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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>
tirimbino
Russell King - ARM Linux 14 years ago committed by Dan Williams
parent 0261f74163
commit 94ae85220a
2 changed files with 72 additions and 117 deletions
Show all changes Ignore whitespace when comparing lines Ignore changes in amount of whitespace Ignore changes in whitespace at EOL
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  1. 146
      drivers/dma/amba-pl08x.c
  2. 43
      include/linux/amba/pl08x.h

146
drivers/dma/amba-pl08x.c
Unescape View File

@ -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,
@ -1045,10 +1020,6 @@ pl08x_dma_tx_status(struct dma_chan *chan,
return ret;
}
/*
* schedule(); could be inserted here
*/
/*
* This cookie not complete yet
*/
@ -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);

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

@ -12,7 +12,6 @@
*
* Please credit ARM.com
* Documentation: ARM DDI 0196D
*
*/
#ifndef AMBA_PL08X_H
@ -55,8 +54,8 @@ enum {
* @circular_buffer: whether the buffer passed in is circular and
* shall simply be looped round round (like a record baby round
* round round round)
* @single: the device connected to this channel will request single
* DMA transfers, not bursts. (Bursts are default.)
* @single: the device connected to this channel will request single DMA
* transfers, not bursts. (Bursts are default.)
* @periph_buses: the device connected to this channel is accessible via
* these buses (use PL08X_AHB1 | PL08X_AHB2).
*/
@ -78,8 +77,7 @@ struct pl08x_channel_data {
* @addr: current address
* @maxwidth: the maximum width of a transfer on this bus
* @buswidth: the width of this bus in bytes: 1, 2 or 4
* @fill_bytes: bytes required to fill to the next bus memory
* boundary
* @fill_bytes: bytes required to fill to the next bus memory boundary
*/
struct pl08x_bus_data {
dma_addr_t addr;
@ -92,10 +90,10 @@ struct pl08x_bus_data {
* struct pl08x_phy_chan - holder for the physical channels
* @id: physical index to this channel
* @lock: a lock to use when altering an instance of this struct
* @signal: the physical signal (aka channel) serving this
* physical channel right now
* @serving: the virtual channel currently being served by this
* physical channel
* @signal: the physical signal (aka channel) serving this physical channel
* right now
* @serving: the virtual channel currently being served by this physical
* channel
*/
struct pl08x_phy_chan {
unsigned int id;
@ -119,7 +117,6 @@ struct pl08x_txd {
size_t len;
dma_addr_t llis_bus;
struct pl08x_lli *llis_va;
bool active;
/* Default cctl value for LLIs */
u32 cctl;
/*
@ -130,8 +127,8 @@ struct pl08x_txd {
};
/**
* struct pl08x_dma_chan_state - holds the PL08x specific virtual
* channel states
* struct pl08x_dma_chan_state - holds the PL08x specific virtual channel
* states
* @PL08X_CHAN_IDLE: the channel is idle
* @PL08X_CHAN_RUNNING: the channel has allocated a physical transport
* channel and is running a transfer on it
@ -152,7 +149,7 @@ enum pl08x_dma_chan_state {
* @chan: wrappped abstract channel
* @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
* have no pending entries
* have no pending entries
* @tasklet: tasklet scheduled by the IRQ to handle actual work etc
* @name: name of channel
* @cd: channel platform data
@ -166,8 +163,8 @@ enum pl08x_dma_chan_state {
* @host: a pointer to the host (internal use)
* @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 {
struct dma_chan chan;
@ -189,16 +186,16 @@ struct pl08x_dma_chan {
};
/**
* 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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