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SubjectRe: [PATCH v3] mmc: Make ID freq configurable
Hi,

This looks like the best of the min_freq patches I've seen, and is
implementing a suggestion of Pierre's. Should we take it?

- Chris.

On Tue, Jan 05, 2010 at 05:58:34AM +0800, Hein_Tibosch wrote:
>
> In my last mail the spaces in the patch were mistreated, sorry for that.
>
> Below a patch which tries mmc-initialization using several frequencies
> from an array 400, 300, 200 and 100.
>
>
> Signed-off-by: Hein Tibosch <hein_tibosch@yahoo.es>
>
> ---
> diff -Nurp a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c
> --- a/drivers/mmc/core/core.c
> +++ b/drivers/mmc/core/core.c
> @@ -891,12 +891,7 @@ static void mmc_power_up(struct mmc_host
> */
> mmc_delay(10);
>
> - if (host->f_min > 400000) {
> - pr_warning("%s: Minimum clock frequency too high for "
> - "identification mode\n", mmc_hostname(host));
> - host->ios.clock = host->f_min;
> - } else
> - host->ios.clock = 400000;
> + host->ios.clock = host->f_init;
>
> host->ios.power_mode = MMC_POWER_ON;
> mmc_set_ios(host);
> @@ -1041,6 +1036,8 @@ void mmc_rescan(struct work_struct *work
> container_of(work, struct mmc_host, detect.work);
> u32 ocr;
> int err;
> + int i;
> + unsigned freqs[] = { 400000, 300000, 200000, 100000 };
>
> mmc_bus_get(host);
>
> @@ -1070,46 +1067,55 @@ void mmc_rescan(struct work_struct *work
> if (host->ops->get_cd && host->ops->get_cd(host) == 0)
> goto out;
>
> - mmc_claim_host(host);
> + for (i = 0; i < ARRAY_SIZE(freqs); i++) {
> + mmc_claim_host(host);
>
> - mmc_power_up(host);
> - mmc_go_idle(host);
> + if (freqs[i] >= host->f_min)
> + host->f_init = freqs[i];
> + else if (i && freqs[i-1] <= host->f_min)
> + goto out;
> + else
> + host->f_init = host->f_min;
>
> - mmc_send_if_cond(host, host->ocr_avail);
> + printk ("mmc_rescan: trying %u Hz\n", host->f_init);
> + mmc_power_up(host);
> + mmc_go_idle(host);
>
> - /*
> - * First we search for SDIO...
> - */
> - err = mmc_send_io_op_cond(host, 0, &ocr);
> - if (!err) {
> - if (mmc_attach_sdio(host, ocr))
> - mmc_power_off(host);
> - goto out;
> - }
> + mmc_send_if_cond(host, host->ocr_avail);
>
> - /*
> - * ...then normal SD...
> - */
> - err = mmc_send_app_op_cond(host, 0, &ocr);
> - if (!err) {
> - if (mmc_attach_sd(host, ocr))
> - mmc_power_off(host);
> - goto out;
> - }
> + /*
> + * First we search for SDIO...
> + */
> + err = mmc_send_io_op_cond(host, 0, &ocr);
> + if (!err) {
> + if (mmc_attach_sdio(host, ocr))
> + mmc_power_off(host);
> + goto out;
> + }
>
> - /*
> - * ...and finally MMC.
> - */
> - err = mmc_send_op_cond(host, 0, &ocr);
> - if (!err) {
> - if (mmc_attach_mmc(host, ocr))
> - mmc_power_off(host);
> - goto out;
> - }
> + /*
> + * ...then normal SD...
> + */
> + err = mmc_send_app_op_cond(host, 0, &ocr);
> + if (!err) {
> + if (mmc_attach_sd(host, ocr))
> + mmc_power_off(host);
> + goto out;
> + }
>
> - mmc_release_host(host);
> - mmc_power_off(host);
> + /*
> + * ...and finally MMC.
> + */
> + err = mmc_send_op_cond(host, 0, &ocr);
> + if (!err) {
> + if (mmc_attach_mmc(host, ocr))
> + mmc_power_off(host);
> + goto out;
> + }
>
> + mmc_release_host(host);
> + mmc_power_off(host);
> + }
> out:
> if (host->caps & MMC_CAP_NEEDS_POLL)
> mmc_schedule_delayed_work(&host->detect, HZ);
> diff -Nurp a/include/linux/mmc/host.h b/include/linux/mmc/host.h
> --- a/include/linux/mmc/host.h
> +++ b/include/linux/mmc/host.h
> @@ -119,6 +119,7 @@ struct mmc_host {
> const struct mmc_host_ops *ops;
> unsigned int f_min;
> unsigned int f_max;
> + unsigned int f_init;
> u32 ocr_avail;
>
> #define MMC_VDD_165_195 0x00000080 /* VDD voltage 1.65 - 1.95 */
>
>
> --

--
Chris Ball <cjb@laptop.org> <http://printf.net/>
One Laptop Per Child


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