Rather than to poll in a busy-loop, let's convert into using
readl_poll_timeout() and insert a small delay between each polling
attempts. In particular, this avoids hogging the CPU.
Additionally, to convert to readl_poll_timeout() we also need to switch
from using a specific number of polling attempts, into a specific timeout
in us instead. The previous 100000 attempts, is translated into a total
timeout of total 1s, as that seemed like reasonable value to pick.
Cc: Sascha Sommer <saschasommer@xxxxxxxxxx>
Signed-off-by: Ulf Hansson <ulf.hansson@xxxxxxxxxx>
---
drivers/mmc/host/sdricoh_cs.c | 25 ++++++++++++++-----------
1 file changed, 14 insertions(+), 11 deletions(-)
diff --git a/drivers/mmc/host/sdricoh_cs.c b/drivers/mmc/host/sdricoh_cs.c
index 97ef7d71375a..7e407fb6dab8 100644
--- a/drivers/mmc/host/sdricoh_cs.c
+++ b/drivers/mmc/host/sdricoh_cs.c
@@ -15,6 +15,7 @@
#include <linux/module.h>
#include <linux/pci.h>
#include <linux/ioport.h>
+#include <linux/iopoll.h>
#include <linux/scatterlist.h>
#include <pcmcia/cistpl.h>
@@ -59,7 +60,7 @@ static unsigned int switchlocked;
/* timeouts */
#define CMD_TIMEOUT 100000
-#define TRANSFER_TIMEOUT 100000
+#define SDRICOH_DATA_TIMEOUT_US 1000000
/* list of supported pcmcia devices */
static const struct pcmcia_device_id pcmcia_ids[] = {
@@ -123,21 +124,23 @@ static inline unsigned int sdricoh_readb(struct sdricoh_host *host,
return value;
}
+static bool sdricoh_status_ok(struct sdricoh_host *host, unsigned int status,
+ unsigned int wanted)
+{
+ sdricoh_writel(host, R2E4_STATUS_RESP, status);
+ return status & wanted;
+}
+
static int sdricoh_query_status(struct sdricoh_host *host, unsigned int wanted)
{
- unsigned int loop;
+ int ret;
unsigned int status = 0;
- unsigned int timeout = TRANSFER_TIMEOUT;
struct device *dev = host->dev;
- for (loop = 0; loop < timeout; loop++) {
- status = sdricoh_readl(host, R21C_STATUS);
- sdricoh_writel(host, R2E4_STATUS_RESP, status);
- if (status & wanted)
- break;
- }
-
- if (loop == timeout) {
+ ret = readl_poll_timeout(host->iobase + R21C_STATUS, status,
+ sdricoh_status_ok(host, status, wanted),
+ 32, SDRICOH_DATA_TIMEOUT_US);
+ if (ret) {
dev_err(dev, "query_status: timeout waiting for %x\n", wanted);
return -ETIMEDOUT;
}
--
2.20.1
