linux/drivers/mmc/core/sd.c
Ben Hutchings bd68e0838f mmc: add module parameter to set whether cards are assumed removable
Some people run general-purpose distribution kernels on netbooks with
a card that is physically non-removable or logically non-removable
(e.g. used for /home) and cannot be cleanly unmounted during suspend.
Add a module parameter to set whether cards are assumed removable or
non-removable, with the default set by CONFIG_MMC_UNSAFE_RESUME.

In general, it is not possible to tell whether a card present in an MMC
slot after resume is the same that was there before suspend.  So there are
two possible behaviours, each of which will cause data loss in some cases:

CONFIG_MMC_UNSAFE_RESUME=n (default): Cards are assumed to be removed
during suspend.  Any filesystem on them must be unmounted before suspend;
otherwise, buffered writes will be lost.

CONFIG_MMC_UNSAFE_RESUME=y: Cards are assumed to remain present during
suspend.  They must not be swapped during suspend; otherwise, buffered
writes will be flushed to the wrong card.

Currently the choice is made at compile time and this allows that to be
overridden at module load time.

Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Cc: Wouter van Heyst <larstiq@larstiq.dyndns.org>
Cc: <linux-mmc@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-12-15 08:53:35 -08:00

715 lines
15 KiB
C

/*
* linux/drivers/mmc/core/sd.c
*
* Copyright (C) 2003-2004 Russell King, All Rights Reserved.
* SD support Copyright (C) 2004 Ian Molton, All Rights Reserved.
* Copyright (C) 2005-2007 Pierre Ossman, All Rights Reserved.
*
* 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/err.h>
#include <linux/mmc/host.h>
#include <linux/mmc/card.h>
#include <linux/mmc/mmc.h>
#include <linux/mmc/sd.h>
#include "core.h"
#include "bus.h"
#include "mmc_ops.h"
#include "sd_ops.h"
static const unsigned int tran_exp[] = {
10000, 100000, 1000000, 10000000,
0, 0, 0, 0
};
static const unsigned char tran_mant[] = {
0, 10, 12, 13, 15, 20, 25, 30,
35, 40, 45, 50, 55, 60, 70, 80,
};
static const unsigned int tacc_exp[] = {
1, 10, 100, 1000, 10000, 100000, 1000000, 10000000,
};
static const unsigned int tacc_mant[] = {
0, 10, 12, 13, 15, 20, 25, 30,
35, 40, 45, 50, 55, 60, 70, 80,
};
#define UNSTUFF_BITS(resp,start,size) \
({ \
const int __size = size; \
const u32 __mask = (__size < 32 ? 1 << __size : 0) - 1; \
const int __off = 3 - ((start) / 32); \
const int __shft = (start) & 31; \
u32 __res; \
\
__res = resp[__off] >> __shft; \
if (__size + __shft > 32) \
__res |= resp[__off-1] << ((32 - __shft) % 32); \
__res & __mask; \
})
/*
* Given the decoded CSD structure, decode the raw CID to our CID structure.
*/
static void mmc_decode_cid(struct mmc_card *card)
{
u32 *resp = card->raw_cid;
memset(&card->cid, 0, sizeof(struct mmc_cid));
/*
* SD doesn't currently have a version field so we will
* have to assume we can parse this.
*/
card->cid.manfid = UNSTUFF_BITS(resp, 120, 8);
card->cid.oemid = UNSTUFF_BITS(resp, 104, 16);
card->cid.prod_name[0] = UNSTUFF_BITS(resp, 96, 8);
card->cid.prod_name[1] = UNSTUFF_BITS(resp, 88, 8);
card->cid.prod_name[2] = UNSTUFF_BITS(resp, 80, 8);
card->cid.prod_name[3] = UNSTUFF_BITS(resp, 72, 8);
card->cid.prod_name[4] = UNSTUFF_BITS(resp, 64, 8);
card->cid.hwrev = UNSTUFF_BITS(resp, 60, 4);
card->cid.fwrev = UNSTUFF_BITS(resp, 56, 4);
card->cid.serial = UNSTUFF_BITS(resp, 24, 32);
card->cid.year = UNSTUFF_BITS(resp, 12, 8);
card->cid.month = UNSTUFF_BITS(resp, 8, 4);
card->cid.year += 2000; /* SD cards year offset */
}
/*
* Given a 128-bit response, decode to our card CSD structure.
*/
static int mmc_decode_csd(struct mmc_card *card)
{
struct mmc_csd *csd = &card->csd;
unsigned int e, m, csd_struct;
u32 *resp = card->raw_csd;
csd_struct = UNSTUFF_BITS(resp, 126, 2);
switch (csd_struct) {
case 0:
m = UNSTUFF_BITS(resp, 115, 4);
e = UNSTUFF_BITS(resp, 112, 3);
csd->tacc_ns = (tacc_exp[e] * tacc_mant[m] + 9) / 10;
csd->tacc_clks = UNSTUFF_BITS(resp, 104, 8) * 100;
m = UNSTUFF_BITS(resp, 99, 4);
e = UNSTUFF_BITS(resp, 96, 3);
csd->max_dtr = tran_exp[e] * tran_mant[m];
csd->cmdclass = UNSTUFF_BITS(resp, 84, 12);
e = UNSTUFF_BITS(resp, 47, 3);
m = UNSTUFF_BITS(resp, 62, 12);
csd->capacity = (1 + m) << (e + 2);
csd->read_blkbits = UNSTUFF_BITS(resp, 80, 4);
csd->read_partial = UNSTUFF_BITS(resp, 79, 1);
csd->write_misalign = UNSTUFF_BITS(resp, 78, 1);
csd->read_misalign = UNSTUFF_BITS(resp, 77, 1);
csd->r2w_factor = UNSTUFF_BITS(resp, 26, 3);
csd->write_blkbits = UNSTUFF_BITS(resp, 22, 4);
csd->write_partial = UNSTUFF_BITS(resp, 21, 1);
break;
case 1:
/*
* This is a block-addressed SDHC card. Most
* interesting fields are unused and have fixed
* values. To avoid getting tripped by buggy cards,
* we assume those fixed values ourselves.
*/
mmc_card_set_blockaddr(card);
csd->tacc_ns = 0; /* Unused */
csd->tacc_clks = 0; /* Unused */
m = UNSTUFF_BITS(resp, 99, 4);
e = UNSTUFF_BITS(resp, 96, 3);
csd->max_dtr = tran_exp[e] * tran_mant[m];
csd->cmdclass = UNSTUFF_BITS(resp, 84, 12);
m = UNSTUFF_BITS(resp, 48, 22);
csd->capacity = (1 + m) << 10;
csd->read_blkbits = 9;
csd->read_partial = 0;
csd->write_misalign = 0;
csd->read_misalign = 0;
csd->r2w_factor = 4; /* Unused */
csd->write_blkbits = 9;
csd->write_partial = 0;
break;
default:
printk(KERN_ERR "%s: unrecognised CSD structure version %d\n",
mmc_hostname(card->host), csd_struct);
return -EINVAL;
}
return 0;
}
/*
* Given a 64-bit response, decode to our card SCR structure.
*/
static int mmc_decode_scr(struct mmc_card *card)
{
struct sd_scr *scr = &card->scr;
unsigned int scr_struct;
u32 resp[4];
resp[3] = card->raw_scr[1];
resp[2] = card->raw_scr[0];
scr_struct = UNSTUFF_BITS(resp, 60, 4);
if (scr_struct != 0) {
printk(KERN_ERR "%s: unrecognised SCR structure version %d\n",
mmc_hostname(card->host), scr_struct);
return -EINVAL;
}
scr->sda_vsn = UNSTUFF_BITS(resp, 56, 4);
scr->bus_widths = UNSTUFF_BITS(resp, 48, 4);
return 0;
}
/*
* Fetches and decodes switch information
*/
static int mmc_read_switch(struct mmc_card *card)
{
int err;
u8 *status;
if (card->scr.sda_vsn < SCR_SPEC_VER_1)
return 0;
if (!(card->csd.cmdclass & CCC_SWITCH)) {
printk(KERN_WARNING "%s: card lacks mandatory switch "
"function, performance might suffer.\n",
mmc_hostname(card->host));
return 0;
}
err = -EIO;
status = kmalloc(64, GFP_KERNEL);
if (!status) {
printk(KERN_ERR "%s: could not allocate a buffer for "
"switch capabilities.\n", mmc_hostname(card->host));
return -ENOMEM;
}
err = mmc_sd_switch(card, 0, 0, 1, status);
if (err) {
/* If the host or the card can't do the switch,
* fail more gracefully. */
if ((err != -EINVAL)
&& (err != -ENOSYS)
&& (err != -EFAULT))
goto out;
printk(KERN_WARNING "%s: problem reading switch "
"capabilities, performance might suffer.\n",
mmc_hostname(card->host));
err = 0;
goto out;
}
if (status[13] & 0x02)
card->sw_caps.hs_max_dtr = 50000000;
out:
kfree(status);
return err;
}
/*
* Test if the card supports high-speed mode and, if so, switch to it.
*/
static int mmc_switch_hs(struct mmc_card *card)
{
int err;
u8 *status;
if (card->scr.sda_vsn < SCR_SPEC_VER_1)
return 0;
if (!(card->csd.cmdclass & CCC_SWITCH))
return 0;
if (!(card->host->caps & MMC_CAP_SD_HIGHSPEED))
return 0;
if (card->sw_caps.hs_max_dtr == 0)
return 0;
err = -EIO;
status = kmalloc(64, GFP_KERNEL);
if (!status) {
printk(KERN_ERR "%s: could not allocate a buffer for "
"switch capabilities.\n", mmc_hostname(card->host));
return -ENOMEM;
}
err = mmc_sd_switch(card, 1, 0, 1, status);
if (err)
goto out;
if ((status[16] & 0xF) != 1) {
printk(KERN_WARNING "%s: Problem switching card "
"into high-speed mode!\n",
mmc_hostname(card->host));
} else {
mmc_card_set_highspeed(card);
mmc_set_timing(card->host, MMC_TIMING_SD_HS);
}
out:
kfree(status);
return err;
}
MMC_DEV_ATTR(cid, "%08x%08x%08x%08x\n", card->raw_cid[0], card->raw_cid[1],
card->raw_cid[2], card->raw_cid[3]);
MMC_DEV_ATTR(csd, "%08x%08x%08x%08x\n", card->raw_csd[0], card->raw_csd[1],
card->raw_csd[2], card->raw_csd[3]);
MMC_DEV_ATTR(scr, "%08x%08x\n", card->raw_scr[0], card->raw_scr[1]);
MMC_DEV_ATTR(date, "%02d/%04d\n", card->cid.month, card->cid.year);
MMC_DEV_ATTR(fwrev, "0x%x\n", card->cid.fwrev);
MMC_DEV_ATTR(hwrev, "0x%x\n", card->cid.hwrev);
MMC_DEV_ATTR(manfid, "0x%06x\n", card->cid.manfid);
MMC_DEV_ATTR(name, "%s\n", card->cid.prod_name);
MMC_DEV_ATTR(oemid, "0x%04x\n", card->cid.oemid);
MMC_DEV_ATTR(serial, "0x%08x\n", card->cid.serial);
static struct attribute *sd_std_attrs[] = {
&dev_attr_cid.attr,
&dev_attr_csd.attr,
&dev_attr_scr.attr,
&dev_attr_date.attr,
&dev_attr_fwrev.attr,
&dev_attr_hwrev.attr,
&dev_attr_manfid.attr,
&dev_attr_name.attr,
&dev_attr_oemid.attr,
&dev_attr_serial.attr,
NULL,
};
static struct attribute_group sd_std_attr_group = {
.attrs = sd_std_attrs,
};
static const struct attribute_group *sd_attr_groups[] = {
&sd_std_attr_group,
NULL,
};
static struct device_type sd_type = {
.groups = sd_attr_groups,
};
/*
* Handle the detection and initialisation of a card.
*
* In the case of a resume, "oldcard" will contain the card
* we're trying to reinitialise.
*/
static int mmc_sd_init_card(struct mmc_host *host, u32 ocr,
struct mmc_card *oldcard)
{
struct mmc_card *card;
int err;
u32 cid[4];
unsigned int max_dtr;
BUG_ON(!host);
WARN_ON(!host->claimed);
/*
* Since we're changing the OCR value, we seem to
* need to tell some cards to go back to the idle
* state. We wait 1ms to give cards time to
* respond.
*/
mmc_go_idle(host);
/*
* If SD_SEND_IF_COND indicates an SD 2.0
* compliant card and we should set bit 30
* of the ocr to indicate that we can handle
* block-addressed SDHC cards.
*/
err = mmc_send_if_cond(host, ocr);
if (!err)
ocr |= 1 << 30;
err = mmc_send_app_op_cond(host, ocr, NULL);
if (err)
goto err;
/*
* Fetch CID from card.
*/
if (mmc_host_is_spi(host))
err = mmc_send_cid(host, cid);
else
err = mmc_all_send_cid(host, cid);
if (err)
goto err;
if (oldcard) {
if (memcmp(cid, oldcard->raw_cid, sizeof(cid)) != 0) {
err = -ENOENT;
goto err;
}
card = oldcard;
} else {
/*
* Allocate card structure.
*/
card = mmc_alloc_card(host, &sd_type);
if (IS_ERR(card)) {
err = PTR_ERR(card);
goto err;
}
card->type = MMC_TYPE_SD;
memcpy(card->raw_cid, cid, sizeof(card->raw_cid));
}
/*
* For native busses: get card RCA and quit open drain mode.
*/
if (!mmc_host_is_spi(host)) {
err = mmc_send_relative_addr(host, &card->rca);
if (err)
goto free_card;
mmc_set_bus_mode(host, MMC_BUSMODE_PUSHPULL);
}
if (!oldcard) {
/*
* Fetch CSD from card.
*/
err = mmc_send_csd(card, card->raw_csd);
if (err)
goto free_card;
err = mmc_decode_csd(card);
if (err)
goto free_card;
mmc_decode_cid(card);
}
/*
* Select card, as all following commands rely on that.
*/
if (!mmc_host_is_spi(host)) {
err = mmc_select_card(card);
if (err)
goto free_card;
}
if (!oldcard) {
/*
* Fetch SCR from card.
*/
err = mmc_app_send_scr(card, card->raw_scr);
if (err)
goto free_card;
err = mmc_decode_scr(card);
if (err < 0)
goto free_card;
/*
* Fetch switch information from card.
*/
err = mmc_read_switch(card);
if (err)
goto free_card;
}
/*
* For SPI, enable CRC as appropriate.
* This CRC enable is located AFTER the reading of the
* card registers because some SDHC cards are not able
* to provide valid CRCs for non-512-byte blocks.
*/
if (mmc_host_is_spi(host)) {
err = mmc_spi_set_crc(host, use_spi_crc);
if (err)
goto free_card;
}
/*
* Attempt to change to high-speed (if supported)
*/
err = mmc_switch_hs(card);
if (err)
goto free_card;
/*
* Compute bus speed.
*/
max_dtr = (unsigned int)-1;
if (mmc_card_highspeed(card)) {
if (max_dtr > card->sw_caps.hs_max_dtr)
max_dtr = card->sw_caps.hs_max_dtr;
} else if (max_dtr > card->csd.max_dtr) {
max_dtr = card->csd.max_dtr;
}
mmc_set_clock(host, max_dtr);
/*
* Switch to wider bus (if supported).
*/
if ((host->caps & MMC_CAP_4_BIT_DATA) &&
(card->scr.bus_widths & SD_SCR_BUS_WIDTH_4)) {
err = mmc_app_set_bus_width(card, MMC_BUS_WIDTH_4);
if (err)
goto free_card;
mmc_set_bus_width(host, MMC_BUS_WIDTH_4);
}
/*
* Check if read-only switch is active.
*/
if (!oldcard) {
if (!host->ops->get_ro || host->ops->get_ro(host) < 0) {
printk(KERN_WARNING "%s: host does not "
"support reading read-only "
"switch. assuming write-enable.\n",
mmc_hostname(host));
} else {
if (host->ops->get_ro(host) > 0)
mmc_card_set_readonly(card);
}
}
if (!oldcard)
host->card = card;
return 0;
free_card:
if (!oldcard)
mmc_remove_card(card);
err:
return err;
}
/*
* Host is being removed. Free up the current card.
*/
static void mmc_sd_remove(struct mmc_host *host)
{
BUG_ON(!host);
BUG_ON(!host->card);
mmc_remove_card(host->card);
host->card = NULL;
}
/*
* Card detection callback from host.
*/
static void mmc_sd_detect(struct mmc_host *host)
{
int err;
BUG_ON(!host);
BUG_ON(!host->card);
mmc_claim_host(host);
/*
* Just check if our card has been removed.
*/
err = mmc_send_status(host->card, NULL);
mmc_release_host(host);
if (err) {
mmc_sd_remove(host);
mmc_claim_host(host);
mmc_detach_bus(host);
mmc_release_host(host);
}
}
/*
* Suspend callback from host.
*/
static int mmc_sd_suspend(struct mmc_host *host)
{
BUG_ON(!host);
BUG_ON(!host->card);
mmc_claim_host(host);
if (!mmc_host_is_spi(host))
mmc_deselect_cards(host);
host->card->state &= ~MMC_STATE_HIGHSPEED;
mmc_release_host(host);
return 0;
}
/*
* Resume callback from host.
*
* This function tries to determine if the same card is still present
* and, if so, restore all state to it.
*/
static int mmc_sd_resume(struct mmc_host *host)
{
int err;
BUG_ON(!host);
BUG_ON(!host->card);
mmc_claim_host(host);
err = mmc_sd_init_card(host, host->ocr, host->card);
mmc_release_host(host);
return err;
}
static void mmc_sd_power_restore(struct mmc_host *host)
{
host->card->state &= ~MMC_STATE_HIGHSPEED;
mmc_claim_host(host);
mmc_sd_init_card(host, host->ocr, host->card);
mmc_release_host(host);
}
static const struct mmc_bus_ops mmc_sd_ops = {
.remove = mmc_sd_remove,
.detect = mmc_sd_detect,
.suspend = NULL,
.resume = NULL,
.power_restore = mmc_sd_power_restore,
};
static const struct mmc_bus_ops mmc_sd_ops_unsafe = {
.remove = mmc_sd_remove,
.detect = mmc_sd_detect,
.suspend = mmc_sd_suspend,
.resume = mmc_sd_resume,
.power_restore = mmc_sd_power_restore,
};
static void mmc_sd_attach_bus_ops(struct mmc_host *host)
{
const struct mmc_bus_ops *bus_ops;
if (host->caps & MMC_CAP_NONREMOVABLE || !mmc_assume_removable)
bus_ops = &mmc_sd_ops_unsafe;
else
bus_ops = &mmc_sd_ops;
mmc_attach_bus(host, bus_ops);
}
/*
* Starting point for SD card init.
*/
int mmc_attach_sd(struct mmc_host *host, u32 ocr)
{
int err;
BUG_ON(!host);
WARN_ON(!host->claimed);
mmc_sd_attach_bus_ops(host);
/*
* We need to get OCR a different way for SPI.
*/
if (mmc_host_is_spi(host)) {
mmc_go_idle(host);
err = mmc_spi_read_ocr(host, 0, &ocr);
if (err)
goto err;
}
/*
* Sanity check the voltages that the card claims to
* support.
*/
if (ocr & 0x7F) {
printk(KERN_WARNING "%s: card claims to support voltages "
"below the defined range. These will be ignored.\n",
mmc_hostname(host));
ocr &= ~0x7F;
}
if (ocr & MMC_VDD_165_195) {
printk(KERN_WARNING "%s: SD card claims to support the "
"incompletely defined 'low voltage range'. This "
"will be ignored.\n", mmc_hostname(host));
ocr &= ~MMC_VDD_165_195;
}
host->ocr = mmc_select_voltage(host, ocr);
/*
* Can we support the voltage(s) of the card(s)?
*/
if (!host->ocr) {
err = -EINVAL;
goto err;
}
/*
* Detect and init the card.
*/
err = mmc_sd_init_card(host, host->ocr, NULL);
if (err)
goto err;
mmc_release_host(host);
err = mmc_add_card(host->card);
if (err)
goto remove_card;
return 0;
remove_card:
mmc_remove_card(host->card);
host->card = NULL;
mmc_claim_host(host);
err:
mmc_detach_bus(host);
mmc_release_host(host);
printk(KERN_ERR "%s: error %d whilst initialising SD card\n",
mmc_hostname(host), err);
return err;
}