[PATCH v2] net: smc911x: convert pxa dma to dmaengine

From: Robert Jarzmik
Date: Wed Mar 16 2016 - 13:27:37 EST

Convert the dma transfers to be dmaengine based, now pxa has a dmaengine
slave driver. This makes this driver a bit more PXA agnostic.

The driver was only compile tested. The risk is quite small as no
current PXA platform I'm aware of is using smc911x driver.

Signed-off-by: Robert Jarzmik <robert.jarzmik@xxxxxxx>
Tested-by: Fabio Estevam <fabio.estevam@xxxxxxx>
---
Since v1: added Fabio's Tested-by
---
drivers/net/ethernet/smsc/smc911x.c | 85 ++++++++++++++++++++++++-------------
drivers/net/ethernet/smsc/smc911x.h | 63 ++++++++++++---------------
2 files changed, 82 insertions(+), 66 deletions(-)

diff --git a/drivers/net/ethernet/smsc/smc911x.c b/drivers/net/ethernet/smsc/smc911x.c
index bd64eb982e52..3f5711061432 100644
--- a/drivers/net/ethernet/smsc/smc911x.c
+++ b/drivers/net/ethernet/smsc/smc911x.c
@@ -73,6 +73,9 @@ static const char version[] =
#include <linux/etherdevice.h>
#include <linux/skbuff.h>

+#include <linux/dmaengine.h>
+#include <linux/dma/pxa-dma.h>
+
#include <asm/io.h>

#include "smc911x.h"
@@ -1174,18 +1177,16 @@ static irqreturn_t smc911x_interrupt(int irq, void *dev_id)

#ifdef SMC_USE_DMA
static void
-smc911x_tx_dma_irq(int dma, void *data)
+smc911x_tx_dma_irq(void *data)
{
- struct net_device *dev = (struct net_device *)data;
- struct smc911x_local *lp = netdev_priv(dev);
+ struct smc911x_local *lp = data;
+ struct net_device *dev = lp->netdev;
struct sk_buff *skb = lp->current_tx_skb;
unsigned long flags;

DBG(SMC_DEBUG_FUNC, dev, "--> %s\n", __func__);

DBG(SMC_DEBUG_TX | SMC_DEBUG_DMA, dev, "TX DMA irq handler\n");
- /* Clear the DMA interrupt sources */
- SMC_DMA_ACK_IRQ(dev, dma);
BUG_ON(skb == NULL);
dma_unmap_single(NULL, tx_dmabuf, tx_dmalen, DMA_TO_DEVICE);
dev->trans_start = jiffies;
@@ -1208,18 +1209,16 @@ smc911x_tx_dma_irq(int dma, void *data)
"TX DMA irq completed\n");
}
static void
-smc911x_rx_dma_irq(int dma, void *data)
+smc911x_rx_dma_irq(void *data)
{
- struct net_device *dev = (struct net_device *)data;
- struct smc911x_local *lp = netdev_priv(dev);
+ struct smc911x_local *lp = data;
+ struct net_device *dev = lp->netdev;
struct sk_buff *skb = lp->current_rx_skb;
unsigned long flags;
unsigned int pkts;

DBG(SMC_DEBUG_FUNC, dev, "--> %s\n", __func__);
DBG(SMC_DEBUG_RX | SMC_DEBUG_DMA, dev, "RX DMA irq handler\n");
- /* Clear the DMA interrupt sources */
- SMC_DMA_ACK_IRQ(dev, dma);
dma_unmap_single(NULL, rx_dmabuf, rx_dmalen, DMA_FROM_DEVICE);
BUG_ON(skb == NULL);
lp->current_rx_skb = NULL;
@@ -1792,6 +1791,9 @@ static int smc911x_probe(struct net_device *dev)
unsigned int val, chip_id, revision;
const char *version_string;
unsigned long irq_flags;
+ struct dma_slave_config config;
+ dma_cap_mask_t mask;
+ struct pxad_param param;

DBG(SMC_DEBUG_FUNC, dev, "--> %s\n", __func__);

@@ -1963,11 +1965,40 @@ static int smc911x_probe(struct net_device *dev)
goto err_out;

#ifdef SMC_USE_DMA
- lp->rxdma = SMC_DMA_REQUEST(dev, smc911x_rx_dma_irq);
- lp->txdma = SMC_DMA_REQUEST(dev, smc911x_tx_dma_irq);
+
+ dma_cap_zero(mask);
+ dma_cap_set(DMA_SLAVE, mask);
+ param.prio = PXAD_PRIO_LOWEST;
+ param.drcmr = -1UL;
+
+ lp->rxdma =
+ dma_request_slave_channel_compat(mask, pxad_filter_fn,
+ &param, &dev->dev, "rx");
+ lp->txdma =
+ dma_request_slave_channel_compat(mask, pxad_filter_fn,
+ &param, &dev->dev, "tx");
lp->rxdma_active = 0;
lp->txdma_active = 0;
- dev->dma = lp->rxdma;
+
+ memset(&config, 0, sizeof(config));
+ config.src_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
+ config.dst_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
+ config.src_addr = lp->physaddr + RX_DATA_FIFO;
+ config.dst_addr = lp->physaddr + TX_DATA_FIFO;
+ config.src_maxburst = 32;
+ config.dst_maxburst = 32;
+ retval = dmaengine_slave_config(lp->rxdma, &config);
+ if (retval) {
+ dev_err(lp->dev, "dma rx channel configuration failed: %d\n",
+ retval);
+ goto err_out;
+ }
+ retval = dmaengine_slave_config(lp->txdma, &config);
+ if (retval) {
+ dev_err(lp->dev, "dma tx channel configuration failed: %d\n",
+ retval);
+ goto err_out;
+ }
#endif

retval = register_netdev(dev);
@@ -1978,11 +2009,11 @@ static int smc911x_probe(struct net_device *dev)
dev->base_addr, dev->irq);

#ifdef SMC_USE_DMA
- if (lp->rxdma != -1)
- pr_cont(" RXDMA %d", lp->rxdma);
+ if (lp->rxdma)
+ pr_cont(" RXDMA %p", lp->rxdma);

- if (lp->txdma != -1)
- pr_cont(" TXDMA %d", lp->txdma);
+ if (lp->txdma)
+ pr_cont(" TXDMA %p", lp->txdma);
#endif
pr_cont("\n");
if (!is_valid_ether_addr(dev->dev_addr)) {
@@ -2005,12 +2036,10 @@ static int smc911x_probe(struct net_device *dev)
err_out:
#ifdef SMC_USE_DMA
if (retval) {
- if (lp->rxdma != -1) {
- SMC_DMA_FREE(dev, lp->rxdma);
- }
- if (lp->txdma != -1) {
- SMC_DMA_FREE(dev, lp->txdma);
- }
+ if (lp->rxdma)
+ dma_release_channel(lp->rxdma);
+ if (lp->txdma)
+ dma_release_channel(lp->txdma);
}
#endif
return retval;
@@ -2112,12 +2141,10 @@ static int smc911x_drv_remove(struct platform_device *pdev)

#ifdef SMC_USE_DMA
{
- if (lp->rxdma != -1) {
- SMC_DMA_FREE(dev, lp->rxdma);
- }
- if (lp->txdma != -1) {
- SMC_DMA_FREE(dev, lp->txdma);
- }
+ if (lp->rxdma)
+ dma_release_channel(lp->rxdma);
+ if (lp->txdma)
+ dma_release_channel(lp->txdma);
}
#endif
iounmap(lp->base);
diff --git a/drivers/net/ethernet/smsc/smc911x.h b/drivers/net/ethernet/smsc/smc911x.h
index 04b35f55df97..fa528ea0ea51 100644
--- a/drivers/net/ethernet/smsc/smc911x.h
+++ b/drivers/net/ethernet/smsc/smc911x.h
@@ -101,8 +101,8 @@ struct smc911x_local {
#ifdef SMC_USE_DMA
/* DMA needs the physical address of the chip */
u_long physaddr;
- int rxdma;
- int txdma;
+ struct dma_chan *rxdma;
+ struct dma_chan *txdma;
int rxdma_active;
int txdma_active;
struct sk_buff *current_rx_skb;
@@ -210,27 +210,6 @@ static inline void SMC_outsl(struct smc911x_local *lp, int reg,

#ifdef SMC_USE_PXA_DMA

-#include <mach/dma.h>
-
-/*
- * Define the request and free functions
- * These are unfortunately architecture specific as no generic allocation
- * mechanism exits
- */
-#define SMC_DMA_REQUEST(dev, handler) \
- pxa_request_dma(dev->name, DMA_PRIO_LOW, handler, dev)
-
-#define SMC_DMA_FREE(dev, dma) \
- pxa_free_dma(dma)
-
-#define SMC_DMA_ACK_IRQ(dev, dma) \
-{ \
- if (DCSR(dma) & DCSR_BUSERR) { \
- netdev_err(dev, "DMA %d bus error!\n", dma); \
- } \
- DCSR(dma) = DCSR_STARTINTR|DCSR_ENDINTR|DCSR_BUSERR; \
-}
-
/*
* Use a DMA for RX and TX packets.
*/
@@ -238,6 +217,8 @@ static inline void SMC_outsl(struct smc911x_local *lp, int reg,

static dma_addr_t rx_dmabuf, tx_dmabuf;
static int rx_dmalen, tx_dmalen;
+static void smc911x_rx_dma_irq(void *data);
+static void smc911x_tx_dma_irq(void *data);

#ifdef SMC_insl
#undef SMC_insl
@@ -246,8 +227,10 @@ static int rx_dmalen, tx_dmalen;

static inline void
smc_pxa_dma_insl(struct smc911x_local *lp, u_long physaddr,
- int reg, int dma, u_char *buf, int len)
+ int reg, struct dma_chan *dma, u_char *buf, int len)
{
+ struct dma_async_tx_descriptor *tx;
+
/* 64 bit alignment is required for memory to memory DMA */
if ((long)buf & 4) {
*((u32 *)buf) = SMC_inl(lp, reg);
@@ -258,12 +241,14 @@ smc_pxa_dma_insl(struct smc911x_local *lp, u_long physaddr,
len *= 4;
rx_dmabuf = dma_map_single(lp->dev, buf, len, DMA_FROM_DEVICE);
rx_dmalen = len;
- DCSR(dma) = DCSR_NODESC;
- DTADR(dma) = rx_dmabuf;
- DSADR(dma) = physaddr + reg;
- DCMD(dma) = (DCMD_INCTRGADDR | DCMD_BURST32 |
- DCMD_WIDTH4 | DCMD_ENDIRQEN | (DCMD_LENGTH & rx_dmalen));
- DCSR(dma) = DCSR_NODESC | DCSR_RUN;
+ tx = dmaengine_prep_slave_single(dma, rx_dmabuf, rx_dmalen,
+ DMA_DEV_TO_MEM, 0);
+ if (tx) {
+ tx->callback = smc911x_rx_dma_irq;
+ tx->callback_param = lp;
+ dmaengine_submit(tx);
+ dma_async_issue_pending(dma);
+ }
}
#endif

@@ -274,8 +259,10 @@ smc_pxa_dma_insl(struct smc911x_local *lp, u_long physaddr,

static inline void
smc_pxa_dma_outsl(struct smc911x_local *lp, u_long physaddr,
- int reg, int dma, u_char *buf, int len)
+ int reg, struct dma_chan *dma, u_char *buf, int len)
{
+ struct dma_async_tx_descriptor *tx;
+
/* 64 bit alignment is required for memory to memory DMA */
if ((long)buf & 4) {
SMC_outl(*((u32 *)buf), lp, reg);
@@ -286,12 +273,14 @@ smc_pxa_dma_outsl(struct smc911x_local *lp, u_long physaddr,
len *= 4;
tx_dmabuf = dma_map_single(lp->dev, buf, len, DMA_TO_DEVICE);
tx_dmalen = len;
- DCSR(dma) = DCSR_NODESC;
- DSADR(dma) = tx_dmabuf;
- DTADR(dma) = physaddr + reg;
- DCMD(dma) = (DCMD_INCSRCADDR | DCMD_BURST32 |
- DCMD_WIDTH4 | DCMD_ENDIRQEN | (DCMD_LENGTH & tx_dmalen));
- DCSR(dma) = DCSR_NODESC | DCSR_RUN;
+ tx = dmaengine_prep_slave_single(dma, tx_dmabuf, tx_dmalen,
+ DMA_DEV_TO_MEM, 0);
+ if (tx) {
+ tx->callback = smc911x_tx_dma_irq;
+ tx->callback_param = lp;
+ dmaengine_submit(tx);
+ dma_async_issue_pending(dma);
+ }
}
#endif
#endif /* SMC_USE_PXA_DMA */
--
2.1.4