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pch_dma: Fix CTL register access issue 

Currently, Mode-Control register is accessed by read-modify-write.

According to DMA hardware specifications datasheet, prohibits this method.
Because this register resets to 0 by DMA HW after DMA transfer completes.
Thus, current read-modify-write processing can cause unexpected behavior.

The datasheet says in case of writing Mode-Control register, set the value for only target channel, the others must set '11b'.
e.g. Set DMA0=01b  DMA11=10b
CTL0=33333331h
CTL2=00002333h

NOTE:
CTL0 includes DMA0~7 Mode-Control register.
CTL2 includes DMA8~11 Mode-Control register.

This patch modifies the issue.

Signed-off-by: Tomoya MORINAGA <tomoya-linux@dsn.okisemi.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
This commit is contained in:
Tomoya MORINAGA 2011-07-14 09:52:38 +09:00 committed by Vinod Koul
parent 95bfea1675
commit 0b052f4a08
1 changed files with 31 additions and 11 deletions
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42
drivers/dma/pch_dma.c
View File

@ -62,6 +62,9 @@
#define MAX_CHAN_NR 8
#define DMA_MASK_CTL0_MODE 0x33333333
#define DMA_MASK_CTL2_MODE 0x00003333
static unsigned int init_nr_desc_per_channel = 64;
module_param(init_nr_desc_per_channel, uint, 0644);
MODULE_PARM_DESC(init_nr_desc_per_channel,
@ -210,10 +213,17 @@ static void pdc_set_dir(struct dma_chan *chan)
struct pch_dma_chan *pd_chan = to_pd_chan(chan);
struct pch_dma *pd = to_pd(chan->device);
u32 val;
u32 mask_mode;
u32 mask_ctl;
if (chan->chan_id < 8) {
val = dma_readl(pd, CTL0);
mask_mode = DMA_CTL0_MODE_MASK_BITS <<
(DMA_CTL0_BITS_PER_CH * chan->chan_id);
mask_ctl = DMA_MASK_CTL0_MODE & ~(DMA_CTL0_MODE_MASK_BITS <<
(DMA_CTL0_BITS_PER_CH * chan->chan_id));
val &= mask_mode;
if (pd_chan->dir == DMA_TO_DEVICE)
val |= 0x1 << (DMA_CTL0_BITS_PER_CH * chan->chan_id +
DMA_CTL0_DIR_SHIFT_BITS);
@ -221,18 +231,24 @@ static void pdc_set_dir(struct dma_chan *chan)
val &= ~(0x1 << (DMA_CTL0_BITS_PER_CH * chan->chan_id +
DMA_CTL0_DIR_SHIFT_BITS));
val |= mask_ctl;
dma_writel(pd, CTL0, val);
} else {
int ch = chan->chan_id - 8; /* ch8-->0 ch9-->1 ... ch11->3 */
val = dma_readl(pd, CTL3);
mask_mode = DMA_CTL0_MODE_MASK_BITS <<
(DMA_CTL0_BITS_PER_CH * ch);
mask_ctl = DMA_MASK_CTL2_MODE & ~(DMA_CTL0_MODE_MASK_BITS <<
(DMA_CTL0_BITS_PER_CH * ch));
val &= mask_mode;
if (pd_chan->dir == DMA_TO_DEVICE)
val |= 0x1 << (DMA_CTL0_BITS_PER_CH * ch +
DMA_CTL0_DIR_SHIFT_BITS);
else
val &= ~(0x1 << (DMA_CTL0_BITS_PER_CH * ch +
DMA_CTL0_DIR_SHIFT_BITS));
val |= mask_ctl;
dma_writel(pd, CTL3, val);
}
@ -244,26 +260,30 @@ static void pdc_set_mode(struct dma_chan *chan, u32 mode)
{
struct pch_dma *pd = to_pd(chan->device);
u32 val;
u32 mask_ctl;
u32 mask_dir;
if (chan->chan_id < 8) {
mask_ctl = DMA_MASK_CTL0_MODE & ~(DMA_CTL0_MODE_MASK_BITS <<
(DMA_CTL0_BITS_PER_CH * chan->chan_id));
mask_dir = 1 << (DMA_CTL0_BITS_PER_CH * chan->chan_id +\
DMA_CTL0_DIR_SHIFT_BITS);
val = dma_readl(pd, CTL0);
val &= ~(DMA_CTL0_MODE_MASK_BITS <<
(DMA_CTL0_BITS_PER_CH * chan->chan_id));
val &= mask_dir;
val |= mode << (DMA_CTL0_BITS_PER_CH * chan->chan_id);
val |= mask_ctl;
dma_writel(pd, CTL0, val);
} else {
int ch = chan->chan_id - 8; /* ch8-->0 ch9-->1 ... ch11->3 */
mask_ctl = DMA_MASK_CTL2_MODE & ~(DMA_CTL0_MODE_MASK_BITS <<
(DMA_CTL0_BITS_PER_CH * ch));
mask_dir = 1 << (DMA_CTL0_BITS_PER_CH * ch +\
DMA_CTL0_DIR_SHIFT_BITS);
val = dma_readl(pd, CTL3);
val &= ~(DMA_CTL0_MODE_MASK_BITS <<
(DMA_CTL0_BITS_PER_CH * ch));
val &= mask_dir;
val |= mode << (DMA_CTL0_BITS_PER_CH * ch);
val |= mask_ctl;
dma_writel(pd, CTL3, val);
}
dev_dbg(chan2dev(chan), "pdc_set_mode: chan %d -> %x\n",