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Subject[PATCH v3 4/4] dmaengine: xilinx_vdma: Use readl_poll_timeout instead of do while loop's
Date
It is sometimes necessary to poll a memory-mapped register until its
value satisfies some condition use convenience macros
that do this instead of do while loop's.

This patch updates the same in the driver.

Signed-off-by: Kedareswara rao Appana <appanad@xilinx.com>
---
Changes for v3:
---> removed patch dmaengine: xilinx_vdma: Improve channel idle checking
from the series as it is not a valid patch.
---> Added this patch.
Changes for v2:
---> splitted the changes into multiple patches.

drivers/dma/xilinx/xilinx_vdma.c | 46 +++++++++++++++++++---------------------
1 file changed, 22 insertions(+), 24 deletions(-)

diff --git a/drivers/dma/xilinx/xilinx_vdma.c b/drivers/dma/xilinx/xilinx_vdma.c
index 70b2b32..bc2ca45 100644
--- a/drivers/dma/xilinx/xilinx_vdma.c
+++ b/drivers/dma/xilinx/xilinx_vdma.c
@@ -28,6 +28,7 @@
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/io.h>
+#include <linux/iopoll.h>
#include <linux/module.h>
#include <linux/of_address.h>
#include <linux/of_dma.h>
@@ -254,6 +255,9 @@ struct xilinx_vdma_device {
container_of(chan, struct xilinx_vdma_chan, common)
#define to_vdma_tx_descriptor(tx) \
container_of(tx, struct xilinx_vdma_tx_descriptor, async_tx)
+#define xilinx_vdma_poll_timeout(chan, reg, val, cond, delay_us, timeout_us) \
+ readl_poll_timeout(chan->xdev->regs + chan->ctrl_offset + reg, val, \
+ cond, delay_us, timeout_us)

/* IO accessors */
static inline u32 vdma_read(struct xilinx_vdma_chan *chan, u32 reg)
@@ -550,18 +554,17 @@ static bool xilinx_vdma_is_idle(struct xilinx_vdma_chan *chan)
*/
static void xilinx_vdma_halt(struct xilinx_vdma_chan *chan)
{
- int loop = XILINX_VDMA_LOOP_COUNT;
+ int err = 0;
+ u32 val;

vdma_ctrl_clr(chan, XILINX_VDMA_REG_DMACR, XILINX_VDMA_DMACR_RUNSTOP);

/* Wait for the hardware to halt */
- do {
- if (vdma_ctrl_read(chan, XILINX_VDMA_REG_DMASR) &
- XILINX_VDMA_DMASR_HALTED)
- break;
- } while (loop--);
+ err = xilinx_vdma_poll_timeout(chan, XILINX_VDMA_REG_DMASR, val,
+ (val & XILINX_VDMA_DMASR_HALTED), 0,
+ XILINX_VDMA_LOOP_COUNT);

- if (!loop) {
+ if (err) {
dev_err(chan->dev, "Cannot stop channel %p: %x\n",
chan, vdma_ctrl_read(chan, XILINX_VDMA_REG_DMASR));
chan->err = true;
@@ -576,18 +579,17 @@ static void xilinx_vdma_halt(struct xilinx_vdma_chan *chan)
*/
static void xilinx_vdma_start(struct xilinx_vdma_chan *chan)
{
- int loop = XILINX_VDMA_LOOP_COUNT;
+ int err = 0;
+ u32 val;

vdma_ctrl_set(chan, XILINX_VDMA_REG_DMACR, XILINX_VDMA_DMACR_RUNSTOP);

/* Wait for the hardware to start */
- do {
- if (!(vdma_ctrl_read(chan, XILINX_VDMA_REG_DMASR) &
- XILINX_VDMA_DMASR_HALTED))
- break;
- } while (loop--);
+ err = xilinx_vdma_poll_timeout(chan, XILINX_VDMA_REG_DMASR, val,
+ !(val & XILINX_VDMA_DMASR_HALTED), 0,
+ XILINX_VDMA_LOOP_COUNT);

- if (!loop) {
+ if (err) {
dev_err(chan->dev, "Cannot start channel %p: %x\n",
chan, vdma_ctrl_read(chan, XILINX_VDMA_REG_DMASR));

@@ -754,21 +756,17 @@ static void xilinx_vdma_complete_descriptor(struct xilinx_vdma_chan *chan)
*/
static int xilinx_vdma_reset(struct xilinx_vdma_chan *chan)
{
- int loop = XILINX_VDMA_LOOP_COUNT;
+ int err = 0;
u32 tmp;

vdma_ctrl_set(chan, XILINX_VDMA_REG_DMACR, XILINX_VDMA_DMACR_RESET);

- tmp = vdma_ctrl_read(chan, XILINX_VDMA_REG_DMACR) &
- XILINX_VDMA_DMACR_RESET;
-
/* Wait for the hardware to finish reset */
- do {
- tmp = vdma_ctrl_read(chan, XILINX_VDMA_REG_DMACR) &
- XILINX_VDMA_DMACR_RESET;
- } while (loop-- && tmp);
+ err = xilinx_vdma_poll_timeout(chan, XILINX_VDMA_REG_DMACR, tmp,
+ !(tmp & XILINX_VDMA_DMACR_RESET), 0,
+ XILINX_VDMA_LOOP_COUNT);

- if (!loop) {
+ if (err) {
dev_err(chan->dev, "reset timeout, cr %x, sr %x\n",
vdma_ctrl_read(chan, XILINX_VDMA_REG_DMACR),
vdma_ctrl_read(chan, XILINX_VDMA_REG_DMASR));
@@ -777,7 +775,7 @@ static int xilinx_vdma_reset(struct xilinx_vdma_chan *chan)

chan->err = false;

- return 0;
+ return err;
}

/**
--
2.1.2
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