Commit ba6c7ac3 authored by Simon Horman's avatar Simon Horman Committed by Ulf Hansson
Browse files

mmc: core: more fine-grained hooks for HS400 tuning 



This adds two new HS400 tuning operations:
* hs400_downgrade
* hs400_complete

These supplement the existing HS400 operation:
* prepare_hs400_tuning

This is motivated by a requirement of Renesas SDHI for the following:
1. Disabling SCC before selecting to HS if selection of HS400 has occurred.
   This can be done in an implementation of prepare_hs400_tuning_downgrade
2. Updating registers after switching to HS400
   This can be done in an implementation of complete_hs400_tuning

If hs400_downgrade or hs400_complete are not implemented then they are not
called. Thus means there should be no affect for existing drivers as none
implemt these ops.

Signed-off-by: default avatarSimon Horman <horms+renesas@verge.net.au>
Signed-off-by: default avatarUlf Hansson <ulf.hansson@linaro.org>
parent ecf7c7c5

drivers/mmc/core/mmc.c

+10 −0
Original line number Diff line number Diff line
@@ -1169,6 +1169,10 @@ static int mmc_select_hs400(struct mmc_card *card) 
	/* Set host controller to HS timing */

	mmc_set_timing(card->host, MMC_TIMING_MMC_HS);



	/* Prepare host to downgrade to HS timing */

	if (host->ops->hs400_downgrade)

		host->ops->hs400_downgrade(host);



	/* Reduce frequency to HS frequency */

	max_dtr = card->ext_csd.hs_max_dtr;

	mmc_set_clock(host, max_dtr);
@@ -1209,6 +1213,9 @@ static int mmc_select_hs400(struct mmc_card *card) 
	if (err)

		goto out_err;



	if (host->ops->hs400_complete)

		host->ops->hs400_complete(host);



	return 0;



out_err:
@@ -1256,6 +1263,9 @@ int mmc_hs400_to_hs200(struct mmc_card *card) 


	mmc_set_timing(host, MMC_TIMING_MMC_HS);



	if (host->ops->hs400_downgrade)

		host->ops->hs400_downgrade(host);



	err = mmc_switch_status(card);

	if (err)

		goto out_err;

include/linux/mmc/host.h

+7 −0
Original line number Diff line number Diff line
@@ -146,6 +146,13 @@ struct mmc_host_ops { 


	/* Prepare HS400 target operating frequency depending host driver */

	int	(*prepare_hs400_tuning)(struct mmc_host *host, struct mmc_ios *ios);



	/* Prepare for switching from HS400 to HS200 */

	void	(*hs400_downgrade)(struct mmc_host *host);



	/* Complete selection of HS400 */

	void	(*hs400_complete)(struct mmc_host *host);



	/* Prepare enhanced strobe depending host driver */

	void	(*hs400_enhanced_strobe)(struct mmc_host *host,

					 struct mmc_ios *ios);

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