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ARM: PL08x: cleanup comments

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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
2011-01-16 20:18:05 +00:00
committed by Dan Williams
parent 0261f74163
commit 94ae85220a
2 changed files with 72 additions and 117 deletions
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146
drivers/dma/amba-pl08x.c
View File

@@ -19,14 +19,14 @@
* this program; if not, write to the Free Software Foundation, Inc., 59 * this program; if not, write to the Free Software Foundation, Inc., 59
* Temple Place - Suite 330, Boston, MA 02111-1307, USA. * Temple Place - Suite 330, Boston, MA 02111-1307, USA.
* *
* The full GNU General Public License is in this distribution in the * The full GNU General Public License is in this distribution in the file
* file called COPYING. * called COPYING.
* *
* Documentation: ARM DDI 0196G == PL080 * 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 * PL080 & PL081 both have 16 sets of DMA signals that can be routed to any
* any channel. * channel.
* *
* The PL080 has 8 channels available for simultaneous use, and the PL081 * 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 * has only two channels. So on these DMA controllers the number of channels
@@ -91,11 +91,9 @@
#define DRIVER_NAME "pl08xdmac" #define DRIVER_NAME "pl08xdmac"
/** /**
* struct vendor_data - vendor-specific config parameters * struct vendor_data - vendor-specific config parameters for PL08x derivatives
* for PL08x derivatives
* @channels: the number of channels available in this variant * @channels: the number of channels available in this variant
* @dualmaster: whether this version supports dual AHB masters * @dualmaster: whether this version supports dual AHB masters or not.
* or not.
*/ */
struct vendor_data { struct vendor_data {
u8 channels; u8 channels;
@@ -241,10 +239,8 @@ static void pl08x_start_txd(struct pl08x_dma_chan *plchan,
* *
* Disabling individual channels could lose data. * Disabling individual channels could lose data.
* *
* Disable the peripheral DMA after disabling the DMAC * Disable the peripheral DMA after disabling the DMAC in order to allow
* in order to allow the DMAC FIFO to drain, and * the DMAC FIFO to drain, and hence allow the channel to show inactive
* hence allow the channel to show inactive
*
*/ */
static void pl08x_pause_phy_chan(struct pl08x_phy_chan *ch) 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 * 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 * static struct pl08x_phy_chan *
pl08x_get_phy_channel(struct pl08x_driver_data *pl08x, 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; unsigned long flags;
int i; 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++) { for (i = 0; i < pl08x->vd->channels; i++) {
ch = &pl08x->phy_chans[i]; ch = &pl08x->phy_chans[i];
@@ -495,9 +489,9 @@ struct pl08x_lli_build_data {
}; };
/* /*
* Autoselect a master bus to use for the transfer * Autoselect a master bus to use for the transfer this prefers the
* this prefers the destination bus if both available * destination bus if both available if fixed address on one bus the
* if fixed address on one bus the other will be chosen * other will be chosen
*/ */
static void pl08x_choose_master_bus(struct pl08x_lli_build_data *bd, static void pl08x_choose_master_bus(struct pl08x_lli_build_data *bd,
struct pl08x_bus_data **mbus, struct pl08x_bus_data **sbus, u32 cctl) 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 * Fills in one LLI for a certain transfer descriptor and advance the counter
* and advance the counter
*/ */
static void pl08x_fill_lli_for_desc(struct pl08x_lli_build_data *bd, static void pl08x_fill_lli_for_desc(struct pl08x_lli_build_data *bd,
int num_llis, int len, u32 cctl) 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 * Choose bus to align to
* - prefers destination bus if both available * - prefers destination bus if both available
* - if fixed address on one bus chooses other * - if fixed address on one bus chooses other
* - modifies cctl to choose an appropriate master
*/ */
pl08x_choose_master_bus(&bd, &mbus, &sbus, cctl); pl08x_choose_master_bus(&bd, &mbus, &sbus, cctl);
if (txd->len < mbus->buswidth) { 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) { while (bd.remainder) {
dev_vdbg(&pl08x->adev->dev, dev_vdbg(&pl08x->adev->dev,
"%s single byte LLIs for a transfer of " "%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++; total_bytes++;
} }
} else { } else {
/* /* Make one byte LLIs until master bus is aligned */
* Make one byte LLIs until master bus is aligned
* - slave will then be aligned also
*/
while ((mbus->addr) % (mbus->buswidth)) { while ((mbus->addr) % (mbus->buswidth)) {
dev_vdbg(&pl08x->adev->dev, dev_vdbg(&pl08x->adev->dev,
"%s adjustment lli for less than bus width " "%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 slave is not then we must set its width down
*/ */
if (sbus->addr % sbus->buswidth) { 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) { if (lli_len == target_len) {
/* /*
* Can send what we wanted * Can send what we wanted.
*/ * Maintain alignment
/*
* Maintain alignment
*/ */
lli_len = (lli_len/mbus->buswidth) * lli_len = (lli_len/mbus->buswidth) *
mbus->buswidth; mbus->buswidth;
@@ -743,17 +727,14 @@ static int pl08x_fill_llis_for_desc(struct pl08x_driver_data *pl08x,
} else { } else {
/* /*
* So now we know how many bytes to transfer * So now we know how many bytes to transfer
* to get to the nearest boundary * to get to the nearest boundary. The next
* The next LLI will past the boundary * LLI will past the boundary. However, we
* - however we may be working to a boundary * may be working to a boundary on the slave
* on the slave bus * bus. We need to ensure the master stays
* We need to ensure the master stays aligned * aligned, and that we are working in
* multiples of the bus widths.
*/ */
odd_bytes = lli_len % mbus->buswidth; odd_bytes = lli_len % mbus->buswidth;
/*
* - and that we are working in multiples
* of the bus widths
*/
lli_len -= odd_bytes; lli_len -= odd_bytes;
} }
@@ -793,8 +774,8 @@ static int pl08x_fill_llis_for_desc(struct pl08x_driver_data *pl08x,
if (odd_bytes) { if (odd_bytes) {
/* /*
* Creep past the boundary, * Creep past the boundary, maintaining
* maintaining master alignment * master alignment
*/ */
int j; int j;
for (j = 0; (j < mbus->buswidth) 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; llis_va = txd->llis_va;
/* /* The final LLI terminates the LLI. */
* The final LLI terminates the LLI.
*/
llis_va[num_llis - 1].lli = 0; 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; llis_va[num_llis - 1].cctl |= PL080_CONTROL_TC_IRQ_EN;
#ifdef VERBOSE_DEBUG #ifdef VERBOSE_DEBUG
@@ -891,7 +868,6 @@ static void pl08x_free_txd_list(struct pl08x_driver_data *pl08x,
list_del(&txdi->node); list_del(&txdi->node);
pl08x_free_txd(pl08x, txdi); 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 * Code accessing dma_async_is_complete() in a tight loop may give problems.
* may give problems - could schedule where indicated. * If slaves are relying on interrupts to signal completion this function
* If slaves are relying on interrupts to signal completion this * must not be called with interrupts disabled.
* function must not be called with interrupts disabled
*/ */
static enum dma_status static enum dma_status
pl08x_dma_tx_status(struct dma_chan *chan, pl08x_dma_tx_status(struct dma_chan *chan,
@@ -1045,10 +1020,6 @@ pl08x_dma_tx_status(struct dma_chan *chan,
return ret; return ret;
} }
/*
* schedule(); could be inserted here
*/
/* /*
* This cookie not complete yet * This cookie not complete yet
*/ */
@@ -1273,11 +1244,10 @@ static int pl08x_prep_channel_resources(struct pl08x_dma_chan *plchan,
} }
} else } else
/* /*
* Else we're all set, paused and ready to roll, * Else we're all set, paused and ready to roll, status
* status will switch to PL08X_CHAN_RUNNING when * will switch to PL08X_CHAN_RUNNING when we call
* we call issue_pending(). If there is something * issue_pending(). If there is something running on the
* running on the channel already we don't change * channel already we don't change its state.
* its state.
*/ */
if (plchan->state == PL08X_CHAN_IDLE) if (plchan->state == PL08X_CHAN_IDLE)
plchan->state = PL08X_CHAN_PAUSED; 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 * Just check that the device is there and active
* TODO: turn this bit on/off depending on the number of * TODO: turn this bit on/off depending on the number of physical channels
* physical channels actually used, if it is zero... well * actually used, if it is zero... well shut it off. That will save some
* shut it off. That will save some power. Cut the clock * power. Cut the clock at the same time.
* at the same time.
*/ */
static void pl08x_ensure_on(struct pl08x_driver_data *pl08x) static void pl08x_ensure_on(struct pl08x_driver_data *pl08x)
{ {
@@ -1579,16 +1548,11 @@ static void pl08x_tasklet(unsigned long data)
plchan->at = NULL; plchan->at = NULL;
if (txd) { if (txd) {
/* /* Update last completed */
* Update last completed
*/
plchan->lc = txd->tx.cookie; 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)) { if (!list_empty(&plchan->pend_list)) {
struct pl08x_txd *next; struct pl08x_txd *next;
@@ -1615,11 +1579,10 @@ static void pl08x_tasklet(unsigned long data)
plchan->state = PL08X_CHAN_IDLE; plchan->state = PL08X_CHAN_IDLE;
/* /*
* And NOW before anyone else can grab that free:d * And NOW before anyone else can grab that free:d up
* up physical channel, see if there is some memcpy * physical channel, see if there is some memcpy pending
* pending that seriously needs to start because of * that seriously needs to start because of being stacked
* being stacked up while we were choking the * up while we were choking the physical channels with data.
* physical channels with data.
*/ */
list_for_each_entry(waiting, &pl08x->memcpy.channels, list_for_each_entry(waiting, &pl08x->memcpy.channels,
chan.device_node) { chan.device_node) {
@@ -1670,9 +1633,7 @@ static irqreturn_t pl08x_irq(int irq, void *dev)
val = readl(pl08x->base + PL080_ERR_STATUS); val = readl(pl08x->base + PL080_ERR_STATUS);
if (val) { if (val) {
/* /* An error interrupt (on one or more channels) */
* An error interrupt (on one or more channels)
*/
dev_err(&pl08x->adev->dev, dev_err(&pl08x->adev->dev,
"%s error interrupt, register value 0x%08x\n", "%s error interrupt, register value 0x%08x\n",
__func__, val); __func__, val);
@@ -1696,9 +1657,7 @@ static irqreturn_t pl08x_irq(int irq, void *dev)
mask |= (1 << i); 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); writel(mask, pl08x->base + PL080_TC_CLEAR);
return mask ? IRQ_HANDLED : IRQ_NONE; return mask ? IRQ_HANDLED : IRQ_NONE;
@@ -1717,6 +1676,7 @@ static int pl08x_dma_init_virtual_channels(struct pl08x_driver_data *pl08x,
int i; int i;
INIT_LIST_HEAD(&dmadev->channels); INIT_LIST_HEAD(&dmadev->channels);
/* /*
* Register as many many memcpy as we have physical 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 * 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 */ /* Turn on the PL08x */
pl08x_ensure_on(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_ERR_CLEAR);
writel(0x000000FF, pl08x->base + PL080_TC_CLEAR); writel(0x000000FF, pl08x->base + PL080_TC_CLEAR);

43
include/linux/amba/pl08x.h
View File

@@ -12,7 +12,6 @@
* *
* Please credit ARM.com * Please credit ARM.com
* Documentation: ARM DDI 0196D * Documentation: ARM DDI 0196D
*
*/ */
#ifndef AMBA_PL08X_H #ifndef AMBA_PL08X_H
@@ -55,8 +54,8 @@ enum {
* @circular_buffer: whether the buffer passed in is circular and * @circular_buffer: whether the buffer passed in is circular and
* shall simply be looped round round (like a record baby round * shall simply be looped round round (like a record baby round
* round round round) * round round round)
* @single: the device connected to this channel will request single * @single: the device connected to this channel will request single DMA
* DMA transfers, not bursts. (Bursts are default.) * transfers, not bursts. (Bursts are default.)
* @periph_buses: the device connected to this channel is accessible via * @periph_buses: the device connected to this channel is accessible via
* these buses (use PL08X_AHB1 | PL08X_AHB2). * these buses (use PL08X_AHB1 | PL08X_AHB2).
*/ */
@@ -78,8 +77,7 @@ struct pl08x_channel_data {
* @addr: current address * @addr: current address
* @maxwidth: the maximum width of a transfer on this bus * @maxwidth: the maximum width of a transfer on this bus
* @buswidth: the width of this bus in bytes: 1, 2 or 4 * @buswidth: the width of this bus in bytes: 1, 2 or 4
* @fill_bytes: bytes required to fill to the next bus memory * @fill_bytes: bytes required to fill to the next bus memory boundary
* boundary
*/ */
struct pl08x_bus_data { struct pl08x_bus_data {
dma_addr_t addr; dma_addr_t addr;
@@ -92,10 +90,10 @@ struct pl08x_bus_data {
* struct pl08x_phy_chan - holder for the physical channels * struct pl08x_phy_chan - holder for the physical channels
* @id: physical index to this channel * @id: physical index to this channel
* @lock: a lock to use when altering an instance of this struct * @lock: a lock to use when altering an instance of this struct
* @signal: the physical signal (aka channel) serving this * @signal: the physical signal (aka channel) serving this physical channel
* physical channel right now * right now
* @serving: the virtual channel currently being served by this * @serving: the virtual channel currently being served by this physical
* physical channel * channel
*/ */
struct pl08x_phy_chan { struct pl08x_phy_chan {
unsigned int id; unsigned int id;
@@ -119,7 +117,6 @@ struct pl08x_txd {
size_t len; size_t len;
dma_addr_t llis_bus; dma_addr_t llis_bus;
struct pl08x_lli *llis_va; struct pl08x_lli *llis_va;
bool active;
/* Default cctl value for LLIs */ /* Default cctl value for LLIs */
u32 cctl; u32 cctl;
/* /*
@@ -130,8 +127,8 @@ struct pl08x_txd {
}; };
/** /**
* struct pl08x_dma_chan_state - holds the PL08x specific virtual * struct pl08x_dma_chan_state - holds the PL08x specific virtual channel
* channel states * states
* @PL08X_CHAN_IDLE: the channel is idle * @PL08X_CHAN_IDLE: the channel is idle
* @PL08X_CHAN_RUNNING: the channel has allocated a physical transport * @PL08X_CHAN_RUNNING: the channel has allocated a physical transport
* channel and is running a transfer on it * channel and is running a transfer on it
@@ -152,7 +149,7 @@ enum pl08x_dma_chan_state {
* @chan: wrappped abstract channel * @chan: wrappped abstract channel
* @phychan: the physical channel utilized by this channel, if there is one * @phychan: the physical channel utilized by this channel, if there is one
* @phychan_hold: if non-zero, hold on to the physical channel even if we * @phychan_hold: if non-zero, hold on to the physical channel even if we
* have no pending entries * have no pending entries
* @tasklet: tasklet scheduled by the IRQ to handle actual work etc * @tasklet: tasklet scheduled by the IRQ to handle actual work etc
* @name: name of channel * @name: name of channel
* @cd: channel platform data * @cd: channel platform data
@@ -166,8 +163,8 @@ enum pl08x_dma_chan_state {
* @host: a pointer to the host (internal use) * @host: a pointer to the host (internal use)
* @state: whether the channel is idle, paused, running etc * @state: whether the channel is idle, paused, running etc
* @slave: whether this channel is a device (slave) or for memcpy * @slave: whether this channel is a device (slave) or for memcpy
* @waiting: a TX descriptor on this channel which is waiting for * @waiting: a TX descriptor on this channel which is waiting for a physical
* a physical channel to become available * channel to become available
*/ */
struct pl08x_dma_chan { struct pl08x_dma_chan {
struct dma_chan chan; struct dma_chan chan;
@@ -189,16 +186,16 @@ struct pl08x_dma_chan {
}; };
/** /**
* struct pl08x_platform_data - the platform configuration for the * struct pl08x_platform_data - the platform configuration for the PL08x
* PL08x PrimeCells. * PrimeCells.
* @slave_channels: the channels defined for the different devices on the * @slave_channels: the channels defined for the different devices on the
* platform, all inclusive, including multiplexed channels. The available * platform, all inclusive, including multiplexed channels. The available
* physical channels will be multiplexed around these signals as they * physical channels will be multiplexed around these signals as they are
* are requested, just enumerate all possible channels. * requested, just enumerate all possible channels.
* @get_signal: request a physical signal to be used for a DMA * @get_signal: request a physical signal to be used for a DMA transfer
* transfer immediately: if there is some multiplexing or similar blocking * immediately: if there is some multiplexing or similar blocking the use
* the use of the channel the transfer can be denied by returning * of the channel the transfer can be denied by returning less than zero,
* less than zero, else it returns the allocated signal number * else it returns the allocated signal number
* @put_signal: indicate to the platform that this physical signal is not * @put_signal: indicate to the platform that this physical signal is not
* running any DMA transfer and multiplexing can be recycled * running any DMA transfer and multiplexing can be recycled
* @lli_buses: buses which LLIs can be fetched from: PL08X_AHB1 | PL08X_AHB2 * @lli_buses: buses which LLIs can be fetched from: PL08X_AHB1 | PL08X_AHB2