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Commit 26ec85b9 authored by Asutosh Das's avatar Asutosh Das
Browse files

mmc: core: support DDR52 bus-speed during eMMC clock scaling 



Add support for DDR52 bus-speed mode during clock scaling.
The reason for this change is DDR52 can be supported at SVS
mode.

Change-Id: I68e5fca57ae5cbc154f5dd7001df368900cb3f57
Signed-off-by: default avatarAsutosh Das <asutoshd@codeaurora.org>
parent abba9462

drivers/mmc/core/mmc.c

+30 −2
Original line number Diff line number Diff line
@@ -1413,6 +1413,24 @@ out: 
	return ret;

}



static int mmc_select_hs_ddr52(struct mmc_host *host)

{

	int err;



	mmc_select_hs(host->card);

	mmc_set_clock(host, MMC_HIGH_52_MAX_DTR);

	err = mmc_select_bus_width(host->card);

	if (err < 0) {

		pr_err("%s: %s: select_bus_width failed(%d)\n",

			mmc_hostname(host), __func__, err);

		return err;

	}



	err = mmc_select_hs_ddr(host->card);



	return err;

}



/*

 * Scale down from HS400 to HS in order to allow frequency change.

 * This is needed for cards that doesn't support changing frequency in HS400
@@ -1424,9 +1442,19 @@ static int mmc_scale_low(struct mmc_host *host, unsigned long freq) 
	mmc_set_timing(host, MMC_TIMING_LEGACY);

	mmc_set_clock(host, MMC_HIGH_26_MAX_DTR);



	if (host->clk_scaling.lower_bus_speed_mode &

	    MMC_SCALING_LOWER_DDR52_MODE) {

		err = mmc_select_hs_ddr52(host);

		if (err)

			pr_err("%s: %s: failed to switch to DDR52: err: %d\n",

			       mmc_hostname(host), __func__, err);

		else

			return err;

	}



	err = mmc_select_hs(host->card);

	if (err) {

		pr_err("%s: %s: selecting HS (52Mhz) failed (%d)\n",

		pr_err("%s: %s: scaling low: failed (%d)\n",

		       mmc_hostname(host), __func__, err);

		return err;

	}

include/linux/mmc/host.h

+2 −0
Original line number Diff line number Diff line
@@ -332,6 +332,8 @@ struct mmc_devfeq_clk_scaling { 
	unsigned long	polling_delay_ms;

	unsigned int	upthreshold;

	unsigned int	downthreshold;

	unsigned int	lower_bus_speed_mode;

#define MMC_SCALING_LOWER_DDR52_MODE	1

	bool		need_freq_change;

	bool		clk_scaling_in_progress;

	bool		is_busy_started;