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Message-ID: <20200204124816.16735-3-vigneshr@ti.com>
Date: Tue, 4 Feb 2020 18:18:16 +0530
From: Vignesh Raghavendra <vigneshr@...com>
To: Mark Brown <broonie@...nel.org>
CC: Vignesh Raghavendra <vigneshr@...com>, <linux-spi@...r.kernel.org>,
<linux-omap@...r.kernel.org>, <linux-kernel@...r.kernel.org>
Subject: [PATCH 2/2] spi: spi-omap2-mcspi: Support probe deferral for DMA channels
dma_request_channel() can return -EPROBE_DEFER, if DMA driver is not
ready. Currently driver just falls back to PIO mode on probe deferral.
Fix this by requesting all required channels during probe and
propagating EPROBE_DEFER error code.
Signed-off-by: Vignesh Raghavendra <vigneshr@...com>
---
drivers/spi/spi-omap2-mcspi.c | 77 +++++++++++++++++------------------
1 file changed, 38 insertions(+), 39 deletions(-)
diff --git a/drivers/spi/spi-omap2-mcspi.c b/drivers/spi/spi-omap2-mcspi.c
index e9bc9cf984d6..e9e256718ef4 100644
--- a/drivers/spi/spi-omap2-mcspi.c
+++ b/drivers/spi/spi-omap2-mcspi.c
@@ -975,20 +975,12 @@ static int omap2_mcspi_setup_transfer(struct spi_device *spi,
* Note that we currently allow DMA only if we get a channel
* for both rx and tx. Otherwise we'll do PIO for both rx and tx.
*/
-static int omap2_mcspi_request_dma(struct spi_device *spi)
+static int omap2_mcspi_request_dma(struct omap2_mcspi *mcspi,
+ struct omap2_mcspi_dma *mcspi_dma)
{
- struct spi_master *master = spi->master;
- struct omap2_mcspi *mcspi;
- struct omap2_mcspi_dma *mcspi_dma;
int ret = 0;
- mcspi = spi_master_get_devdata(master);
- mcspi_dma = mcspi->dma_channels + spi->chip_select;
-
- init_completion(&mcspi_dma->dma_rx_completion);
- init_completion(&mcspi_dma->dma_tx_completion);
-
- mcspi_dma->dma_rx = dma_request_chan(&master->dev,
+ mcspi_dma->dma_rx = dma_request_chan(mcspi->dev,
mcspi_dma->dma_rx_ch_name);
if (IS_ERR(mcspi_dma->dma_rx)) {
ret = PTR_ERR(mcspi_dma->dma_rx);
@@ -996,7 +988,7 @@ static int omap2_mcspi_request_dma(struct spi_device *spi)
goto no_dma;
}
- mcspi_dma->dma_tx = dma_request_chan(&master->dev,
+ mcspi_dma->dma_tx = dma_request_chan(mcspi->dev,
mcspi_dma->dma_tx_ch_name);
if (IS_ERR(mcspi_dma->dma_tx)) {
ret = PTR_ERR(mcspi_dma->dma_tx);
@@ -1005,20 +997,40 @@ static int omap2_mcspi_request_dma(struct spi_device *spi)
mcspi_dma->dma_rx = NULL;
}
+ init_completion(&mcspi_dma->dma_rx_completion);
+ init_completion(&mcspi_dma->dma_tx_completion);
+
no_dma:
return ret;
}
+static void omap2_mcspi_release_dma(struct spi_master *master)
+{
+ struct omap2_mcspi *mcspi = spi_master_get_devdata(master);
+ struct omap2_mcspi_dma *mcspi_dma;
+ int i;
+
+ for (i = 0; i < master->num_chipselect; i++) {
+ mcspi_dma = &mcspi->dma_channels[i];
+
+ if (mcspi_dma->dma_rx) {
+ dma_release_channel(mcspi_dma->dma_rx);
+ mcspi_dma->dma_rx = NULL;
+ }
+ if (mcspi_dma->dma_tx) {
+ dma_release_channel(mcspi_dma->dma_tx);
+ mcspi_dma->dma_tx = NULL;
+ }
+ }
+}
+
static int omap2_mcspi_setup(struct spi_device *spi)
{
int ret;
struct omap2_mcspi *mcspi = spi_master_get_devdata(spi->master);
struct omap2_mcspi_regs *ctx = &mcspi->ctx;
- struct omap2_mcspi_dma *mcspi_dma;
struct omap2_mcspi_cs *cs = spi->controller_state;
- mcspi_dma = &mcspi->dma_channels[spi->chip_select];
-
if (!cs) {
cs = kzalloc(sizeof *cs, GFP_KERNEL);
if (!cs)
@@ -1043,13 +1055,6 @@ static int omap2_mcspi_setup(struct spi_device *spi)
}
}
- if (!mcspi_dma->dma_rx || !mcspi_dma->dma_tx) {
- ret = omap2_mcspi_request_dma(spi);
- if (ret)
- dev_warn(&spi->dev, "not using DMA for McSPI (%d)\n",
- ret);
- }
-
ret = pm_runtime_get_sync(mcspi->dev);
if (ret < 0) {
pm_runtime_put_noidle(mcspi->dev);
@@ -1066,12 +1071,8 @@ static int omap2_mcspi_setup(struct spi_device *spi)
static void omap2_mcspi_cleanup(struct spi_device *spi)
{
- struct omap2_mcspi *mcspi;
- struct omap2_mcspi_dma *mcspi_dma;
struct omap2_mcspi_cs *cs;
- mcspi = spi_master_get_devdata(spi->master);
-
if (spi->controller_state) {
/* Unlink controller state from context save list */
cs = spi->controller_state;
@@ -1080,19 +1081,6 @@ static void omap2_mcspi_cleanup(struct spi_device *spi)
kfree(cs);
}
- if (spi->chip_select < spi->master->num_chipselect) {
- mcspi_dma = &mcspi->dma_channels[spi->chip_select];
-
- if (mcspi_dma->dma_rx) {
- dma_release_channel(mcspi_dma->dma_rx);
- mcspi_dma->dma_rx = NULL;
- }
- if (mcspi_dma->dma_tx) {
- dma_release_channel(mcspi_dma->dma_tx);
- mcspi_dma->dma_tx = NULL;
- }
- }
-
if (gpio_is_valid(spi->cs_gpio))
gpio_free(spi->cs_gpio);
}
@@ -1303,6 +1291,9 @@ static bool omap2_mcspi_can_dma(struct spi_master *master,
if (spi_controller_is_slave(master))
return true;
+ master->dma_rx = mcspi_dma->dma_rx;
+ master->dma_tx = mcspi_dma->dma_tx;
+
return (xfer->len >= DMA_MIN_BYTES);
}
@@ -1490,6 +1481,11 @@ static int omap2_mcspi_probe(struct platform_device *pdev)
for (i = 0; i < master->num_chipselect; i++) {
sprintf(mcspi->dma_channels[i].dma_rx_ch_name, "rx%d", i);
sprintf(mcspi->dma_channels[i].dma_tx_ch_name, "tx%d", i);
+
+ status = omap2_mcspi_request_dma(mcspi,
+ &mcspi->dma_channels[i]);
+ if (status == -EPROBE_DEFER)
+ goto free_master;
}
status = platform_get_irq(pdev, 0);
@@ -1527,6 +1523,7 @@ static int omap2_mcspi_probe(struct platform_device *pdev)
pm_runtime_put_sync(&pdev->dev);
pm_runtime_disable(&pdev->dev);
free_master:
+ omap2_mcspi_release_dma(master);
spi_master_put(master);
return status;
}
@@ -1536,6 +1533,8 @@ static int omap2_mcspi_remove(struct platform_device *pdev)
struct spi_master *master = platform_get_drvdata(pdev);
struct omap2_mcspi *mcspi = spi_master_get_devdata(master);
+ omap2_mcspi_release_dma(master);
+
pm_runtime_dont_use_autosuspend(mcspi->dev);
pm_runtime_put_sync(mcspi->dev);
pm_runtime_disable(&pdev->dev);
--
2.25.0
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