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kernel/linux-rt-4.4.41/drivers/mmc/host/sdhci-cns3xxx.c 2.66 KB
5113f6f70   김현기   kernel add
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  /*
   * SDHCI support for CNS3xxx SoC
   *
   * Copyright 2008 Cavium Networks
   * Copyright 2010 MontaVista Software, LLC.
   *
   * Authors: Scott Shu
   *	    Anton Vorontsov <avorontsov@mvista.com>
   *
   * This program is free software; you can redistribute it and/or modify
   * it under the terms of the GNU General Public License version 2 as
   * published by the Free Software Foundation.
   */
  
  #include <linux/delay.h>
  #include <linux/device.h>
  #include <linux/mmc/host.h>
  #include <linux/module.h>
  #include "sdhci-pltfm.h"
  
  static unsigned int sdhci_cns3xxx_get_max_clk(struct sdhci_host *host)
  {
  	return 150000000;
  }
  
  static void sdhci_cns3xxx_set_clock(struct sdhci_host *host, unsigned int clock)
  {
  	struct device *dev = mmc_dev(host->mmc);
  	int div = 1;
  	u16 clk;
  	unsigned long timeout;
  
  	host->mmc->actual_clock = 0;
  
  	sdhci_writew(host, 0, SDHCI_CLOCK_CONTROL);
  
  	if (clock == 0)
  		return;
  
  	while (host->max_clk / div > clock) {
  		/*
  		 * On CNS3xxx divider grows linearly up to 4, and then
  		 * exponentially up to 256.
  		 */
  		if (div < 4)
  			div += 1;
  		else if (div < 256)
  			div *= 2;
  		else
  			break;
  	}
  
  	dev_dbg(dev, "desired SD clock: %d, actual: %d
  ",
  		clock, host->max_clk / div);
  
  	/* Divide by 3 is special. */
  	if (div != 3)
  		div >>= 1;
  
  	clk = div << SDHCI_DIVIDER_SHIFT;
  	clk |= SDHCI_CLOCK_INT_EN;
  	sdhci_writew(host, clk, SDHCI_CLOCK_CONTROL);
  
  	timeout = 20;
  	while (!((clk = sdhci_readw(host, SDHCI_CLOCK_CONTROL))
  			& SDHCI_CLOCK_INT_STABLE)) {
  		if (timeout == 0) {
  			dev_warn(dev, "clock is unstable");
  			break;
  		}
  		timeout--;
  		mdelay(1);
  	}
  
  	clk |= SDHCI_CLOCK_CARD_EN;
  	sdhci_writew(host, clk, SDHCI_CLOCK_CONTROL);
  }
  
  static const struct sdhci_ops sdhci_cns3xxx_ops = {
  	.get_max_clock	= sdhci_cns3xxx_get_max_clk,
  	.set_clock	= sdhci_cns3xxx_set_clock,
  	.set_bus_width	= sdhci_set_bus_width,
  	.reset          = sdhci_reset,
  	.set_uhs_signaling = sdhci_set_uhs_signaling,
  };
  
  static const struct sdhci_pltfm_data sdhci_cns3xxx_pdata = {
  	.ops = &sdhci_cns3xxx_ops,
  	.quirks = SDHCI_QUIRK_BROKEN_DMA |
  		  SDHCI_QUIRK_DATA_TIMEOUT_USES_SDCLK |
  		  SDHCI_QUIRK_INVERTED_WRITE_PROTECT |
  		  SDHCI_QUIRK_CAP_CLOCK_BASE_BROKEN |
  		  SDHCI_QUIRK_BROKEN_TIMEOUT_VAL,
  };
  
  static int sdhci_cns3xxx_probe(struct platform_device *pdev)
  {
  	return sdhci_pltfm_register(pdev, &sdhci_cns3xxx_pdata, 0);
  }
  
  static struct platform_driver sdhci_cns3xxx_driver = {
  	.driver		= {
  		.name	= "sdhci-cns3xxx",
  		.pm	= SDHCI_PLTFM_PMOPS,
  	},
  	.probe		= sdhci_cns3xxx_probe,
  	.remove		= sdhci_pltfm_unregister,
  };
  
  module_platform_driver(sdhci_cns3xxx_driver);
  
  MODULE_DESCRIPTION("SDHCI driver for CNS3xxx");
  MODULE_AUTHOR("Scott Shu, "
  	      "Anton Vorontsov <avorontsov@mvista.com>");
  MODULE_LICENSE("GPL v2");