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android_kernel_samsung_msm8976/drivers/mmc/core/mmc.c
Philip Langdale 55556da012 MMC: Fix handling of low-voltage cards 
Fix handling of low voltage MMC cards.

The latest MMC and SD specs both agree that support for
low-voltage operations is indicated by bit 7 in the OCR.
The MMC spec states that the low voltage range is
1.65-1.95V while the SD spec leaves the actual voltage
range undefined - meaning that there is still no such
thing as a low voltage SD card.

However, an old Sandisk spec implied that bits 7.0
represented voltages below 2.0V in 1V or 0.5V increments,
and the code was accordingly written with that expectation.

This confusion meant that host drivers attempting to support
the typical low voltage (1.8V) would set the wrong bits in
the host OCR mask (usually bits 5 and/or 6) resulting in the
the low voltage mode never being used.

This change corrects the low voltage range and adds sanity
checks on the reserved bits (0-6) and for SD cards that
claim to support low-voltage operations.

Signed-off-by: Philip Langdale <philipl@overt.org>
Signed-off-by: Pierre Ossman <drzeus@drzeus.cx>
2007-05-01 14:14:50 +02:00

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/*
* linux/drivers/mmc/mmc.c
*
* Copyright (C) 2003-2004 Russell King, All Rights Reserved.
* Copyright (C) 2005-2007 Pierre Ossman, All Rights Reserved.
* MMCv4 support Copyright (C) 2006 Philip Langdale, 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 "core.h"
#include "sysfs.h"
#include "mmc_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;
/*
* The selection of the format here is based upon published
* specs from sandisk and from what people have reported.
*/
switch (card->csd.mmca_vsn) {
case 0: /* MMC v1.0 - v1.2 */
case 1: /* MMC v1.4 */
card->cid.manfid = UNSTUFF_BITS(resp, 104, 24);
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.prod_name[5] = UNSTUFF_BITS(resp, 56, 8);
card->cid.prod_name[6] = UNSTUFF_BITS(resp, 48, 8);
card->cid.hwrev = UNSTUFF_BITS(resp, 44, 4);
card->cid.fwrev = UNSTUFF_BITS(resp, 40, 4);
card->cid.serial = UNSTUFF_BITS(resp, 16, 24);
card->cid.month = UNSTUFF_BITS(resp, 12, 4);
card->cid.year = UNSTUFF_BITS(resp, 8, 4) + 1997;
break;
case 2: /* MMC v2.0 - v2.2 */
case 3: /* MMC v3.1 - v3.3 */
case 4: /* MMC v4 */
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.prod_name[5] = UNSTUFF_BITS(resp, 56, 8);
card->cid.serial = UNSTUFF_BITS(resp, 16, 32);
card->cid.month = UNSTUFF_BITS(resp, 12, 4);
card->cid.year = UNSTUFF_BITS(resp, 8, 4) + 1997;
break;
default:
printk("%s: card has unknown MMCA version %d\n",
mmc_hostname(card->host), card->csd.mmca_vsn);
mmc_card_set_bad(card);
break;
}
}
/*
* Given a 128-bit response, decode to our card CSD structure.
*/
static void mmc_decode_csd(struct mmc_card *card)
{
struct mmc_csd *csd = &card->csd;
unsigned int e, m, csd_struct;
u32 *resp = card->raw_csd;
/*
* We only understand CSD structure v1.1 and v1.2.
* v1.2 has extra information in bits 15, 11 and 10.
*/
csd_struct = UNSTUFF_BITS(resp, 126, 2);
if (csd_struct != 1 && csd_struct != 2) {
printk("%s: unrecognised CSD structure version %d\n",
mmc_hostname(card->host), csd_struct);
mmc_card_set_bad(card);
return;
}
csd->mmca_vsn = UNSTUFF_BITS(resp, 122, 4);
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);
}
/*
* Read and decode extended CSD. Switch to high-speed and wide bus
* if supported.
*/
static int mmc_process_ext_csd(struct mmc_card *card)
{
int err;
u8 *ext_csd;
BUG_ON(!card);
err = MMC_ERR_FAILED;
if (card->csd.mmca_vsn < CSD_SPEC_VER_4)
return MMC_ERR_NONE;
/*
* As the ext_csd is so large and mostly unused, we don't store the
* raw block in mmc_card.
*/
ext_csd = kmalloc(512, GFP_KERNEL);
if (!ext_csd) {
printk(KERN_ERR "%s: could not allocate a buffer to "
"receive the ext_csd. mmc v4 cards will be "
"treated as v3.\n", mmc_hostname(card->host));
return MMC_ERR_FAILED;
}
err = mmc_send_ext_csd(card, ext_csd);
if (err != MMC_ERR_NONE) {
/*
* High capacity cards should have this "magic" size
* stored in their CSD.
*/
if (card->csd.capacity == (4096 * 512)) {
printk(KERN_ERR "%s: unable to read EXT_CSD "
"on a possible high capacity card. "
"Card will be ignored.\n",
mmc_hostname(card->host));
} else {
printk(KERN_WARNING "%s: unable to read "
"EXT_CSD, performance might "
"suffer.\n",
mmc_hostname(card->host));
err = MMC_ERR_NONE;
}
goto out;
}
card->ext_csd.sectors =
ext_csd[EXT_CSD_SEC_CNT + 0] << 0 |
ext_csd[EXT_CSD_SEC_CNT + 1] << 8 |
ext_csd[EXT_CSD_SEC_CNT + 2] << 16 |
ext_csd[EXT_CSD_SEC_CNT + 3] << 24;
if (card->ext_csd.sectors)
mmc_card_set_blockaddr(card);
switch (ext_csd[EXT_CSD_CARD_TYPE]) {
case EXT_CSD_CARD_TYPE_52 | EXT_CSD_CARD_TYPE_26:
card->ext_csd.hs_max_dtr = 52000000;
break;
case EXT_CSD_CARD_TYPE_26:
card->ext_csd.hs_max_dtr = 26000000;
break;
default:
/* MMC v4 spec says this cannot happen */
printk(KERN_WARNING "%s: card is mmc v4 but doesn't "
"support any high-speed modes.\n",
mmc_hostname(card->host));
goto out;
}
if (card->host->caps & MMC_CAP_MMC_HIGHSPEED) {
/* Activate highspeed support. */
err = mmc_switch(card, EXT_CSD_CMD_SET_NORMAL,
EXT_CSD_HS_TIMING, 1);
if (err != MMC_ERR_NONE) {
printk(KERN_WARNING "%s: failed to switch "
"card to mmc v4 high-speed mode.\n",
mmc_hostname(card->host));
err = MMC_ERR_NONE;
goto out;
}
mmc_card_set_highspeed(card);
mmc_set_timing(card->host, MMC_TIMING_MMC_HS);
}
/* Check for host support for wide-bus modes. */
if (card->host->caps & MMC_CAP_4_BIT_DATA) {
/* Activate 4-bit support. */
err = mmc_switch(card, EXT_CSD_CMD_SET_NORMAL,
EXT_CSD_BUS_WIDTH, EXT_CSD_BUS_WIDTH_4);
if (err != MMC_ERR_NONE) {
printk(KERN_WARNING "%s: failed to switch "
"card to mmc v4 4-bit bus mode.\n",
mmc_hostname(card->host));
err = MMC_ERR_NONE;
goto out;
}
mmc_set_bus_width(card->host, MMC_BUS_WIDTH_4);
}
out:
kfree(ext_csd);
return err;
}
/*
* Host is being removed. Free up the current card.
*/
static void mmc_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_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_ERR_NONE) {
mmc_remove_card(host->card);
host->card = NULL;
mmc_claim_host(host);
mmc_detach_bus(host);
mmc_release_host(host);
}
}
static const struct mmc_bus_ops mmc_ops = {
.remove = mmc_remove,
.detect = mmc_detect,
};
/*
* Starting point for MMC card init.
*/
int mmc_attach_mmc(struct mmc_host *host, u32 ocr)
{
struct mmc_card *card;
int err;
u32 cid[4];
unsigned int max_dtr;
BUG_ON(!host);
BUG_ON(!host->claimed);
mmc_attach_bus(host, &mmc_ops);
/*
* 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;
}
host->ocr = mmc_select_voltage(host, ocr);
/*
* Can we support the voltage of the card?
*/
if (!host->ocr)
goto err;
/*
* 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);
/* The extra bit indicates that we support high capacity */
mmc_send_op_cond(host, host->ocr | (1 << 30), NULL);
/*
* Fetch CID from card.
*/
err = mmc_all_send_cid(host, cid);
if (err != MMC_ERR_NONE)
goto err;
/*
* Allocate card structure.
*/
card = mmc_alloc_card(host);
if (IS_ERR(card))
goto err;
card->type = MMC_TYPE_MMC;
card->rca = 1;
memcpy(card->raw_cid, cid, sizeof(card->raw_cid));
/*
* Set card RCA.
*/
err = mmc_set_relative_addr(card);
if (err != MMC_ERR_NONE)
goto free_card;
mmc_set_bus_mode(host, MMC_BUSMODE_PUSHPULL);
/*
* Fetch CSD from card.
*/
err = mmc_send_csd(card, card->raw_csd);
if (err != MMC_ERR_NONE)
goto free_card;
mmc_decode_csd(card);
mmc_decode_cid(card);
/*
* Fetch and process extened CSD.
* This will switch into high-speed and wide bus modes,
* as available.
*/
err = mmc_select_card(card);
if (err != MMC_ERR_NONE)
goto free_card;
err = mmc_process_ext_csd(card);
if (err != MMC_ERR_NONE)
goto free_card;
/*
* Compute bus speed.
*/
max_dtr = (unsigned int)-1;
if (mmc_card_highspeed(card)) {
if (max_dtr > card->ext_csd.hs_max_dtr)
max_dtr = card->ext_csd.hs_max_dtr;
} else if (max_dtr > card->csd.max_dtr) {
max_dtr = card->csd.max_dtr;
}
mmc_set_clock(host, max_dtr);
host->card = card;
mmc_release_host(host);
err = mmc_register_card(card);
if (err)
goto reclaim_host;
return 0;
reclaim_host:
mmc_claim_host(host);
free_card:
mmc_remove_card(card);
host->card = NULL;
err:
mmc_detach_bus(host);
mmc_release_host(host);
return 0;
}
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