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>
diff --git a/drivers/dma/mxs-dma.c b/drivers/dma/mxs-dma.c
index be641cb..b4588bd 100644
--- a/drivers/dma/mxs-dma.c
+++ b/drivers/dma/mxs-dma.c
@@ -130,6 +130,23 @@
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 @@
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 @@
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;