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/*
* 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>
#include <mach/timer.h>
#include <mach/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 (timer_get_us() - bcm_host->last_write < bcm_host->twoticks_delay)
;
writel(val, host->ioaddr + reg);
bcm_host->last_write = timer_get_us();
}
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 = calloc(1, sizeof(*bcm_host));
if (!bcm_host) {
printf("sdhci_host calloc fail!\n");
return -ENOMEM;
}
/*
* 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 *)(unsigned long)regbase;
host->quirks = SDHCI_QUIRK_BROKEN_VOLTAGE | SDHCI_QUIRK_BROKEN_R1B |
SDHCI_QUIRK_WAIT_SEND_CMD | SDHCI_QUIRK_NO_HISPD_BIT;
host->voltages = MMC_VDD_32_33 | MMC_VDD_33_34 | MMC_VDD_165_195;
host->ops = &bcm2835_ops;
add_sdhci(host, emmc_freq, MIN_FREQ);
return 0;
}
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