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Message-Id: <200701281746.l0SHkJTh010386@ignucius.se.axis.com>
Date: Sun, 28 Jan 2007 18:46:19 +0100
From: Hans-Peter Nilsson <hans-peter.nilsson@...s.com>
To: david-b@...bell.net
CC: linux-kernel@...r.kernel.org, mikael.starvik@...s.com,
spi-devel-general@...ts.sourceforge.net
Subject: Re: [PATCH] take 4: mmc_spi with SPI_TX_1 2.6.20-rc6
> Date: Sat, 27 Jan 2007 21:59:49 +0100
> From: Hans-Peter Nilsson <hp@...s.com>
> Lightly tested: mounted, deleted a file, verified contents
> elsewhere (that the directory entry was gone).
...though not without SPI_TX_1 support, because then I'd have
noticed a few typos. Sorry about that.
> --- a/drivers/mmc/mmc_spi.c 1970-01-01 01:00:00.000000000 +0100
> +mmc_spi_setup_message(
> + /*
> + * Maybe because we specified SPI_TX_1, and the controller
> + * can't handle it. We'll fall back on using a buffer
> + * with ones.
> + */
> + spi->mode |= (SPI_CPOL|SPI_CPHA);
Should have been assignment, "=". Bah.
> + mmc = mmc_alloc_host(sizeof *host
> + + ((host->spi->mode & SPI_TX_1) == 0
> + ? ONES_BUFFER_SIZE : 0), &spi->dev);
Not healthy before "host" is assigned. I missed a big fat
warning from gcc.
This one is tested a little more; it's just the two bugs above fixed.
(Previous authors: Mike Lavender, David Brownell, no explicit signoff)
Signed-off-by: Hans-Peter Nilsson <hp@...s.com>
diff -uprN a/drivers/mmc/Kconfig b/drivers/mmc/Kconfig
--- a/drivers/mmc/Kconfig 2007-01-13 18:59:19.000000000 +0100
+++ b/drivers/mmc/Kconfig 2007-01-14 12:52:17.000000000 +0100
@@ -125,4 +125,15 @@ config MMC_TIFM_SD
To compile this driver as a module, choose M here: the
module will be called tifm_sd.
+config MMC_SPI
+ tristate "MMC/SD over SPI"
+ depends on MMC && SPI && EXPERIMENTAL
+ help
+ Some systems accss MMC/SD cards using the SPI protocol instead of
+ using an MMC/SD controller. The disadvantage of using SPI is that
+ it's often not as fast; its compensating advantage is that SPI is
+ available on many systems without MMC/SD controllers.
+
+ If unsure, or if your system has no SPI controller driver, say N.
+
endmenu
diff -uprN a/drivers/mmc/Makefile b/drivers/mmc/Makefile
--- a/drivers/mmc/Makefile 2007-01-13 18:59:19.000000000 +0100
+++ b/drivers/mmc/Makefile 2007-01-14 12:54:06.000000000 +0100
@@ -24,6 +24,7 @@ obj-$(CONFIG_MMC_AU1X) += au1xmmc.o
obj-$(CONFIG_MMC_OMAP) += omap.o
obj-$(CONFIG_MMC_AT91RM9200) += at91_mci.o
obj-$(CONFIG_MMC_TIFM_SD) += tifm_sd.o
+obj-$(CONFIG_MMC_SPI) += mmc_spi.o
mmc_core-y := mmc.o mmc_sysfs.o sdio.o
mmc_core-$(CONFIG_BLOCK) += mmc_queue.o
diff -uprN a/drivers/mmc/mmc_spi.c b/drivers/mmc/mmc_spi.c
--- a/drivers/mmc/mmc_spi.c 1970-01-01 01:00:00.000000000 +0100
+++ b/drivers/mmc/mmc_spi.c 2007-01-28 13:30:55.293469236 +0100
@@ -0,0 +1,1499 @@
+/*
+ * mmc_spi.c - Access an SD/MMC card using the SPI bus
+ *
+ * (C) Copyright 2005, Intec Automation,
+ * Mike Lavender (mike@...roidmicros)
+ * (C) Copyright 2006, David Brownell
+ * (C) Copyright 2007, Axis Communications,
+ * Hans-Peter Nilsson (hp@...s.com)
+ *
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * 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.
+ */
+
+#include <linux/autoconf.h>
+#include <linux/init.h>
+#include <linux/types.h>
+#include <linux/delay.h>
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/device.h>
+#include <linux/blkdev.h>
+#include <linux/dma-mapping.h>
+
+#include <linux/mmc/host.h>
+#include <linux/mmc/protocol.h>
+
+#include <linux/spi/spi.h>
+#include <linux/spi/mmc_spi.h>
+
+
+/* NOTES:
+ *
+ * - For now, we won't try to interoperate with a real mmc/sd/sdio
+ * controller. The main reason for such configs would be mmc-format
+ * cards which (like dataflash) don't support that "other" protocol.
+ * SPI mode is a bit slower than non-parallel versions of MMC.
+ *
+ * - Likewise we don't try to detect dataflash cards, which would
+ * imply switching to a different driver. Not many folk folk use
+ * both dataflash cards and MMC/SD cards, and Linux doesn't have
+ * an "MMC/SD interface" abstraction for coupling to drivers.
+ *
+ * - This version gets part way through enumeration of MMC cards.
+ *
+ * - Protocol details, including timings, need to be audited
+ *
+ * - A "use CRCs" option would probably be useful.
+ */
+
+
+/*
+ * Local defines
+ */
+
+// MOVE TO <linux/mmc/protocol.h> ?
+#define SPI_MMC_COMMAND 0x40 /* mask into mmc command */
+
+/* class 0 */
+#define SPI_MMC_READ_OCR 58 /* R3, SPI-only */
+#define SPI_MMC_CRC_ON_OFF 59 /* SPI-only */
+
+/* R1 response status to almost all commands */
+#define SPI_MMC_R1_IDLE 0x01
+#define SPI_MMC_R1_ERASE_RESET 0x02
+#define SPI_MMC_R1_ILLEGAL_COMMAND 0x04
+#define SPI_MMC_R1_COM_CRC 0x08
+#define SPI_MMC_R1_ERASE_SEQ 0x10
+#define SPI_MMC_R1_ADDRESS 0x20
+#define SPI_MMC_R1_PARAMETER 0x40
+
+/* R2 response to CMD13 (SEND_STATUS) is an R1 plus a high byte */
+#define SPI_MMC_R2_CARD_LOCKED 0x01
+#define SPI_MMC_R2_WP_ERASE_SKIP 0x02
+#define SPI_MMC_R2_ERROR 0x04
+#define SPI_MMC_R2_CC_ERROR 0x08
+#define SPI_MMC_R2_CARD_ECC_ERROR 0x10
+#define SPI_MMC_R2_WP_VIOLATION 0x20
+#define SPI_MMC_R2_ERASE_PARAM 0x40
+#define SPI_MMC_R2_OUT_OF_RANGE 0x80
+
+/* response tokens used to ack each block written: */
+#define SPI_MMC_RESPONSE_CODE(x) ((x) & (7 << 1))
+#define SPI_RESPONSE_ACCEPTED (2 << 1)
+#define SPI_RESPONSE_CRC_ERR (5 << 1)
+#define SPI_RESPONSE_WRITE_ERR (6 << 1)
+
+/* read and write blocks start with these tokens and end with crc;
+ * on error, read tokens act like SPI_MMC_R2 values.
+ */
+#define SPI_TOKEN_SINGLE 0xfe /* single block r/w, multiblock read */
+#define SPI_TOKEN_MULTI_WRITE 0xfc /* multiblock write */
+#define SPI_TOKEN_STOP_TRAN 0xfd /* terminate multiblock write */
+// END MOVE
+
+
+#define NO_ARG 0x00000000 // No argument all 0's
+
+#define CRC_GO_IDLE_STATE 0x95
+#define CRC_NO_CRC 0x01
+
+#define MMC_POWERCYCLE_MSECS 20 /* board-specific? */
+
+
+/* The unit for these timeouts is milliseconds. See mmc_spi_scanbyte. */
+#define MINI_TIMEOUT 1
+#define READ_TIMEOUT 100
+#define WRITE_TIMEOUT 250
+
+
+/****************************************************************************/
+
+/*
+ * Local Data Structures
+ */
+
+union mmc_spi_command {
+ u8 buf[7];
+ struct {
+ u8 dummy;
+ u8 code;
+ u8 addr1;
+ u8 addr2;
+ u8 addr3;
+ u8 addr4;
+ u8 crc;
+ } command;
+};
+
+
+struct mmc_spi_host {
+ struct mmc_host *mmc;
+ struct spi_device *spi;
+ u8 *rx_buf;
+ u8 *tx_buf;
+ u32 tx_idx;
+ u32 rx_idx;
+ u8 cid_sequence;
+ u8 rsp_type;
+ u8 app_cmd;
+
+ struct mmc_spi_platform_data *pdata;
+
+ /* for bulk data transfers */
+ struct spi_transfer token, t, crc;
+ struct spi_message m;
+ struct spi_transfer early_status;
+
+ /* for status readback */
+ struct spi_transfer status;
+ struct spi_message readback;
+
+ /* underlying controller might support dma, but we can't
+ * rely on it being used for any particular request
+ */
+ struct device *dma_dev;
+ dma_addr_t dma; /* of mmc_spi_host */
+
+ /* pre-allocated dma-safe buffers */
+ union mmc_spi_command command;
+ u8 data_token;
+ u8 status_byte;
+ u16 crc_val;
+ u8 response[2];
+ u8 bundled_status[2];
+
+ /* specs describe always writing ones even if we
+ * don't think the card should care what it sees.
+ * (Unused if the spi controller can specify default tx data.)
+ */
+ u8 ones[];
+#define ONES_BUFFER_SIZE 512
+};
+
+#ifdef DEBUG
+static unsigned debug = 1;
+module_param(debug, uint, 0644);
+#else
+#define debug 0
+#endif
+
+/****************************************************************************/
+
+static inline int mmc_spi_readbyte(struct mmc_spi_host *host)
+{
+ int status = spi_sync(host->spi, &host->readback);
+ if (status < 0)
+ return status;
+ return host->status_byte;
+}
+
+static inline int
+mmc_spi_readbytes(struct mmc_spi_host *host, void *bytes, unsigned len)
+{
+ int status;
+
+ host->status.rx_buf = bytes;
+ host->status.len = len;
+
+ host->readback.is_dma_mapped = 0;
+ status = spi_sync(host->spi, &host->readback);
+ host->readback.is_dma_mapped = 1;
+
+ host->status.rx_buf = &host->status_byte;
+ host->status.len = 1;
+ return status;
+}
+
+
+/* REVISIT: is this fast enough? these kinds of sync points could easily
+ * be offloaded to irq-ish code called by controller drivers, eliminating
+ * context switch costs.
+ *
+ * REVISIT: after writes and erases, mmc_spi_busy() == true might be a
+ * fair hint to yield exclusive access to the card (so another driver can
+ * use the bus) and msleep if busy-waiting doesn't succeed quickly.
+ * Measurements on half a dozen cards show however that a simple
+ * implementation doing msleep(1) every 100 busy-iterations (when
+ * busy, increment and test a static variable, reset it after the
+ * msleep) doesn't provide any consistent speedup or increased
+ * user-level system performance (less load).
+ */
+static int mmc_spi_busy(u8 byte)
+{
+ return byte == 0;
+}
+
+static int mmc_spi_delayed(u8 byte)
+{
+ return byte == 0xff;
+}
+
+static int
+mmc_spi_scanbyte(struct mmc_spi_host *host, int (*fail)(u8), unsigned delay)
+{
+ int value;
+ unsigned wait;
+
+ /*
+ * Because we might (we will, for bitbanged SPI) be scheduled
+ * out for extensive periods in this call, we'd get an
+ * abundance of timeouts if we counted in jiffies on a system
+ * with load, so instead we calculate it in the max number of
+ * bytes we could theoretically scan before the timeout, if
+ * everything else took zero time.
+ */
+ unsigned long end_wait = delay * host->spi->max_speed_hz / 1000 / 8;
+
+ for (wait = 0; wait < end_wait; wait++) {
+ value = mmc_spi_readbyte(host);
+ if (value < 0)
+ return value;
+ if (!fail(value)) {
+ if (debug > 1)
+ dev_dbg(&host->spi->dev,
+ " mmc_spi: token %02x, wait %d\n",
+ value, wait);
+ return value;
+ }
+ }
+
+ return -ETIMEDOUT;
+}
+
+static inline void mmc_spi_map_r1(struct mmc_command *cmd, u8 r1)
+{
+ u32 mapped = 0;
+
+ /* spi mode doesn't expose the mmc/sd state machine, but
+ * we can at least avoid lying about the IDLE state
+ */
+ if (!(r1 & SPI_MMC_R1_IDLE))
+ mapped |= (3 /*standby*/ << 9);
+
+ if (r1 & (SPI_MMC_R1_ERASE_RESET
+ | SPI_MMC_R1_ERASE_SEQ
+ | SPI_MMC_R1_ADDRESS
+ | SPI_MMC_R1_PARAMETER)) {
+ cmd->error = MMC_ERR_FAILED;
+ if (r1 & SPI_MMC_R1_ERASE_RESET)
+ mapped |= R1_ERASE_RESET;
+ if (r1 & SPI_MMC_R1_ERASE_SEQ)
+ mapped |= R1_ERASE_SEQ_ERROR;
+ if (r1 & SPI_MMC_R1_ADDRESS)
+ mapped |= R1_ADDRESS_ERROR;
+ /* this one's a loose match... */
+ if (r1 & SPI_MMC_R1_PARAMETER)
+ mapped |= R1_BLOCK_LEN_ERROR;
+ }
+ if (r1 & SPI_MMC_R1_ILLEGAL_COMMAND) {
+ cmd->error = MMC_ERR_INVALID;
+ mapped |= R1_ILLEGAL_COMMAND;
+ }
+ if (r1 & SPI_MMC_R1_COM_CRC) {
+ cmd->error = MMC_ERR_BADCRC;
+ mapped |= R1_COM_CRC_ERROR;
+ }
+
+ cmd->resp[0] = mapped;
+}
+
+static void mmc_spi_map_r2(struct mmc_command *cmd, u8 r2)
+{
+ u32 mapped = 0;
+
+ if (!r2)
+ return;
+
+ if (r2 & SPI_MMC_R2_CARD_LOCKED)
+ mapped |= R1_CARD_IS_LOCKED;
+ if (r2 & SPI_MMC_R2_WP_ERASE_SKIP)
+ mapped |= R1_WP_ERASE_SKIP;
+ if (r2 & SPI_MMC_R2_ERROR)
+ mapped |= R1_ERROR;
+ if (r2 & SPI_MMC_R2_CC_ERROR)
+ mapped |= R1_CC_ERROR;
+ if (r2 & SPI_MMC_R2_CARD_ECC_ERROR)
+ mapped |= R1_CARD_ECC_FAILED;
+ if (r2 & SPI_MMC_R2_WP_VIOLATION)
+ mapped |= R1_WP_VIOLATION;
+ if (r2 & SPI_MMC_R2_ERASE_PARAM)
+ mapped |= R1_ERASE_PARAM;
+ if (r2 & SPI_MMC_R2_OUT_OF_RANGE)
+ mapped |= R1_OUT_OF_RANGE | R1_CID_CSD_OVERWRITE;
+
+ if (mapped) {
+ cmd->resp[0] |= mapped;
+ if (cmd->error == MMC_ERR_NONE)
+ cmd->error = MMC_ERR_FAILED;
+ }
+}
+
+#ifdef DEBUG
+static char *maptype(u8 type)
+{
+ switch (type) {
+ case MMC_RSP_R1: return "R1";
+ case MMC_RSP_R1B: return "R1B";
+ case MMC_RSP_R2: return "R2";
+ case MMC_RSP_R3: return "R3";
+ case MMC_RSP_NONE: return "NONE";
+ default: return "?";
+ }
+}
+#endif
+
+static void
+mmc_spi_response_get(struct mmc_spi_host *host, struct mmc_command *cmd)
+{
+ int value;
+
+ dev_dbg(&host->spi->dev,
+ "%sCMD%d response SPI_%s: ",
+ host->app_cmd ? "A" : "",
+ cmd->opcode, maptype(host->rsp_type));
+
+ if (cmd->opcode == MMC_STOP_TRANSMISSION) {
+ /*
+ * We can't tell whether we read block data or the
+ * command reply, so to cope with trash data during
+ * the latency, we just read in 14 bytes (8 would be
+ * enough according to the MMC spec; SD doesn't say)
+ * after the command and fake a clean reply. We could
+ * avoid this if we saved what the card sent us while
+ * we sent the command, and treat it like a normal
+ * response if we didn't get a SPI_TOKEN_SINGLE.
+ */
+ (void) mmc_spi_readbytes(host, host->command.buf,
+ sizeof host->command.buf);
+ (void) mmc_spi_readbytes(host, host->command.buf,
+ sizeof host->command.buf);
+ value = 0;
+ } else
+ value = mmc_spi_scanbyte(host, mmc_spi_delayed, MINI_TIMEOUT);
+ host->response[0] = value;
+ host->response[1] = 0;
+
+ if (value < 0) {
+ dev_dbg(&host->spi->dev,
+ "mmc_spi: response error, %d\n", value);
+ cmd->error = MMC_ERR_FAILED;
+ return;
+ }
+
+ if (host->response[0] & 0x80) {
+ dev_err(&host->spi->dev, "INVALID RESPONSE, %02x\n",
+ host->response[0]);
+ cmd->error = MMC_ERR_FAILED;
+ return;
+ }
+
+ cmd->error = MMC_ERR_NONE;
+ mmc_spi_map_r1(cmd, host->response[0]);
+
+ switch (host->rsp_type) {
+
+ /* SPI R1 and R1B are a subset of the MMC/SD R1 */
+ case MMC_RSP_R1B:
+ /* wait for not-busy (could be deferred...) */
+ // REVISIT: could be a (shorter) read timeout
+ // ... and the timeouts derived from chip parameters
+ // will likely be nicer/shorter
+ (void) mmc_spi_scanbyte(host, mmc_spi_busy, WRITE_TIMEOUT);
+ /* FALLTHROUGH */
+ case MMC_RSP_R1:
+ /* no more */
+ break;
+
+ /* SPI R2 is bigger subset of the MMC/SD R1; unrelated to MMC/SD R2 */
+ case MMC_RSP_R2:
+ /* read second status byte */
+ host->response[1] = mmc_spi_readbyte(host);
+ mmc_spi_map_r2(cmd, host->response[1]);
+ break;
+
+ /* SPI R3 is SPI R1 plus OCR */
+ case MMC_RSP_R3:
+ /* NOTE: many controllers can't support 32 bit words,
+ * which is why we use byteswapping here instead.
+ */
+ (void) mmc_spi_readbytes(host, &cmd->resp[0], 4);
+ be32_to_cpus(&cmd->resp[0]);
+ be32_to_cpus(&cmd->resp[1]);
+ be32_to_cpus(&cmd->resp[2]);
+ be32_to_cpus(&cmd->resp[3]);
+ break;
+
+ default:
+ dev_dbg(&host->spi->dev,
+ "unknown rsp_type\n");
+ }
+
+ if (host->response[0] || host->response[1])
+ dev_dbg(&host->spi->dev,
+ " mmc_spi: resp %02x.%02x\n",
+ host->response[1],
+ host->response[0]);
+
+ /* The SPI binding to MMC/SD cards uses different conventions
+ * than the other one. Unless/until the mmc core learns about
+ * SPI rules, we must handle it here...
+ */
+ switch (mmc_resp_type(cmd)) {
+ case MMC_RSP_R1:
+ case MMC_RSP_R1B:
+ switch (host->rsp_type) {
+ case MMC_RSP_R1B:
+ case MMC_RSP_R1:
+ case MMC_RSP_R2:
+ /* spi doesn't explicitly expose this bit */
+ if (cmd->error == MMC_ERR_NONE
+ && cmd->opcode == MMC_APP_CMD)
+ cmd->resp[0] |= R1_APP_CMD;
+ break;
+ default:
+badmap:
+ dev_dbg(&host->spi->dev,
+ "mmc_spi: no map SPI_%s --> MMC_%s/%02x\n",
+ maptype(host->rsp_type),
+ maptype(mmc_resp_type(cmd)),
+ mmc_resp_type(cmd));
+ if (cmd->error == MMC_ERR_NONE)
+ cmd->error = MMC_ERR_FAILED;
+ }
+ break;
+ case MMC_RSP_R2:
+ switch (cmd->opcode) {
+ case MMC_SEND_CID:
+ case MMC_SEND_CSD:
+ /* we special case these by waiting for the
+ * data stage (with CID/CSD)
+ */
+ break;
+ default:
+ goto badmap;
+ }
+ break;
+ case MMC_RSP_R3:
+ /* for some cases, OCR is patched up later */
+ if (host->rsp_type != MMC_RSP_R3
+ && cmd->error == MMC_ERR_NONE
+ && !( (cmd->opcode == MMC_SEND_OP_COND
+ && !host->app_cmd)
+ || (cmd->opcode == SD_APP_OP_COND
+ && host->app_cmd))
+ ) {
+ dev_dbg(&host->spi->dev,
+ "** MMC_R3 mismatch to SPI_%s\n",
+ maptype(host->rsp_type));
+ cmd->error = MMC_ERR_FAILED;
+ }
+ break;
+ case MMC_RSP_NONE:
+ if (cmd->opcode == MMC_GO_IDLE_STATE) {
+ if (!(host->response[0] & SPI_MMC_R1_IDLE)
+ && cmd->error == MMC_ERR_NONE) {
+ /* maybe it finished initialization early */
+ dev_dbg(&host->spi->dev, " ?? not idle ??\n");
+ }
+ } else
+ goto badmap;
+ }
+}
+
+/* SPI response types aren't always good matches for "native" ones */
+
+/* REVISIT probably should have SPI_RSP_R1 etc */
+
+static const u8 resp_map[64] = {
+ [ 0] = MMC_RSP_R1,
+ [ 1] = MMC_RSP_R1,
+ [ 6] = MMC_RSP_R1,
+ [ 9] = MMC_RSP_R1,
+
+ [10] = MMC_RSP_R1,
+ [12] = MMC_RSP_R1B,
+ [13] = MMC_RSP_R2,
+ [16] = MMC_RSP_R1,
+ [17] = MMC_RSP_R1,
+ [18] = MMC_RSP_R1,
+
+ [24] = MMC_RSP_R1,
+ [25] = MMC_RSP_R1,
+ [27] = MMC_RSP_R1,
+ [28] = MMC_RSP_R1B,
+ [29] = MMC_RSP_R1B,
+
+ [30] = MMC_RSP_R1,
+ [32] = MMC_RSP_R1,
+ [33] = MMC_RSP_R1,
+ [34] = MMC_RSP_R1,
+ [35] = MMC_RSP_R1,
+ [36] = MMC_RSP_R1,
+ [37] = MMC_RSP_R1,
+ [38] = MMC_RSP_R1B,
+
+ [42] = MMC_RSP_R1B,
+
+ [55] = MMC_RSP_R1,
+ [56] = MMC_RSP_R1,
+ [58] = MMC_RSP_R3, /* SPI-only command */
+ [59] = MMC_RSP_R1, /* SPI-only command */
+};
+
+static const u8 acmd_map[64] = {
+ [13] = MMC_RSP_R2,
+
+ [22] = MMC_RSP_R1,
+ [23] = MMC_RSP_R1,
+
+ [41] = MMC_RSP_R1,
+ [42] = MMC_RSP_R1,
+
+ [51] = MMC_RSP_R1,
+};
+
+
+/* Issue command and read its response.
+ * Returns zero on success, negative for error.
+ *
+ * On error, caller must cope with mmc core retry mechanism. That
+ * means immediate low-level resubmit, which affects the bus lock...
+ */
+static int
+mmc_spi_command_send(struct mmc_spi_host *host,
+ struct mmc_request *mrq, u32 crc,
+ struct mmc_command *cmd)
+{
+ union mmc_spi_command *tx = &host->command;
+ u32 arg = cmd->arg;
+ int status;
+ unsigned opcode;
+ unsigned opcond_retries = 25;
+
+again:
+ opcode = cmd->opcode;
+ if (host->app_cmd)
+ host->rsp_type = acmd_map[opcode & 0x3f];
+ else
+ host->rsp_type = resp_map[opcode & 0x3f];
+
+ if (host->rsp_type == MMC_RSP_NONE) {
+ dev_dbg(&host->spi->dev,
+ " mmc_spi: INVALID %sCMD%d (%02x)\n",
+ host->app_cmd ? "A" : "",
+ opcode, opcode);
+ cmd->error = MMC_ERR_INVALID;
+ cmd->resp[0] = R1_ILLEGAL_COMMAND;
+ return -EBADR;
+ }
+
+ /* after 8 clock cycles the card is ready, and done previous cmd */
+ tx->command.dummy = 0xFF;
+
+ tx->command.code = opcode | SPI_MMC_COMMAND;
+ tx->command.addr1 = (arg & 0xFF000000) >> 24;
+ tx->command.addr2 = (arg & 0x00FF0000) >> 16;
+ tx->command.addr3 = (arg & 0x0000FF00) >> 8;
+ tx->command.addr4 = (arg & 0x000000FF);
+ tx->command.crc = crc & 0x000000FF;
+
+ dev_dbg(&host->spi->dev, " mmc_spi: %scmd%d (%02x)\n",
+ host->app_cmd ? "a" : "", opcode, opcode);
+ status = spi_write(host->spi, tx->buf, sizeof(tx->buf));
+ if (status < 0) {
+ dev_dbg(&host->spi->dev, " ... write returned %d\n", status);
+ cmd->error = MMC_ERR_FAILED;
+ return -EBADR;
+ }
+
+ mmc_spi_response_get(host, cmd);
+ if (cmd->error != MMC_ERR_NONE)
+ return -EBADR;
+
+ switch (opcode) {
+ case MMC_SEND_CID:
+ case MMC_SEND_CSD:
+ if (host->app_cmd)
+ goto done;
+ /* we report success later, after making it look like
+ * there was no data stage (just a big status stage)
+ */
+ break;
+ case SD_APP_OP_COND:
+ if (!host->app_cmd)
+ goto done;
+ /* retry MMC's OP_COND; it does the same thing, and it's
+ * simpler to not send MMC_APP_COND then SD_APP_OP_COND
+ */
+ host->app_cmd = 0;
+ cmd->opcode = MMC_SEND_OP_COND;
+ /* FALLTHROUGH */
+ case MMC_SEND_OP_COND:
+ if (host->app_cmd)
+ goto done;
+ /* without retries, the OCR we read is garbage */
+ if (host->status_byte & 0x01) {
+ if (opcond_retries == 0) {
+ dev_err(&host->spi->dev, "init failed\n");
+ goto done;
+ }
+ dev_dbg(&host->spi->dev,
+ " retry for init complete...\n");
+ msleep(50);
+ opcond_retries--;
+ goto again;
+ }
+ dev_dbg(&host->spi->dev, " patchup R3/OCR ...\n");
+ cmd->opcode = SPI_MMC_READ_OCR;
+ goto again;
+ default:
+done:
+ /*
+ * If this was part of a request that has a stop-part,
+ * don't signal the request as done; the caller will
+ * do that. Just return successfully.
+ */
+ if (mrq->stop != NULL)
+ return 0;
+ mmc_request_done(host->mmc, mrq);
+ }
+ return 0;
+}
+
+/* Set up data message: first byte, data block (filled in later), then CRC. */
+static void
+mmc_spi_setup_message(
+ struct mmc_spi_host *host,
+ int multiple,
+ enum dma_data_direction direction)
+{
+ struct device *dma_dev = host->dma_dev;
+ struct spi_transfer *t;
+
+ spi_message_init(&host->m);
+ if (dma_dev)
+ host->m.is_dma_mapped = 1;
+
+ /* for reads, we (manually) skip 0xff bytes before finding
+ * the token; for writes, we issue it ourselves.
+ */
+ if (direction == DMA_TO_DEVICE) {
+ t = &host->token;
+ memset(t, 0, sizeof *t);
+ t->len = 1;
+ if (multiple)
+ host->data_token = SPI_TOKEN_MULTI_WRITE;
+ else
+ host->data_token = SPI_TOKEN_SINGLE;
+ t->tx_buf = &host->data_token;
+ spi_message_add_tail(t, &host->m);
+ }
+
+ t = &host->t;
+ memset(t, 0, sizeof *t);
+ spi_message_add_tail(t, &host->m);
+
+ t = &host->crc;
+ memset(t, 0, sizeof *t);
+ t->len = 2;
+ spi_message_add_tail(t, &host->m);
+
+ t = &host->early_status;
+ memset(t, 0, sizeof *t);
+
+ /*
+ * If this is a read, we need room for 0xFF (for
+ * N\subscript{AC}) and the next token. For a write, we need
+ * room just for the one-byte data response.
+ */
+ t->len = (direction == DMA_FROM_DEVICE) ? 2 : 1;
+ spi_message_add_tail(t, &host->m);
+ t->rx_buf = host->bundled_status;
+ if (dma_dev)
+ t->rx_dma = host->dma
+ + offsetof(struct mmc_spi_host, bundled_status);
+ if ((host->spi->mode & SPI_TX_1) == 0) {
+ t->tx_buf = &host->ones;
+ if (dma_dev)
+ t->tx_dma = host->dma
+ + offsetof(struct mmc_spi_host, ones);
+ }
+
+ t = &host->crc;
+
+ /* REVISIT crc wordsize == 2, avoid byteswap issues ... */
+
+ if (direction == DMA_TO_DEVICE) {
+ host->crc_val = CRC_NO_CRC;
+ t->tx_buf = &host->crc_val;
+ if (dma_dev) {
+ host->token.tx_dma = host->dma
+ + offsetof(struct mmc_spi_host, data_token);
+ t->tx_dma = host->dma
+ + offsetof(struct mmc_spi_host, crc_val);
+ }
+ } else {
+ t->rx_buf = &host->crc_val;
+ if (dma_dev)
+ t->rx_dma = host->dma
+ + offsetof(struct mmc_spi_host, crc_val);
+
+ /* while we read data, write all-ones */
+ if ((host->spi->mode & SPI_TX_1) == 0) {
+ t->tx_buf = host->t.tx_buf = &host->ones;
+ if (dma_dev)
+ t->tx_dma = host->t.tx_dma = host->dma
+ + offsetof(struct mmc_spi_host, ones);
+ }
+ }
+}
+
+
+static inline int resp2status(u8 write_resp)
+{
+ switch (SPI_MMC_RESPONSE_CODE(write_resp)) {
+ case SPI_RESPONSE_ACCEPTED:
+ return 0;
+ case SPI_RESPONSE_CRC_ERR:
+ case SPI_RESPONSE_WRITE_ERR:
+ /* host shall then issue MMC_STOP_TRANSMISSION */
+ return -EIO;
+ default:
+ return -EILSEQ;
+ }
+}
+
+
+static void
+mmc_spi_data_do(struct mmc_spi_host *host, struct mmc_command *cmd,
+ struct mmc_data *data, u32 blk_size)
+{
+ struct spi_device *spi = host->spi;
+ struct device *dma_dev = host->dma_dev;
+ struct spi_transfer *t;
+ enum dma_data_direction direction;
+ struct scatterlist *sg;
+ unsigned n_sg;
+ int multiple;
+
+ if (data->flags & MMC_DATA_READ) {
+ direction = DMA_FROM_DEVICE;
+ multiple = (cmd->opcode == MMC_READ_MULTIPLE_BLOCK);
+
+ /*
+ * We need to scan for the SPI_TOKEN_SINGLE token
+ * *before* we issue the first (of multiple)
+ * spi_messages reading the data plus two extra bytes,
+ * (implying N\subscript{AC} and the *next* token), so
+ * to avoid looking at garbage from an earlier
+ * command, we reset the location where we'll read in
+ * subsequent tokens.
+ */
+ host->bundled_status[0] = 0xff;
+ host->bundled_status[1] = 0xff;
+ } else {
+ direction = DMA_TO_DEVICE;
+ multiple = (cmd->opcode == MMC_WRITE_MULTIPLE_BLOCK);
+ }
+ mmc_spi_setup_message(host, multiple, direction);
+ t = &host->t;
+
+ /* Handle scatterlist segments one at a time, with synch for
+ * each 512-byte block
+ */
+ for (sg = data->sg, n_sg = data->sg_len; n_sg; n_sg--, sg++) {
+ int status = 0;
+ dma_addr_t dma_addr = 0;
+ void *kmap_addr;
+ unsigned length = sg->length;
+
+ /* set up dma mapping for controller drivers that might
+ * use DMA ... though they may fall back to PIO
+ */
+ if (dma_dev) {
+ dma_addr = dma_map_page(dma_dev, sg->page, 0,
+ PAGE_SIZE, direction);
+ if (direction == DMA_TO_DEVICE)
+ t->tx_dma = dma_addr + sg->offset;
+ else
+ t->rx_dma = dma_addr + sg->offset;
+ dma_sync_single_for_device(host->dma_dev,
+ host->dma, sizeof *host, direction);
+ }
+
+ /* allow pio too, with kmap handling any highmem */
+ kmap_addr = kmap_atomic(sg->page, 0);
+ if (direction == DMA_TO_DEVICE)
+ t->tx_buf = kmap_addr + sg->offset;
+ else
+ t->rx_buf = kmap_addr + sg->offset;
+
+ /* transfer each block, and update request status */
+ while (length && status == 0) {
+ t->len = min(length, blk_size);
+
+ dev_dbg(&host->spi->dev,
+ " mmc_spi: %s block, %d bytes\n",
+ (direction == DMA_TO_DEVICE)
+ ? "write"
+ : "read",
+ t->len);
+
+ if (direction == DMA_TO_DEVICE) {
+ int response;
+
+ /* REVISIT once we start using TX crc, first
+ * compute that value then dma_sync
+ */
+
+ status = spi_sync(spi, &host->m);
+ if (status != 0) {
+ dev_err(&spi->dev,
+ "write error (%d)\n", status);
+ break;
+ }
+
+ /*
+ * Get the transmission data-response
+ * reply. It must follow immediately
+ * after the data block we
+ * transferred. This reply doesn't
+ * necessarily tell whether the write
+ * operation succeeded, it just tells
+ * that the transmission was ok and
+ * whether *earlier* writes succeeded;
+ * see the standard.
+ */
+ response = host->bundled_status[0];
+ if (response == 0xff) {
+ dev_err(&spi->dev,
+ "missing card response\n");
+ status = -EIO;
+ break;
+ }
+
+ if (response < 0)
+ status = response;
+ else
+ status = resp2status(response);
+ if (status != 0) {
+ dev_err(&spi->dev,
+ "write error %02x (%d)\n",
+ response, status);
+ break;
+ }
+ t->tx_buf += t->len;
+ if (dma_dev)
+ t->tx_dma += t->len;
+
+ /* Wait until not busy. */
+ response = mmc_spi_scanbyte(host, mmc_spi_busy,
+ WRITE_TIMEOUT);
+ } else {
+ /*
+ * Note that N\subscript{AC} is *at
+ * least* one byte, so we should never
+ * see a card that responds in the
+ * first byte (otherwise defined to be
+ * 0xff). Right, better assert that...
+ */
+ if (host->bundled_status[0] != 0xff) {
+ /* We either make it an error or
+ * somehow wedge in the next byte,
+ * because that's then the first
+ * in the block we read. */
+ dev_err(&spi->dev,
+ "too-early card "
+ "response %02x %02x\n",
+ host->bundled_status[0],
+ host->bundled_status[1]);
+ status = -EIO;
+ break;
+ }
+
+ if (host->bundled_status[1] != 0xff)
+ status = host->bundled_status[1];
+ else
+ status = mmc_spi_scanbyte(host, mmc_spi_delayed,
+ READ_TIMEOUT);
+
+ if (status == SPI_TOKEN_SINGLE) {
+ status = spi_sync(spi, &host->m);
+ dma_sync_single_for_cpu(host->dma_dev,
+ host->dma, sizeof *host,
+ direction);
+ } else {
+ /* we've read extra garbage */
+ dev_err(&spi->dev,
+ "read error %02x\n",
+ status);
+ cmd->resp[0] = 0;
+ mmc_spi_map_r2(cmd, status);
+ if (cmd->error == MMC_ERR_NONE)
+ cmd->error = MMC_ERR_FAILED;
+ break;
+ }
+
+ /* REVISIT eventually, check crc */
+ t->rx_buf += t->len;
+ if (dma_dev)
+ t->rx_dma += t->len;
+ }
+
+ data->bytes_xfered += t->len;
+ if (status == 0) {
+ status = host->m.status;
+ length -= t->len;
+ }
+
+ if (!multiple)
+ break;
+ }
+
+ /* discard mappings */
+ kunmap_atomic(addr, 0);
+ if (direction == DMA_FROM_DEVICE)
+ flush_kernel_dcache_page(sg->page);
+ if (dma_dev)
+ dma_unmap_page(dma_dev, dma_addr,
+ PAGE_SIZE, direction);
+
+ if (status < 0) {
+ dev_dbg(&spi->dev, "%s status %d\n",
+ (direction == DMA_TO_DEVICE)
+ ? "write" : "read",
+ status);
+ if (cmd->error == MMC_ERR_NONE)
+ cmd->error = MMC_ERR_FAILED;
+ break;
+ }
+ }
+
+ if (direction == DMA_TO_DEVICE && multiple) {
+ /*
+ * Send the SPI_TOKEN_STOP_TRAN byte, ignoring the
+ * received byte (presumably 0xff).
+ */
+ u8 dat = SPI_TOKEN_STOP_TRAN;
+ ssize_t status = spi_write(spi, &dat, 1);
+
+ if (status < 0) {
+ cmd->error = MMC_ERR_FAILED;
+ return;
+ }
+
+ /*
+ * Then skip the next byte. This is the maximum
+ * non-busy time before the first busy-token. If we
+ * don't skip it, we'll mistake it for the end of the
+ * busy-period. See also "Figure 5-28" in SanDisk's
+ * ProdManRS-MMCv1.3.pdf; this is marked "X"
+ * (undefined value) of length N\subscript{BR} (min 0
+ * max 1 byte).
+ */
+ status = mmc_spi_readbyte(host);
+ if (status < 0) {
+ cmd->error = MMC_ERR_FAILED;
+ return;
+ }
+
+ /*
+ * Now wait until the end of the busy period. If
+ * N\subscript{BR} (see ref above) was 0, we'll never
+ * see any busy period. FIXME: defer the wait to next
+ * command; sleep.
+ */
+ status = mmc_spi_scanbyte(host, mmc_spi_busy, WRITE_TIMEOUT);
+ if (status < 0) {
+ cmd->error = MMC_ERR_FAILED;
+ return;
+ }
+ }
+}
+
+static int
+mmc_spi_command_do(struct mmc_spi_host *host, struct mmc_request *mrq)
+{
+ int status;
+
+ status = mmc_spi_command_send(host, mrq, CRC_NO_CRC, mrq->cmd);
+
+ if (status == 0 && mrq->data)
+ mmc_spi_data_do(host, mrq->cmd, mrq->data,
+ mrq->data->blksz);
+ if (mrq->stop) {
+ if (status == 0) {
+ status = mmc_spi_command_send(host, mrq, CRC_NO_CRC,
+ mrq->stop);
+ if (status != 0)
+ mrq->stop->error = MMC_ERR_FAILED;
+ mmc_request_done(host->mmc, mrq);
+ }
+ }
+
+ return status;
+}
+
+static int
+mmc_spi_send_cXd(struct mmc_spi_host *host, struct mmc_request *mrq)
+{
+ int status;
+ u32 *resp = mrq->cmd->resp;
+
+ mrq->cmd->arg = NO_ARG;
+ status = mmc_spi_command_send(host, mrq, CRC_NO_CRC, mrq->cmd);
+ if (status < 0)
+ return status;
+
+ /* response_get() saw an SPI R1 response, but command_send()
+ * knew we'd patch the expected MMC/SD "R2" style status here.
+ */
+ mmc_spi_setup_message(host, 0, DMA_FROM_DEVICE);
+ host->m.is_dma_mapped = 0;
+ host->t.rx_buf = resp;
+ host->t.len = 16;
+
+ status = mmc_spi_scanbyte(host, mmc_spi_delayed, READ_TIMEOUT);
+
+ if (status == SPI_TOKEN_SINGLE) {
+ /* NOTE: many controllers can't support 32 bit words,
+ * which is why we use byteswapping here instead.
+ */
+ status = spi_sync(host->spi, &host->m);
+ if (status < 0)
+ mrq->cmd->error = MMC_ERR_FAILED;
+ else {
+ be32_to_cpus(&resp[0]);
+ be32_to_cpus(&resp[1]);
+ be32_to_cpus(&resp[2]);
+ be32_to_cpus(&resp[3]);
+ }
+ } else {
+ if (status >= 0) {
+ dev_dbg(&host->spi->dev,
+ "mmc_spi: read cXd err %02x\n",
+ status);
+ mmc_spi_map_r2(mrq->cmd, status);
+ status = -ETIMEDOUT;
+ }
+ mrq->cmd->error = MMC_ERR_TIMEOUT;
+ }
+ if (status == 0)
+ mmc_request_done(host->mmc, mrq);
+ else
+ dev_dbg(&host->spi->dev,
+ "mmc_spi: read cXd, %d \n", status);
+ return status;
+}
+
+/* reset ... with cmd->opcode == MMC_GO_IDLE_STATE */
+static int
+mmc_spi_initialize(struct mmc_spi_host *host, struct mmc_request *mrq)
+{
+ struct mmc_command *cmd = mrq->cmd;
+ int status;
+ int could_invert_cs = 0;
+
+ host->cid_sequence = 0;
+
+ /* REVISIT put a powercycle reset here? */
+
+ /* try to be very sure any previous command has completed;
+ * wait till not-busy, skip debris from any old commands,
+ */
+ (void) mmc_spi_scanbyte(host, mmc_spi_busy, WRITE_TIMEOUT);
+ (void) mmc_spi_readbytes(host, host->command.buf,
+ sizeof host->command.buf);
+
+ /*
+ * Do a burst with chipselect deactivated. We need to do this
+ * to meet the requirement of 74 clock cycles with chipselect
+ * high before CMD0. (Section 6.4.1, in "Simplified Physical
+ * Layer Specification 2.0".) Some cards are particularly
+ * needy of this (e.g. Viking "SD256") while most others don't
+ * seem to care. Note that it's not enough to deactivate
+ * chipselect without toggling the clock. Beware of the hack:
+ * we "know" that mmc_spi_readbytes uses the host->status
+ * spi_transfer.
+ */
+ host->spi->mode |= SPI_CS_HIGH;
+ if (spi_setup(host->spi) != 0)
+ /* Just a brief warning; most cards work without it. */
+ dev_warn(&host->spi->dev,
+ "can't invert the active chip-select level\n");
+ else
+ could_invert_cs = 1;
+
+ (void) mmc_spi_readbytes(host, host->command.buf,
+ sizeof host->command.buf);
+ (void) mmc_spi_readbytes(host, host->command.buf,
+ sizeof host->command.buf);
+
+ host->spi->mode &= ~SPI_CS_HIGH;
+ if (spi_setup(host->spi) != 0) {
+ /* Wot, we can't get (back) the same setup we had before? */
+ dev_err(&host->spi->dev,
+ "failed inverting the active chip-select level\n");
+ return -EIO;
+ }
+
+ /* issue software reset */
+ cmd->arg = 0;
+ status = mmc_spi_command_send(host, mrq, CRC_GO_IDLE_STATE, cmd);
+ if (status < 0) {
+ /* maybe:
+ * - there's no card present
+ * - the card isn't seated correctly (bad contacts)
+ * - it didn't leave MMC/SD mode
+ * - there's other confusion in the card state
+ *
+ * power cycling the card ought to help a lot.
+ * At any rate, let's try again.
+ */
+ status = mmc_spi_command_send(host, mrq, CRC_GO_IDLE_STATE,
+ cmd);
+ if (status < 0)
+ dev_err(&host->spi->dev,
+ "can't initialize the card: no card%s?\n",
+ !could_invert_cs
+ ? (" or because the active chip-select"
+ " level can't be inverted") : "");
+ }
+ return status;
+}
+
+/****************************************************************************/
+
+/*
+ * MMC Implementation
+ */
+
+static void mmc_spi_request(struct mmc_host *mmc, struct mmc_request *mrq)
+{
+ struct mmc_spi_host *host = mmc_priv(mmc);
+ int status = 0;
+ u8 opcode = mrq->cmd->opcode;
+
+ /*
+ * Translation between MMC/SD protocol commands and SPI ones
+ */
+ if (!host->app_cmd) {
+ switch (opcode) {
+ case MMC_GO_IDLE_STATE:
+ status = mmc_spi_initialize(host, mrq);
+ break;
+ case MMC_APP_CMD:
+ status = mmc_spi_command_do(host, mrq);
+ if (status == 0) {
+ host->app_cmd = 1;
+ mrq->cmd->resp[0] |= R1_APP_CMD;
+ }
+ break;
+ case MMC_ALL_SEND_CID:
+ /* fake a one-node broadcast */
+ if (host->cid_sequence) {
+ mrq->cmd->retries = 0;
+ mrq->cmd->error = MMC_ERR_TIMEOUT;
+ host->cid_sequence = 0;
+ status = -ETIMEDOUT;
+ } else {
+ mrq->cmd->opcode = MMC_SEND_CID;
+ status = mmc_spi_send_cXd(host, mrq);
+ host->cid_sequence++;
+ }
+ break;
+ case MMC_SEND_CID:
+ case MMC_SEND_CSD:
+ status = mmc_spi_send_cXd(host, mrq);
+ break;
+
+ /* No honest translation for these in SPI mode :(
+ * ... mmc core shouldn't issue them, then!!
+ */
+ case MMC_SET_RELATIVE_ADDR:
+ case MMC_SET_DSR:
+ case MMC_SELECT_CARD:
+ case MMC_READ_DAT_UNTIL_STOP:
+ case MMC_GO_INACTIVE_STATE:
+ case MMC_SET_BLOCK_COUNT:
+ case MMC_PROGRAM_CID:
+ mmc_request_done(host->mmc, mrq);
+ break;
+
+ case MMC_SEND_STATUS:
+ /*
+ * This command must be allowed to fail, else we
+ * won't notice card changes (de/insertion).
+ */
+ status = mmc_spi_command_do(host, mrq);
+
+ if (status == 0) {
+ mrq->cmd->resp[0] |= R1_READY_FOR_DATA;
+ /*
+ * The mmc_spi_map_r2 function in the
+ * mmc_spi_command_do call helpfully filled in the
+ * "failed" status, but we're just the messenger.
+ * We have no way to show that *this* command
+ * actually failed.
+ */
+ mrq->cmd->error = MMC_ERR_NONE;
+ }
+ break;
+
+ default:
+ status = mmc_spi_command_do(host, mrq);
+ }
+ } else {
+ status = mmc_spi_command_do(host, mrq);
+ host->app_cmd = 0;
+ }
+
+ /*
+ * No need to wait before the next command. The minimum time
+ * between commands is handled by the "dummy" byte in the command.
+ */
+
+ /*
+ * If status was ok, the request would have been signalled done by
+ * mmc_spi_command_do.
+ */
+ if (status < 0)
+ mmc_request_done(host->mmc, mrq);
+}
+
+
+static void mmc_spi_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)
+{
+ struct mmc_spi_host *host = mmc_priv(mmc);
+
+ if (host->pdata && host->pdata->setpower) {
+ dev_dbg(&host->spi->dev,
+ "mmc_spi: power %08x\n", ios->vdd);
+ host->pdata->setpower(&host->spi->dev, ios->vdd);
+ msleep(MMC_POWERCYCLE_MSECS);
+ }
+
+ if (host->spi->max_speed_hz != ios->clock && ios->clock != 0) {
+ int status;
+
+ host->spi->max_speed_hz = ios->clock;
+ status = spi_setup(host->spi);
+ dev_dbg(&host->spi->dev,
+ "mmc_spi: clock to %d Hz, %d\n",
+ host->spi->max_speed_hz, status);
+ }
+}
+
+static int mmc_spi_get_ro(struct mmc_host *mmc)
+{
+ struct mmc_spi_host *host = mmc_priv(mmc);
+
+ if (host->pdata && host->pdata->get_ro)
+ return host->pdata->get_ro(mmc->dev);
+ /* board doesn't support read only detection; assume writeable */
+ return 0;
+}
+
+
+static struct mmc_host_ops mmc_spi_ops = {
+ .request = mmc_spi_request,
+ .set_ios = mmc_spi_set_ios,
+ .get_ro = mmc_spi_get_ro,
+};
+
+
+/****************************************************************************/
+
+/*
+ * Generic Device driver routines and interface implementation
+ */
+
+static irqreturn_t
+mmc_spi_detect_irq(int irq, void *mmc)
+{
+ struct mmc_spi_host *host = mmc_priv(mmc);
+
+ mmc_detect_change(mmc, host->pdata->detect_delay);
+ return IRQ_HANDLED;
+}
+
+static int __devinit mmc_spi_probe(struct spi_device *spi)
+{
+ struct mmc_host *mmc;
+ struct mmc_spi_host *host;
+ int status;
+ int power_manageable = 1;
+
+ spi->mode |= (SPI_CPOL|SPI_CPHA|SPI_TX_1);
+ spi->bits_per_word = 8;
+
+ status = spi_setup(spi);
+ if (status < 0) {
+ dev_dbg(&spi->dev, "can't handle SPI_TX_1?\n");
+
+ /*
+ * Maybe because we specified SPI_TX_1, and the controller
+ * can't handle it. We'll fall back on using a buffer
+ * with ones.
+ */
+ spi->mode = SPI_CPOL|SPI_CPHA;
+ status = spi_setup(spi);
+ if (status < 0) {
+ /* Nope, guess it's the mode then. */
+ dev_dbg(&spi->dev, "needs SPI mode 3\n");
+ return status;
+ }
+ }
+
+ mmc = mmc_alloc_host(sizeof *host
+ + ((spi->mode & SPI_TX_1) == 0
+ ? ONES_BUFFER_SIZE : 0), &spi->dev);
+ if (!mmc)
+ /* Luckily, there's no spi_takedown or any need for it. */
+ return -ENOMEM;
+
+ mmc->ops = &mmc_spi_ops;
+ mmc->ocr_avail = 0xFFFFFFFF;
+
+ /*
+ * As long as we keep track of the number of successfully
+ * transmitted blocks, we're good for this. The lesser bytes
+ * over the wire, the better.
+ */
+ mmc->caps |= MMC_CAP_MULTIWRITE;
+
+ mmc->f_min = 125000;
+ mmc->f_max = 25 * 1000 * 1000;
+
+ host = mmc_priv(mmc);
+ host->mmc = mmc;
+ host->spi = spi;
+ host->cid_sequence = 0;
+ if ((host->spi->mode & SPI_TX_1) == 0)
+ memset(host->ones, 0xff, ONES_BUFFER_SIZE);
+
+ /* platform data is used to hook up things like card sensing
+ * and power switching gpios
+ */
+ host->pdata = spi->dev.platform_data;
+ mmc->ocr_avail = host->pdata
+ ? host->pdata->ocr_mask
+ : MMC_VDD_32_33|MMC_VDD_33_34;
+
+ dev_set_drvdata(&spi->dev, mmc);
+
+ /* setup message for status readback/write-ones */
+ spi_message_init(&host->readback);
+ spi_message_add_tail(&host->status, &host->readback);
+ if ((host->spi->mode & SPI_TX_1) == 0)
+ host->status.tx_buf = host->ones;
+ host->status.rx_buf = &host->status_byte;
+ host->status.len = 1;
+
+ if (spi->master->cdev.dev->dma_mask) {
+ host->dma_dev = spi->master->cdev.dev;
+ host->dma = dma_map_single(host->dma_dev, host,
+ sizeof *host, DMA_BIDIRECTIONAL);
+#ifdef CONFIG_HIGHMEM
+ dev_dbg(&spi->dev, "highmem + dma-or-pio ...\n");
+#endif
+ }
+
+ /* once card enters SPI mode it stays that way till power cycled.
+ * power cycling can be used as a hard reset for fault recovery.
+ */
+ if (!host->pdata || !host->pdata->setpower)
+ power_manageable = 0;
+ else
+ host->pdata->setpower(&spi->dev, 0);
+
+ if (host->pdata && host->pdata->init) {
+ status = host->pdata->init(&spi->dev,
+ mmc_spi_detect_irq, mmc);
+ if (status != 0)
+ goto fail_glue_init;
+ }
+
+ status = mmc_add_host(mmc);
+ if (status != 0)
+ goto fail_add_host;
+
+ dev_info(&spi->dev, "SD/MMC <-> SPI proxy driver%s\n",
+ power_manageable ? "" : ", no card power management");
+ return 0;
+
+ fail_add_host:
+ mmc_remove_host (mmc);
+ if (host->dma_dev)
+ dma_unmap_single(host->dma_dev, host->dma,
+ sizeof *host, DMA_BIDIRECTIONAL);
+ fail_glue_init:
+ mmc_free_host(mmc);
+ dev_set_drvdata(&spi->dev, NULL);
+ return status;
+}
+
+
+static int __devexit mmc_spi_remove(struct spi_device *spi)
+{
+ struct mmc_host *mmc = dev_get_drvdata(&spi->dev);
+ struct mmc_spi_host *host;
+
+ if (mmc) {
+ mmc_remove_host(mmc);
+ host = mmc_priv(mmc);
+
+ if (host->pdata && host->pdata->exit)
+ host->pdata->exit(&spi->dev, mmc);
+ if (host->dma_dev)
+ dma_unmap_single(host->dma_dev, host->dma,
+ sizeof *host, DMA_BIDIRECTIONAL);
+
+ mmc_free_host(mmc);
+ dev_set_drvdata(&spi->dev, NULL);
+ }
+ return 0;
+}
+
+
+static struct spi_driver mmc_spi_driver = {
+ .driver = {
+ .name = "mmc_spi",
+ .bus = &spi_bus_type,
+ .owner = THIS_MODULE,
+ },
+ .probe = mmc_spi_probe,
+ .remove = __devexit_p(mmc_spi_remove),
+};
+
+
+static int __init mmc_spi_init(void)
+{
+ return spi_register_driver(&mmc_spi_driver);
+}
+module_init(mmc_spi_init);
+
+
+static void __exit mmc_spi_exit(void)
+{
+ spi_unregister_driver(&mmc_spi_driver);
+}
+module_exit(mmc_spi_exit);
+
+
+MODULE_AUTHOR("Mike Lavender, David Brownell");
+MODULE_DESCRIPTION("SPI SD/MMC driver");
+MODULE_LICENSE("GPL");
--- a/include/linux/spi/mmc_spi.h 1970-01-01 01:00:00.000000000 +0100
+++ b/include/linux/spi/mmc_spi.h 2007-01-24 06:09:08.000000000 +0100
@@ -0,0 +1,34 @@
+#ifndef __LINUX_SPI_MMC_SPI_H
+#define __LINUX_SPI_MMC_SPI_H
+
+#include <linux/mmc/protocol.h>
+#include <linux/interrupt.h>
+
+struct device;
+struct mmc_host;
+
+/* something to put in platform_data of a device being used
+ * to manage an MMC/SD card slot
+ *
+ * REVISIT this isn't spi-specific, any card slot should be
+ * able to handle it
+ */
+struct mmc_spi_platform_data {
+ /* driver activation and (optional) card detect irq */
+ int (*init)(struct device *,
+ irqreturn_t (*)(int, void *),
+ void *);
+ void (*exit)(struct device *, void *);
+
+ /* how long to debounce card detect, in jiffies */
+ unsigned long detect_delay;
+
+ /* sense switch on sd cards */
+ int (*get_ro)(struct device *);
+
+ /* power management */
+ unsigned int ocr_mask; /* available voltages */
+ void (*setpower)(struct device *, unsigned int);
+};
+
+#endif /* __LINUX_SPI_MMC_SPI_H */
brgds, H-P
brgds, H-P
-
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