alistair23-linux/drivers/mmc/core/mmc_ops.h
Ulf Hansson aa33ce3c41 mmc: core: Enable __mmc_switch() to change bus speed timing for the host
In cases when a speed mode change is requested for mmc cards, a CMD6 is
sent by calling __mmc_switch() during the card initialization. The CMD6
leads to the card entering a busy period. When that is completed, the host
must parse the CMD6 status to find out whether the change of the speed mode
succeeded.

To enable the mmc core to poll the card by using CMD13 to find out when the
busy period is completed, it's reasonable to make sure polling is done by
having the mmc host and the mmc card, being configured to operate at the
same selected bus speed timing.

Therefore, let's extend __mmc_switch() to take yet another parameter, which
allow its callers to update the bus speed timing of the mmc host. In this
way, __mmc_switch() also becomes capable of reading and validating the CMD6
status by sending a CMD13, in cases when that's desired.

If __mmc_switch() encounters a failure, we make sure to restores the old
bus speed timing for the mmc host, before propagating the error code.

Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Tested-by: Linus Walleij <linus.walleij@linaro.org>
Acked-by: Adrian Hunter <adrian.hunter@intel.com>
2016-11-29 09:05:25 +01:00

37 lines
1.4 KiB
C

/*
* linux/drivers/mmc/core/mmc_ops.h
*
* Copyright 2006-2007 Pierre Ossman
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or (at
* your option) any later version.
*/
#ifndef _MMC_MMC_OPS_H
#define _MMC_MMC_OPS_H
int mmc_select_card(struct mmc_card *card);
int mmc_deselect_cards(struct mmc_host *host);
int mmc_set_dsr(struct mmc_host *host);
int mmc_go_idle(struct mmc_host *host);
int mmc_send_op_cond(struct mmc_host *host, u32 ocr, u32 *rocr);
int mmc_all_send_cid(struct mmc_host *host, u32 *cid);
int mmc_set_relative_addr(struct mmc_card *card);
int mmc_send_csd(struct mmc_card *card, u32 *csd);
int mmc_send_status(struct mmc_card *card, u32 *status);
int mmc_send_cid(struct mmc_host *host, u32 *cid);
int mmc_spi_read_ocr(struct mmc_host *host, int highcap, u32 *ocrp);
int mmc_spi_set_crc(struct mmc_host *host, int use_crc);
int mmc_bus_test(struct mmc_card *card, u8 bus_width);
int mmc_send_hpi_cmd(struct mmc_card *card, u32 *status);
int mmc_can_ext_csd(struct mmc_card *card);
int mmc_switch_status(struct mmc_card *card);
int __mmc_switch(struct mmc_card *card, u8 set, u8 index, u8 value,
unsigned int timeout_ms, unsigned char timing,
bool use_busy_signal, bool send_status, bool retry_crc_err);
#endif