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NET: sa11x0-ir: convert sa11x0-ir driver to use DMA engine API
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Convert the sa11x0 IrDA driver to use the sa11x0 DMA engine driver
rather than our own platform specific DMA API.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
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Russell King committed Mar 7, 2012
1 parent bb8c950 commit bf95154
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Showing 2 changed files with 92 additions and 30 deletions.
2 changes: 1 addition & 1 deletion drivers/net/irda/Kconfig
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Original file line number Diff line number Diff line change
Expand Up @@ -356,7 +356,7 @@ config VLSI_FIR

config SA1100_FIR
tristate "SA1100 Internal IR"
depends on ARCH_SA1100 && IRDA
depends on ARCH_SA1100 && IRDA && DMA_SA11X0

config VIA_FIR
tristate "VIA VT8231/VT1211 SIR/MIR/FIR"
Expand Down
120 changes: 91 additions & 29 deletions drivers/net/irda/sa1100_ir.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -30,12 +30,13 @@
#include <linux/delay.h>
#include <linux/platform_device.h>
#include <linux/dma-mapping.h>
#include <linux/dmaengine.h>
#include <linux/sa11x0-dma.h>

#include <net/irda/irda.h>
#include <net/irda/wrapper.h>
#include <net/irda/irda_device.h>

#include <mach/dma.h>
#include <mach/hardware.h>
#include <asm/mach/irda.h>

Expand All @@ -47,7 +48,8 @@ struct sa1100_buf {
struct device *dev;
struct sk_buff *skb;
struct scatterlist sg;
dma_regs_t *regs;
struct dma_chan *chan;
dma_cookie_t cookie;
};

struct sa1100_irda {
Expand Down Expand Up @@ -79,6 +81,75 @@ static int sa1100_irda_set_speed(struct sa1100_irda *, int);

#define HPSIR_MAX_RXLEN 2047

static struct dma_slave_config sa1100_irda_fir_rx = {
.direction = DMA_FROM_DEVICE,
.src_addr = __PREG(Ser2HSDR),
.src_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE,
.src_maxburst = 8,
};

static struct dma_slave_config sa1100_irda_fir_tx = {
.direction = DMA_TO_DEVICE,
.dst_addr = __PREG(Ser2HSDR),
.dst_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE,
.dst_maxburst = 8,
};

static unsigned sa1100_irda_dma_xferred(struct sa1100_buf *buf)
{
struct dma_chan *chan = buf->chan;
struct dma_tx_state state;
enum dma_status status;

status = chan->device->device_tx_status(chan, buf->cookie, &state);
if (status != DMA_PAUSED)
return 0;

return sg_dma_len(&buf->sg) - state.residue;
}

static int sa1100_irda_dma_request(struct device *dev, struct sa1100_buf *buf,
const char *name, struct dma_slave_config *cfg)
{
dma_cap_mask_t m;
int ret;

dma_cap_zero(m);
dma_cap_set(DMA_SLAVE, m);

buf->chan = dma_request_channel(m, sa11x0_dma_filter_fn, (void *)name);
if (!buf->chan) {
dev_err(dev, "unable to request DMA channel for %s\n",
name);
return -ENOENT;
}

ret = dmaengine_slave_config(buf->chan, cfg);
if (ret)
dev_warn(dev, "DMA slave_config for %s returned %d\n",
name, ret);

buf->dev = buf->chan->device->dev;

return 0;
}

static void sa1100_irda_dma_start(struct sa1100_buf *buf,
enum dma_transfer_direction dir, dma_async_tx_callback cb, void *cb_p)
{
struct dma_async_tx_descriptor *desc;
struct dma_chan *chan = buf->chan;

desc = chan->device->device_prep_slave_sg(chan, &buf->sg, 1, dir,
DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
if (desc) {
desc->callback = cb;
desc->callback_param = cb_p;
buf->cookie = dmaengine_submit(desc);
dma_async_issue_pending(chan);
}
}

/*
* Allocate and map the receive buffer, unless it is already allocated.
*/
Expand Down Expand Up @@ -127,9 +198,9 @@ static void sa1100_irda_rx_dma_start(struct sa1100_irda *si)
/*
* Enable the DMA, receiver and receive interrupt.
*/
sa1100_clear_dma(si->dma_rx.regs);
sa1100_start_dma(si->dma_rx.regs, sg_dma_address(&si->dma_rx.sg),
sg_dma_len(&si->dma_rx.sg));
dmaengine_terminate_all(si->dma_rx.chan);
sa1100_irda_dma_start(&si->dma_rx, DMA_DEV_TO_MEM, NULL, NULL);

Ser2HSCR0 = HSCR0_HSSP | HSCR0_RXE;
}

Expand Down Expand Up @@ -326,8 +397,7 @@ static int sa1100_irda_fir_tx_start(struct sk_buff *skb, struct net_device *dev,
return NETDEV_TX_OK;
}

sa1100_start_dma(si->dma_tx.regs, sg_dma_address(&si->dma_tx.sg),
sg_dma_len(&si->dma_tx.sg));
sa1100_irda_dma_start(&si->dma_tx, DMA_MEM_TO_DEV, sa1100_irda_firtxdma_irq, dev);

/*
* If we have a mean turn-around time, impose the specified
Expand All @@ -345,7 +415,6 @@ static int sa1100_irda_fir_tx_start(struct sk_buff *skb, struct net_device *dev,
static void sa1100_irda_fir_error(struct sa1100_irda *si, struct net_device *dev)
{
struct sk_buff *skb = si->dma_rx.skb;
dma_addr_t dma_addr;
unsigned int len, stat, data;

if (!skb) {
Expand All @@ -356,8 +425,7 @@ static void sa1100_irda_fir_error(struct sa1100_irda *si, struct net_device *dev
/*
* Get the current data position.
*/
dma_addr = sa1100_get_dma_pos(si->dma_rx.regs);
len = dma_addr - sg_dma_address(&si->dma_rx.sg);
len = sa1100_irda_dma_xferred(&si->dma_rx);
if (len > HPSIR_MAX_RXLEN)
len = HPSIR_MAX_RXLEN;
dma_unmap_sg(si->dma_rx.dev, &si->dma_rx.sg, 1, DMA_FROM_DEVICE);
Expand Down Expand Up @@ -421,7 +489,7 @@ static irqreturn_t sa1100_irda_fir_irq(struct net_device *dev, struct sa1100_ird
/*
* Stop RX DMA
*/
sa1100_stop_dma(si->dma_rx.regs);
dmaengine_pause(si->dma_rx.chan);

/*
* Framing error - we throw away the packet completely.
Expand Down Expand Up @@ -476,11 +544,9 @@ static int sa1100_irda_set_speed(struct sa1100_irda *si, int speed)
case 57600: case 115200:
brd = 3686400 / (16 * speed) - 1;

/*
* Stop the receive DMA.
*/
/* Stop the receive DMA, and configure transmit. */
if (IS_FIR(si))
sa1100_stop_dma(si->dma_rx.regs);
dmaengine_terminate_all(si->dma_rx.chan);

local_irq_save(flags);

Expand Down Expand Up @@ -698,8 +764,8 @@ static void sa1100_irda_shutdown(struct sa1100_irda *si)
/*
* Stop all DMA activity.
*/
sa1100_stop_dma(si->dma_rx.regs);
sa1100_stop_dma(si->dma_tx.regs);
dmaengine_terminate_all(si->dma_rx.chan);
dmaengine_terminate_all(si->dma_tx.chan);

/* Disable the port. */
Ser2UTCR3 = 0;
Expand All @@ -716,20 +782,16 @@ static int sa1100_irda_start(struct net_device *dev)

si->speed = 9600;

err = sa1100_request_dma(DMA_Ser2HSSPRd, "IrDA receive",
NULL, NULL, &si->dma_rx.regs);
err = sa1100_irda_dma_request(si->dev, &si->dma_rx, "Ser2ICPRc",
&sa1100_irda_fir_rx);
if (err)
goto err_rx_dma;

err = sa1100_request_dma(DMA_Ser2HSSPWr, "IrDA transmit",
sa1100_irda_firtxdma_irq, dev,
&si->dma_tx.regs);
err = sa1100_irda_dma_request(si->dev, &si->dma_tx, "Ser2ICPTr",
&sa1100_irda_sir_tx);
if (err)
goto err_tx_dma;

si->dma_rx.dev = si->dev;
si->dma_tx.dev = si->dev;

/*
* Setup the serial port for the specified speed.
*/
Expand Down Expand Up @@ -764,9 +826,9 @@ static int sa1100_irda_start(struct net_device *dev)
si->open = 0;
sa1100_irda_shutdown(si);
err_startup:
sa1100_free_dma(si->dma_tx.regs);
dma_release_channel(si->dma_tx.chan);
err_tx_dma:
sa1100_free_dma(si->dma_rx.regs);
dma_release_channel(si->dma_rx.chan);
err_rx_dma:
return err;
}
Expand Down Expand Up @@ -810,8 +872,8 @@ static int sa1100_irda_stop(struct net_device *dev)
/*
* Free resources
*/
sa1100_free_dma(si->dma_tx.regs);
sa1100_free_dma(si->dma_rx.regs);
dma_release_channel(si->dma_tx.chan);
dma_release_channel(si->dma_rx.chan);
free_irq(dev->irq, dev);

sa1100_set_power(si, 0);
Expand Down

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