On Wednesday 19 November 2014 10:16:47 Wolfram Sang wrote:
> On Fri, Nov 14, 2014 at 02:47:59PM +0100, Ludovic Desroches wrote:
> > Return probe defer if requesting a dma channel without a dma controller probed.
> >
> > Signed-off-by: Ludovic Desroches <ludovic.desroches@xxxxxxxxx>
> > ---
> > drivers/i2c/busses/i2c-at91.c | 22 ++++++++++++++++------
> > 1 file changed, 16 insertions(+), 6 deletions(-)
> >
> > diff --git a/drivers/i2c/busses/i2c-at91.c b/drivers/i2c/busses/i2c-at91.c
> > index 77fb647..df3f4c4 100644
> > --- a/drivers/i2c/busses/i2c-at91.c
> > +++ b/drivers/i2c/busses/i2c-at91.c
> > @@ -679,14 +679,21 @@ static int at91_twi_configure_dma(struct at91_twi_dev *dev, u32 phy_addr)
> > dma_cap_zero(mask);
> > dma_cap_set(DMA_SLAVE, mask);
> >
> > - dma->chan_tx = dma_request_slave_channel_compat(mask, filter, pdata,
> > - dev->dev, "tx");
> > - if (!dma->chan_tx) {
> > + dma->chan_tx = dma_request_slave_channel_reason(dev->dev, "tx");
>
> Will it cause regressions if you drop the compat-version of requesting
> a channel?
I got curious about this, since the patch looks obviously wrong, but
actually it's ok. However the entire DMA support for non-DT platforms
can be dropped in this driver, see patch below
> > + if (IS_ERR(dma->chan_tx)) {
> > + ret = PTR_ERR(dma->chan_tx);
> > + if (ret == -EPROBE_DEFER) {
> > + dev_warn(dev->dev, "no DMA channel available at the moment\n");
>
> I'd say drop this warning. The core usually prints when deferred probing
> takes place.
Definitely yes.
Arnd
8<---
[PATCH] i2c: at91: remove legacy DMA supoprt
Since at91sam9g45 is now DT-only, all DMA capable users of this driver are
using the DT case, and the legacy support can be removed. While at it, fix
the deferred probe case.
Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx>
diff --git a/drivers/i2c/busses/i2c-at91.c b/drivers/i2c/busses/i2c-at91.c
index 917d54588d95..534f4c07bfb6 100644
--- a/drivers/i2c/busses/i2c-at91.c
+++ b/drivers/i2c/busses/i2c-at91.c
@@ -72,8 +72,6 @@ struct at91_twi_pdata {
unsigned clk_max_div;
unsigned clk_offset;
bool has_unre_flag;
- bool has_dma_support;
- struct at_dma_slave dma_slave;
};
struct at91_twi_dma {
@@ -541,35 +539,30 @@ static struct at91_twi_pdata at91rm9200_config = {
.clk_max_div = 5,
.clk_offset = 3,
.has_unre_flag = true,
- .has_dma_support = false,
};
static struct at91_twi_pdata at91sam9261_config = {
.clk_max_div = 5,
.clk_offset = 4,
.has_unre_flag = false,
- .has_dma_support = false,
};
static struct at91_twi_pdata at91sam9260_config = {
.clk_max_div = 7,
.clk_offset = 4,
.has_unre_flag = false,
- .has_dma_support = false,
};
static struct at91_twi_pdata at91sam9g20_config = {
.clk_max_div = 7,
.clk_offset = 4,
.has_unre_flag = false,
- .has_dma_support = false,
};
static struct at91_twi_pdata at91sam9g10_config = {
.clk_max_div = 7,
.clk_offset = 4,
.has_unre_flag = false,
- .has_dma_support = false,
};
static const struct platform_device_id at91_twi_devtypes[] = {
@@ -598,7 +591,6 @@ static struct at91_twi_pdata at91sam9x5_config = {
.clk_max_div = 7,
.clk_offset = 4,
.has_unre_flag = false,
- .has_dma_support = true,
};
static const struct of_device_id atmel_twi_dt_ids[] = {
@@ -627,30 +619,11 @@ static const struct of_device_id atmel_twi_dt_ids[] = {
MODULE_DEVICE_TABLE(of, atmel_twi_dt_ids);
#endif
-static bool filter(struct dma_chan *chan, void *pdata)
-{
- struct at91_twi_pdata *sl_pdata = pdata;
- struct at_dma_slave *sl;
-
- if (!sl_pdata)
- return false;
-
- sl = &sl_pdata->dma_slave;
- if (sl && (sl->dma_dev == chan->device->dev)) {
- chan->private = sl;
- return true;
- } else {
- return false;
- }
-}
-
static int at91_twi_configure_dma(struct at91_twi_dev *dev, u32 phy_addr)
{
int ret = 0;
- struct at91_twi_pdata *pdata = dev->pdata;
struct dma_slave_config slave_config;
struct at91_twi_dma *dma = &dev->dma;
- dma_cap_mask_t mask;
memset(&slave_config, 0, sizeof(slave_config));
slave_config.src_addr = (dma_addr_t)phy_addr + AT91_TWI_RHR;
@@ -661,22 +634,17 @@ static int at91_twi_configure_dma(struct at91_twi_dev *dev, u32 phy_addr)
slave_config.dst_maxburst = 1;
slave_config.device_fc = false;
- dma_cap_zero(mask);
- dma_cap_set(DMA_SLAVE, mask);
-
- dma->chan_tx = dma_request_slave_channel_compat(mask, filter, pdata,
- dev->dev, "tx");
- if (!dma->chan_tx) {
- dev_err(dev->dev, "can't get a DMA channel for tx\n");
- ret = -EBUSY;
+ dma->chan_tx = dma_request_slave_channel_reason(dev->dev, "tx");
+ if (IS_ERR(dma->chan_tx)) {
+ ret = PTR_ERR(dma->chan_tx);
+ dma->chan_tx = NULL;
goto error;
}
- dma->chan_rx = dma_request_slave_channel_compat(mask, filter, pdata,
- dev->dev, "rx");
- if (!dma->chan_rx) {
- dev_err(dev->dev, "can't get a DMA channel for rx\n");
- ret = -EBUSY;
+ dma->chan_rx = dma_request_slave_channel_reason(dev->dev, "rx");
+ if (IS_ERR(dma->chan_rx)) {
+ ret = PTR_ERR(dma->chan_rx);
+ dma->chan_rx = NULL;
goto error;
}
@@ -697,6 +665,7 @@ static int at91_twi_configure_dma(struct at91_twi_dev *dev, u32 phy_addr)
sg_init_table(&dma->sg, 1);
dma->buf_mapped = false;
dma->xfer_in_progress = false;
+ dev->use_dma = true;
dev_info(dev->dev, "using %s (tx) and %s (rx) for DMA transfers\n",
dma_chan_name(dma->chan_tx), dma_chan_name(dma->chan_rx));
@@ -704,7 +673,8 @@ static int at91_twi_configure_dma(struct at91_twi_dev *dev, u32 phy_addr)
return ret;
error:
- dev_info(dev->dev, "can't use DMA\n");
+ if (ret != -EPROBE_DEFER)
+ dev_info(dev->dev, "can't use DMA, error %d\n", ret);
if (dma->chan_rx)
dma_release_channel(dma->chan_rx);
if (dma->chan_tx)
@@ -772,10 +742,8 @@ static int at91_twi_probe(struct platform_device *pdev)
}
clk_prepare_enable(dev->clk);
- if (dev->pdata->has_dma_support) {
- if (at91_twi_configure_dma(dev, phy_addr) == 0)
- dev->use_dma = true;
- }
+ if (dev->of_node)
+ at91_twi_configure_dma(dev, phy_addr);
rc = of_property_read_u32(dev->dev->of_node, "clock-frequency",
&bus_clk_rate);
--
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