Re: [PATCHv2 1/2] mmc: omap_hsmmc: convert from IP timer to hrtimer

Felipe Balbi
2012-08-28T13:25:50Z

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On Tue, Aug 28, 2012 at 06:49:06PM +0530, Venkatraman S wrote:
> omap hsmmc controller IP has a built in timer that can be programmed to
> guard against unresponsive operations. But its range is very narrow,
> and the maximum countable time is a few seconds.
>
> Card maintenance operations like BKOPS and MMC_ERASE and long
> stream writes like packed command require timers of order of
> several minutes, much beyond the capability of the IP timer.
> So get rid of using the IP timer entirely and use kernel's hrtimer
> functionality for guarding the device operations.
> As part of this change, a workaround that disabled timeouts for
> MMC_ERASE command is removed, and the arbitary timing of 100ms
> is used only when the timeout is not explicitly specified by core.
>
> A trivial change to get rid of unnecessary dealiasing of host->data
> in omap_hsmmc_do_irq is also included.
>
> Signed-off-by: Venkatraman S <svenkatr@ti.com>

Now it looks good:

Reviewed-by: Felipe Balbi <balbi@ti.com>

> ---
>
> v1->v2:
> Fix typos in commit message.
> Add checks to handle subtle races between MMC IRQ and HRTIMER IRQ
> Mark set_guard_timer function as static
> (Felipe's comment to use macros for INT_EN_MASK is done as a separate patch )
> drivers/mmc/host/omap_hsmmc.c | 96 ++++++++++++++++++++++---------------------
> 1 file changed, 50 insertions(+), 46 deletions(-)
>
> diff --git a/drivers/mmc/host/omap_hsmmc.c b/drivers/mmc/host/omap_hsmmc.c
> index 9afdd20..57e86a4 100644
> --- a/drivers/mmc/host/omap_hsmmc.c
> +++ b/drivers/mmc/host/omap_hsmmc.c
> @@ -79,7 +79,7 @@
> #define CLKD_SHIFT 6
> #define DTO_MASK 0x000F0000
> #define DTO_SHIFT 16
> -#define INT_EN_MASK 0x307F0033
> +#define INT_EN_MASK 0x306E0033
> #define BWR_ENABLE (1 << 4)
> #define BRR_ENABLE (1 << 5)
> #define DTO_ENABLE (1 << 20)
> @@ -160,6 +160,7 @@ struct omap_hsmmc_host {
> unsigned int dma_sg_idx;
> unsigned char bus_mode;
> unsigned char power_mode;
> + unsigned int ns_per_clk_cycle;
> int suspended;
> int irq;
> int use_dma, dma_ch;
> @@ -172,6 +173,7 @@ struct omap_hsmmc_host {
> int reqs_blocked;
> int use_reg;
> int req_in_progress;
> + struct hrtimer guard_timer;
> struct omap_hsmmc_next next_data;
>
> struct omap_mmc_platform_data *pdata;
> @@ -455,10 +457,6 @@ static void omap_hsmmc_enable_irq(struct omap_hsmmc_host *host,
> else
> irq_mask = INT_EN_MASK;
>
> - /* Disable timeout for erases */
> - if (cmd->opcode == MMC_ERASE)
> - irq_mask &= ~DTO_ENABLE;
> -
> OMAP_HSMMC_WRITE(host->base, STAT, STAT_CLEAR);
> OMAP_HSMMC_WRITE(host->base, ISE, irq_mask);
> OMAP_HSMMC_WRITE(host->base, IE, irq_mask);
> @@ -508,6 +506,9 @@ static void omap_hsmmc_set_clock(struct omap_hsmmc_host *host)
> && time_before(jiffies, timeout))
> cpu_relax();
>
> + if (ios->clock)
> + host->ns_per_clk_cycle = DIV_ROUND_UP(NSEC_PER_SEC, ios->clock);
> +
> omap_hsmmc_start_clock(host);
> }
>
> @@ -824,7 +825,7 @@ omap_hsmmc_xfer_done(struct omap_hsmmc_host *host, struct mmc_data *data)
> omap_hsmmc_request_done(host, mrq);
> return;
> }
> -
> + hrtimer_cancel(&host->guard_timer);
> host->data = NULL;
>
> if (!data->error)
> @@ -859,8 +860,11 @@ omap_hsmmc_cmd_done(struct omap_hsmmc_host *host, struct mmc_command *cmd)
> cmd->resp[0] = OMAP_HSMMC_READ(host->base, RSP10);
> }
> }
> - if ((host->data == NULL && !host->response_busy) || cmd->error)
> + if ((host->data == NULL && !host->response_busy) || cmd->error) {
> + if (cmd->error != -ETIMEDOUT)
> + hrtimer_cancel(&host->guard_timer);
> omap_hsmmc_request_done(host, cmd->mrq);
> + }
> }
>
> /*
> @@ -992,7 +996,7 @@ static void omap_hsmmc_do_irq(struct omap_hsmmc_host *host, int status)
> hsmmc_command_incomplete(host, -EILSEQ);
>
> end_cmd = 1;
> - if (host->data || host->response_busy) {
> + if (data || host->response_busy) {
> end_trans = 1;
> host->response_busy = 0;
> }
> @@ -1292,41 +1296,35 @@ static int omap_hsmmc_start_dma_transfer(struct omap_hsmmc_host *host,
> return 0;
> }
>
> -static void set_data_timeout(struct omap_hsmmc_host *host,
> - unsigned int timeout_ns,
> - unsigned int timeout_clks)
> +static void set_guard_timer(struct omap_hsmmc_host *host,
> + unsigned long timeout_ms, unsigned long timeout_ns,
> + unsigned int timeout_clks)
> {
> - unsigned int timeout, cycle_ns;
> - uint32_t reg, clkd, dto = 0;
> + ktime_t gtime;
> + unsigned int sec, nsec;
>
> - reg = OMAP_HSMMC_READ(host->base, SYSCTL);
> - clkd = (reg & CLKD_MASK) >> CLKD_SHIFT;
> - if (clkd == 0)
> - clkd = 1;
> + sec = timeout_ms / MSEC_PER_SEC;
> + nsec = (timeout_ms % MSEC_PER_SEC) * NSEC_PER_MSEC + timeout_ns;
>
> - cycle_ns = 1000000000 / (clk_get_rate(host->fclk) / clkd);
> - timeout = timeout_ns / cycle_ns;
> - timeout += timeout_clks;
> - if (timeout) {
> - while ((timeout & 0x80000000) == 0) {
> - dto += 1;
> - timeout <<= 1;
> - }
> - dto = 31 - dto;
> - timeout <<= 1;
> - if (timeout && dto)
> - dto += 1;
> - if (dto >= 13)
> - dto -= 13;
> - else
> - dto = 0;
> - if (dto > 14)
> - dto = 14;
> - }
> + nsec += timeout_clks * host->ns_per_clk_cycle;
> + gtime = ktime_set(sec, nsec);
>
> - reg &= ~DTO_MASK;
> - reg |= dto << DTO_SHIFT;
> - OMAP_HSMMC_WRITE(host->base, SYSCTL, reg);
> + hrtimer_start(&host->guard_timer, gtime, HRTIMER_MODE_REL);
> +}
> +
> +static enum hrtimer_restart omap_hsmmc_timedout(struct hrtimer *gtimer)
> +{
> + struct omap_hsmmc_host *host;
> + host = container_of(gtimer, struct omap_hsmmc_host, guard_timer);
> + if (host->req_in_progress) {
> + omap_hsmmc_disable_irq(host);
> + hsmmc_command_incomplete(host, -ETIMEDOUT);
> + host->response_busy = 0;
> + omap_hsmmc_cmd_done(host, host->cmd);
> + if (host->data)
> + omap_hsmmc_xfer_done(host, host->data);
> + }
> + return HRTIMER_NORESTART;
> }
>
> /*
> @@ -1340,18 +1338,22 @@ omap_hsmmc_prepare_data(struct omap_hsmmc_host *host, struct mmc_request *req)
>
> if (req->data == NULL) {
> OMAP_HSMMC_WRITE(host->base, BLK, 0);
> - /*
> - * Set an arbitrary 100ms data timeout for commands with
> - * busy signal.
> - */
> - if (req->cmd->flags & MMC_RSP_BUSY)
> - set_data_timeout(host, 100000000U, 0);
> + if (req->cmd->cmd_timeout_ms == 0) {
> + /*
> + * Set an arbitrary 100ms data timeout for commands with
> + * busy signal.
> + */
> + set_guard_timer(host, 100, 0, 0);
> + } else {
> + set_guard_timer(host, req->cmd->cmd_timeout_ms, 0, 0);
> + }
> return 0;
> }
>
> OMAP_HSMMC_WRITE(host->base, BLK, (req->data->blksz)
> | (req->data->blocks << 16));
> - set_data_timeout(host, req->data->timeout_ns, req->data->timeout_clks);
> + set_guard_timer(host, 0, req->data->timeout_ns,
> + req->data->timeout_clks);
>
> if (host->use_dma) {
> ret = omap_hsmmc_start_dma_transfer(host, req);
> @@ -1921,6 +1923,8 @@ static int __devinit omap_hsmmc_probe(struct platform_device *pdev)
> pdata->suspend = omap_hsmmc_suspend_cdirq;
> pdata->resume = omap_hsmmc_resume_cdirq;
> }
> + hrtimer_init(&host->guard_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
> + host->guard_timer.function = omap_hsmmc_timedout;
>
> omap_hsmmc_disable_irq(host);
>
> --
> 1.7.11.1.25.g0e18bef
>

--
balbi

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