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mxs-dma: enable CLKGATE before accessing registers

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After calling mxs_dma_disable_chan() for a channel, that channel
becomes unusable because some controller registers can only be written
when the clock is enabled via CLKGATE.

Signed-off-by: Lothar Waßmann <LW@KARO-electronics.de>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
This commit is contained in:
Lothar Waßmann 2011-08-08 14:47:47 +02:00 committed by Vinod Koul
parent a16e470caa
commit ef298c21c0
1 changed files with 24 additions and 21 deletions
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45
drivers/dma/mxs-dma.c
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@ -130,6 +130,23 @@ struct mxs_dma_engine {
struct mxs_dma_chan mxs_chans[MXS_DMA_CHANNELS];
};
static inline void mxs_dma_clkgate(struct mxs_dma_chan *mxs_chan, int enable)
{
struct mxs_dma_engine *mxs_dma = mxs_chan->mxs_dma;
int chan_id = mxs_chan->chan.chan_id;
int set_clr = enable ? MXS_CLR_ADDR : MXS_SET_ADDR;
/* enable apbh channel clock */
if (dma_is_apbh()) {
if (apbh_is_old())
writel(1 << (chan_id + BP_APBH_CTRL0_CLKGATE_CHANNEL),
mxs_dma->base + HW_APBHX_CTRL0 + set_clr);
else
writel(1 << chan_id,
mxs_dma->base + HW_APBHX_CTRL0 + set_clr);
}
}
static void mxs_dma_reset_chan(struct mxs_dma_chan *mxs_chan)
{
struct mxs_dma_engine *mxs_dma = mxs_chan->mxs_dma;
@ -148,38 +165,21 @@ static void mxs_dma_enable_chan(struct mxs_dma_chan *mxs_chan)
struct mxs_dma_engine *mxs_dma = mxs_chan->mxs_dma;
int chan_id = mxs_chan->chan.chan_id;
/* clkgate needs to be enabled before writing other registers */
mxs_dma_clkgate(mxs_chan, 1);
/* set cmd_addr up */
writel(mxs_chan->ccw_phys,
mxs_dma->base + HW_APBHX_CHn_NXTCMDAR(chan_id));
/* enable apbh channel clock */
if (dma_is_apbh()) {
if (apbh_is_old())
writel(1 << (chan_id + BP_APBH_CTRL0_CLKGATE_CHANNEL),
mxs_dma->base + HW_APBHX_CTRL0 + MXS_CLR_ADDR);
else
writel(1 << chan_id,
mxs_dma->base + HW_APBHX_CTRL0 + MXS_CLR_ADDR);
}
/* write 1 to SEMA to kick off the channel */
writel(1, mxs_dma->base + HW_APBHX_CHn_SEMA(chan_id));
}
static void mxs_dma_disable_chan(struct mxs_dma_chan *mxs_chan)
{
struct mxs_dma_engine *mxs_dma = mxs_chan->mxs_dma;
int chan_id = mxs_chan->chan.chan_id;
/* disable apbh channel clock */
if (dma_is_apbh()) {
if (apbh_is_old())
writel(1 << (chan_id + BP_APBH_CTRL0_CLKGATE_CHANNEL),
mxs_dma->base + HW_APBHX_CTRL0 + MXS_SET_ADDR);
else
writel(1 << chan_id,
mxs_dma->base + HW_APBHX_CTRL0 + MXS_SET_ADDR);
}
mxs_dma_clkgate(mxs_chan, 0);
mxs_chan->status = DMA_SUCCESS;
}
@ -338,7 +338,10 @@ static int mxs_dma_alloc_chan_resources(struct dma_chan *chan)
if (ret)
goto err_clk;
/* clkgate needs to be enabled for reset to finish */
mxs_dma_clkgate(mxs_chan, 1);
mxs_dma_reset_chan(mxs_chan);
mxs_dma_clkgate(mxs_chan, 0);
dma_async_tx_descriptor_init(&mxs_chan->desc, chan);
mxs_chan->desc.tx_submit = mxs_dma_tx_submit;