--- /dev/null
+/*
+ * mmc_spi.c - Access SD/MMC cards through SPI master controllers
+ *
+ * (C) Copyright 2005, Intec Automation,
+ * Mike Lavender (mike@steroidmicros)
+ * (C) Copyright 2006-2007, David Brownell
+ * (C) Copyright 2007, Axis Communications,
+ * Hans-Peter Nilsson (hp@axis.com)
+ * (C) Copyright 2007, ATRON electronic GmbH,
+ * Jan Nikitenko <jan.nikitenko@gmail.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/hrtimer.h>
+#include <linux/delay.h>
+#include <linux/blkdev.h>
+#include <linux/dma-mapping.h>
+#include <linux/crc7.h>
+#include <linux/crc-itu-t.h>
+
+#include <linux/mmc/host.h>
+#include <linux/mmc/mmc.h> /* for R1_SPI_* bit values */
+
+#include <linux/spi/spi.h>
+#include <linux/spi/mmc_spi.h>
+
+#include <asm/unaligned.h>
+
+
+/* NOTES:
+ *
+ * - For now, we won't try to interoperate with a real mmc/sd/sdio
+ * controller, although some of them do have hardware support for
+ * SPI protocol. The main reason for such configs would be mmc-ish
+ * cards like DataFlash, which don't support that "native" protocol.
+ *
+ * We don't have a "DataFlash/MMC/SD/SDIO card slot" abstraction to
+ * switch between driver stacks, and in any case if "native" mode
+ * is available, it will be faster and hence preferable.
+ *
+ * - MMC depends on a different chipselect management policy than the
+ * SPI interface currently supports for shared bus segments: it needs
+ * to issue multiple spi_message requests with the chipselect active,
+ * using the results of one message to decide the next one to issue.
+ *
+ * Pending updates to the programming interface, this driver expects
+ * that it not share the bus with other drivers (precluding conflicts).
+ *
+ * - We tell the controller to keep the chipselect active from the
+ * beginning of an mmc_host_ops.request until the end. So beware
+ * of SPI controller drivers that mis-handle the cs_change flag!
+ *
+ * However, many cards seem OK with chipselect flapping up/down
+ * during that time ... at least on unshared bus segments.
+ */
+
+
+/*
+ * Local protocol constants, internal to data block protocols.
+ */
+
+/* Response tokens used to ack each block written: */
+#define SPI_MMC_RESPONSE_CODE(x) ((x) & 0x1f)
+#define SPI_RESPONSE_ACCEPTED ((2 << 1)|1)
+#define SPI_RESPONSE_CRC_ERR ((5 << 1)|1)
+#define SPI_RESPONSE_WRITE_ERR ((6 << 1)|1)
+
+/* Read and write blocks start with these tokens and end with crc;
+ * on error, read tokens act like a subset of R2_SPI_* 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 */
+
+#define MMC_SPI_BLOCKSIZE 512
+
+
+/* These fixed timeouts come from the latest SD specs, which say to ignore
+ * the CSD values. The R1B value is for card erase (e.g. the "I forgot the
+ * card's password" scenario); it's mostly applied to STOP_TRANSMISSION after
+ * reads which takes nowhere near that long. Older cards may be able to use
+ * shorter timeouts ... but why bother?
+ */
+#define readblock_timeout ktime_set(0, 100 * 1000 * 1000)
+#define writeblock_timeout ktime_set(0, 250 * 1000 * 1000)
+#define r1b_timeout ktime_set(3, 0)
+
+
+/****************************************************************************/
+
+/*
+ * Local Data Structures
+ */
+
+/* "scratch" is per-{command,block} data exchanged with the card */
+struct scratch {
+ u8 status[29];
+ u8 data_token;
+ __be16 crc_val;
+};
+
+struct mmc_spi_host {
+ struct mmc_host *mmc;
+ struct spi_device *spi;
+
+ unsigned char power_mode;
+ u16 powerup_msecs;
+
+ struct mmc_spi_platform_data *pdata;
+
+ /* for bulk data transfers */
+ struct spi_transfer token, t, crc, early_status;
+ struct spi_message m;
+
+ /* for status readback */
+ struct spi_transfer status;
+ struct spi_message readback;
+
+ /* underlying DMA-aware controller, or null */
+ struct device *dma_dev;
+
+ /* buffer used for commands and for message "overhead" */
+ struct scratch *data;
+ dma_addr_t data_dma;
+
+ /* Specs say to write ones most of the time, even when the card
+ * has no need to read its input data; and many cards won't care.
+ * This is our source of those ones.
+ */
+ void *ones;
+ dma_addr_t ones_dma;
+};
+
+
+/****************************************************************************/
+
+/*
+ * MMC-over-SPI protocol glue, used by the MMC stack interface
+ */
+
+static inline int mmc_cs_off(struct mmc_spi_host *host)
+{
+ /* chipselect will always be inactive after setup() */
+ return spi_setup(host->spi);
+}
+
+static int
+mmc_spi_readbytes(struct mmc_spi_host *host, unsigned len)
+{
+ int status;
+
+ if (len > sizeof(*host->data)) {
+ WARN_ON(1);
+ return -EIO;
+ }
+
+ host->status.len = len;
+
+ if (host->dma_dev)
+ dma_sync_single_for_device(host->dma_dev,
+ host->data_dma, sizeof(*host->data),
+ DMA_FROM_DEVICE);
+
+ status = spi_sync(host->spi, &host->readback);
+ if (status == 0)
+ status = host->readback.status;
+
+ if (host->dma_dev)
+ dma_sync_single_for_cpu(host->dma_dev,
+ host->data_dma, sizeof(*host->data),
+ DMA_FROM_DEVICE);
+
+ return status;
+}
+
+static int
+mmc_spi_skip(struct mmc_spi_host *host, ktime_t timeout, unsigned n, u8 byte)
+{
+ u8 *cp = host->data->status;
+
+ timeout = ktime_add(timeout, ktime_get());
+
+ while (1) {
+ int status;
+ unsigned i;
+
+ status = mmc_spi_readbytes(host, n);
+ if (status < 0)
+ return status;
+
+ for (i = 0; i < n; i++) {
+ if (cp[i] != byte)
+ return cp[i];
+ }
+
+ /* REVISIT investigate msleep() to avoid busy-wait I/O
+ * in at least some cases.
+ */
+ if (ktime_to_ns(ktime_sub(ktime_get(), timeout)) > 0)
+ break;
+ }
+ return -ETIMEDOUT;
+}
+
+static inline int
+mmc_spi_wait_unbusy(struct mmc_spi_host *host, ktime_t timeout)
+{
+ return mmc_spi_skip(host, timeout, sizeof(host->data->status), 0);
+}
+
+static int mmc_spi_readtoken(struct mmc_spi_host *host)
+{
+ return mmc_spi_skip(host, readblock_timeout, 1, 0xff);
+}
+
+
+/*
+ * Note that for SPI, cmd->resp[0] is not the same data as "native" protocol
+ * hosts return! The low byte holds R1_SPI bits. The next byte may hold
+ * R2_SPI bits ... for SEND_STATUS, or after data read errors.
+ *
+ * cmd->resp[1] holds any four-byte response, for R3 (READ_OCR) and on
+ * newer cards R7 (IF_COND).
+ */
+
+static char *maptype(struct mmc_command *cmd)
+{
+ switch (mmc_spi_resp_type(cmd)) {
+ case MMC_RSP_SPI_R1: return "R1";
+ case MMC_RSP_SPI_R1B: return "R1B";
+ case MMC_RSP_SPI_R2: return "R2/R5";
+ case MMC_RSP_SPI_R3: return "R3/R4/R7";
+ default: return "?";
+ }
+}
+
+/* return zero, else negative errno after setting cmd->error */
+static int mmc_spi_response_get(struct mmc_spi_host *host,
+ struct mmc_command *cmd, int cs_on)
+{
+ u8 *cp = host->data->status;
+ u8 *end = cp + host->t.len;
+ int value = 0;
+ char tag[32];
+
+ snprintf(tag, sizeof(tag), " ... CMD%d response SPI_%s",
+ cmd->opcode, maptype(cmd));
+
+ /* Except for data block reads, the whole response will already
+ * be stored in the scratch buffer. It's somewhere after the
+ * command and the first byte we read after it. We ignore that
+ * first byte. After STOP_TRANSMISSION command it may include
+ * two data bits, but otherwise it's all ones.
+ */
+ cp += 8;
+ while (cp < end && *cp == 0xff)
+ cp++;
+
+ /* Data block reads (R1 response types) may need more data... */
+ if (cp == end) {
+ unsigned i;
+
+ cp = host->data->status;
+
+ /* Card sends N(CR) (== 1..8) bytes of all-ones then one
+ * status byte ... and we already scanned 2 bytes.
+ *
+ * REVISIT block read paths use nasty byte-at-a-time I/O
+ * so it can always DMA directly into the target buffer.
+ * It'd probably be better to memcpy() the first chunk and
+ * avoid extra i/o calls...
+ */
+ for (i = 2; i < 9; i++) {
+ value = mmc_spi_readbytes(host, 1);
+ if (value < 0)
+ goto done;
+ if (*cp != 0xff)
+ goto checkstatus;
+ }
+ value = -ETIMEDOUT;
+ goto done;
+ }
+
+checkstatus:
+ if (*cp & 0x80) {
+ dev_dbg(&host->spi->dev, "%s: INVALID RESPONSE, %02x\n",
+ tag, *cp);
+ value = -EBADR;
+ goto done;
+ }
+
+ cmd->resp[0] = *cp++;
+ cmd->error = 0;
+
+ /* Status byte: the entire seven-bit R1 response. */
+ if (cmd->resp[0] != 0) {
+ if ((R1_SPI_PARAMETER | R1_SPI_ADDRESS
+ | R1_SPI_ILLEGAL_COMMAND)
+ & cmd->resp[0])
+ value = -EINVAL;
+ else if (R1_SPI_COM_CRC & cmd->resp[0])
+ value = -EILSEQ;
+ else if ((R1_SPI_ERASE_SEQ | R1_SPI_ERASE_RESET)
+ & cmd->resp[0])
+ value = -EIO;
+ /* else R1_SPI_IDLE, "it's resetting" */
+ }
+
+ switch (mmc_spi_resp_type(cmd)) {
+
+ /* SPI R1B == R1 + busy; STOP_TRANSMISSION (for multiblock reads)
+ * and less-common stuff like various erase operations.
+ */
+ case MMC_RSP_SPI_R1B:
+ /* maybe we read all the busy tokens already */
+ while (cp < end && *cp == 0)
+ cp++;
+ if (cp == end)
+ mmc_spi_wait_unbusy(host, r1b_timeout);
+ break;
+
+ /* SPI R2 == R1 + second status byte; SEND_STATUS
+ * SPI R5 == R1 + data byte; IO_RW_DIRECT
+ */
+ case MMC_RSP_SPI_R2:
+ cmd->resp[0] |= *cp << 8;
+ break;
+
+ /* SPI R3, R4, or R7 == R1 + 4 bytes */
+ case MMC_RSP_SPI_R3:
+ cmd->resp[1] = be32_to_cpu(get_unaligned((u32 *)cp));
+ break;
+
+ /* SPI R1 == just one status byte */
+ case MMC_RSP_SPI_R1:
+ break;
+
+ default:
+ dev_dbg(&host->spi->dev, "bad response type %04x\n",
+ mmc_spi_resp_type(cmd));
+ if (value >= 0)
+ value = -EINVAL;
+ goto done;
+ }
+
+ if (value < 0)
+ dev_dbg(&host->spi->dev, "%s: resp %04x %08x\n",
+ tag, cmd->resp[0], cmd->resp[1]);
+
+ /* disable chipselect on errors and some success cases */
+ if (value >= 0 && cs_on)
+ return value;
+done:
+ if (value < 0)
+ cmd->error = value;
+ mmc_cs_off(host);
+ return value;
+}
+
+/* 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,
+ struct mmc_command *cmd, int cs_on)
+{
+ struct scratch *data = host->data;
+ u8 *cp = data->status;
+ u32 arg = cmd->arg;
+ int status;
+ struct spi_transfer *t;
+
+ /* We can handle most commands (except block reads) in one full
+ * duplex I/O operation before either starting the next transfer
+ * (data block or command) or else deselecting the card.
+ *
+ * First, write 7 bytes:
+ * - an all-ones byte to ensure the card is ready
+ * - opcode byte (plus start and transmission bits)
+ * - four bytes of big-endian argument
+ * - crc7 (plus end bit) ... always computed, it's cheap
+ *
+ * We init the whole buffer to all-ones, which is what we need
+ * to write while we're reading (later) response data.
+ */
+ memset(cp++, 0xff, sizeof(data->status));
+
+ *cp++ = 0x40 | cmd->opcode;
+ *cp++ = (u8)(arg >> 24);
+ *cp++ = (u8)(arg >> 16);
+ *cp++ = (u8)(arg >> 8);
+ *cp++ = (u8)arg;
+ *cp++ = (crc7(0, &data->status[1], 5) << 1) | 0x01;
+
+ /* Then, read up to 13 bytes (while writing all-ones):
+ * - N(CR) (== 1..8) bytes of all-ones
+ * - status byte (for all response types)
+ * - the rest of the response, either:
+ * + nothing, for R1 or R1B responses
+ * + second status byte, for R2 responses
+ * + four data bytes, for R3 and R7 responses
+ *
+ * Finally, read some more bytes ... in the nice cases we know in
+ * advance how many, and reading 1 more is always OK:
+ * - N(EC) (== 0..N) bytes of all-ones, before deselect/finish
+ * - N(RC) (== 1..N) bytes of all-ones, before next command
+ * - N(WR) (== 1..N) bytes of all-ones, before data write
+ *
+ * So in those cases one full duplex I/O of at most 21 bytes will
+ * handle the whole command, leaving the card ready to receive a
+ * data block or new command. We do that whenever we can, shaving
+ * CPU and IRQ costs (especially when using DMA or FIFOs).
+ *
+ * There are two other cases, where it's not generally practical
+ * to rely on a single I/O:
+ *
+ * - R1B responses need at least N(EC) bytes of all-zeroes.
+ *
+ * In this case we can *try* to fit it into one I/O, then
+ * maybe read more data later.
+ *
+ * - Data block reads are more troublesome, since a variable
+ * number of padding bytes precede the token and data.
+ * + N(CX) (== 0..8) bytes of all-ones, before CSD or CID
+ * + N(AC) (== 1..many) bytes of all-ones
+ *
+ * In this case we currently only have minimal speedups here:
+ * when N(CR) == 1 we can avoid I/O in response_get().
+ */
+ if (cs_on && (mrq->data->flags & MMC_DATA_READ)) {
+ cp += 2; /* min(N(CR)) + status */
+ /* R1 */
+ } else {
+ cp += 10; /* max(N(CR)) + status + min(N(RC),N(WR)) */
+ if (cmd->flags & MMC_RSP_SPI_S2) /* R2/R5 */
+ cp++;
+ else if (cmd->flags & MMC_RSP_SPI_B4) /* R3/R4/R7 */
+ cp += 4;
+ else if (cmd->flags & MMC_RSP_BUSY) /* R1B */
+ cp = data->status + sizeof(data->status);
+ /* else: R1 (most commands) */
+ }
+
+ dev_dbg(&host->spi->dev, " mmc_spi: CMD%d, resp %s\n",
+ cmd->opcode, maptype(cmd));
+
+ /* send command, leaving chipselect active */
+ spi_message_init(&host->m);
+
+ t = &host->t;
+ memset(t, 0, sizeof(*t));
+ t->tx_buf = t->rx_buf = data->status;
+ t->tx_dma = t->rx_dma = host->data_dma;
+ t->len = cp - data->status;
+ t->cs_change = 1;
+ spi_message_add_tail(t, &host->m);
+
+ if (host->dma_dev) {
+ host->m.is_dma_mapped = 1;
+ dma_sync_single_for_device(host->dma_dev,
+ host->data_dma, sizeof(*host->data),
+ DMA_BIDIRECTIONAL);
+ }
+ status = spi_sync(host->spi, &host->m);
+ if (status == 0)
+ status = host->m.status;
+
+ if (host->dma_dev)
+ dma_sync_single_for_cpu(host->dma_dev,
+ host->data_dma, sizeof(*host->data),
+ DMA_BIDIRECTIONAL);
+ if (status < 0) {
+ dev_dbg(&host->spi->dev, " ... write returned %d\n", status);
+ cmd->error = status;
+ return status;
+ }
+
+ /* after no-data commands and STOP_TRANSMISSION, chipselect off */
+ return mmc_spi_response_get(host, cmd, cs_on);
+}
+
+/* Build data message with up to four separate transfers. For TX, we
+ * start by writing the data token. And in most cases, we finish with
+ * a status transfer.
+ *
+ * We always provide TX data for data and CRC. The MMC/SD protocol
+ * requires us to write ones; but Linux defaults to writing zeroes;
+ * so we explicitly initialize it to all ones on RX paths.
+ *
+ * We also handle DMA mapping, so the underlying SPI controller does
+ * not need to (re)do it for each message.
+ */
+static void
+mmc_spi_setup_data_message(
+ struct mmc_spi_host *host,
+ int multiple,
+ enum dma_data_direction direction)
+{
+ struct spi_transfer *t;
+ struct scratch *scratch = host->data;
+ dma_addr_t dma = host->data_dma;
+
+ spi_message_init(&host->m);
+ if (dma)
+ host->m.is_dma_mapped = 1;
+
+ /* for reads, readblock() skips 0xff bytes before finding
+ * the token; for writes, this transfer issues that token.
+ */
+ if (direction == DMA_TO_DEVICE) {
+ t = &host->token;
+ memset(t, 0, sizeof(*t));
+ t->len = 1;
+ if (multiple)
+ scratch->data_token = SPI_TOKEN_MULTI_WRITE;
+ else
+ scratch->data_token = SPI_TOKEN_SINGLE;
+ t->tx_buf = &scratch->data_token;
+ if (dma)
+ t->tx_dma = dma + offsetof(struct scratch, data_token);
+ spi_message_add_tail(t, &host->m);
+ }
+
+ /* Body of transfer is buffer, then CRC ...
+ * either TX-only, or RX with TX-ones.
+ */
+ t = &host->t;
+ memset(t, 0, sizeof(*t));
+ t->tx_buf = host->ones;
+ t->tx_dma = host->ones_dma;
+ /* length and actual buffer info are written later */
+ spi_message_add_tail(t, &host->m);
+
+ t = &host->crc;
+ memset(t, 0, sizeof(*t));
+ t->len = 2;
+ if (direction == DMA_TO_DEVICE) {
+ /* the actual CRC may get written later */
+ t->tx_buf = &scratch->crc_val;
+ if (dma)
+ t->tx_dma = dma + offsetof(struct scratch, crc_val);
+ } else {
+ t->tx_buf = host->ones;
+ t->tx_dma = host->ones_dma;
+ t->rx_buf = &scratch->crc_val;
+ if (dma)
+ t->rx_dma = dma + offsetof(struct scratch, crc_val);
+ }
+ spi_message_add_tail(t, &host->m);
+
+ /*
+ * A single block read is followed by N(EC) [0+] all-ones bytes
+ * before deselect ... don't bother.
+ *
+ * Multiblock reads are followed by N(AC) [1+] all-ones bytes before
+ * the next block is read, or a STOP_TRANSMISSION is issued. We'll
+ * collect that single byte, so readblock() doesn't need to.
+ *
+ * For a write, the one-byte data response follows immediately, then
+ * come zero or more busy bytes, then N(WR) [1+] all-ones bytes.
+ * Then single block reads may deselect, and multiblock ones issue
+ * the next token (next data block, or STOP_TRAN). We can try to
+ * minimize I/O ops by using a single read to collect end-of-busy.
+ */
+ if (multiple || direction == DMA_TO_DEVICE) {
+ t = &host->early_status;
+ memset(t, 0, sizeof(*t));
+ t->len = (direction == DMA_TO_DEVICE)
+ ? sizeof(scratch->status)
+ : 1;
+ t->tx_buf = host->ones;
+ t->tx_dma = host->ones_dma;
+ t->rx_buf = scratch->status;
+ if (dma)
+ t->rx_dma = dma + offsetof(struct scratch, status);
+ t->cs_change = 1;
+ spi_message_add_tail(t, &host->m);
+ }
+}
+
+/*
+ * Write one block:
+ * - caller handled preceding N(WR) [1+] all-ones bytes
+ * - data block
+ * + token
+ * + data bytes
+ * + crc16
+ * - an all-ones byte ... card writes a data-response byte
+ * - followed by N(EC) [0+] all-ones bytes, card writes zero/'busy'
+ *
+ * Return negative errno, else success.
+ */
+static int
+mmc_spi_writeblock(struct mmc_spi_host *host, struct spi_transfer *t)
+{
+ struct spi_device *spi = host->spi;
+ int status, i;
+ struct scratch *scratch = host->data;
+
+ if (host->mmc->use_spi_crc)
+ scratch->crc_val = cpu_to_be16(
+ crc_itu_t(0, t->tx_buf, t->len));
+ if (host->dma_dev)
+ dma_sync_single_for_device(host->dma_dev,
+ host->data_dma, sizeof(*scratch),
+ DMA_BIDIRECTIONAL);
+
+ status = spi_sync(spi, &host->m);
+ if (status == 0)
+ status = host->m.status;
+
+ if (status != 0) {
+ dev_dbg(&spi->dev, "write error (%d)\n", status);
+ return status;
+ }
+
+ if (host->dma_dev)
+ dma_sync_single_for_cpu(host->dma_dev,
+ host->data_dma, sizeof(*scratch),
+ DMA_BIDIRECTIONAL);
+
+ /*
+ * 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 says if the transmission was ok and whether *earlier*
+ * writes succeeded; see the standard.
+ */
+ switch (SPI_MMC_RESPONSE_CODE(scratch->status[0])) {
+ case SPI_RESPONSE_ACCEPTED:
+ status = 0;
+ break;
+ case SPI_RESPONSE_CRC_ERR:
+ /* host shall then issue MMC_STOP_TRANSMISSION */
+ status = -EILSEQ;
+ break;
+ case SPI_RESPONSE_WRITE_ERR:
+ /* host shall then issue MMC_STOP_TRANSMISSION,
+ * and should MMC_SEND_STATUS to sort it out
+ */
+ status = -EIO;
+ break;
+ default:
+ status = -EPROTO;
+ break;
+ }
+ if (status != 0) {
+ dev_dbg(&spi->dev, "write error %02x (%d)\n",
+ scratch->status[0], status);
+ return status;
+ }
+
+ t->tx_buf += t->len;
+ if (host->dma_dev)
+ t->tx_dma += t->len;
+
+ /* Return when not busy. If we didn't collect that status yet,
+ * we'll need some more I/O.
+ */
+ for (i = 1; i < sizeof(scratch->status); i++) {
+ if (scratch->status[i] != 0)
+ return 0;
+ }
+ return mmc_spi_wait_unbusy(host, writeblock_timeout);
+}
+
+/*
+ * Read one block:
+ * - skip leading all-ones bytes ... either
+ * + N(AC) [1..f(clock,CSD)] usually, else
+ * + N(CX) [0..8] when reading CSD or CID
+ * - data block
+ * + token ... if error token, no data or crc
+ * + data bytes
+ * + crc16
+ *
+ * After single block reads, we're done; N(EC) [0+] all-ones bytes follow
+ * before dropping chipselect.
+ *
+ * For multiblock reads, caller either reads the next block or issues a
+ * STOP_TRANSMISSION command.
+ */
+static int
+mmc_spi_readblock(struct mmc_spi_host *host, struct spi_transfer *t)
+{
+ struct spi_device *spi = host->spi;
+ int status;
+ struct scratch *scratch = host->data;
+
+ /* At least one SD card sends an all-zeroes byte when N(CX)
+ * applies, before the all-ones bytes ... just cope with that.
+ */
+ status = mmc_spi_readbytes(host, 1);
+ if (status < 0)
+ return status;
+ status = scratch->status[0];
+ if (status == 0xff || status == 0)
+ status = mmc_spi_readtoken(host);
+
+ if (status == SPI_TOKEN_SINGLE) {
+ if (host->dma_dev) {
+ dma_sync_single_for_device(host->dma_dev,
+ host->data_dma, sizeof(*scratch),
+ DMA_BIDIRECTIONAL);
+ dma_sync_single_for_device(host->dma_dev,
+ t->rx_dma, t->len,
+ DMA_FROM_DEVICE);
+ }
+
+ status = spi_sync(spi, &host->m);
+ if (status == 0)
+ status = host->m.status;
+
+ if (host->dma_dev) {
+ dma_sync_single_for_cpu(host->dma_dev,
+ host->data_dma, sizeof(*scratch),
+ DMA_BIDIRECTIONAL);
+ dma_sync_single_for_cpu(host->dma_dev,
+ t->rx_dma, t->len,
+ DMA_FROM_DEVICE);
+ }
+
+ } else {
+ dev_dbg(&spi->dev, "read error %02x (%d)\n", status, status);
+
+ /* we've read extra garbage, timed out, etc */
+ if (status < 0)
+ return status;
+
+ /* low four bits are an R2 subset, fifth seems to be
+ * vendor specific ... map them all to generic error..
+ */
+ return -EIO;
+ }
+
+ if (host->mmc->use_spi_crc) {
+ u16 crc = crc_itu_t(0, t->rx_buf, t->len);
+
+ be16_to_cpus(&scratch->crc_val);
+ if (scratch->crc_val != crc) {
+ dev_dbg(&spi->dev, "read - crc error: crc_val=0x%04x, "
+ "computed=0x%04x len=%d\n",
+ scratch->crc_val, crc, t->len);
+ return -EILSEQ;
+ }
+ }
+
+ t->rx_buf += t->len;
+ if (host->dma_dev)
+ t->rx_dma += t->len;
+
+ return 0;
+}
+
+/*
+ * An MMC/SD data stage includes one or more blocks, optional CRCs,
+ * and inline handshaking. That handhaking makes it unlike most
+ * other SPI protocol stacks.
+ */
+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 = (data->blocks > 1);
+
+ if (data->flags & MMC_DATA_READ)
+ direction = DMA_FROM_DEVICE;
+ else
+ direction = DMA_TO_DEVICE;
+ mmc_spi_setup_data_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;
+ enum dma_data_direction dir = direction;
+
+ /* set up dma mapping for controller drivers that might
+ * use DMA ... though they may fall back to PIO
+ */
+ if (dma_dev) {
+ /* never invalidate whole *shared* pages ... */
+ if ((sg->offset != 0 || length != PAGE_SIZE)
+ && dir == DMA_FROM_DEVICE)
+ dir = DMA_BIDIRECTIONAL;
+
+ dma_addr = dma_map_page(dma_dev, sg->page, 0,
+ PAGE_SIZE, dir);
+ if (direction == DMA_TO_DEVICE)
+ t->tx_dma = dma_addr + sg->offset;
+ else
+ t->rx_dma = dma_addr + sg->offset;
+ }
+
+ /* allow pio too; we don't allow highmem */
+ kmap_addr = kmap(sg->page);
+ 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) {
+ 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)
+ status = mmc_spi_writeblock(host, t);
+ else
+ status = mmc_spi_readblock(host, t);
+ if (status < 0)
+ break;
+
+ data->bytes_xfered += t->len;
+ length -= t->len;
+
+ if (!multiple)
+ break;
+ }
+
+ /* discard mappings */
+ if (direction == DMA_FROM_DEVICE)
+ flush_kernel_dcache_page(sg->page);
+ kunmap(sg->page);
+ if (dma_dev)
+ dma_unmap_page(dma_dev, dma_addr, PAGE_SIZE, dir);
+
+ if (status < 0) {
+ data->error = status;
+ dev_dbg(&spi->dev, "%s status %d\n",
+ (direction == DMA_TO_DEVICE)
+ ? "write" : "read",
+ status);
+ break;
+ }
+ }
+
+ /* NOTE some docs describe an MMC-only SET_BLOCK_COUNT (CMD23) that
+ * can be issued before multiblock writes. Unlike its more widely
+ * documented analogue for SD cards (SET_WR_BLK_ERASE_COUNT, ACMD23),
+ * that can affect the STOP_TRAN logic. Complete (and current)
+ * MMC specs should sort that out before Linux starts using CMD23.
+ */
+ if (direction == DMA_TO_DEVICE && multiple) {
+ struct scratch *scratch = host->data;
+ int tmp;
+ const unsigned statlen = sizeof(scratch->status);
+
+ dev_dbg(&spi->dev, " mmc_spi: STOP_TRAN\n");
+
+ /* Tweak the per-block message we set up earlier by morphing
+ * it to hold single buffer with the token followed by some
+ * all-ones bytes ... skip N(BR) (0..1), scan the rest for
+ * "not busy any longer" status, and leave chip selected.
+ */
+ INIT_LIST_HEAD(&host->m.transfers);
+ list_add(&host->early_status.transfer_list,
+ &host->m.transfers);
+
+ memset(scratch->status, 0xff, statlen);
+ scratch->status[0] = SPI_TOKEN_STOP_TRAN;
+
+ host->early_status.tx_buf = host->early_status.rx_buf;
+ host->early_status.tx_dma = host->early_status.rx_dma;
+ host->early_status.len = statlen;
+
+ if (host->dma_dev)
+ dma_sync_single_for_device(host->dma_dev,
+ host->data_dma, sizeof(*scratch),
+ DMA_BIDIRECTIONAL);
+
+ tmp = spi_sync(spi, &host->m);
+ if (tmp == 0)
+ tmp = host->m.status;
+
+ if (host->dma_dev)
+ dma_sync_single_for_cpu(host->dma_dev,
+ host->data_dma, sizeof(*scratch),
+ DMA_BIDIRECTIONAL);
+
+ if (tmp < 0) {
+ if (!data->error)
+ data->error = tmp;
+ return;
+ }
+
+ /* Ideally we collected "not busy" status with one I/O,
+ * avoiding wasteful byte-at-a-time scanning... but more
+ * I/O is often needed.
+ */
+ for (tmp = 2; tmp < statlen; tmp++) {
+ if (scratch->status[tmp] != 0)
+ return;
+ }
+ tmp = mmc_spi_wait_unbusy(host, writeblock_timeout);
+ if (tmp < 0 && !data->error)
+ data->error = tmp;
+ }
+}
+
+/****************************************************************************/
+
+/*
+ * MMC driver implementation -- the interface to the MMC stack
+ */
+
+static void mmc_spi_request(struct mmc_host *mmc, struct mmc_request *mrq)
+{
+ struct mmc_spi_host *host = mmc_priv(mmc);
+ int status = -EINVAL;
+
+#ifdef DEBUG
+ /* MMC core and layered drivers *MUST* issue SPI-aware commands */
+ {
+ struct mmc_command *cmd;
+ int invalid = 0;
+
+ cmd = mrq->cmd;
+ if (!mmc_spi_resp_type(cmd)) {
+ dev_dbg(&host->spi->dev, "bogus command\n");
+ cmd->error = -EINVAL;
+ invalid = 1;
+ }
+
+ cmd = mrq->stop;
+ if (cmd && !mmc_spi_resp_type(cmd)) {
+ dev_dbg(&host->spi->dev, "bogus STOP command\n");
+ cmd->error = -EINVAL;
+ invalid = 1;
+ }
+
+ if (invalid) {
+ dump_stack();
+ mmc_request_done(host->mmc, mrq);
+ return;
+ }
+ }
+#endif
+
+ /* issue command; then optionally data and stop */
+ status = mmc_spi_command_send(host, mrq, mrq->cmd, mrq->data != NULL);
+ if (status == 0 && mrq->data) {
+ mmc_spi_data_do(host, mrq->cmd, mrq->data, mrq->data->blksz);
+ if (mrq->stop)
+ status = mmc_spi_command_send(host, mrq, mrq->stop, 0);
+ else
+ mmc_cs_off(host);
+ }
+
+ mmc_request_done(host->mmc, mrq);
+}
+
+/* See Section 6.4.1, in SD "Simplified Physical Layer Specification 2.0"
+ *
+ * NOTE that here we can't know that the card has just been powered up;
+ * not all MMC/SD sockets support power switching.
+ *
+ * FIXME when the card is still in SPI mode, e.g. from a previous kernel,
+ * this doesn't seem to do the right thing at all...
+ */
+static void mmc_spi_initsequence(struct mmc_spi_host *host)
+{
+ /* Try to be very sure any previous command has completed;
+ * wait till not-busy, skip debris from any old commands.
+ */
+ mmc_spi_wait_unbusy(host, r1b_timeout);
+ mmc_spi_readbytes(host, 10);
+
+ /*
+ * Do a burst with chipselect active-high. We need to do this to
+ * meet the requirement of 74 clock cycles with both chipselect
+ * and CMD (MOSI) high before CMD0 ... after the card has been
+ * powered up to Vdd(min), and so is ready to take commands.
+ *
+ * Some cards are particularly needy of this (e.g. Viking "SD256")
+ * while most others don't seem to care.
+ *
+ * Note that this is one of the places MMC/SD plays games with the
+ * SPI protocol. Another is that when chipselect is released while
+ * the card returns BUSY status, the clock must issue several cycles
+ * with chipselect high before the card will stop driving its output.
+ */
+ host->spi->mode |= SPI_CS_HIGH;
+ if (spi_setup(host->spi) != 0) {
+ /* Just warn; most cards work without it. */
+ dev_warn(&host->spi->dev,
+ "can't change chip-select polarity\n");
+ host->spi->mode &= ~SPI_CS_HIGH;
+ } else {
+ mmc_spi_readbytes(host, 18);
+
+ host->spi->mode &= ~SPI_CS_HIGH;
+ if (spi_setup(host->spi) != 0) {
+ /* Wot, we can't get the same setup we had before? */
+ dev_err(&host->spi->dev,
+ "can't restore chip-select polarity\n");
+ }
+ }
+}
+
+static char *mmc_powerstring(u8 power_mode)
+{
+ switch (power_mode) {
+ case MMC_POWER_OFF: return "off";
+ case MMC_POWER_UP: return "up";
+ case MMC_POWER_ON: return "on";
+ }
+ return "?";
+}
+
+static void mmc_spi_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)
+{
+ struct mmc_spi_host *host = mmc_priv(mmc);
+
+ if (host->power_mode != ios->power_mode) {
+ int canpower;
+
+ canpower = host->pdata && host->pdata->setpower;
+
+ dev_dbg(&host->spi->dev, "mmc_spi: power %s (%d)%s\n",
+ mmc_powerstring(ios->power_mode),
+ ios->vdd,
+ canpower ? ", can switch" : "");
+
+ /* switch power on/off if possible, accounting for
+ * max 250msec powerup time if needed.
+ */
+ if (canpower) {
+ switch (ios->power_mode) {
+ case MMC_POWER_OFF:
+ case MMC_POWER_UP:
+ host->pdata->setpower(&host->spi->dev,
+ ios->vdd);
+ if (ios->power_mode == MMC_POWER_UP)
+ msleep(host->powerup_msecs);
+ }
+ }
+
+ /* See 6.4.1 in the simplified SD card physical spec 2.0 */
+ if (ios->power_mode == MMC_POWER_ON)
+ mmc_spi_initsequence(host);
+
+ /* If powering down, ground all card inputs to avoid power
+ * delivery from data lines! On a shared SPI bus, this
+ * will probably be temporary; 6.4.2 of the simplified SD
+ * spec says this must last at least 1msec.
+ *
+ * - Clock low means CPOL 0, e.g. mode 0
+ * - MOSI low comes from writing zero
+ * - Chipselect is usually active low...
+ */
+ if (canpower && ios->power_mode == MMC_POWER_OFF) {
+ int mres;
+
+ host->spi->mode &= ~(SPI_CPOL|SPI_CPHA);
+ mres = spi_setup(host->spi);
+ if (mres < 0)
+ dev_dbg(&host->spi->dev,
+ "switch to SPI mode 0 failed\n");
+
+ if (spi_w8r8(host->spi, 0x00) < 0)
+ dev_dbg(&host->spi->dev,
+ "put spi signals to low failed\n");
+
+ /*
+ * Now clock should be low due to spi mode 0;
+ * MOSI should be low because of written 0x00;
+ * chipselect should be low (it is active low)
+ * power supply is off, so now MMC is off too!
+ *
+ * FIXME no, chipselect can be high since the
+ * device is inactive and SPI_CS_HIGH is clear...
+ */
+ msleep(10);
+ if (mres == 0) {
+ host->spi->mode |= (SPI_CPOL|SPI_CPHA);
+ mres = spi_setup(host->spi);
+ if (mres < 0)
+ dev_dbg(&host->spi->dev,
+ "switch back to SPI mode 3"
+ " failed\n");
+ }
+ }
+
+ host->power_mode = ios->power_mode;
+ }
+
+ 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->parent);
+ /* board doesn't support read only detection; assume writeable */
+ return 0;
+}
+
+
+static const struct mmc_host_ops mmc_spi_ops = {
+ .request = mmc_spi_request,
+ .set_ios = mmc_spi_set_ios,
+ .get_ro = mmc_spi_get_ro,
+};
+
+
+/****************************************************************************/
+
+/*
+ * SPI driver implementation
+ */
+
+static irqreturn_t
+mmc_spi_detect_irq(int irq, void *mmc)
+{
+ struct mmc_spi_host *host = mmc_priv(mmc);
+ u16 delay_msec = max(host->pdata->detect_delay, (u16)100);
+
+ mmc_detect_change(mmc, msecs_to_jiffies(delay_msec));
+ return IRQ_HANDLED;
+}
+
+static int mmc_spi_probe(struct spi_device *spi)
+{
+ void *ones;
+ struct mmc_host *mmc;
+ struct mmc_spi_host *host;
+ int status;
+
+ /* MMC and SD specs only seem to care that sampling is on the
+ * rising edge ... meaning SPI modes 0 or 3. So either SPI mode
+ * should be legit. We'll use mode 0 since it seems to be a
+ * bit less troublesome on some hardware ... unclear why.
+ */
+ spi->mode = SPI_MODE_0;
+ spi->bits_per_word = 8;
+
+ status = spi_setup(spi);
+ if (status < 0) {
+ dev_dbg(&spi->dev, "needs SPI mode %02x, %d KHz; %d\n",
+ spi->mode, spi->max_speed_hz / 1000,
+ status);
+ return status;
+ }
+
+ /* We can use the bus safely iff nobody else will interfere with
+ * us. That is, either we have the experimental exclusive access
+ * primitives ... or else there's nobody to share it with.
+ */
+ if (spi->master->num_chipselect > 1) {
+ struct device *parent = spi->dev.parent;
+
+ /* If there are multiple devices on this bus, we
+ * can't proceed.
+ */
+ spin_lock(&parent->klist_children.k_lock);
+ if (parent->klist_children.k_list.next
+ != parent->klist_children.k_list.prev)
+ status = -EMLINK;
+ else
+ status = 0;
+ spin_unlock(&parent->klist_children.k_lock);
+ if (status < 0) {
+ dev_err(&spi->dev, "can't share SPI bus\n");
+ return status;
+ }
+
+ /* REVISIT we can't guarantee another device won't
+ * be added later. It's uncommon though ... for now,
+ * work as if this is safe.
+ */
+ dev_warn(&spi->dev, "ASSUMING unshared SPI bus!\n");
+ }
+
+ /* We need a supply of ones to transmit. This is the only time
+ * the CPU touches these, so cache coherency isn't a concern.
+ *
+ * NOTE if many systems use more than one MMC-over-SPI connector
+ * it'd save some memory to share this. That's evidently rare.
+ */
+ status = -ENOMEM;
+ ones = kmalloc(MMC_SPI_BLOCKSIZE, GFP_KERNEL);
+ if (!ones)
+ goto nomem;
+ memset(ones, 0xff, MMC_SPI_BLOCKSIZE);
+
+ mmc = mmc_alloc_host(sizeof(*host), &spi->dev);
+ if (!mmc)
+ goto nomem;
+
+ mmc->ops = &mmc_spi_ops;
+ mmc->max_blk_size = MMC_SPI_BLOCKSIZE;
+
+ /* As long as we keep track of the number of successfully
+ * transmitted blocks, we're good for multiwrite.
+ */
+ mmc->caps = MMC_CAP_SPI | MMC_CAP_MULTIWRITE;
+
+ /* SPI doesn't need the lowspeed device identification thing for
+ * MMC or SD cards, since it never comes up in open drain mode.
+ * That's good; some SPI masters can't handle very low speeds!
+ *
+ * However, low speed SDIO cards need not handle over 400 KHz;
+ * that's the only reason not to use a few MHz for f_min (until
+ * the upper layer reads the target frequency from the CSD).
+ */
+ mmc->f_min = 400000;
+ mmc->f_max = spi->max_speed_hz;
+
+ host = mmc_priv(mmc);
+ host->mmc = mmc;
+ host->spi = spi;
+
+ host->ones = ones;
+
+ /* Platform data is used to hook up things like card sensing
+ * and power switching gpios.
+ */
+ host->pdata = spi->dev.platform_data;
+ if (host->pdata)
+ mmc->ocr_avail = host->pdata->ocr_mask;
+ if (!mmc->ocr_avail) {
+ dev_warn(&spi->dev, "ASSUMING 3.2-3.4 V slot power\n");
+ mmc->ocr_avail = MMC_VDD_32_33|MMC_VDD_33_34;
+ }
+ if (host->pdata && host->pdata->setpower) {
+ host->powerup_msecs = host->pdata->powerup_msecs;
+ if (!host->powerup_msecs || host->powerup_msecs > 250)
+ host->powerup_msecs = 250;
+ }
+
+ dev_set_drvdata(&spi->dev, mmc);
+
+ /* preallocate dma buffers */
+ host->data = kmalloc(sizeof(*host->data), GFP_KERNEL);
+ if (!host->data)
+ goto fail_nobuf1;
+
+ if (spi->master->cdev.dev->dma_mask) {
+ struct device *dev = spi->master->cdev.dev;
+
+ host->dma_dev = dev;
+ host->ones_dma = dma_map_single(dev, ones,
+ MMC_SPI_BLOCKSIZE, DMA_TO_DEVICE);
+ host->data_dma = dma_map_single(dev, host->data,
+ sizeof(*host->data), DMA_BIDIRECTIONAL);
+
+ /* REVISIT in theory those map operations can fail... */
+
+ dma_sync_single_for_cpu(host->dma_dev,
+ host->data_dma, sizeof(*host->data),
+ DMA_BIDIRECTIONAL);
+ }
+
+ /* setup message for status/busy readback */
+ spi_message_init(&host->readback);
+ host->readback.is_dma_mapped = (host->dma_dev != NULL);
+
+ spi_message_add_tail(&host->status, &host->readback);
+ host->status.tx_buf = host->ones;
+ host->status.tx_dma = host->ones_dma;
+ host->status.rx_buf = &host->data->status;
+ host->status.rx_dma = host->data_dma + offsetof(struct scratch, status);
+ host->status.cs_change = 1;
+
+ /* register card detect irq */
+ 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 host %s%s%s%s\n",
+ mmc->class_dev.bus_id,
+ host->dma_dev ? "" : ", no DMA",
+ (host->pdata && host->pdata->get_ro)
+ ? "" : ", no WP",
+ (host->pdata && host->pdata->setpower)
+ ? "" : ", no poweroff");
+ return 0;
+
+fail_add_host:
+ mmc_remove_host (mmc);
+fail_glue_init:
+ if (host->dma_dev)
+ dma_unmap_single(host->dma_dev, host->data_dma,
+ sizeof(*host->data), DMA_BIDIRECTIONAL);
+ kfree(host->data);
+
+fail_nobuf1:
+ mmc_free_host(mmc);
+ dev_set_drvdata(&spi->dev, NULL);
+
+nomem:
+ kfree(ones);
+ 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) {
+ host = mmc_priv(mmc);
+
+ /* prevent new mmc_detect_change() calls */
+ if (host->pdata && host->pdata->exit)
+ host->pdata->exit(&spi->dev, mmc);
+
+ mmc_remove_host(mmc);
+
+ if (host->dma_dev) {
+ dma_unmap_single(host->dma_dev, host->ones_dma,
+ MMC_SPI_BLOCKSIZE, DMA_TO_DEVICE);
+ dma_unmap_single(host->dma_dev, host->data_dma,
+ sizeof(*host->data), DMA_BIDIRECTIONAL);
+ }
+
+ kfree(host->data);
+ kfree(host->ones);
+
+ spi->max_speed_hz = mmc->f_max;
+ 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, "
+ "Hans-Peter Nilsson, Jan Nikitenko");
+MODULE_DESCRIPTION("SPI SD/MMC host driver");
+MODULE_LICENSE("GPL");
projects / GitHub / mt8127 / android_kernel_alcatel_ttab.git / commitdiff