mmc: Add runtime and system-wide PM to the TMIO MMC driver

Add runtime and system-wide power management to the TMIO MMC driver
in PIO and DMA modes, allowing it to properly save and restore its
state during system suspend. Runtime PM is very crude ATM, because
the controller has to be powered on all the time to detect card
hotplug events.

Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Signed-off-by: Chris Ball <cjb@laptop.org>

1 files changed, 12 insertions, 9 deletions

diff --git a/drivers/mmc/host/tmio_mmc_dma.c b/drivers/mmc/host/tmio_mmc_dma.c
index d3de74ab633e..25f1ad6cbe09 100644
--- a/drivers/mmc/host/tmio_mmc_dma.c
+++ b/drivers/mmc/host/tmio_mmc_dma.c
@@ -256,7 +256,10 @@ static bool tmio_mmc_filter(struct dma_chan *chan, void *arg)
 void tmio_mmc_request_dma(struct tmio_mmc_host *host, struct tmio_mmc_data *pdata)
 {
         /* We can only either use DMA for both Tx and Rx or not use it at all */
-        if (pdata->dma) {
+        if (!pdata->dma)
+                return;
+
+        if (!host->chan_tx && !host->chan_rx) {
                 dma_cap_mask_t mask;
 
                 dma_cap_zero(mask);
@@ -284,18 +287,18 @@ void tmio_mmc_request_dma(struct tmio_mmc_host *host, struct tmio_mmc_data *pdat
 
                 tasklet_init(&host->dma_complete, tmio_mmc_tasklet_fn, (unsigned long)host);
                 tasklet_init(&host->dma_issue, tmio_mmc_issue_tasklet_fn, (unsigned long)host);
+        }
 
-                tmio_mmc_enable_dma(host, true);
+        tmio_mmc_enable_dma(host, true);
+
+        return;
 
-                return;
 ebouncebuf:
-                dma_release_channel(host->chan_rx);
-                host->chan_rx = NULL;
+        dma_release_channel(host->chan_rx);
+        host->chan_rx = NULL;
 ereqrx:
-                dma_release_channel(host->chan_tx);
-                host->chan_tx = NULL;
-                return;
-        }
+        dma_release_channel(host->chan_tx);
+        host->chan_tx = NULL;
 }
 
 void tmio_mmc_release_dma(struct tmio_mmc_host *host)