+++ /dev/null
-/*
- * BCM2835 SDHCI
- * Copyright (C) 2012 Stephen Warren
- * Based on U-Boot's MMC driver for the BCM2835 by Oleksandr Tymoshenko & me
- * Portions of the code there were obviously based on the Linux kernel at:
- * git://github.com/raspberrypi/linux.git rpi-3.6.y
- * commit f5b930b "Main bcm2708 linux port" signed-off-by Dom Cobley.
- *
- * This program is free software; you can redistribute it and/or modify it
- * under the terms and conditions of the GNU General Public License,
- * version 2, as published by the Free Software Foundation.
- *
- * This program is distributed in the hope it will be useful, but WITHOUT
- * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
- * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
- * more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program. If not, see <http://www.gnu.org/licenses/>.
- */
-
-#include <linux/delay.h>
-#include <linux/module.h>
-#include <linux/mmc/host.h>
-#include "sdhci-pltfm.h"
-
-/*
- * 400KHz is max freq for card ID etc. Use that as min card clock. We need to
- * know the min to enable static calculation of max BCM2835_SDHCI_WRITE_DELAY.
- */
-#define MIN_FREQ 400000
-
-/*
- * The Arasan has a bugette whereby it may lose the content of successive
- * writes to registers that are within two SD-card clock cycles of each other
- * (a clock domain crossing problem). It seems, however, that the data
- * register does not have this problem, which is just as well - otherwise we'd
- * have to nobble the DMA engine too.
- *
- * This should probably be dynamically calculated based on the actual card
- * frequency. However, this is the longest we'll have to wait, and doesn't
- * seem to slow access down too much, so the added complexity doesn't seem
- * worth it for now.
- *
- * 1/MIN_FREQ is (max) time per tick of eMMC clock.
- * 2/MIN_FREQ is time for two ticks.
- * Multiply by 1000000 to get uS per two ticks.
- * *1000000 for uSecs.
- * +1 for hack rounding.
- */
-#define BCM2835_SDHCI_WRITE_DELAY (((2 * 1000000) / MIN_FREQ) + 1)
-
-struct bcm2835_sdhci {
- u32 shadow;
-};
-
-static void bcm2835_sdhci_writel(struct sdhci_host *host, u32 val, int reg)
-{
- writel(val, host->ioaddr + reg);
-
- udelay(BCM2835_SDHCI_WRITE_DELAY);
-}
-
-static inline u32 bcm2835_sdhci_readl(struct sdhci_host *host, int reg)
-{
- u32 val = readl(host->ioaddr + reg);
-
- if (reg == SDHCI_CAPABILITIES)
- val |= SDHCI_CAN_VDD_330;
-
- return val;
-}
-
-static void bcm2835_sdhci_writew(struct sdhci_host *host, u16 val, int reg)
-{
- struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
- struct bcm2835_sdhci *bcm2835_host = sdhci_pltfm_priv(pltfm_host);
- u32 oldval = (reg == SDHCI_COMMAND) ? bcm2835_host->shadow :
- bcm2835_sdhci_readl(host, reg & ~3);
- u32 word_num = (reg >> 1) & 1;
- u32 word_shift = word_num * 16;
- u32 mask = 0xffff << word_shift;
- u32 newval = (oldval & ~mask) | (val << word_shift);
-
- if (reg == SDHCI_TRANSFER_MODE)
- bcm2835_host->shadow = newval;
- else
- bcm2835_sdhci_writel(host, newval, reg & ~3);
-}
-
-static u16 bcm2835_sdhci_readw(struct sdhci_host *host, int reg)
-{
- u32 val = bcm2835_sdhci_readl(host, (reg & ~3));
- u32 word_num = (reg >> 1) & 1;
- u32 word_shift = word_num * 16;
- u32 word = (val >> word_shift) & 0xffff;
-
- return word;
-}
-
-static void bcm2835_sdhci_writeb(struct sdhci_host *host, u8 val, int reg)
-{
- u32 oldval = bcm2835_sdhci_readl(host, reg & ~3);
- u32 byte_num = reg & 3;
- u32 byte_shift = byte_num * 8;
- u32 mask = 0xff << byte_shift;
- u32 newval = (oldval & ~mask) | (val << byte_shift);
-
- bcm2835_sdhci_writel(host, newval, reg & ~3);
-}
-
-static u8 bcm2835_sdhci_readb(struct sdhci_host *host, int reg)
-{
- u32 val = bcm2835_sdhci_readl(host, (reg & ~3));
- u32 byte_num = reg & 3;
- u32 byte_shift = byte_num * 8;
- u32 byte = (val >> byte_shift) & 0xff;
-
- return byte;
-}
-
-static unsigned int bcm2835_sdhci_get_min_clock(struct sdhci_host *host)
-{
- return MIN_FREQ;
-}
-
-static const struct sdhci_ops bcm2835_sdhci_ops = {
- .write_l = bcm2835_sdhci_writel,
- .write_w = bcm2835_sdhci_writew,
- .write_b = bcm2835_sdhci_writeb,
- .read_l = bcm2835_sdhci_readl,
- .read_w = bcm2835_sdhci_readw,
- .read_b = bcm2835_sdhci_readb,
- .set_clock = sdhci_set_clock,
- .get_max_clock = sdhci_pltfm_clk_get_max_clock,
- .get_min_clock = bcm2835_sdhci_get_min_clock,
- .set_bus_width = sdhci_set_bus_width,
- .reset = sdhci_reset,
- .set_uhs_signaling = sdhci_set_uhs_signaling,
-};
-
-static const struct sdhci_pltfm_data bcm2835_sdhci_pdata = {
- .quirks = SDHCI_QUIRK_BROKEN_CARD_DETECTION |
- SDHCI_QUIRK_DATA_TIMEOUT_USES_SDCLK,
- .ops = &bcm2835_sdhci_ops,
-};
-
-static int bcm2835_sdhci_probe(struct platform_device *pdev)
-{
- struct sdhci_host *host;
- struct bcm2835_sdhci *bcm2835_host;
- struct sdhci_pltfm_host *pltfm_host;
- int ret;
-
- host = sdhci_pltfm_init(pdev, &bcm2835_sdhci_pdata,
- sizeof(*bcm2835_host));
- if (IS_ERR(host))
- return PTR_ERR(host);
-
- pltfm_host = sdhci_priv(host);
-
- pltfm_host->clk = devm_clk_get(&pdev->dev, NULL);
- if (IS_ERR(pltfm_host->clk)) {
- ret = PTR_ERR(pltfm_host->clk);
- goto err;
- }
- ret = clk_prepare_enable(pltfm_host->clk);
- if (ret) {
- dev_err(&pdev->dev, "failed to enable host clk\n");
- goto err;
- }
-
- ret = sdhci_add_host(host);
- if (ret)
- goto err_clk;
-
- return 0;
-err_clk:
- clk_disable_unprepare(pltfm_host->clk);
-err:
- sdhci_pltfm_free(pdev);
- return ret;
-}
-
-static const struct of_device_id bcm2835_sdhci_of_match[] = {
- { .compatible = "brcm,bcm2835-sdhci" },
- { }
-};
-MODULE_DEVICE_TABLE(of, bcm2835_sdhci_of_match);
-
-static struct platform_driver bcm2835_sdhci_driver = {
- .driver = {
- .name = "sdhci-bcm2835",
- .of_match_table = bcm2835_sdhci_of_match,
- .pm = SDHCI_PLTFM_PMOPS,
- },
- .probe = bcm2835_sdhci_probe,
- .remove = sdhci_pltfm_unregister,
-};
-module_platform_driver(bcm2835_sdhci_driver);
-
-MODULE_DESCRIPTION("BCM2835 SDHCI driver");
-MODULE_AUTHOR("Stephen Warren");
-MODULE_LICENSE("GPL v2");
projects / cascardo / linux.git / commitdiff