ARM: PL08x: cleanup comments
Cleanup the formatting of comments, remove some which don't make sense
anymore.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
[fix conflict with 96a608a4]
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
This commit is contained in:
Russell King - ARM Linux
Dan Williams
Родитель
0261f74163
Коммит
94ae85220a
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@ -19,14 +19,14 @@
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* this program; if not, write to the Free Software Foundation, Inc., 59
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* Temple Place - Suite 330, Boston, MA 02111-1307, USA.
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*
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* The full GNU General Public License is in this distribution in the
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* file called COPYING.
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* The full GNU General Public License is in this distribution in the file
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* called COPYING.
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*
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* Documentation: ARM DDI 0196G == PL080
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* Documentation: ARM DDI 0218E == PL081
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* Documentation: ARM DDI 0218E == PL081
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*
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* PL080 & PL081 both have 16 sets of DMA signals that can be routed to
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* any channel.
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* PL080 & PL081 both have 16 sets of DMA signals that can be routed to any
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* channel.
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*
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* The PL080 has 8 channels available for simultaneous use, and the PL081
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* has only two channels. So on these DMA controllers the number of channels
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@ -91,11 +91,9 @@
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#define DRIVER_NAME "pl08xdmac"
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/**
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* struct vendor_data - vendor-specific config parameters
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* for PL08x derivatives
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* struct vendor_data - vendor-specific config parameters for PL08x derivatives
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* @channels: the number of channels available in this variant
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* @dualmaster: whether this version supports dual AHB masters
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* or not.
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* @dualmaster: whether this version supports dual AHB masters or not.
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*/
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struct vendor_data {
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u8 channels;
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@ -241,10 +239,8 @@ static void pl08x_start_txd(struct pl08x_dma_chan *plchan,
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*
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* Disabling individual channels could lose data.
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*
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* Disable the peripheral DMA after disabling the DMAC
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* in order to allow the DMAC FIFO to drain, and
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* hence allow the channel to show inactive
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*
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* Disable the peripheral DMA after disabling the DMAC in order to allow
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* the DMAC FIFO to drain, and hence allow the channel to show inactive
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*/
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static void pl08x_pause_phy_chan(struct pl08x_phy_chan *ch)
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{
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@ -367,6 +363,10 @@ static u32 pl08x_getbytes_chan(struct pl08x_dma_chan *plchan)
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/*
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* Allocate a physical channel for a virtual channel
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*
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* Try to locate a physical channel to be used for this transfer. If all
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* are taken return NULL and the requester will have to cope by using
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* some fallback PIO mode or retrying later.
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*/
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static struct pl08x_phy_chan *
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pl08x_get_phy_channel(struct pl08x_driver_data *pl08x,
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@ -376,12 +376,6 @@ pl08x_get_phy_channel(struct pl08x_driver_data *pl08x,
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unsigned long flags;
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int i;
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/*
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* Try to locate a physical channel to be used for
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* this transfer. If all are taken return NULL and
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* the requester will have to cope by using some fallback
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* PIO mode or retrying later.
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*/
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for (i = 0; i < pl08x->vd->channels; i++) {
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ch = &pl08x->phy_chans[i];
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@ -495,9 +489,9 @@ struct pl08x_lli_build_data {
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};
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/*
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* Autoselect a master bus to use for the transfer
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* this prefers the destination bus if both available
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* if fixed address on one bus the other will be chosen
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* Autoselect a master bus to use for the transfer this prefers the
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* destination bus if both available if fixed address on one bus the
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* other will be chosen
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*/
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static void pl08x_choose_master_bus(struct pl08x_lli_build_data *bd,
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struct pl08x_bus_data **mbus, struct pl08x_bus_data **sbus, u32 cctl)
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@ -530,8 +524,7 @@ static void pl08x_choose_master_bus(struct pl08x_lli_build_data *bd,
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}
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/*
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* Fills in one LLI for a certain transfer descriptor
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* and advance the counter
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* Fills in one LLI for a certain transfer descriptor and advance the counter
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*/
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static void pl08x_fill_lli_for_desc(struct pl08x_lli_build_data *bd,
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int num_llis, int len, u32 cctl)
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@ -640,15 +633,11 @@ static int pl08x_fill_llis_for_desc(struct pl08x_driver_data *pl08x,
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* Choose bus to align to
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* - prefers destination bus if both available
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* - if fixed address on one bus chooses other
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* - modifies cctl to choose an appropriate master
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*/
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pl08x_choose_master_bus(&bd, &mbus, &sbus, cctl);
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if (txd->len < mbus->buswidth) {
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/*
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* Less than a bus width available
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* - send as single bytes
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*/
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/* Less than a bus width available - send as single bytes */
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while (bd.remainder) {
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dev_vdbg(&pl08x->adev->dev,
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"%s single byte LLIs for a transfer of "
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@ -659,10 +648,7 @@ static int pl08x_fill_llis_for_desc(struct pl08x_driver_data *pl08x,
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total_bytes++;
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}
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} else {
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/*
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* Make one byte LLIs until master bus is aligned
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* - slave will then be aligned also
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*/
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/* Make one byte LLIs until master bus is aligned */
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while ((mbus->addr) % (mbus->buswidth)) {
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dev_vdbg(&pl08x->adev->dev,
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"%s adjustment lli for less than bus width "
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@ -674,7 +660,7 @@ static int pl08x_fill_llis_for_desc(struct pl08x_driver_data *pl08x,
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}
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/*
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* Master now aligned
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* Master now aligned
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* - if slave is not then we must set its width down
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*/
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if (sbus->addr % sbus->buswidth) {
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@ -732,10 +718,8 @@ static int pl08x_fill_llis_for_desc(struct pl08x_driver_data *pl08x,
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if (lli_len == target_len) {
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/*
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* Can send what we wanted
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*/
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/*
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* Maintain alignment
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* Can send what we wanted.
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* Maintain alignment
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*/
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lli_len = (lli_len/mbus->buswidth) *
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mbus->buswidth;
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@ -743,17 +727,14 @@ static int pl08x_fill_llis_for_desc(struct pl08x_driver_data *pl08x,
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} else {
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/*
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* So now we know how many bytes to transfer
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* to get to the nearest boundary
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* The next LLI will past the boundary
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* - however we may be working to a boundary
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* on the slave bus
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* We need to ensure the master stays aligned
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* to get to the nearest boundary. The next
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* LLI will past the boundary. However, we
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* may be working to a boundary on the slave
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* bus. We need to ensure the master stays
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* aligned, and that we are working in
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* multiples of the bus widths.
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*/
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odd_bytes = lli_len % mbus->buswidth;
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/*
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* - and that we are working in multiples
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* of the bus widths
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*/
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lli_len -= odd_bytes;
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}
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@ -793,8 +774,8 @@ static int pl08x_fill_llis_for_desc(struct pl08x_driver_data *pl08x,
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if (odd_bytes) {
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/*
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* Creep past the boundary,
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* maintaining master alignment
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* Creep past the boundary, maintaining
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* master alignment
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*/
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int j;
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for (j = 0; (j < mbus->buswidth)
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@ -837,13 +818,9 @@ static int pl08x_fill_llis_for_desc(struct pl08x_driver_data *pl08x,
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}
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llis_va = txd->llis_va;
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/*
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* The final LLI terminates the LLI.
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*/
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/* The final LLI terminates the LLI. */
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llis_va[num_llis - 1].lli = 0;
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/*
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* The final LLI element shall also fire an interrupt
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*/
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/* The final LLI element shall also fire an interrupt. */
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llis_va[num_llis - 1].cctl |= PL080_CONTROL_TC_IRQ_EN;
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#ifdef VERBOSE_DEBUG
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@ -891,7 +868,6 @@ static void pl08x_free_txd_list(struct pl08x_driver_data *pl08x,
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list_del(&txdi->node);
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pl08x_free_txd(pl08x, txdi);
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}
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}
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}
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@ -1020,10 +996,9 @@ static struct dma_async_tx_descriptor *pl08x_prep_dma_interrupt(
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}
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/*
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* Code accessing dma_async_is_complete() in a tight loop
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* may give problems - could schedule where indicated.
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* If slaves are relying on interrupts to signal completion this
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* function must not be called with interrupts disabled
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* Code accessing dma_async_is_complete() in a tight loop may give problems.
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* If slaves are relying on interrupts to signal completion this function
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* must not be called with interrupts disabled.
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*/
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static enum dma_status
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pl08x_dma_tx_status(struct dma_chan *chan,
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@ -1045,10 +1020,6 @@ pl08x_dma_tx_status(struct dma_chan *chan,
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return ret;
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}
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/*
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* schedule(); could be inserted here
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*/
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/*
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* This cookie not complete yet
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*/
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@ -1273,11 +1244,10 @@ static int pl08x_prep_channel_resources(struct pl08x_dma_chan *plchan,
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}
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} else
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/*
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* Else we're all set, paused and ready to roll,
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* status will switch to PL08X_CHAN_RUNNING when
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* we call issue_pending(). If there is something
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* running on the channel already we don't change
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* its state.
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* Else we're all set, paused and ready to roll, status
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* will switch to PL08X_CHAN_RUNNING when we call
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* issue_pending(). If there is something running on the
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* channel already we don't change its state.
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*/
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if (plchan->state == PL08X_CHAN_IDLE)
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plchan->state = PL08X_CHAN_PAUSED;
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@ -1528,10 +1498,9 @@ bool pl08x_filter_id(struct dma_chan *chan, void *chan_id)
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/*
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* Just check that the device is there and active
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* TODO: turn this bit on/off depending on the number of
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* physical channels actually used, if it is zero... well
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* shut it off. That will save some power. Cut the clock
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* at the same time.
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* TODO: turn this bit on/off depending on the number of physical channels
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* actually used, if it is zero... well shut it off. That will save some
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* power. Cut the clock at the same time.
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*/
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static void pl08x_ensure_on(struct pl08x_driver_data *pl08x)
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{
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@ -1579,16 +1548,11 @@ static void pl08x_tasklet(unsigned long data)
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plchan->at = NULL;
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if (txd) {
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/*
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* Update last completed
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*/
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/* Update last completed */
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plchan->lc = txd->tx.cookie;
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}
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/*
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* If a new descriptor is queued, set it up
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* plchan->at is NULL here
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*/
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/* If a new descriptor is queued, set it up plchan->at is NULL here */
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if (!list_empty(&plchan->pend_list)) {
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struct pl08x_txd *next;
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@ -1615,11 +1579,10 @@ static void pl08x_tasklet(unsigned long data)
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plchan->state = PL08X_CHAN_IDLE;
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/*
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* And NOW before anyone else can grab that free:d
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* up physical channel, see if there is some memcpy
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* pending that seriously needs to start because of
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* being stacked up while we were choking the
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* physical channels with data.
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* And NOW before anyone else can grab that free:d up
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* physical channel, see if there is some memcpy pending
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* that seriously needs to start because of being stacked
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* up while we were choking the physical channels with data.
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*/
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list_for_each_entry(waiting, &pl08x->memcpy.channels,
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chan.device_node) {
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@ -1670,9 +1633,7 @@ static irqreturn_t pl08x_irq(int irq, void *dev)
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val = readl(pl08x->base + PL080_ERR_STATUS);
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if (val) {
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/*
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* An error interrupt (on one or more channels)
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*/
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/* An error interrupt (on one or more channels) */
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dev_err(&pl08x->adev->dev,
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"%s error interrupt, register value 0x%08x\n",
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__func__, val);
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@ -1696,9 +1657,7 @@ static irqreturn_t pl08x_irq(int irq, void *dev)
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mask |= (1 << i);
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}
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}
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/*
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* Clear only the terminal interrupts on channels we processed
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*/
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/* Clear only the terminal interrupts on channels we processed */
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writel(mask, pl08x->base + PL080_TC_CLEAR);
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return mask ? IRQ_HANDLED : IRQ_NONE;
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@ -1717,6 +1676,7 @@ static int pl08x_dma_init_virtual_channels(struct pl08x_driver_data *pl08x,
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int i;
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INIT_LIST_HEAD(&dmadev->channels);
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/*
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* Register as many many memcpy as we have physical channels,
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* we won't always be able to use all but the code will have
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@ -1950,9 +1910,7 @@ static int pl08x_probe(struct amba_device *adev, struct amba_id *id)
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/* Turn on the PL08x */
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pl08x_ensure_on(pl08x);
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/*
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* Attach the interrupt handler
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*/
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/* Attach the interrupt handler */
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writel(0x000000FF, pl08x->base + PL080_ERR_CLEAR);
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writel(0x000000FF, pl08x->base + PL080_TC_CLEAR);
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@ -12,7 +12,6 @@
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*
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* Please credit ARM.com
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* Documentation: ARM DDI 0196D
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*
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*/
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#ifndef AMBA_PL08X_H
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@ -55,8 +54,8 @@ enum {
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* @circular_buffer: whether the buffer passed in is circular and
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* shall simply be looped round round (like a record baby round
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* round round round)
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* @single: the device connected to this channel will request single
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* DMA transfers, not bursts. (Bursts are default.)
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* @single: the device connected to this channel will request single DMA
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* transfers, not bursts. (Bursts are default.)
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* @periph_buses: the device connected to this channel is accessible via
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* these buses (use PL08X_AHB1 | PL08X_AHB2).
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*/
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@ -78,8 +77,7 @@ struct pl08x_channel_data {
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* @addr: current address
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* @maxwidth: the maximum width of a transfer on this bus
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* @buswidth: the width of this bus in bytes: 1, 2 or 4
|
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* @fill_bytes: bytes required to fill to the next bus memory
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* boundary
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* @fill_bytes: bytes required to fill to the next bus memory boundary
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*/
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struct pl08x_bus_data {
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dma_addr_t addr;
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@ -92,10 +90,10 @@ struct pl08x_bus_data {
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* struct pl08x_phy_chan - holder for the physical channels
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* @id: physical index to this channel
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* @lock: a lock to use when altering an instance of this struct
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* @signal: the physical signal (aka channel) serving this
|
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* physical channel right now
|
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* @serving: the virtual channel currently being served by this
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* physical channel
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* @signal: the physical signal (aka channel) serving this physical channel
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* right now
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* @serving: the virtual channel currently being served by this physical
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* channel
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*/
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struct pl08x_phy_chan {
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unsigned int id;
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@ -119,7 +117,6 @@ struct pl08x_txd {
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size_t len;
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dma_addr_t llis_bus;
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struct pl08x_lli *llis_va;
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bool active;
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/* Default cctl value for LLIs */
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u32 cctl;
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/*
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@ -130,8 +127,8 @@ struct pl08x_txd {
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};
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/**
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* struct pl08x_dma_chan_state - holds the PL08x specific virtual
|
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* channel states
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* struct pl08x_dma_chan_state - holds the PL08x specific virtual channel
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* states
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* @PL08X_CHAN_IDLE: the channel is idle
|
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* @PL08X_CHAN_RUNNING: the channel has allocated a physical transport
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* channel and is running a transfer on it
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@ -152,7 +149,7 @@ enum pl08x_dma_chan_state {
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* @chan: wrappped abstract channel
|
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* @phychan: the physical channel utilized by this channel, if there is one
|
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* @phychan_hold: if non-zero, hold on to the physical channel even if we
|
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* have no pending entries
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* have no pending entries
|
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* @tasklet: tasklet scheduled by the IRQ to handle actual work etc
|
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* @name: name of channel
|
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* @cd: channel platform data
|
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@ -166,8 +163,8 @@ enum pl08x_dma_chan_state {
|
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* @host: a pointer to the host (internal use)
|
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* @state: whether the channel is idle, paused, running etc
|
||||
* @slave: whether this channel is a device (slave) or for memcpy
|
||||
* @waiting: a TX descriptor on this channel which is waiting for
|
||||
* a physical channel to become available
|
||||
* @waiting: a TX descriptor on this channel which is waiting for a physical
|
||||
* channel to become available
|
||||
*/
|
||||
struct pl08x_dma_chan {
|
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struct dma_chan chan;
|
||||
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@ -189,16 +186,16 @@ struct pl08x_dma_chan {
|
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};
|
||||
|
||||
/**
|
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* struct pl08x_platform_data - the platform configuration for the
|
||||
* PL08x PrimeCells.
|
||||
* struct pl08x_platform_data - the platform configuration for the PL08x
|
||||
* PrimeCells.
|
||||
* @slave_channels: the channels defined for the different devices on the
|
||||
* platform, all inclusive, including multiplexed channels. The available
|
||||
* physical channels will be multiplexed around these signals as they
|
||||
* are requested, just enumerate all possible channels.
|
||||
* @get_signal: request a physical signal to be used for a DMA
|
||||
* transfer immediately: if there is some multiplexing or similar blocking
|
||||
* the use of the channel the transfer can be denied by returning
|
||||
* less than zero, else it returns the allocated signal number
|
||||
* physical channels will be multiplexed around these signals as they are
|
||||
* requested, just enumerate all possible channels.
|
||||
* @get_signal: request a physical signal to be used for a DMA transfer
|
||||
* immediately: if there is some multiplexing or similar blocking the use
|
||||
* of the channel the transfer can be denied by returning less than zero,
|
||||
* else it returns the allocated signal number
|
||||
* @put_signal: indicate to the platform that this physical signal is not
|
||||
* running any DMA transfer and multiplexing can be recycled
|
||||
* @lli_buses: buses which LLIs can be fetched from: PL08X_AHB1 | PL08X_AHB2
|
||||
|
|
|
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