diff options
| author | Lothar Waßmann <LW@KARO-electronics.de> | 2011-08-08 14:47:47 +0200 |
|---|---|---|
| committer | Vinod Koul <vinod.koul@intel.com> | 2011-08-16 18:33:42 +0530 |
| commit | ef298c21c0d9c06ed89ea2fa724c3a018acfff39 (patch) | |
| tree | 1b43a0b45cc2d5cb863bea0ea9e8e1271ffd378f /drivers/dma | |
| parent | a16e470caa173d323ef68dcac98c899b95fa4f84 (diff) | |
| download | linux-ef298c21c0d9c06ed89ea2fa724c3a018acfff39.tar.bz2 | |
mxs-dma: enable CLKGATE before accessing registers
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>
Diffstat (limited to 'drivers/dma')
| -rw-r--r-- | drivers/dma/mxs-dma.c | 45 |
1 files changed, 24 insertions, 21 deletions
diff --git a/drivers/dma/mxs-dma.c b/drivers/dma/mxs-dma.c index be641cbd36fc..b4588bdd98bb 100644 --- a/drivers/dma/mxs-dma.c +++ b/drivers/dma/mxs-dma.c @@ -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; |