Skip to content

Commit

Permalink
[PATCH] mmc: Add support for mmc v4 high speed mode
Browse files Browse the repository at this point in the history 
This adds support for the high-speed modes defined by mmc v4
(assuming the host controller is up to it). On a TI sdhci controller,
it improves read speed from 1.3MBps to 2.3MBps. The TI controller can
only go up to 24MHz, but everything helps. Another person has taken
this basic patch and used it on a Nokia 770 to get a bigger boost
because that controller can run at 48MHZ.

Signed-off-by: Philip Langdale <philipl@overt.org>
Signed-off-by: Pierre Ossman <drzeus@drzeus.cx>
  • Loading branch information
Philip Langdale authored and Pierre Ossman committed Dec 1, 2006
1 parent 9c9c261 commit bce40a3
Show file tree
Hide file tree
Showing 3 changed files with 171 additions and 5 deletions.
121 changes: 119 additions & 2 deletions drivers/mmc/mmc.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -4,6 +4,7 @@
* Copyright (C) 2003-2004 Russell King, All Rights Reserved.
* SD support Copyright (C) 2004 Ian Molton, All Rights Reserved.
* SD support Copyright (C) 2005 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
Expand Down Expand Up @@ -953,6 +954,114 @@ static void mmc_read_csds(struct mmc_host *host)
}
}

static void mmc_process_ext_csds(struct mmc_host *host)
{
int err;
struct mmc_card *card;

struct mmc_request mrq;
struct mmc_command cmd;
struct mmc_data data;

struct scatterlist sg;

/*
* As the ext_csd is so large and mostly unused, we don't store the
* raw block in mmc_card.
*/
u8 *ext_csd;
ext_csd = kmalloc(512, GFP_KERNEL);
if (!ext_csd) {
printk("%s: could not allocate a buffer to receive the ext_csd."
"mmc v4 cards will be treated as v3.\n",
mmc_hostname(host));
return;
}

list_for_each_entry(card, &host->cards, node) {
if (card->state & (MMC_STATE_DEAD|MMC_STATE_PRESENT))
continue;
if (mmc_card_sd(card))
continue;
if (card->csd.mmca_vsn < CSD_SPEC_VER_4)
continue;

err = mmc_select_card(host, card);
if (err != MMC_ERR_NONE) {
mmc_card_set_dead(card);
continue;
}

memset(&cmd, 0, sizeof(struct mmc_command));

cmd.opcode = MMC_SEND_EXT_CSD;
cmd.arg = 0;
cmd.flags = MMC_RSP_R1 | MMC_CMD_ADTC;

memset(&data, 0, sizeof(struct mmc_data));

mmc_set_data_timeout(&data, card, 0);

data.blksz = 512;
data.blocks = 1;
data.flags = MMC_DATA_READ;
data.sg = &sg;
data.sg_len = 1;

memset(&mrq, 0, sizeof(struct mmc_request));

mrq.cmd = &cmd;
mrq.data = &data;

sg_init_one(&sg, ext_csd, 512);

mmc_wait_for_req(host, &mrq);

if (cmd.error != MMC_ERR_NONE || data.error != MMC_ERR_NONE) {
mmc_card_set_dead(card);
continue;
}

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("%s: card is mmc v4 but doesn't support "
"any high-speed modes.\n",
mmc_hostname(card->host));
mmc_card_set_bad(card);
continue;
}

/* Activate highspeed support. */
cmd.opcode = MMC_SWITCH;
cmd.arg = (MMC_SWITCH_MODE_WRITE_BYTE << 24) |
(EXT_CSD_HS_TIMING << 16) |
(1 << 8) |
EXT_CSD_CMD_SET_NORMAL;
cmd.flags = MMC_RSP_R1B | MMC_CMD_AC;

err = mmc_wait_for_cmd(host, &cmd, CMD_RETRIES);
if (err != MMC_ERR_NONE) {
printk("%s: failed to switch card to mmc v4 "
"high-speed mode.\n",
mmc_hostname(card->host));
continue;
}

mmc_card_set_highspeed(card);
}

kfree(ext_csd);

mmc_deselect_cards(host);
}

static void mmc_read_scrs(struct mmc_host *host)
{
int err;
Expand Down Expand Up @@ -1031,8 +1140,14 @@ static unsigned int mmc_calculate_clock(struct mmc_host *host)
unsigned int max_dtr = host->f_max;

list_for_each_entry(card, &host->cards, node)
if (!mmc_card_dead(card) && max_dtr > card->csd.max_dtr)
max_dtr = card->csd.max_dtr;
if (!mmc_card_dead(card)) {
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;
}
}

pr_debug("%s: selected %d.%03dMHz transfer rate\n",
mmc_hostname(host),
Expand Down Expand Up @@ -1152,6 +1267,8 @@ static void mmc_setup(struct mmc_host *host)

if (host->mode == MMC_MODE_SD)
mmc_read_scrs(host);
else
mmc_process_ext_csds(host);
}


Expand Down
8 changes: 8 additions & 0 deletions include/linux/mmc/card.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -39,6 +39,10 @@ struct mmc_csd {
write_misalign:1;
};

struct mmc_ext_csd {
unsigned int hs_max_dtr;
};

struct sd_scr {
unsigned char sda_vsn;
unsigned char bus_widths;
Expand All @@ -62,11 +66,13 @@ struct mmc_card {
#define MMC_STATE_BAD (1<<2) /* unrecognised device */
#define MMC_STATE_SDCARD (1<<3) /* is an SD card */
#define MMC_STATE_READONLY (1<<4) /* card is read-only */
#define MMC_STATE_HIGHSPEED (1<<5) /* card is in mmc4 highspeed mode */
u32 raw_cid[4]; /* raw card CID */
u32 raw_csd[4]; /* raw card CSD */
u32 raw_scr[2]; /* raw card SCR */
struct mmc_cid cid; /* card identification */
struct mmc_csd csd; /* card specific */
struct mmc_ext_csd ext_csd; /* mmc v4 extended card specific */
struct sd_scr scr; /* extra SD information */
};

Expand All @@ -75,12 +81,14 @@ struct mmc_card {
#define mmc_card_bad(c) ((c)->state & MMC_STATE_BAD)
#define mmc_card_sd(c) ((c)->state & MMC_STATE_SDCARD)
#define mmc_card_readonly(c) ((c)->state & MMC_STATE_READONLY)
#define mmc_card_highspeed(c) ((c)->state & MMC_STATE_HIGHSPEED)

#define mmc_card_set_present(c) ((c)->state |= MMC_STATE_PRESENT)
#define mmc_card_set_dead(c) ((c)->state |= MMC_STATE_DEAD)
#define mmc_card_set_bad(c) ((c)->state |= MMC_STATE_BAD)
#define mmc_card_set_sd(c) ((c)->state |= MMC_STATE_SDCARD)
#define mmc_card_set_readonly(c) ((c)->state |= MMC_STATE_READONLY)
#define mmc_card_set_highspeed(c) ((c)->state |= MMC_STATE_HIGHSPEED)

#define mmc_card_name(c) ((c)->cid.prod_name)
#define mmc_card_id(c) ((c)->dev.bus_id)
Expand Down
47 changes: 44 additions & 3 deletions include/linux/mmc/protocol.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -25,14 +25,16 @@
#ifndef MMC_MMC_PROTOCOL_H
#define MMC_MMC_PROTOCOL_H

/* Standard MMC commands (3.1) type argument response */
/* Standard MMC commands (4.1) type argument response */
/* class 1 */
#define MMC_GO_IDLE_STATE 0 /* bc */
#define MMC_SEND_OP_COND 1 /* bcr [31:0] OCR R3 */
#define MMC_ALL_SEND_CID 2 /* bcr R2 */
#define MMC_SET_RELATIVE_ADDR 3 /* ac [31:16] RCA R1 */
#define MMC_SET_DSR 4 /* bc [31:16] RCA */
#define MMC_SWITCH 6 /* ac [31:0] See below R1b */
#define MMC_SELECT_CARD 7 /* ac [31:16] RCA R1 */
#define MMC_SEND_EXT_CSD 8 /* adtc R1 */
#define MMC_SEND_CSD 9 /* ac [31:16] RCA R2 */
#define MMC_SEND_CID 10 /* ac [31:16] RCA R2 */
#define MMC_READ_DAT_UNTIL_STOP 11 /* adtc [31:0] dadr R1 */
Expand Down Expand Up @@ -87,6 +89,17 @@
#define SD_APP_OP_COND 41 /* bcr [31:0] OCR R3 */
#define SD_APP_SEND_SCR 51 /* adtc R1 */

/*
* MMC_SWITCH argument format:
*
* [31:26] Always 0
* [25:24] Access Mode
* [23:16] Location of target Byte in EXT_CSD
* [15:08] Value Byte
* [07:03] Always 0
* [02:00] Command Set
*/

/*
MMC status in R1
Type
Expand Down Expand Up @@ -230,13 +243,41 @@ struct _mmc_csd {

#define CSD_STRUCT_VER_1_0 0 /* Valid for system specification 1.0 - 1.2 */
#define CSD_STRUCT_VER_1_1 1 /* Valid for system specification 1.4 - 2.2 */
#define CSD_STRUCT_VER_1_2 2 /* Valid for system specification 3.1 */
#define CSD_STRUCT_VER_1_2 2 /* Valid for system specification 3.1 - 3.2 - 3.31 - 4.0 - 4.1 */
#define CSD_STRUCT_EXT_CSD 3 /* Version is coded in CSD_STRUCTURE in EXT_CSD */

#define CSD_SPEC_VER_0 0 /* Implements system specification 1.0 - 1.2 */
#define CSD_SPEC_VER_1 1 /* Implements system specification 1.4 */
#define CSD_SPEC_VER_2 2 /* Implements system specification 2.0 - 2.2 */
#define CSD_SPEC_VER_3 3 /* Implements system specification 3.1 */
#define CSD_SPEC_VER_3 3 /* Implements system specification 3.1 - 3.2 - 3.31 */
#define CSD_SPEC_VER_4 4 /* Implements system specification 4.0 - 4.1 */

/*
* EXT_CSD fields
*/

#define EXT_CSD_HS_TIMING 185 /* R/W */
#define EXT_CSD_CARD_TYPE 196 /* RO */

/*
* EXT_CSD field definitions
*/

#define EXT_CSD_CMD_SET_NORMAL (1<<0)
#define EXT_CSD_CMD_SET_SECURE (1<<1)
#define EXT_CSD_CMD_SET_CPSECURE (1<<2)

#define EXT_CSD_CARD_TYPE_26 (1<<0) /* Card can run at 26MHz */
#define EXT_CSD_CARD_TYPE_52 (1<<1) /* Card can run at 52MHz */

/*
* MMC_SWITCH access modes
*/

#define MMC_SWITCH_MODE_CMD_SET 0x00 /* Change the command set */
#define MMC_SWITCH_MODE_SET_BITS 0x01 /* Set bits which are 1 in value */
#define MMC_SWITCH_MODE_CLEAR_BITS 0x02 /* Clear bits which are 1 in value */
#define MMC_SWITCH_MODE_WRITE_BYTE 0x03 /* Set target to value */

/*
* SD bus widths
Expand Down

0 comments on commit bce40a3

Please sign in to comment.