98 lines
2.1 KiB
C
98 lines
2.1 KiB
C
/*
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* SDHCI support for CNS3xxx SoC
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*
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* Copyright 2008 Cavium Networks
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* Copyright 2010 MontaVista Software, LLC.
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*
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* Authors: Scott Shu
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* Anton Vorontsov <avorontsov@mvista.com>
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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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#include <linux/delay.h>
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#include <linux/device.h>
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#include <linux/mmc/host.h>
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#include <linux/mmc/sdhci-pltfm.h>
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#include <mach/cns3xxx.h>
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#include "sdhci.h"
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#include "sdhci-pltfm.h"
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static unsigned int sdhci_cns3xxx_get_max_clk(struct sdhci_host *host)
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{
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return 150000000;
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}
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static void sdhci_cns3xxx_set_clock(struct sdhci_host *host, unsigned int clock)
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{
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struct device *dev = mmc_dev(host->mmc);
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int div = 1;
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u16 clk;
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unsigned long timeout;
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if (clock == host->clock)
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return;
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sdhci_writew(host, 0, SDHCI_CLOCK_CONTROL);
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if (clock == 0)
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goto out;
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while (host->max_clk / div > clock) {
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/*
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* On CNS3xxx divider grows linearly up to 4, and then
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* exponentially up to 256.
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*/
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if (div < 4)
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div += 1;
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else if (div < 256)
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div *= 2;
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else
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break;
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}
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dev_dbg(dev, "desired SD clock: %d, actual: %d\n",
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clock, host->max_clk / div);
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/* Divide by 3 is special. */
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if (div != 3)
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div >>= 1;
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clk = div << SDHCI_DIVIDER_SHIFT;
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clk |= SDHCI_CLOCK_INT_EN;
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sdhci_writew(host, clk, SDHCI_CLOCK_CONTROL);
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timeout = 20;
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while (!((clk = sdhci_readw(host, SDHCI_CLOCK_CONTROL))
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& SDHCI_CLOCK_INT_STABLE)) {
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if (timeout == 0) {
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dev_warn(dev, "clock is unstable");
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break;
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}
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timeout--;
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mdelay(1);
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}
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clk |= SDHCI_CLOCK_CARD_EN;
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sdhci_writew(host, clk, SDHCI_CLOCK_CONTROL);
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out:
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host->clock = clock;
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}
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static struct sdhci_ops sdhci_cns3xxx_ops = {
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.get_max_clock = sdhci_cns3xxx_get_max_clk,
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.set_clock = sdhci_cns3xxx_set_clock,
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};
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struct sdhci_pltfm_data sdhci_cns3xxx_pdata = {
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.ops = &sdhci_cns3xxx_ops,
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.quirks = SDHCI_QUIRK_BROKEN_DMA |
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SDHCI_QUIRK_DATA_TIMEOUT_USES_SDCLK |
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SDHCI_QUIRK_INVERTED_WRITE_PROTECT |
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SDHCI_QUIRK_CAP_CLOCK_BASE_BROKEN |
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SDHCI_QUIRK_BROKEN_TIMEOUT_VAL |
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SDHCI_QUIRK_NONSTANDARD_CLOCK,
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};
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