diff options
| author | Ulf Hansson <ulf.hansson@linaro.org> | 2020-05-08 11:52:10 +0200 |
|---|---|---|
| committer | Ulf Hansson <ulf.hansson@linaro.org> | 2020-05-28 11:22:14 +0200 |
| commit | eadb7897652d5bf9fbab393b3774598a04846aff (patch) | |
| tree | 1a699f7fccf72c0c3dbd4b5265bbabc04ed907f2 /drivers/mmc/host | |
| parent | 85a3f77c1be5ee143615e47f98f653d65806b8ae (diff) | |
mmc: sdricoh_cs: Throttle polling rate for data transfers
Rather than to poll in a busy-loop, let's convert into using
read_poll_timeout() and insert a small delay between each polling attempts.
In particular, this avoids hogging the CPU.
Additionally, to convert to read_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@freenet.de>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Link: https://lore.kernel.org/r/20200508095210.14123-1-ulf.hansson@linaro.org
Diffstat (limited to 'drivers/mmc/host')
| -rw-r--r-- | drivers/mmc/host/sdricoh_cs.c | 26 |
1 files changed, 15 insertions, 11 deletions
diff --git a/drivers/mmc/host/sdricoh_cs.c b/drivers/mmc/host/sdricoh_cs.c index 97ef7d71375a..8392158e2e9f 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 +124,24 @@ 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 = read_poll_timeout(sdricoh_readl, status, + sdricoh_status_ok(host, status, wanted), + 32, SDRICOH_DATA_TIMEOUT_US, false, + host, R21C_STATUS); + if (ret) { dev_err(dev, "query_status: timeout waiting for %x\n", wanted); return -ETIMEDOUT; } |