diff options
Diffstat (limited to 'drivers/dma/amba-pl08x.c')
| -rw-r--r-- | drivers/dma/amba-pl08x.c | 146 |
1 files changed, 52 insertions, 94 deletions
diff --git a/drivers/dma/amba-pl08x.c b/drivers/dma/amba-pl08x.c index bebc678ed4f..297f48b0cba 100644 --- a/drivers/dma/amba-pl08x.c +++ b/drivers/dma/amba-pl08x.c @@ -19,14 +19,14 @@ * this program; if not, write to the Free Software Foundation, Inc., 59 * Temple Place - Suite 330, Boston, MA 02111-1307, USA. * - * The full GNU General Public License is in this distribution in the - * file called COPYING. + * The full GNU General Public License is in this distribution in the file + * called COPYING. * * Documentation: ARM DDI 0196G == PL080 - * Documentation: ARM DDI 0218E == PL081 + * Documentation: ARM DDI 0218E == PL081 * - * PL080 & PL081 both have 16 sets of DMA signals that can be routed to - * any channel. + * PL080 & PL081 both have 16 sets of DMA signals that can be routed to any + * channel. * * The PL080 has 8 channels available for simultaneous use, and the PL081 * has only two channels. So on these DMA controllers the number of channels @@ -91,11 +91,9 @@ #define DRIVER_NAME "pl08xdmac" /** - * struct vendor_data - vendor-specific config parameters - * for PL08x derivatives + * struct vendor_data - vendor-specific config parameters for PL08x derivatives * @channels: the number of channels available in this variant - * @dualmaster: whether this version supports dual AHB masters - * or not. + * @dualmaster: whether this version supports dual AHB masters or not. */ struct vendor_data { u8 channels; @@ -241,10 +239,8 @@ static void pl08x_start_txd(struct pl08x_dma_chan *plchan, * * Disabling individual channels could lose data. * - * Disable the peripheral DMA after disabling the DMAC - * in order to allow the DMAC FIFO to drain, and - * hence allow the channel to show inactive - * + * Disable the peripheral DMA after disabling the DMAC in order to allow + * the DMAC FIFO to drain, and hence allow the channel to show inactive */ static void pl08x_pause_phy_chan(struct pl08x_phy_chan *ch) { @@ -367,6 +363,10 @@ static u32 pl08x_getbytes_chan(struct pl08x_dma_chan *plchan) /* * Allocate a physical channel for a virtual channel + * + * Try to locate a physical channel to be used for this transfer. If all + * are taken return NULL and the requester will have to cope by using + * some fallback PIO mode or retrying later. */ static struct pl08x_phy_chan * pl08x_get_phy_channel(struct pl08x_driver_data *pl08x, @@ -376,12 +376,6 @@ pl08x_get_phy_channel(struct pl08x_driver_data *pl08x, unsigned long flags; int i; - /* - * Try to locate a physical channel to be used for - * this transfer. If all are taken return NULL and - * the requester will have to cope by using some fallback - * PIO mode or retrying later. - */ for (i = 0; i < pl08x->vd->channels; i++) { ch = &pl08x->phy_chans[i]; @@ -495,9 +489,9 @@ struct pl08x_lli_build_data { }; /* - * Autoselect a master bus to use for the transfer - * this prefers the destination bus if both available - * if fixed address on one bus the other will be chosen + * Autoselect a master bus to use for the transfer this prefers the + * destination bus if both available if fixed address on one bus the + * other will be chosen */ static void pl08x_choose_master_bus(struct pl08x_lli_build_data *bd, struct pl08x_bus_data **mbus, struct pl08x_bus_data **sbus, u32 cctl) @@ -530,8 +524,7 @@ static void pl08x_choose_master_bus(struct pl08x_lli_build_data *bd, } /* - * Fills in one LLI for a certain transfer descriptor - * and advance the counter + * Fills in one LLI for a certain transfer descriptor and advance the counter */ static void pl08x_fill_lli_for_desc(struct pl08x_lli_build_data *bd, int num_llis, int len, u32 cctl) @@ -640,15 +633,11 @@ static int pl08x_fill_llis_for_desc(struct pl08x_driver_data *pl08x, * Choose bus to align to * - prefers destination bus if both available * - if fixed address on one bus chooses other - * - modifies cctl to choose an appropriate master */ pl08x_choose_master_bus(&bd, &mbus, &sbus, cctl); if (txd->len < mbus->buswidth) { - /* - * Less than a bus width available - * - send as single bytes - */ + /* Less than a bus width available - send as single bytes */ while (bd.remainder) { dev_vdbg(&pl08x->adev->dev, "%s single byte LLIs for a transfer of " @@ -659,10 +648,7 @@ static int pl08x_fill_llis_for_desc(struct pl08x_driver_data *pl08x, total_bytes++; } } else { - /* - * Make one byte LLIs until master bus is aligned - * - slave will then be aligned also - */ + /* Make one byte LLIs until master bus is aligned */ while ((mbus->addr) % (mbus->buswidth)) { dev_vdbg(&pl08x->adev->dev, "%s adjustment lli for less than bus width " @@ -674,7 +660,7 @@ static int pl08x_fill_llis_for_desc(struct pl08x_driver_data *pl08x, } /* - * Master now aligned + * Master now aligned * - if slave is not then we must set its width down */ if (sbus->addr % sbus->buswidth) { @@ -732,10 +718,8 @@ static int pl08x_fill_llis_for_desc(struct pl08x_driver_data *pl08x, if (lli_len == target_len) { /* - * Can send what we wanted - */ - /* - * Maintain alignment + * Can send what we wanted. + * Maintain alignment */ lli_len = (lli_len/mbus->buswidth) * mbus->buswidth; @@ -743,17 +727,14 @@ static int pl08x_fill_llis_for_desc(struct pl08x_driver_data *pl08x, } else { /* * So now we know how many bytes to transfer - * to get to the nearest boundary - * The next LLI will past the boundary - * - however we may be working to a boundary - * on the slave bus - * We need to ensure the master stays aligned + * to get to the nearest boundary. The next + * LLI will past the boundary. However, we + * may be working to a boundary on the slave + * bus. We need to ensure the master stays + * aligned, and that we are working in + * multiples of the bus widths. */ odd_bytes = lli_len % mbus->buswidth; - /* - * - and that we are working in multiples - * of the bus widths - */ lli_len -= odd_bytes; } @@ -793,8 +774,8 @@ static int pl08x_fill_llis_for_desc(struct pl08x_driver_data *pl08x, if (odd_bytes) { /* - * Creep past the boundary, - * maintaining master alignment + * Creep past the boundary, maintaining + * master alignment */ int j; for (j = 0; (j < mbus->buswidth) @@ -837,13 +818,9 @@ static int pl08x_fill_llis_for_desc(struct pl08x_driver_data *pl08x, } llis_va = txd->llis_va; - /* - * The final LLI terminates the LLI. - */ + /* The final LLI terminates the LLI. */ llis_va[num_llis - 1].lli = 0; - /* - * The final LLI element shall also fire an interrupt - */ + /* The final LLI element shall also fire an interrupt. */ llis_va[num_llis - 1].cctl |= PL080_CONTROL_TC_IRQ_EN; #ifdef VERBOSE_DEBUG @@ -891,7 +868,6 @@ static void pl08x_free_txd_list(struct pl08x_driver_data *pl08x, list_del(&txdi->node); pl08x_free_txd(pl08x, txdi); } - } } @@ -1020,10 +996,9 @@ static struct dma_async_tx_descriptor *pl08x_prep_dma_interrupt( } /* - * Code accessing dma_async_is_complete() in a tight loop - * may give problems - could schedule where indicated. - * If slaves are relying on interrupts to signal completion this - * function must not be called with interrupts disabled + * Code accessing dma_async_is_complete() in a tight loop may give problems. + * If slaves are relying on interrupts to signal completion this function + * must not be called with interrupts disabled. */ static enum dma_status pl08x_dma_tx_status(struct dma_chan *chan, @@ -1046,10 +1021,6 @@ pl08x_dma_tx_status(struct dma_chan *chan, } /* - * schedule(); could be inserted here - */ - - /* * This cookie not complete yet */ last_used = plchan->chan.cookie; @@ -1273,11 +1244,10 @@ static int pl08x_prep_channel_resources(struct pl08x_dma_chan *plchan, } } else /* - * Else we're all set, paused and ready to roll, - * status will switch to PL08X_CHAN_RUNNING when - * we call issue_pending(). If there is something - * running on the channel already we don't change - * its state. + * Else we're all set, paused and ready to roll, status + * will switch to PL08X_CHAN_RUNNING when we call + * issue_pending(). If there is something running on the + * channel already we don't change its state. */ if (plchan->state == PL08X_CHAN_IDLE) plchan->state = PL08X_CHAN_PAUSED; @@ -1528,10 +1498,9 @@ bool pl08x_filter_id(struct dma_chan *chan, void *chan_id) /* * Just check that the device is there and active - * TODO: turn this bit on/off depending on the number of - * physical channels actually used, if it is zero... well - * shut it off. That will save some power. Cut the clock - * at the same time. + * TODO: turn this bit on/off depending on the number of physical channels + * actually used, if it is zero... well shut it off. That will save some + * power. Cut the clock at the same time. */ static void pl08x_ensure_on(struct pl08x_driver_data *pl08x) { @@ -1579,16 +1548,11 @@ static void pl08x_tasklet(unsigned long data) plchan->at = NULL; if (txd) { - /* - * Update last completed - */ + /* Update last completed */ plchan->lc = txd->tx.cookie; } - /* - * If a new descriptor is queued, set it up - * plchan->at is NULL here - */ + /* If a new descriptor is queued, set it up plchan->at is NULL here */ if (!list_empty(&plchan->pend_list)) { struct pl08x_txd *next; @@ -1615,11 +1579,10 @@ static void pl08x_tasklet(unsigned long data) plchan->state = PL08X_CHAN_IDLE; /* - * And NOW before anyone else can grab that free:d - * up physical channel, see if there is some memcpy - * pending that seriously needs to start because of - * being stacked up while we were choking the - * physical channels with data. + * And NOW before anyone else can grab that free:d up + * physical channel, see if there is some memcpy pending + * that seriously needs to start because of being stacked + * up while we were choking the physical channels with data. */ list_for_each_entry(waiting, &pl08x->memcpy.channels, chan.device_node) { @@ -1670,9 +1633,7 @@ static irqreturn_t pl08x_irq(int irq, void *dev) val = readl(pl08x->base + PL080_ERR_STATUS); if (val) { - /* - * An error interrupt (on one or more channels) - */ + /* An error interrupt (on one or more channels) */ dev_err(&pl08x->adev->dev, "%s error interrupt, register value 0x%08x\n", __func__, val); @@ -1696,9 +1657,7 @@ static irqreturn_t pl08x_irq(int irq, void *dev) mask |= (1 << i); } } - /* - * Clear only the terminal interrupts on channels we processed - */ + /* Clear only the terminal interrupts on channels we processed */ writel(mask, pl08x->base + PL080_TC_CLEAR); return mask ? IRQ_HANDLED : IRQ_NONE; @@ -1717,6 +1676,7 @@ static int pl08x_dma_init_virtual_channels(struct pl08x_driver_data *pl08x, int i; INIT_LIST_HEAD(&dmadev->channels); + /* * Register as many many memcpy as we have physical channels, * we won't always be able to use all but the code will have @@ -1950,9 +1910,7 @@ static int pl08x_probe(struct amba_device *adev, struct amba_id *id) /* Turn on the PL08x */ pl08x_ensure_on(pl08x); - /* - * Attach the interrupt handler - */ + /* Attach the interrupt handler */ writel(0x000000FF, pl08x->base + PL080_ERR_CLEAR); writel(0x000000FF, pl08x->base + PL080_TC_CLEAR); |