This adds a simple driver for the BCM2835's SD controller.
Workarounds are implemented for: * Register writes can't be too close to each-other in time, or they will be lost. * Register accesses must all be 32-bit, so implement custom accessors.
This code was extracted from: git://github.com/gonzoua/u-boot-pi.git master which was created by Oleksandr Tymoshenko.
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.
swarren changed the following for upstream: * Removed hack udelay()s in bcm2835_sdhci_raw_writel(); setting SDHCI_QUIRK_WAIT_SEND_CMD appears to solve the issues. * Remove register logging from read*/write* functions. * Sort out confusion with min/max_freq values passed to add_sdhci(). * Use more descriptive variable names and calculations in IO accessors. * Simplified and commented twoticks_delay calculation. * checkpatch fixes.
Cc: Andy Fleming afleming@gmail.com Signed-off-by: Oleksandr Tymoshenko gonzo@bluezbox.com Signed-off-by: Stephen Warren swarren@wwwdotorg.org --- v5: Invent struct bcm2835_sdhci_host to avoid static/global variables. v4: * Merged with video patch series due to dependencies in rpi_b.h. * Rebased onto latest u-boot-arm/master; no real changes. v3: No such version was posted. v2: * Use more descriptive variable names and calculations in IO accessors. * Add Oleksandr's S-o-b. * Rewrite commit description to note that the Linux code this was derived from was S-o-b Dom Cobley. --- arch/arm/include/asm/arch-bcm2835/sdhci.h | 24 ++++ drivers/mmc/Makefile | 1 + drivers/mmc/bcm2835_sdhci.c | 189 +++++++++++++++++++++++++++++ 3 files changed, 214 insertions(+) create mode 100644 arch/arm/include/asm/arch-bcm2835/sdhci.h create mode 100644 drivers/mmc/bcm2835_sdhci.c
diff --git a/arch/arm/include/asm/arch-bcm2835/sdhci.h b/arch/arm/include/asm/arch-bcm2835/sdhci.h new file mode 100644 index 0000000..a4f867b --- /dev/null +++ b/arch/arm/include/asm/arch-bcm2835/sdhci.h @@ -0,0 +1,24 @@ +/* + * (C) Copyright 2012 Stephen Warren + * + * See file CREDITS for list of people who contributed to this + * project. + * + * 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. + * + * This program is distributed in the hope that 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. + */ + +#ifndef _BCM2835_SDHCI_H_ +#define _BCM2835_SDHCI_H_ + +#define BCM2835_SDHCI_BASE 0x20300000 + +int bcm2835_sdhci_init(u32 regbase, u32 emmc_freq); + +#endif diff --git a/drivers/mmc/Makefile b/drivers/mmc/Makefile index a1dd730..6be36f2 100644 --- a/drivers/mmc/Makefile +++ b/drivers/mmc/Makefile @@ -43,6 +43,7 @@ COBJS-$(CONFIG_MXS_MMC) += mxsmmc.o COBJS-$(CONFIG_OMAP_HSMMC) += omap_hsmmc.o COBJS-$(CONFIG_PXA_MMC_GENERIC) += pxa_mmc_gen.o COBJS-$(CONFIG_SDHCI) += sdhci.o +COBJS-$(CONFIG_BCM2835_SDHCI) += bcm2835_sdhci.o COBJS-$(CONFIG_S5P_SDHCI) += s5p_sdhci.o COBJS-$(CONFIG_SH_MMCIF) += sh_mmcif.o COBJS-$(CONFIG_TEGRA_MMC) += tegra_mmc.o diff --git a/drivers/mmc/bcm2835_sdhci.c b/drivers/mmc/bcm2835_sdhci.c new file mode 100644 index 0000000..b0afc3c --- /dev/null +++ b/drivers/mmc/bcm2835_sdhci.c @@ -0,0 +1,189 @@ +/* + * This code was extracted from: + * git://github.com/gonzoua/u-boot-pi.git master + * and hence presumably (C) 2012 Oleksandr Tymoshenko + * + * Tweaks for U-Boot upstreaming + * (C) 2012 Stephen Warren + * + * Portions (e.g. read/write macros, concepts for back-to-back register write + * timing workarounds) obviously extracted from the Linux kernel at: + * https://github.com/raspberrypi/linux.git rpi-3.6.y + * + * The Linux kernel code has the following (c) and license, which is hence + * propagated to Oleksandr's tree and here: + * + * Support for SDHCI device on 2835 + * Based on sdhci-bcm2708.c (c) 2010 Broadcom + * + * 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. + * + * This program is distributed in the hope that 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, write to the Free Software + * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. + */ + +/* Supports: + * SDHCI platform device - Arasan SD controller in BCM2708 + * + * Inspired by sdhci-pci.c, by Pierre Ossman + */ + +#include <common.h> +#include <malloc.h> +#include <sdhci.h> + +/* 400KHz is max freq for card ID etc. Use that as min */ +#define MIN_FREQ 400000 + +struct bcm2835_sdhci_host { + struct sdhci_host host; + uint twoticks_delay; + ulong last_write; +}; + +static inline struct bcm2835_sdhci_host *to_bcm(struct sdhci_host *host) +{ + return (struct bcm2835_sdhci_host *)host; +} + +static inline void bcm2835_sdhci_raw_writel(struct sdhci_host *host, u32 val, + int reg) +{ + struct bcm2835_sdhci_host *bcm_host = to_bcm(host); + + /* + * 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) + */ + while (get_timer(bcm_host->last_write) < bcm_host->twoticks_delay) + ; + + writel(val, host->ioaddr + reg); + bcm_host->last_write = get_timer(0); +} + +static inline u32 bcm2835_sdhci_raw_readl(struct sdhci_host *host, int reg) +{ + return readl(host->ioaddr + reg); +} + +static void bcm2835_sdhci_writel(struct sdhci_host *host, u32 val, int reg) +{ + bcm2835_sdhci_raw_writel(host, val, reg); +} + +static void bcm2835_sdhci_writew(struct sdhci_host *host, u16 val, int reg) +{ + static u32 shadow; + u32 oldval = (reg == SDHCI_COMMAND) ? shadow : + bcm2835_sdhci_raw_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) + shadow = newval; + else + bcm2835_sdhci_raw_writel(host, newval, reg & ~3); +} + +static void bcm2835_sdhci_writeb(struct sdhci_host *host, u8 val, int reg) +{ + u32 oldval = bcm2835_sdhci_raw_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_raw_writel(host, newval, reg & ~3); +} + +static u32 bcm2835_sdhci_readl(struct sdhci_host *host, int reg) +{ + u32 val = bcm2835_sdhci_raw_readl(host, reg); + + return val; +} + +static u16 bcm2835_sdhci_readw(struct sdhci_host *host, int reg) +{ + u32 val = bcm2835_sdhci_raw_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 u8 bcm2835_sdhci_readb(struct sdhci_host *host, int reg) +{ + u32 val = bcm2835_sdhci_raw_readl(host, (reg & ~3)); + u32 byte_num = reg & 3; + u32 byte_shift = byte_num * 8; + u32 byte = (val >> byte_shift) & 0xff; + + return byte; +} + +static const struct sdhci_ops bcm2835_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, +}; + +int bcm2835_sdhci_init(u32 regbase, u32 emmc_freq) +{ + struct bcm2835_sdhci_host *bcm_host; + struct sdhci_host *host; + + bcm_host = malloc(sizeof(*bcm_host)); + if (!bcm_host) { + printf("sdhci_host malloc fail!\n"); + return 1; + } + + /* + * See the comments in bcm2835_sdhci_raw_writel(). + * + * This should probably be dynamically calculated based on the actual + * 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. + * +1 for hack rounding. + */ + bcm_host->twoticks_delay = ((2 * 1000000) / MIN_FREQ) + 1; + bcm_host->last_write = 0; + + host = &bcm_host->host; + host->name = "bcm2835_sdhci"; + host->ioaddr = (void *)regbase; + host->quirks = SDHCI_QUIRK_BROKEN_VOLTAGE | SDHCI_QUIRK_BROKEN_R1B | + SDHCI_QUIRK_WAIT_SEND_CMD; + host->voltages = MMC_VDD_32_33 | MMC_VDD_33_34 | MMC_VDD_165_195; + host->ops = &bcm2835_ops; + + host->version = sdhci_readw(host, SDHCI_HOST_VERSION); + add_sdhci(host, emmc_freq, MIN_FREQ); + + return 0; +}