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04566831a7
This patch modifies the MMC core code to optionally call the set_ios()
operation on the driver with the clock frequency set to 0 (gate) after
a grace period of at least 8 MCLK cycles, then restore it (ungate)
before any new request. This gives the driver the option to shut down
the MCI clock to the MMC/SD card when the clock frequency is 0, i.e.
the core has stated that the MCI clock does not need to be generated.
It is inspired by existing clock gating code found in the OMAP and
Atmel drivers and brings this up to the host abstraction. Gating is
performed before and after any MMC request.
This patchset implements this for the MMCI/PL180 MMC/SD host controller,
but it should be simple to switch OMAP/Atmel over to using this instead.
mmc_set_{gated,ungated}() add variable protection to the state holders
for the clock gating code. This is particularly important when ordinary
.set_ios() calls would race with the .set_ios() call resulting from a
delayed gate operation.
Signed-off-by: Linus Walleij <linus.walleij@stericsson.com>
Reviewed-by: Chris Ball <cjb@laptop.org>
Tested-by: Chris Ball <cjb@laptop.org>
Signed-off-by: Chris Ball <cjb@laptop.org>
76 lines
2.2 KiB
C
76 lines
2.2 KiB
C
/*
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* linux/drivers/mmc/core/core.h
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*
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* Copyright (C) 2003 Russell King, All Rights Reserved.
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* Copyright 2007 Pierre Ossman
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*/
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#ifndef _MMC_CORE_CORE_H
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#define _MMC_CORE_CORE_H
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#include <linux/delay.h>
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#define MMC_CMD_RETRIES 3
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struct mmc_bus_ops {
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int (*awake)(struct mmc_host *);
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int (*sleep)(struct mmc_host *);
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void (*remove)(struct mmc_host *);
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void (*detect)(struct mmc_host *);
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int (*suspend)(struct mmc_host *);
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int (*resume)(struct mmc_host *);
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int (*power_save)(struct mmc_host *);
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int (*power_restore)(struct mmc_host *);
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};
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void mmc_attach_bus(struct mmc_host *host, const struct mmc_bus_ops *ops);
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void mmc_detach_bus(struct mmc_host *host);
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void mmc_init_erase(struct mmc_card *card);
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void mmc_set_chip_select(struct mmc_host *host, int mode);
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void mmc_set_clock(struct mmc_host *host, unsigned int hz);
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void mmc_gate_clock(struct mmc_host *host);
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void mmc_ungate_clock(struct mmc_host *host);
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void mmc_set_ungated(struct mmc_host *host);
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void mmc_set_bus_mode(struct mmc_host *host, unsigned int mode);
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void mmc_set_bus_width(struct mmc_host *host, unsigned int width);
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void mmc_set_bus_width_ddr(struct mmc_host *host, unsigned int width,
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unsigned int ddr);
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u32 mmc_select_voltage(struct mmc_host *host, u32 ocr);
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void mmc_set_timing(struct mmc_host *host, unsigned int timing);
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static inline void mmc_delay(unsigned int ms)
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{
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if (ms < 1000 / HZ) {
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cond_resched();
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mdelay(ms);
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} else {
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msleep(ms);
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}
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}
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void mmc_rescan(struct work_struct *work);
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void mmc_start_host(struct mmc_host *host);
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void mmc_stop_host(struct mmc_host *host);
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int mmc_attach_mmc(struct mmc_host *host, u32 ocr);
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int mmc_attach_sd(struct mmc_host *host, u32 ocr);
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int mmc_attach_sdio(struct mmc_host *host, u32 ocr);
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/* Module parameters */
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extern int use_spi_crc;
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/* Debugfs information for hosts and cards */
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void mmc_add_host_debugfs(struct mmc_host *host);
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void mmc_remove_host_debugfs(struct mmc_host *host);
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void mmc_add_card_debugfs(struct mmc_card *card);
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void mmc_remove_card_debugfs(struct mmc_card *card);
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#endif
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