diff options
Diffstat (limited to 'drivers/dma')
| -rw-r--r-- | drivers/dma/at_xdmac.c | 82 | ||||
| -rw-r--r-- | drivers/dma/hsu/hsu.c | 90 | ||||
| -rw-r--r-- | drivers/dma/hsu/pci.c | 11 | ||||
| -rw-r--r-- | drivers/dma/mv_xor.c | 10 |
4 files changed, 141 insertions, 52 deletions
diff --git a/drivers/dma/at_xdmac.c b/drivers/dma/at_xdmac.c index 0d5c7ce43e0e..e434ffe7bc5c 100644 --- a/drivers/dma/at_xdmac.c +++ b/drivers/dma/at_xdmac.c @@ -242,7 +242,7 @@ struct at_xdmac_lld { u32 mbr_dus; /* Destination Microblock Stride Register */ }; - +/* 64-bit alignment needed to update CNDA and CUBC registers in an atomic way. */ struct at_xdmac_desc { struct at_xdmac_lld lld; enum dma_transfer_direction direction; @@ -253,7 +253,7 @@ struct at_xdmac_desc { unsigned int xfer_size; struct list_head descs_list; struct list_head xfer_node; -}; +} __aligned(sizeof(u64)); static inline void __iomem *at_xdmac_chan_reg_base(struct at_xdmac *atxdmac, unsigned int chan_nb) { @@ -1400,6 +1400,7 @@ at_xdmac_tx_status(struct dma_chan *chan, dma_cookie_t cookie, u32 cur_nda, check_nda, cur_ubc, mask, value; u8 dwidth = 0; unsigned long flags; + bool initd; ret = dma_cookie_status(chan, cookie, txstate); if (ret == DMA_COMPLETE) @@ -1424,7 +1425,16 @@ at_xdmac_tx_status(struct dma_chan *chan, dma_cookie_t cookie, residue = desc->xfer_size; /* * Flush FIFO: only relevant when the transfer is source peripheral - * synchronized. + * synchronized. Flush is needed before reading CUBC because data in + * the FIFO are not reported by CUBC. Reporting a residue of the + * transfer length while we have data in FIFO can cause issue. + * Usecase: atmel USART has a timeout which means I have received + * characters but there is no more character received for a while. On + * timeout, it requests the residue. If the data are in the DMA FIFO, + * we will return a residue of the transfer length. It means no data + * received. If an application is waiting for these data, it will hang + * since we won't have another USART timeout without receiving new + * data. */ mask = AT_XDMAC_CC_TYPE | AT_XDMAC_CC_DSYNC; value = AT_XDMAC_CC_TYPE_PER_TRAN | AT_XDMAC_CC_DSYNC_PER2MEM; @@ -1435,34 +1445,43 @@ at_xdmac_tx_status(struct dma_chan *chan, dma_cookie_t cookie, } /* - * When processing the residue, we need to read two registers but we - * can't do it in an atomic way. AT_XDMAC_CNDA is used to find where - * we stand in the descriptor list and AT_XDMAC_CUBC is used - * to know how many data are remaining for the current descriptor. - * Since the dma channel is not paused to not loose data, between the - * AT_XDMAC_CNDA and AT_XDMAC_CUBC read, we may have change of - * descriptor. - * For that reason, after reading AT_XDMAC_CUBC, we check if we are - * still using the same descriptor by reading a second time - * AT_XDMAC_CNDA. If AT_XDMAC_CNDA has changed, it means we have to - * read again AT_XDMAC_CUBC. + * The easiest way to compute the residue should be to pause the DMA + * but doing this can lead to miss some data as some devices don't + * have FIFO. + * We need to read several registers because: + * - DMA is running therefore a descriptor change is possible while + * reading these registers + * - When the block transfer is done, the value of the CUBC register + * is set to its initial value until the fetch of the next descriptor. + * This value will corrupt the residue calculation so we have to skip + * it. + * + * INITD -------- ------------ + * |____________________| + * _______________________ _______________ + * NDA @desc2 \/ @desc3 + * _______________________/\_______________ + * __________ ___________ _______________ + * CUBC 0 \/ MAX desc1 \/ MAX desc2 + * __________/\___________/\_______________ + * + * Since descriptors are aligned on 64 bits, we can assume that + * the update of NDA and CUBC is atomic. * Memory barriers are used to ensure the read order of the registers. - * A max number of retries is set because unlikely it can never ends if - * we are transferring a lot of data with small buffers. + * A max number of retries is set because unlikely it could never ends. */ - cur_nda = at_xdmac_chan_read(atchan, AT_XDMAC_CNDA) & 0xfffffffc; - rmb(); - cur_ubc = at_xdmac_chan_read(atchan, AT_XDMAC_CUBC); for (retry = 0; retry < AT_XDMAC_RESIDUE_MAX_RETRIES; retry++) { - rmb(); check_nda = at_xdmac_chan_read(atchan, AT_XDMAC_CNDA) & 0xfffffffc; - - if (likely(cur_nda == check_nda)) - break; - - cur_nda = check_nda; + rmb(); + initd = !!(at_xdmac_chan_read(atchan, AT_XDMAC_CC) & AT_XDMAC_CC_INITD); rmb(); cur_ubc = at_xdmac_chan_read(atchan, AT_XDMAC_CUBC); + rmb(); + cur_nda = at_xdmac_chan_read(atchan, AT_XDMAC_CNDA) & 0xfffffffc; + rmb(); + + if ((check_nda == cur_nda) && initd) + break; } if (unlikely(retry >= AT_XDMAC_RESIDUE_MAX_RETRIES)) { @@ -1471,6 +1490,19 @@ at_xdmac_tx_status(struct dma_chan *chan, dma_cookie_t cookie, } /* + * Flush FIFO: only relevant when the transfer is source peripheral + * synchronized. Another flush is needed here because CUBC is updated + * when the controller sends the data write command. It can lead to + * report data that are not written in the memory or the device. The + * FIFO flush ensures that data are really written. + */ + if ((desc->lld.mbr_cfg & mask) == value) { + at_xdmac_write(atxdmac, AT_XDMAC_GSWF, atchan->mask); + while (!(at_xdmac_chan_read(atchan, AT_XDMAC_CIS) & AT_XDMAC_CIS_FIS)) + cpu_relax(); + } + + /* * Remove size of all microblocks already transferred and the current * one. Then add the remaining size to transfer of the current * microblock. 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; } diff --git a/drivers/dma/mv_xor.c b/drivers/dma/mv_xor.c index 55815c1dfb04..f4c9f98ec35e 100644 --- a/drivers/dma/mv_xor.c +++ b/drivers/dma/mv_xor.c @@ -703,8 +703,9 @@ static int mv_chan_memcpy_self_test(struct mv_xor_chan *mv_chan) goto free_resources; } - src_dma = dma_map_page(dma_chan->device->dev, virt_to_page(src), 0, - PAGE_SIZE, DMA_TO_DEVICE); + src_dma = dma_map_page(dma_chan->device->dev, virt_to_page(src), + (size_t)src & ~PAGE_MASK, PAGE_SIZE, + DMA_TO_DEVICE); unmap->addr[0] = src_dma; ret = dma_mapping_error(dma_chan->device->dev, src_dma); @@ -714,8 +715,9 @@ static int mv_chan_memcpy_self_test(struct mv_xor_chan *mv_chan) } unmap->to_cnt = 1; - dest_dma = dma_map_page(dma_chan->device->dev, virt_to_page(dest), 0, - PAGE_SIZE, DMA_FROM_DEVICE); + dest_dma = dma_map_page(dma_chan->device->dev, virt_to_page(dest), + (size_t)dest & ~PAGE_MASK, PAGE_SIZE, + DMA_FROM_DEVICE); unmap->addr[1] = dest_dma; ret = dma_mapping_error(dma_chan->device->dev, dest_dma); |