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serial: mxs-auart: move to use generic DMA helper

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With the generic DMA device tree helper supported by mxs-dma driver,
client devices only need to call dma_request_slave_channel() for
requesting a DMA channel from dmaengine.

Signed-off-by: Shawn Guo <shawn.guo@linaro.org>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
This commit is contained in:
Shawn Guo 2013-02-26 13:47:41 +08:00
parent 5fac0e18bd
commit bcc20f9e40
2 changed files with 11 additions and 57 deletions
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16
Documentation/devicetree/bindings/tty/serial/fsl-mxs-auart.txt
View File

@ -5,20 +5,18 @@ Required properties:
imx23 and imx28.
- reg : Address and length of the register set for the device
- interrupts : Should contain the auart interrupt numbers
Optional properties:
- fsl,auart-dma-channel : The DMA channels, the first is for RX, the other
is for TX. If you add this property, it also means that you
will enable the DMA support for the auart.
Note: due to the hardware bug in imx23(see errata : 2836),
only the imx28 can enable the DMA support for the auart.
- dmas: DMA specifier, consisting of a phandle to DMA controller node
and AUART DMA channel ID.
Refer to dma.txt and fsl-mxs-dma.txt for details.
- dma-names: "rx" for RX channel, "tx" for TX channel.
Example:
auart0: serial@8006a000 {
compatible = "fsl,imx28-auart", "fsl,imx23-auart";
reg = <0x8006a000 0x2000>;
interrupts = <112 70 71>;
fsl,auart-dma-channel = <8 9>;
interrupts = <112>;
dmas = <&dma_apbx 8>, <&dma_apbx 9>;
dma-names = "rx", "tx";
};
Note: Each auart port should have an alias correctly numbered in "aliases"

52
drivers/tty/serial/mxs-auart.c
View File

@ -35,7 +35,7 @@
#include <linux/pinctrl/consumer.h>
#include <linux/of_device.h>
#include <linux/dma-mapping.h>
#include <linux/fsl/mxs-dma.h>
#include <linux/dmaengine.h>
#include <asm/cacheflush.h>
@ -148,11 +148,6 @@ struct mxs_auart_port {
struct device *dev;
/* for DMA */
struct mxs_dma_data dma_data;
int dma_channel_rx, dma_channel_tx;
int dma_irq_rx, dma_irq_tx;
int dma_channel;
struct scatterlist tx_sgl;
struct dma_chan *tx_dma_chan;
void *tx_dma_buf;
@ -440,20 +435,6 @@ static u32 mxs_auart_get_mctrl(struct uart_port *u)
return mctrl;
}
static bool mxs_auart_dma_filter(struct dma_chan *chan, void *param)
{
struct mxs_auart_port *s = param;
if (!mxs_dma_is_apbx(chan))
return false;
if (s->dma_channel == chan->chan_id) {
chan->private = &s->dma_data;
return true;
}
return false;
}
static int mxs_auart_dma_prep_rx(struct mxs_auart_port *s);
static void dma_rx_callback(void *arg)
{
@ -545,21 +526,11 @@ static void mxs_auart_dma_exit(struct mxs_auart_port *s)
static int mxs_auart_dma_init(struct mxs_auart_port *s)
{
dma_cap_mask_t mask;
if (auart_dma_enabled(s))
return 0;
/* We do not get the right DMA channels. */
if (s->dma_channel_rx == -1 || s->dma_channel_tx == -1)
return -EINVAL;
/* init for RX */
dma_cap_zero(mask);
dma_cap_set(DMA_SLAVE, mask);
s->dma_channel = s->dma_channel_rx;
s->dma_data.chan_irq = s->dma_irq_rx;
s->rx_dma_chan = dma_request_channel(mask, mxs_auart_dma_filter, s);
s->rx_dma_chan = dma_request_slave_channel(s->dev, "rx");
if (!s->rx_dma_chan)
goto err_out;
s->rx_dma_buf = kzalloc(UART_XMIT_SIZE, GFP_KERNEL | GFP_DMA);
@ -567,9 +538,7 @@ static int mxs_auart_dma_init(struct mxs_auart_port *s)
goto err_out;
/* init for TX */
s->dma_channel = s->dma_channel_tx;
s->dma_data.chan_irq = s->dma_irq_tx;
s->tx_dma_chan = dma_request_channel(mask, mxs_auart_dma_filter, s);
s->tx_dma_chan = dma_request_slave_channel(s->dev, "tx");
if (!s->tx_dma_chan)
goto err_out;
s->tx_dma_buf = kzalloc(UART_XMIT_SIZE, GFP_KERNEL | GFP_DMA);
@ -1020,7 +989,6 @@ static int serial_mxs_probe_dt(struct mxs_auart_port *s,
struct platform_device *pdev)
{
struct device_node *np = pdev->dev.of_node;
u32 dma_channel[2];
int ret;
if (!np)
@ -1034,20 +1002,8 @@ static int serial_mxs_probe_dt(struct mxs_auart_port *s,
}
s->port.line = ret;
s->dma_irq_rx = platform_get_irq(pdev, 1);
s->dma_irq_tx = platform_get_irq(pdev, 2);
ret = of_property_read_u32_array(np, "fsl,auart-dma-channel",
dma_channel, 2);
if (ret == 0) {
s->dma_channel_rx = dma_channel[0];
s->dma_channel_tx = dma_channel[1];
s->flags |= MXS_AUART_DMA_CONFIG;
} else {
s->dma_channel_rx = -1;
s->dma_channel_tx = -1;
}
return 0;
}