error and Descriptor Done interrupts. + * This function should be called after determining that the DMA interrupt + * is not a normal timeout interrupt, ie. hsu_dma_get_status() returned 0. + * + * Return: + * IRQ_NONE for invalid channel number, IRQ_HANDLED otherwise. + */ +irqreturn_t hsu_dma_do_irq(struct hsu_dma_chip *chip, unsigned short nr, + u32 status) +{ + struct hsu_dma_chan *hsuc; + struct hsu_dma_desc *desc; + unsigned long flags; + + /* Sanity check */ + if (nr >= chip->hsu->nr_channels) + return IRQ_NONE; + + hsuc = &chip->hsu->chan[nr]; spin_lock_irqsave(&hsuc->vchan.lock, flags); desc = hsuc->desc; if (desc) { - if (sr & HSU_CH_SR_CHE) { + if (status & HSU_CH_SR_CHE) { desc->status = DMA_ERROR; } else if (desc->active < desc->nents) { hsu_dma_start_channel(hsuc); @@ -184,7 +232,7 @@ irqreturn_t hsu_dma_irq(struct hsu_dma_chip *chip, unsigned short nr) return IRQ_HANDLED; } -EXPORT_SYMBOL_GPL(hsu_dma_irq); +EXPORT_SYMBOL_GPL(hsu_dma_do_irq); static struct hsu_dma_desc *hsu_dma_alloc_desc(unsigned int nents) { diff --git a/drivers/dma/hsu/pci.c b/drivers/dma/hsu/pci.c index e2db76bd56d8..9916058531d9 100644 --- a/drivers/dma/hsu/pci.c +++ b/drivers/dma/hsu/pci.c @@ -27,13 +27,20 @@ static irqreturn_t hsu_pci_irq(int irq, void *dev) { struct hsu_dma_chip *chip = dev; u32 dmaisr; + u32 status; unsigned short i; irqreturn_t ret = IRQ_NONE; + int err; dmaisr = readl(chip->regs + HSU_PCI_DMAISR); for (i = 0; i < chip->hsu->nr_channels; i++) { - if (dmaisr & 0x1) - ret |= hsu_dma_irq(chip, i); + if (dmaisr & 0x1) { + err = hsu_dma_get_status(chip, i, &status); + if (err > 0) + ret |= IRQ_HANDLED; + else if (err == 0) + ret |= hsu_dma_do_irq(chip, i, status); + } dmaisr >>= 1; } |