[PATCH 07/13] mmc: davinci_mmc: Support for deferred probing when requesting DMA channels

Peter Ujfalusi
2015-05-26T13:26:02Z

Switch to use ma_request_slave_channel_compat_reason() to request the DMA
channels. Only fall back to pio mode if the error code returned is not
-EPROBE_DEFER, otherwise return from the probe with the -EPROBE_DEFER.

Signed-off-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
CC: Ulf Hansson <ulf.hansson@linaro.org>
---
drivers/mmc/host/davinci_mmc.c | 26 +++++++++++++++-----------
1 file changed, 15 insertions(+), 11 deletions(-)

diff --git a/drivers/mmc/host/davinci_mmc.c b/drivers/mmc/host/davinci_mmc.c
index b2b3f8bbfd8c..df81e4e2f662 100644
--- a/drivers/mmc/host/davinci_mmc.c
+++ b/drivers/mmc/host/davinci_mmc.c
@@ -530,20 +530,20 @@ static int __init davinci_acquire_dma_channels(struct mmc_davinci_host *host)
dma_cap_zero(mask);
dma_cap_set(DMA_SLAVE, mask);

- host->dma_tx =
- dma_request_slave_channel_compat(mask, edma_filter_fn,
- &host->txdma, mmc_dev(host->mmc), "tx");
- if (!host->dma_tx) {
+ host->dma_tx = dma_request_slave_channel_compat_reason(mask,
+ edma_filter_fn, &host->txdma,
+ mmc_dev(host->mmc), "tx");
+ if (IS_ERR(host->dma_tx)) {
dev_err(mmc_dev(host->mmc), "Can't get dma_tx channel\n");
- return -ENODEV;
+ return PTR_ERR(host->dma_tx);
}

- host->dma_rx =
- dma_request_slave_channel_compat(mask, edma_filter_fn,
- &host->rxdma, mmc_dev(host->mmc), "rx");
- if (!host->dma_rx) {
+ host->dma_rx = dma_request_slave_channel_compat_reason(mask,
+ edma_filter_fn, &host->rxdma,
+ mmc_dev(host->mmc), "rx");
+ if (IS_ERR(host->dma_rx)) {
dev_err(mmc_dev(host->mmc), "Can't get dma_rx channel\n");
- r = -ENODEV;
+ r = PTR_ERR(host->dma_rx);
goto free_master_write;
}

@@ -1307,8 +1307,12 @@ static int __init davinci_mmcsd_probe(struct platform_device *pdev)
host->mmc_irq = irq;
host->sdio_irq = platform_get_irq(pdev, 1);

- if (host->use_dma && davinci_acquire_dma_channels(host) != 0)
+ if (host->use_dma) {
+ ret = davinci_acquire_dma_channels(host);
+ if (ret == -EPROBE_DEFER)
+ goto out;
host->use_dma = 0;
+ }

/* REVISIT: someday, support IRQ-driven card detection. */
mmc->caps |= MMC_CAP_NEEDS_POLL;
--
2.3.5