diff options
| author | Tomoya MORINAGA <tomoya-linux@dsn.okisemi.com> | 2011-07-14 09:52:38 +0900 |
|---|---|---|
| committer | Vinod Koul <vinod.koul@intel.com> | 2011-07-25 19:11:12 +0530 |
| commit | 0b052f4a088ddc47a5da23dd733522241314cfb4 (patch) | |
| tree | 8367cd4cb3dd7fd7e5c01c2b6117755c6e9ea72e /drivers | |
| parent | 95bfea1675c02d83cf1923272e62f91db11cbb8f (diff) | |
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>
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/dma/pch_dma.c | 42 |
1 files changed, 31 insertions, 11 deletions
diff --git a/drivers/dma/pch_dma.c b/drivers/dma/pch_dma.c index d9d95a4dd854..1ac8d4b580b7 100644 --- a/drivers/dma/pch_dma.c +++ b/drivers/dma/pch_dma.c @@ -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", |