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linux-next/drivers/mmc/host/davinci_mmc.c
Sudhakar Rajashekhara ca2afb6dbe davinci: mmc: pass number of SG segments as platform data
On some platforms like DM355, the number of EDMA parameter slots available
for EDMA_SLOT_ANY usage are few.  In such cases, if MMC/SD uses 16 slots
for each instance of MMC controller, then the number of slots available
for other modules will be very few.

By passing the number of EDMA slots to be used in MMC driver from platform
data, EDMA slots available for other purposes can be controlled.

Most of the platforms will not use this platform data variable.  But on
DM355, as the number of EDMA resources available is limited, the number of
scatter- gather segments used inside the MMC driver can be 8 (passed as
platform data) instead of 16.  On DM355, when the number of scatter-gather
segments was reduced to 8, I saw a performance difference of about
0.25-0.4 Mbytes/sec during write.  Read performance variations were
negligible.

Signed-off-by: Sudhakar Rajashekhara <sudhakar.raj@ti.com>
Acked-by: Kevin Hilman <khilman@deeprootsystems.com>
Cc: <linux-mmc@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-05-27 09:12:39 -07:00

1385 lines
38 KiB
C

/*
* davinci_mmc.c - TI DaVinci MMC/SD/SDIO driver
*
* Copyright (C) 2006 Texas Instruments.
* Original author: Purushotam Kumar
* Copyright (C) 2009 David Brownell
*
* 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/module.h>
#include <linux/ioport.h>
#include <linux/platform_device.h>
#include <linux/clk.h>
#include <linux/err.h>
#include <linux/cpufreq.h>
#include <linux/mmc/host.h>
#include <linux/io.h>
#include <linux/irq.h>
#include <linux/delay.h>
#include <linux/dma-mapping.h>
#include <linux/mmc/mmc.h>
#include <mach/mmc.h>
#include <mach/edma.h>
/*
* Register Definitions
*/
#define DAVINCI_MMCCTL 0x00 /* Control Register */
#define DAVINCI_MMCCLK 0x04 /* Memory Clock Control Register */
#define DAVINCI_MMCST0 0x08 /* Status Register 0 */
#define DAVINCI_MMCST1 0x0C /* Status Register 1 */
#define DAVINCI_MMCIM 0x10 /* Interrupt Mask Register */
#define DAVINCI_MMCTOR 0x14 /* Response Time-Out Register */
#define DAVINCI_MMCTOD 0x18 /* Data Read Time-Out Register */
#define DAVINCI_MMCBLEN 0x1C /* Block Length Register */
#define DAVINCI_MMCNBLK 0x20 /* Number of Blocks Register */
#define DAVINCI_MMCNBLC 0x24 /* Number of Blocks Counter Register */
#define DAVINCI_MMCDRR 0x28 /* Data Receive Register */
#define DAVINCI_MMCDXR 0x2C /* Data Transmit Register */
#define DAVINCI_MMCCMD 0x30 /* Command Register */
#define DAVINCI_MMCARGHL 0x34 /* Argument Register */
#define DAVINCI_MMCRSP01 0x38 /* Response Register 0 and 1 */
#define DAVINCI_MMCRSP23 0x3C /* Response Register 0 and 1 */
#define DAVINCI_MMCRSP45 0x40 /* Response Register 0 and 1 */
#define DAVINCI_MMCRSP67 0x44 /* Response Register 0 and 1 */
#define DAVINCI_MMCDRSP 0x48 /* Data Response Register */
#define DAVINCI_MMCETOK 0x4C
#define DAVINCI_MMCCIDX 0x50 /* Command Index Register */
#define DAVINCI_MMCCKC 0x54
#define DAVINCI_MMCTORC 0x58
#define DAVINCI_MMCTODC 0x5C
#define DAVINCI_MMCBLNC 0x60
#define DAVINCI_SDIOCTL 0x64
#define DAVINCI_SDIOST0 0x68
#define DAVINCI_SDIOEN 0x6C
#define DAVINCI_SDIOST 0x70
#define DAVINCI_MMCFIFOCTL 0x74 /* FIFO Control Register */
/* DAVINCI_MMCCTL definitions */
#define MMCCTL_DATRST (1 << 0)
#define MMCCTL_CMDRST (1 << 1)
#define MMCCTL_WIDTH_8_BIT (1 << 8)
#define MMCCTL_WIDTH_4_BIT (1 << 2)
#define MMCCTL_DATEG_DISABLED (0 << 6)
#define MMCCTL_DATEG_RISING (1 << 6)
#define MMCCTL_DATEG_FALLING (2 << 6)
#define MMCCTL_DATEG_BOTH (3 << 6)
#define MMCCTL_PERMDR_LE (0 << 9)
#define MMCCTL_PERMDR_BE (1 << 9)
#define MMCCTL_PERMDX_LE (0 << 10)
#define MMCCTL_PERMDX_BE (1 << 10)
/* DAVINCI_MMCCLK definitions */
#define MMCCLK_CLKEN (1 << 8)
#define MMCCLK_CLKRT_MASK (0xFF << 0)
/* IRQ bit definitions, for DAVINCI_MMCST0 and DAVINCI_MMCIM */
#define MMCST0_DATDNE BIT(0) /* data done */
#define MMCST0_BSYDNE BIT(1) /* busy done */
#define MMCST0_RSPDNE BIT(2) /* command done */
#define MMCST0_TOUTRD BIT(3) /* data read timeout */
#define MMCST0_TOUTRS BIT(4) /* command response timeout */
#define MMCST0_CRCWR BIT(5) /* data write CRC error */
#define MMCST0_CRCRD BIT(6) /* data read CRC error */
#define MMCST0_CRCRS BIT(7) /* command response CRC error */
#define MMCST0_DXRDY BIT(9) /* data transmit ready (fifo empty) */
#define MMCST0_DRRDY BIT(10) /* data receive ready (data in fifo)*/
#define MMCST0_DATED BIT(11) /* DAT3 edge detect */
#define MMCST0_TRNDNE BIT(12) /* transfer done */
/* DAVINCI_MMCST1 definitions */
#define MMCST1_BUSY (1 << 0)
/* DAVINCI_MMCCMD definitions */
#define MMCCMD_CMD_MASK (0x3F << 0)
#define MMCCMD_PPLEN (1 << 7)
#define MMCCMD_BSYEXP (1 << 8)
#define MMCCMD_RSPFMT_MASK (3 << 9)
#define MMCCMD_RSPFMT_NONE (0 << 9)
#define MMCCMD_RSPFMT_R1456 (1 << 9)
#define MMCCMD_RSPFMT_R2 (2 << 9)
#define MMCCMD_RSPFMT_R3 (3 << 9)
#define MMCCMD_DTRW (1 << 11)
#define MMCCMD_STRMTP (1 << 12)
#define MMCCMD_WDATX (1 << 13)
#define MMCCMD_INITCK (1 << 14)
#define MMCCMD_DCLR (1 << 15)
#define MMCCMD_DMATRIG (1 << 16)
/* DAVINCI_MMCFIFOCTL definitions */
#define MMCFIFOCTL_FIFORST (1 << 0)
#define MMCFIFOCTL_FIFODIR_WR (1 << 1)
#define MMCFIFOCTL_FIFODIR_RD (0 << 1)
#define MMCFIFOCTL_FIFOLEV (1 << 2) /* 0 = 128 bits, 1 = 256 bits */
#define MMCFIFOCTL_ACCWD_4 (0 << 3) /* access width of 4 bytes */
#define MMCFIFOCTL_ACCWD_3 (1 << 3) /* access width of 3 bytes */
#define MMCFIFOCTL_ACCWD_2 (2 << 3) /* access width of 2 bytes */
#define MMCFIFOCTL_ACCWD_1 (3 << 3) /* access width of 1 byte */
/* MMCSD Init clock in Hz in opendrain mode */
#define MMCSD_INIT_CLOCK 200000
/*
* One scatterlist dma "segment" is at most MAX_CCNT rw_threshold units,
* and we handle up to MAX_NR_SG segments. MMC_BLOCK_BOUNCE kicks in only
* for drivers with max_hw_segs == 1, making the segments bigger (64KB)
* than the page or two that's otherwise typical. nr_sg (passed from
* platform data) == 16 gives at least the same throughput boost, using
* EDMA transfer linkage instead of spending CPU time copying pages.
*/
#define MAX_CCNT ((1 << 16) - 1)
#define MAX_NR_SG 16
static unsigned rw_threshold = 32;
module_param(rw_threshold, uint, S_IRUGO);
MODULE_PARM_DESC(rw_threshold,
"Read/Write threshold. Default = 32");
static unsigned __initdata use_dma = 1;
module_param(use_dma, uint, 0);
MODULE_PARM_DESC(use_dma, "Whether to use DMA or not. Default = 1");
struct mmc_davinci_host {
struct mmc_command *cmd;
struct mmc_data *data;
struct mmc_host *mmc;
struct clk *clk;
unsigned int mmc_input_clk;
void __iomem *base;
struct resource *mem_res;
int irq;
unsigned char bus_mode;
#define DAVINCI_MMC_DATADIR_NONE 0
#define DAVINCI_MMC_DATADIR_READ 1
#define DAVINCI_MMC_DATADIR_WRITE 2
unsigned char data_dir;
/* buffer is used during PIO of one scatterlist segment, and
* is updated along with buffer_bytes_left. bytes_left applies
* to all N blocks of the PIO transfer.
*/
u8 *buffer;
u32 buffer_bytes_left;
u32 bytes_left;
u32 rxdma, txdma;
bool use_dma;
bool do_dma;
/* Scatterlist DMA uses one or more parameter RAM entries:
* the main one (associated with rxdma or txdma) plus zero or
* more links. The entries for a given transfer differ only
* by memory buffer (address, length) and link field.
*/
struct edmacc_param tx_template;
struct edmacc_param rx_template;
unsigned n_link;
u32 links[MAX_NR_SG - 1];
/* For PIO we walk scatterlists one segment at a time. */
unsigned int sg_len;
struct scatterlist *sg;
/* Version of the MMC/SD controller */
u8 version;
/* for ns in one cycle calculation */
unsigned ns_in_one_cycle;
/* Number of sg segments */
u8 nr_sg;
#ifdef CONFIG_CPU_FREQ
struct notifier_block freq_transition;
#endif
};
/* PIO only */
static void mmc_davinci_sg_to_buf(struct mmc_davinci_host *host)
{
host->buffer_bytes_left = sg_dma_len(host->sg);
host->buffer = sg_virt(host->sg);
if (host->buffer_bytes_left > host->bytes_left)
host->buffer_bytes_left = host->bytes_left;
}
static void davinci_fifo_data_trans(struct mmc_davinci_host *host,
unsigned int n)
{
u8 *p;
unsigned int i;
if (host->buffer_bytes_left == 0) {
host->sg = sg_next(host->data->sg);
mmc_davinci_sg_to_buf(host);
}
p = host->buffer;
if (n > host->buffer_bytes_left)
n = host->buffer_bytes_left;
host->buffer_bytes_left -= n;
host->bytes_left -= n;
/* NOTE: we never transfer more than rw_threshold bytes
* to/from the fifo here; there's no I/O overlap.
* This also assumes that access width( i.e. ACCWD) is 4 bytes
*/
if (host->data_dir == DAVINCI_MMC_DATADIR_WRITE) {
for (i = 0; i < (n >> 2); i++) {
writel(*((u32 *)p), host->base + DAVINCI_MMCDXR);
p = p + 4;
}
if (n & 3) {
iowrite8_rep(host->base + DAVINCI_MMCDXR, p, (n & 3));
p = p + (n & 3);
}
} else {
for (i = 0; i < (n >> 2); i++) {
*((u32 *)p) = readl(host->base + DAVINCI_MMCDRR);
p = p + 4;
}
if (n & 3) {
ioread8_rep(host->base + DAVINCI_MMCDRR, p, (n & 3));
p = p + (n & 3);
}
}
host->buffer = p;
}
static void mmc_davinci_start_command(struct mmc_davinci_host *host,
struct mmc_command *cmd)
{
u32 cmd_reg = 0;
u32 im_val;
dev_dbg(mmc_dev(host->mmc), "CMD%d, arg 0x%08x%s\n",
cmd->opcode, cmd->arg,
({ char *s;
switch (mmc_resp_type(cmd)) {
case MMC_RSP_R1:
s = ", R1/R5/R6/R7 response";
break;
case MMC_RSP_R1B:
s = ", R1b response";
break;
case MMC_RSP_R2:
s = ", R2 response";
break;
case MMC_RSP_R3:
s = ", R3/R4 response";
break;
default:
s = ", (R? response)";
break;
}; s; }));
host->cmd = cmd;
switch (mmc_resp_type(cmd)) {
case MMC_RSP_R1B:
/* There's some spec confusion about when R1B is
* allowed, but if the card doesn't issue a BUSY
* then it's harmless for us to allow it.
*/
cmd_reg |= MMCCMD_BSYEXP;
/* FALLTHROUGH */
case MMC_RSP_R1: /* 48 bits, CRC */
cmd_reg |= MMCCMD_RSPFMT_R1456;
break;
case MMC_RSP_R2: /* 136 bits, CRC */
cmd_reg |= MMCCMD_RSPFMT_R2;
break;
case MMC_RSP_R3: /* 48 bits, no CRC */
cmd_reg |= MMCCMD_RSPFMT_R3;
break;
default:
cmd_reg |= MMCCMD_RSPFMT_NONE;
dev_dbg(mmc_dev(host->mmc), "unknown resp_type %04x\n",
mmc_resp_type(cmd));
break;
}
/* Set command index */
cmd_reg |= cmd->opcode;
/* Enable EDMA transfer triggers */
if (host->do_dma)
cmd_reg |= MMCCMD_DMATRIG;
if (host->version == MMC_CTLR_VERSION_2 && host->data != NULL &&
host->data_dir == DAVINCI_MMC_DATADIR_READ)
cmd_reg |= MMCCMD_DMATRIG;
/* Setting whether command involves data transfer or not */
if (cmd->data)
cmd_reg |= MMCCMD_WDATX;
/* Setting whether stream or block transfer */
if (cmd->flags & MMC_DATA_STREAM)
cmd_reg |= MMCCMD_STRMTP;
/* Setting whether data read or write */
if (host->data_dir == DAVINCI_MMC_DATADIR_WRITE)
cmd_reg |= MMCCMD_DTRW;
if (host->bus_mode == MMC_BUSMODE_PUSHPULL)
cmd_reg |= MMCCMD_PPLEN;
/* set Command timeout */
writel(0x1FFF, host->base + DAVINCI_MMCTOR);
/* Enable interrupt (calculate here, defer until FIFO is stuffed). */
im_val = MMCST0_RSPDNE | MMCST0_CRCRS | MMCST0_TOUTRS;
if (host->data_dir == DAVINCI_MMC_DATADIR_WRITE) {
im_val |= MMCST0_DATDNE | MMCST0_CRCWR;
if (!host->do_dma)
im_val |= MMCST0_DXRDY;
} else if (host->data_dir == DAVINCI_MMC_DATADIR_READ) {
im_val |= MMCST0_DATDNE | MMCST0_CRCRD | MMCST0_TOUTRD;
if (!host->do_dma)
im_val |= MMCST0_DRRDY;
}
/*
* Before non-DMA WRITE commands the controller needs priming:
* FIFO should be populated with 32 bytes i.e. whatever is the FIFO size
*/
if (!host->do_dma && (host->data_dir == DAVINCI_MMC_DATADIR_WRITE))
davinci_fifo_data_trans(host, rw_threshold);
writel(cmd->arg, host->base + DAVINCI_MMCARGHL);
writel(cmd_reg, host->base + DAVINCI_MMCCMD);
writel(im_val, host->base + DAVINCI_MMCIM);
}
/*----------------------------------------------------------------------*/
/* DMA infrastructure */
static void davinci_abort_dma(struct mmc_davinci_host *host)
{
int sync_dev;
if (host->data_dir == DAVINCI_MMC_DATADIR_READ)
sync_dev = host->rxdma;
else
sync_dev = host->txdma;
edma_stop(sync_dev);
edma_clean_channel(sync_dev);
}
static void
mmc_davinci_xfer_done(struct mmc_davinci_host *host, struct mmc_data *data);
static void mmc_davinci_dma_cb(unsigned channel, u16 ch_status, void *data)
{
if (DMA_COMPLETE != ch_status) {
struct mmc_davinci_host *host = data;
/* Currently means: DMA Event Missed, or "null" transfer
* request was seen. In the future, TC errors (like bad
* addresses) might be presented too.
*/
dev_warn(mmc_dev(host->mmc), "DMA %s error\n",
(host->data->flags & MMC_DATA_WRITE)
? "write" : "read");
host->data->error = -EIO;
mmc_davinci_xfer_done(host, host->data);
}
}
/* Set up tx or rx template, to be modified and updated later */
static void __init mmc_davinci_dma_setup(struct mmc_davinci_host *host,
bool tx, struct edmacc_param *template)
{
unsigned sync_dev;
const u16 acnt = 4;
const u16 bcnt = rw_threshold >> 2;
const u16 ccnt = 0;
u32 src_port = 0;
u32 dst_port = 0;
s16 src_bidx, dst_bidx;
s16 src_cidx, dst_cidx;
/*
* A-B Sync transfer: each DMA request is for one "frame" of
* rw_threshold bytes, broken into "acnt"-size chunks repeated
* "bcnt" times. Each segment needs "ccnt" such frames; since
* we tell the block layer our mmc->max_seg_size limit, we can
* trust (later) that it's within bounds.
*
* The FIFOs are read/written in 4-byte chunks (acnt == 4) and
* EDMA will optimize memory operations to use larger bursts.
*/
if (tx) {
sync_dev = host->txdma;
/* src_prt, ccnt, and link to be set up later */
src_bidx = acnt;
src_cidx = acnt * bcnt;
dst_port = host->mem_res->start + DAVINCI_MMCDXR;
dst_bidx = 0;
dst_cidx = 0;
} else {
sync_dev = host->rxdma;
src_port = host->mem_res->start + DAVINCI_MMCDRR;
src_bidx = 0;
src_cidx = 0;
/* dst_prt, ccnt, and link to be set up later */
dst_bidx = acnt;
dst_cidx = acnt * bcnt;
}
/*
* We can't use FIFO mode for the FIFOs because MMC FIFO addresses
* are not 256-bit (32-byte) aligned. So we use INCR, and the W8BIT
* parameter is ignored.
*/
edma_set_src(sync_dev, src_port, INCR, W8BIT);
edma_set_dest(sync_dev, dst_port, INCR, W8BIT);
edma_set_src_index(sync_dev, src_bidx, src_cidx);
edma_set_dest_index(sync_dev, dst_bidx, dst_cidx);
edma_set_transfer_params(sync_dev, acnt, bcnt, ccnt, 8, ABSYNC);
edma_read_slot(sync_dev, template);
/* don't bother with irqs or chaining */
template->opt |= EDMA_CHAN_SLOT(sync_dev) << 12;
}
static void mmc_davinci_send_dma_request(struct mmc_davinci_host *host,
struct mmc_data *data)
{
struct edmacc_param *template;
int channel, slot;
unsigned link;
struct scatterlist *sg;
unsigned sg_len;
unsigned bytes_left = host->bytes_left;
const unsigned shift = ffs(rw_threshold) - 1;;
if (host->data_dir == DAVINCI_MMC_DATADIR_WRITE) {
template = &host->tx_template;
channel = host->txdma;
} else {
template = &host->rx_template;
channel = host->rxdma;
}
/* We know sg_len and ccnt will never be out of range because
* we told the mmc layer which in turn tells the block layer
* to ensure that it only hands us one scatterlist segment
* per EDMA PARAM entry. Update the PARAM
* entries needed for each segment of this scatterlist.
*/
for (slot = channel, link = 0, sg = data->sg, sg_len = host->sg_len;
sg_len-- != 0 && bytes_left;
sg = sg_next(sg), slot = host->links[link++]) {
u32 buf = sg_dma_address(sg);
unsigned count = sg_dma_len(sg);
template->link_bcntrld = sg_len
? (EDMA_CHAN_SLOT(host->links[link]) << 5)
: 0xffff;
if (count > bytes_left)
count = bytes_left;
bytes_left -= count;
if (host->data_dir == DAVINCI_MMC_DATADIR_WRITE)
template->src = buf;
else
template->dst = buf;
template->ccnt = count >> shift;
edma_write_slot(slot, template);
}
if (host->version == MMC_CTLR_VERSION_2)
edma_clear_event(channel);
edma_start(channel);
}
static int mmc_davinci_start_dma_transfer(struct mmc_davinci_host *host,
struct mmc_data *data)
{
int i;
int mask = rw_threshold - 1;
host->sg_len = dma_map_sg(mmc_dev(host->mmc), data->sg, data->sg_len,
((data->flags & MMC_DATA_WRITE)
? DMA_TO_DEVICE
: DMA_FROM_DEVICE));
/* no individual DMA segment should need a partial FIFO */
for (i = 0; i < host->sg_len; i++) {
if (sg_dma_len(data->sg + i) & mask) {
dma_unmap_sg(mmc_dev(host->mmc),
data->sg, data->sg_len,
(data->flags & MMC_DATA_WRITE)
? DMA_TO_DEVICE
: DMA_FROM_DEVICE);
return -1;
}
}
host->do_dma = 1;
mmc_davinci_send_dma_request(host, data);
return 0;
}
static void __init_or_module
davinci_release_dma_channels(struct mmc_davinci_host *host)
{
unsigned i;
if (!host->use_dma)
return;
for (i = 0; i < host->n_link; i++)
edma_free_slot(host->links[i]);
edma_free_channel(host->txdma);
edma_free_channel(host->rxdma);
}
static int __init davinci_acquire_dma_channels(struct mmc_davinci_host *host)
{
u32 link_size;
int r, i;
/* Acquire master DMA write channel */
r = edma_alloc_channel(host->txdma, mmc_davinci_dma_cb, host,
EVENTQ_DEFAULT);
if (r < 0) {
dev_warn(mmc_dev(host->mmc), "alloc %s channel err %d\n",
"tx", r);
return r;
}
mmc_davinci_dma_setup(host, true, &host->tx_template);
/* Acquire master DMA read channel */
r = edma_alloc_channel(host->rxdma, mmc_davinci_dma_cb, host,
EVENTQ_DEFAULT);
if (r < 0) {
dev_warn(mmc_dev(host->mmc), "alloc %s channel err %d\n",
"rx", r);
goto free_master_write;
}
mmc_davinci_dma_setup(host, false, &host->rx_template);
/* Allocate parameter RAM slots, which will later be bound to a
* channel as needed to handle a scatterlist.
*/
link_size = min_t(unsigned, host->nr_sg, ARRAY_SIZE(host->links));
for (i = 0; i < link_size; i++) {
r = edma_alloc_slot(EDMA_CTLR(host->txdma), EDMA_SLOT_ANY);
if (r < 0) {
dev_dbg(mmc_dev(host->mmc), "dma PaRAM alloc --> %d\n",
r);
break;
}
host->links[i] = r;
}
host->n_link = i;
return 0;
free_master_write:
edma_free_channel(host->txdma);
return r;
}
/*----------------------------------------------------------------------*/
static void
mmc_davinci_prepare_data(struct mmc_davinci_host *host, struct mmc_request *req)
{
int fifo_lev = (rw_threshold == 32) ? MMCFIFOCTL_FIFOLEV : 0;
int timeout;
struct mmc_data *data = req->data;
if (host->version == MMC_CTLR_VERSION_2)
fifo_lev = (rw_threshold == 64) ? MMCFIFOCTL_FIFOLEV : 0;
host->data = data;
if (data == NULL) {
host->data_dir = DAVINCI_MMC_DATADIR_NONE;
writel(0, host->base + DAVINCI_MMCBLEN);
writel(0, host->base + DAVINCI_MMCNBLK);
return;
}
dev_dbg(mmc_dev(host->mmc), "%s %s, %d blocks of %d bytes\n",
(data->flags & MMC_DATA_STREAM) ? "stream" : "block",
(data->flags & MMC_DATA_WRITE) ? "write" : "read",
data->blocks, data->blksz);
dev_dbg(mmc_dev(host->mmc), " DTO %d cycles + %d ns\n",
data->timeout_clks, data->timeout_ns);
timeout = data->timeout_clks +
(data->timeout_ns / host->ns_in_one_cycle);
if (timeout > 0xffff)
timeout = 0xffff;
writel(timeout, host->base + DAVINCI_MMCTOD);
writel(data->blocks, host->base + DAVINCI_MMCNBLK);
writel(data->blksz, host->base + DAVINCI_MMCBLEN);
/* Configure the FIFO */
switch (data->flags & MMC_DATA_WRITE) {
case MMC_DATA_WRITE:
host->data_dir = DAVINCI_MMC_DATADIR_WRITE;
writel(fifo_lev | MMCFIFOCTL_FIFODIR_WR | MMCFIFOCTL_FIFORST,
host->base + DAVINCI_MMCFIFOCTL);
writel(fifo_lev | MMCFIFOCTL_FIFODIR_WR,
host->base + DAVINCI_MMCFIFOCTL);
break;
default:
host->data_dir = DAVINCI_MMC_DATADIR_READ;
writel(fifo_lev | MMCFIFOCTL_FIFODIR_RD | MMCFIFOCTL_FIFORST,
host->base + DAVINCI_MMCFIFOCTL);
writel(fifo_lev | MMCFIFOCTL_FIFODIR_RD,
host->base + DAVINCI_MMCFIFOCTL);
break;
}
host->buffer = NULL;
host->bytes_left = data->blocks * data->blksz;
/* For now we try to use DMA whenever we won't need partial FIFO
* reads or writes, either for the whole transfer (as tested here)
* or for any individual scatterlist segment (tested when we call
* start_dma_transfer).
*
* While we *could* change that, unusual block sizes are rarely
* used. The occasional fallback to PIO should't hurt.
*/
if (host->use_dma && (host->bytes_left & (rw_threshold - 1)) == 0
&& mmc_davinci_start_dma_transfer(host, data) == 0) {
/* zero this to ensure we take no PIO paths */
host->bytes_left = 0;
} else {
/* Revert to CPU Copy */
host->sg_len = data->sg_len;
host->sg = host->data->sg;
mmc_davinci_sg_to_buf(host);
}
}
static void mmc_davinci_request(struct mmc_host *mmc, struct mmc_request *req)
{
struct mmc_davinci_host *host = mmc_priv(mmc);
unsigned long timeout = jiffies + msecs_to_jiffies(900);
u32 mmcst1 = 0;
/* Card may still be sending BUSY after a previous operation,
* typically some kind of write. If so, we can't proceed yet.
*/
while (time_before(jiffies, timeout)) {
mmcst1 = readl(host->base + DAVINCI_MMCST1);
if (!(mmcst1 & MMCST1_BUSY))
break;
cpu_relax();
}
if (mmcst1 & MMCST1_BUSY) {
dev_err(mmc_dev(host->mmc), "still BUSY? bad ... \n");
req->cmd->error = -ETIMEDOUT;
mmc_request_done(mmc, req);
return;
}
host->do_dma = 0;
mmc_davinci_prepare_data(host, req);
mmc_davinci_start_command(host, req->cmd);
}
static unsigned int calculate_freq_for_card(struct mmc_davinci_host *host,
unsigned int mmc_req_freq)
{
unsigned int mmc_freq = 0, mmc_pclk = 0, mmc_push_pull_divisor = 0;
mmc_pclk = host->mmc_input_clk;
if (mmc_req_freq && mmc_pclk > (2 * mmc_req_freq))
mmc_push_pull_divisor = ((unsigned int)mmc_pclk
/ (2 * mmc_req_freq)) - 1;
else
mmc_push_pull_divisor = 0;
mmc_freq = (unsigned int)mmc_pclk
/ (2 * (mmc_push_pull_divisor + 1));
if (mmc_freq > mmc_req_freq)
mmc_push_pull_divisor = mmc_push_pull_divisor + 1;
/* Convert ns to clock cycles */
if (mmc_req_freq <= 400000)
host->ns_in_one_cycle = (1000000) / (((mmc_pclk
/ (2 * (mmc_push_pull_divisor + 1)))/1000));
else
host->ns_in_one_cycle = (1000000) / (((mmc_pclk
/ (2 * (mmc_push_pull_divisor + 1)))/1000000));
return mmc_push_pull_divisor;
}
static void calculate_clk_divider(struct mmc_host *mmc, struct mmc_ios *ios)
{
unsigned int open_drain_freq = 0, mmc_pclk = 0;
unsigned int mmc_push_pull_freq = 0;
struct mmc_davinci_host *host = mmc_priv(mmc);
if (ios->bus_mode == MMC_BUSMODE_OPENDRAIN) {
u32 temp;
/* Ignoring the init clock value passed for fixing the inter
* operability with different cards.
*/
open_drain_freq = ((unsigned int)mmc_pclk
/ (2 * MMCSD_INIT_CLOCK)) - 1;
if (open_drain_freq > 0xFF)
open_drain_freq = 0xFF;
temp = readl(host->base + DAVINCI_MMCCLK) & ~MMCCLK_CLKRT_MASK;
temp |= open_drain_freq;
writel(temp, host->base + DAVINCI_MMCCLK);
/* Convert ns to clock cycles */
host->ns_in_one_cycle = (1000000) / (MMCSD_INIT_CLOCK/1000);
} else {
u32 temp;
mmc_push_pull_freq = calculate_freq_for_card(host, ios->clock);
if (mmc_push_pull_freq > 0xFF)
mmc_push_pull_freq = 0xFF;
temp = readl(host->base + DAVINCI_MMCCLK) & ~MMCCLK_CLKEN;
writel(temp, host->base + DAVINCI_MMCCLK);
udelay(10);
temp = readl(host->base + DAVINCI_MMCCLK) & ~MMCCLK_CLKRT_MASK;
temp |= mmc_push_pull_freq;
writel(temp, host->base + DAVINCI_MMCCLK);
writel(temp | MMCCLK_CLKEN, host->base + DAVINCI_MMCCLK);
udelay(10);
}
}
static void mmc_davinci_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)
{
struct mmc_davinci_host *host = mmc_priv(mmc);
dev_dbg(mmc_dev(host->mmc),
"clock %dHz busmode %d powermode %d Vdd %04x\n",
ios->clock, ios->bus_mode, ios->power_mode,
ios->vdd);
switch (ios->bus_width) {
case MMC_BUS_WIDTH_8:
dev_dbg(mmc_dev(host->mmc), "Enabling 8 bit mode\n");
writel((readl(host->base + DAVINCI_MMCCTL) &
~MMCCTL_WIDTH_4_BIT) | MMCCTL_WIDTH_8_BIT,
host->base + DAVINCI_MMCCTL);
break;
case MMC_BUS_WIDTH_4:
dev_dbg(mmc_dev(host->mmc), "Enabling 4 bit mode\n");
if (host->version == MMC_CTLR_VERSION_2)
writel((readl(host->base + DAVINCI_MMCCTL) &
~MMCCTL_WIDTH_8_BIT) | MMCCTL_WIDTH_4_BIT,
host->base + DAVINCI_MMCCTL);
else
writel(readl(host->base + DAVINCI_MMCCTL) |
MMCCTL_WIDTH_4_BIT,
host->base + DAVINCI_MMCCTL);
break;
case MMC_BUS_WIDTH_1:
dev_dbg(mmc_dev(host->mmc), "Enabling 1 bit mode\n");
if (host->version == MMC_CTLR_VERSION_2)
writel(readl(host->base + DAVINCI_MMCCTL) &
~(MMCCTL_WIDTH_8_BIT | MMCCTL_WIDTH_4_BIT),
host->base + DAVINCI_MMCCTL);
else
writel(readl(host->base + DAVINCI_MMCCTL) &
~MMCCTL_WIDTH_4_BIT,
host->base + DAVINCI_MMCCTL);
break;
}
calculate_clk_divider(mmc, ios);
host->bus_mode = ios->bus_mode;
if (ios->power_mode == MMC_POWER_UP) {
unsigned long timeout = jiffies + msecs_to_jiffies(50);
bool lose = true;
/* Send clock cycles, poll completion */
writel(0, host->base + DAVINCI_MMCARGHL);
writel(MMCCMD_INITCK, host->base + DAVINCI_MMCCMD);
while (time_before(jiffies, timeout)) {
u32 tmp = readl(host->base + DAVINCI_MMCST0);
if (tmp & MMCST0_RSPDNE) {
lose = false;
break;
}
cpu_relax();
}
if (lose)
dev_warn(mmc_dev(host->mmc), "powerup timeout\n");
}
/* FIXME on power OFF, reset things ... */
}
static void
mmc_davinci_xfer_done(struct mmc_davinci_host *host, struct mmc_data *data)
{
host->data = NULL;
if (host->do_dma) {
davinci_abort_dma(host);
dma_unmap_sg(mmc_dev(host->mmc), data->sg, data->sg_len,
(data->flags & MMC_DATA_WRITE)
? DMA_TO_DEVICE
: DMA_FROM_DEVICE);
host->do_dma = false;
}
host->data_dir = DAVINCI_MMC_DATADIR_NONE;
if (!data->stop || (host->cmd && host->cmd->error)) {
mmc_request_done(host->mmc, data->mrq);
writel(0, host->base + DAVINCI_MMCIM);
} else
mmc_davinci_start_command(host, data->stop);
}
static void mmc_davinci_cmd_done(struct mmc_davinci_host *host,
struct mmc_command *cmd)
{
host->cmd = NULL;
if (cmd->flags & MMC_RSP_PRESENT) {
if (cmd->flags & MMC_RSP_136) {
/* response type 2 */
cmd->resp[3] = readl(host->base + DAVINCI_MMCRSP01);
cmd->resp[2] = readl(host->base + DAVINCI_MMCRSP23);
cmd->resp[1] = readl(host->base + DAVINCI_MMCRSP45);
cmd->resp[0] = readl(host->base + DAVINCI_MMCRSP67);
} else {
/* response types 1, 1b, 3, 4, 5, 6 */
cmd->resp[0] = readl(host->base + DAVINCI_MMCRSP67);
}
}
if (host->data == NULL || cmd->error) {
if (cmd->error == -ETIMEDOUT)
cmd->mrq->cmd->retries = 0;
mmc_request_done(host->mmc, cmd->mrq);
writel(0, host->base + DAVINCI_MMCIM);
}
}
static void
davinci_abort_data(struct mmc_davinci_host *host, struct mmc_data *data)
{
u32 temp;
/* reset command and data state machines */
temp = readl(host->base + DAVINCI_MMCCTL);
writel(temp | MMCCTL_CMDRST | MMCCTL_DATRST,
host->base + DAVINCI_MMCCTL);
temp &= ~(MMCCTL_CMDRST | MMCCTL_DATRST);
udelay(10);
writel(temp, host->base + DAVINCI_MMCCTL);
}
static irqreturn_t mmc_davinci_irq(int irq, void *dev_id)
{
struct mmc_davinci_host *host = (struct mmc_davinci_host *)dev_id;
unsigned int status, qstatus;
int end_command = 0;
int end_transfer = 0;
struct mmc_data *data = host->data;
if (host->cmd == NULL && host->data == NULL) {
status = readl(host->base + DAVINCI_MMCST0);
dev_dbg(mmc_dev(host->mmc),
"Spurious interrupt 0x%04x\n", status);
/* Disable the interrupt from mmcsd */
writel(0, host->base + DAVINCI_MMCIM);
return IRQ_NONE;
}
status = readl(host->base + DAVINCI_MMCST0);
qstatus = status;
/* handle FIFO first when using PIO for data.
* bytes_left will decrease to zero as I/O progress and status will
* read zero over iteration because this controller status
* register(MMCST0) reports any status only once and it is cleared
* by read. So, it is not unbouned loop even in the case of
* non-dma.
*/
while (host->bytes_left && (status & (MMCST0_DXRDY | MMCST0_DRRDY))) {
davinci_fifo_data_trans(host, rw_threshold);
status = readl(host->base + DAVINCI_MMCST0);
if (!status)
break;
qstatus |= status;
}
if (qstatus & MMCST0_DATDNE) {
/* All blocks sent/received, and CRC checks passed */
if (data != NULL) {
if ((host->do_dma == 0) && (host->bytes_left > 0)) {
/* if datasize < rw_threshold
* no RX ints are generated
*/
davinci_fifo_data_trans(host, host->bytes_left);
}
end_transfer = 1;
data->bytes_xfered = data->blocks * data->blksz;
} else {
dev_err(mmc_dev(host->mmc),
"DATDNE with no host->data\n");
}
}
if (qstatus & MMCST0_TOUTRD) {
/* Read data timeout */
data->error = -ETIMEDOUT;
end_transfer = 1;
dev_dbg(mmc_dev(host->mmc),
"read data timeout, status %x\n",
qstatus);
davinci_abort_data(host, data);
}
if (qstatus & (MMCST0_CRCWR | MMCST0_CRCRD)) {
/* Data CRC error */
data->error = -EILSEQ;
end_transfer = 1;
/* NOTE: this controller uses CRCWR to report both CRC
* errors and timeouts (on writes). MMCDRSP values are
* only weakly documented, but 0x9f was clearly a timeout
* case and the two three-bit patterns in various SD specs
* (101, 010) aren't part of it ...
*/
if (qstatus & MMCST0_CRCWR) {
u32 temp = readb(host->base + DAVINCI_MMCDRSP);
if (temp == 0x9f)
data->error = -ETIMEDOUT;
}
dev_dbg(mmc_dev(host->mmc), "data %s %s error\n",
(qstatus & MMCST0_CRCWR) ? "write" : "read",
(data->error == -ETIMEDOUT) ? "timeout" : "CRC");
davinci_abort_data(host, data);
}
if (qstatus & MMCST0_TOUTRS) {
/* Command timeout */
if (host->cmd) {
dev_dbg(mmc_dev(host->mmc),
"CMD%d timeout, status %x\n",
host->cmd->opcode, qstatus);
host->cmd->error = -ETIMEDOUT;
if (data) {
end_transfer = 1;
davinci_abort_data(host, data);
} else
end_command = 1;
}
}
if (qstatus & MMCST0_CRCRS) {
/* Command CRC error */
dev_dbg(mmc_dev(host->mmc), "Command CRC error\n");
if (host->cmd) {
host->cmd->error = -EILSEQ;
end_command = 1;
}
}
if (qstatus & MMCST0_RSPDNE) {
/* End of command phase */
end_command = (int) host->cmd;
}
if (end_command)
mmc_davinci_cmd_done(host, host->cmd);
if (end_transfer)
mmc_davinci_xfer_done(host, data);
return IRQ_HANDLED;
}
static int mmc_davinci_get_cd(struct mmc_host *mmc)
{
struct platform_device *pdev = to_platform_device(mmc->parent);
struct davinci_mmc_config *config = pdev->dev.platform_data;
if (!config || !config->get_cd)
return -ENOSYS;
return config->get_cd(pdev->id);
}
static int mmc_davinci_get_ro(struct mmc_host *mmc)
{
struct platform_device *pdev = to_platform_device(mmc->parent);
struct davinci_mmc_config *config = pdev->dev.platform_data;
if (!config || !config->get_ro)
return -ENOSYS;
return config->get_ro(pdev->id);
}
static struct mmc_host_ops mmc_davinci_ops = {
.request = mmc_davinci_request,
.set_ios = mmc_davinci_set_ios,
.get_cd = mmc_davinci_get_cd,
.get_ro = mmc_davinci_get_ro,
};
/*----------------------------------------------------------------------*/
#ifdef CONFIG_CPU_FREQ
static int mmc_davinci_cpufreq_transition(struct notifier_block *nb,
unsigned long val, void *data)
{
struct mmc_davinci_host *host;
unsigned int mmc_pclk;
struct mmc_host *mmc;
unsigned long flags;
host = container_of(nb, struct mmc_davinci_host, freq_transition);
mmc = host->mmc;
mmc_pclk = clk_get_rate(host->clk);
if (val == CPUFREQ_POSTCHANGE) {
spin_lock_irqsave(&mmc->lock, flags);
host->mmc_input_clk = mmc_pclk;
calculate_clk_divider(mmc, &mmc->ios);
spin_unlock_irqrestore(&mmc->lock, flags);
}
return 0;
}
static inline int mmc_davinci_cpufreq_register(struct mmc_davinci_host *host)
{
host->freq_transition.notifier_call = mmc_davinci_cpufreq_transition;
return cpufreq_register_notifier(&host->freq_transition,
CPUFREQ_TRANSITION_NOTIFIER);
}
static inline void mmc_davinci_cpufreq_deregister(struct mmc_davinci_host *host)
{
cpufreq_unregister_notifier(&host->freq_transition,
CPUFREQ_TRANSITION_NOTIFIER);
}
#else
static inline int mmc_davinci_cpufreq_register(struct mmc_davinci_host *host)
{
return 0;
}
static inline void mmc_davinci_cpufreq_deregister(struct mmc_davinci_host *host)
{
}
#endif
static void __init init_mmcsd_host(struct mmc_davinci_host *host)
{
/* DAT line portion is diabled and in reset state */
writel(readl(host->base + DAVINCI_MMCCTL) | MMCCTL_DATRST,
host->base + DAVINCI_MMCCTL);
/* CMD line portion is diabled and in reset state */
writel(readl(host->base + DAVINCI_MMCCTL) | MMCCTL_CMDRST,
host->base + DAVINCI_MMCCTL);
udelay(10);
writel(0, host->base + DAVINCI_MMCCLK);
writel(MMCCLK_CLKEN, host->base + DAVINCI_MMCCLK);
writel(0x1FFF, host->base + DAVINCI_MMCTOR);
writel(0xFFFF, host->base + DAVINCI_MMCTOD);
writel(readl(host->base + DAVINCI_MMCCTL) & ~MMCCTL_DATRST,
host->base + DAVINCI_MMCCTL);
writel(readl(host->base + DAVINCI_MMCCTL) & ~MMCCTL_CMDRST,
host->base + DAVINCI_MMCCTL);
udelay(10);
}
static int __init davinci_mmcsd_probe(struct platform_device *pdev)
{
struct davinci_mmc_config *pdata = pdev->dev.platform_data;
struct mmc_davinci_host *host = NULL;
struct mmc_host *mmc = NULL;
struct resource *r, *mem = NULL;
int ret = 0, irq = 0;
size_t mem_size;
/* REVISIT: when we're fully converted, fail if pdata is NULL */
ret = -ENODEV;
r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
irq = platform_get_irq(pdev, 0);
if (!r || irq == NO_IRQ)
goto out;
ret = -EBUSY;
mem_size = resource_size(r);
mem = request_mem_region(r->start, mem_size, pdev->name);
if (!mem)
goto out;
ret = -ENOMEM;
mmc = mmc_alloc_host(sizeof(struct mmc_davinci_host), &pdev->dev);
if (!mmc)
goto out;
host = mmc_priv(mmc);
host->mmc = mmc; /* Important */
r = platform_get_resource(pdev, IORESOURCE_DMA, 0);
if (!r)
goto out;
host->rxdma = r->start;
r = platform_get_resource(pdev, IORESOURCE_DMA, 1);
if (!r)
goto out;
host->txdma = r->start;
host->mem_res = mem;
host->base = ioremap(mem->start, mem_size);
if (!host->base)
goto out;
ret = -ENXIO;
host->clk = clk_get(&pdev->dev, "MMCSDCLK");
if (IS_ERR(host->clk)) {
ret = PTR_ERR(host->clk);
goto out;
}
clk_enable(host->clk);
host->mmc_input_clk = clk_get_rate(host->clk);
init_mmcsd_host(host);
if (pdata->nr_sg)
host->nr_sg = pdata->nr_sg - 1;
if (host->nr_sg > MAX_NR_SG || !host->nr_sg)
host->nr_sg = MAX_NR_SG;
host->use_dma = use_dma;
host->irq = irq;
if (host->use_dma && davinci_acquire_dma_channels(host) != 0)
host->use_dma = 0;
/* REVISIT: someday, support IRQ-driven card detection. */
mmc->caps |= MMC_CAP_NEEDS_POLL;
mmc->caps |= MMC_CAP_WAIT_WHILE_BUSY;
if (pdata && (pdata->wires == 4 || pdata->wires == 0))
mmc->caps |= MMC_CAP_4_BIT_DATA;
if (pdata && (pdata->wires == 8))
mmc->caps |= (MMC_CAP_4_BIT_DATA | MMC_CAP_8_BIT_DATA);
host->version = pdata->version;
mmc->ops = &mmc_davinci_ops;
mmc->f_min = 312500;
mmc->f_max = 25000000;
if (pdata && pdata->max_freq)
mmc->f_max = pdata->max_freq;
if (pdata && pdata->caps)
mmc->caps |= pdata->caps;
mmc->ocr_avail = MMC_VDD_32_33 | MMC_VDD_33_34;
/* With no iommu coalescing pages, each phys_seg is a hw_seg.
* Each hw_seg uses one EDMA parameter RAM slot, always one
* channel and then usually some linked slots.
*/
mmc->max_hw_segs = 1 + host->n_link;
mmc->max_phys_segs = mmc->max_hw_segs;
/* EDMA limit per hw segment (one or two MBytes) */
mmc->max_seg_size = MAX_CCNT * rw_threshold;
/* MMC/SD controller limits for multiblock requests */
mmc->max_blk_size = 4095; /* BLEN is 12 bits */
mmc->max_blk_count = 65535; /* NBLK is 16 bits */
mmc->max_req_size = mmc->max_blk_size * mmc->max_blk_count;
dev_dbg(mmc_dev(host->mmc), "max_phys_segs=%d\n", mmc->max_phys_segs);
dev_dbg(mmc_dev(host->mmc), "max_hw_segs=%d\n", mmc->max_hw_segs);
dev_dbg(mmc_dev(host->mmc), "max_blk_size=%d\n", mmc->max_blk_size);
dev_dbg(mmc_dev(host->mmc), "max_req_size=%d\n", mmc->max_req_size);
dev_dbg(mmc_dev(host->mmc), "max_seg_size=%d\n", mmc->max_seg_size);
platform_set_drvdata(pdev, host);
ret = mmc_davinci_cpufreq_register(host);
if (ret) {
dev_err(&pdev->dev, "failed to register cpufreq\n");
goto cpu_freq_fail;
}
ret = mmc_add_host(mmc);
if (ret < 0)
goto out;
ret = request_irq(irq, mmc_davinci_irq, 0, mmc_hostname(mmc), host);
if (ret)
goto out;
rename_region(mem, mmc_hostname(mmc));
dev_info(mmc_dev(host->mmc), "Using %s, %d-bit mode\n",
host->use_dma ? "DMA" : "PIO",
(mmc->caps & MMC_CAP_4_BIT_DATA) ? 4 : 1);
return 0;
out:
mmc_davinci_cpufreq_deregister(host);
cpu_freq_fail:
if (host) {
davinci_release_dma_channels(host);
if (host->clk) {
clk_disable(host->clk);
clk_put(host->clk);
}
if (host->base)
iounmap(host->base);
}
if (mmc)
mmc_free_host(mmc);
if (mem)
release_resource(mem);
dev_dbg(&pdev->dev, "probe err %d\n", ret);
return ret;
}
static int __exit davinci_mmcsd_remove(struct platform_device *pdev)
{
struct mmc_davinci_host *host = platform_get_drvdata(pdev);
platform_set_drvdata(pdev, NULL);
if (host) {
mmc_davinci_cpufreq_deregister(host);
mmc_remove_host(host->mmc);
free_irq(host->irq, host);
davinci_release_dma_channels(host);
clk_disable(host->clk);
clk_put(host->clk);
iounmap(host->base);
release_resource(host->mem_res);
mmc_free_host(host->mmc);
}
return 0;
}
#ifdef CONFIG_PM
static int davinci_mmcsd_suspend(struct platform_device *pdev, pm_message_t msg)
{
struct mmc_davinci_host *host = platform_get_drvdata(pdev);
return mmc_suspend_host(host->mmc, msg);
}
static int davinci_mmcsd_resume(struct platform_device *pdev)
{
struct mmc_davinci_host *host = platform_get_drvdata(pdev);
return mmc_resume_host(host->mmc);
}
#else
#define davinci_mmcsd_suspend NULL
#define davinci_mmcsd_resume NULL
#endif
static struct platform_driver davinci_mmcsd_driver = {
.driver = {
.name = "davinci_mmc",
.owner = THIS_MODULE,
},
.remove = __exit_p(davinci_mmcsd_remove),
.suspend = davinci_mmcsd_suspend,
.resume = davinci_mmcsd_resume,
};
static int __init davinci_mmcsd_init(void)
{
return platform_driver_probe(&davinci_mmcsd_driver,
davinci_mmcsd_probe);
}
module_init(davinci_mmcsd_init);
static void __exit davinci_mmcsd_exit(void)
{
platform_driver_unregister(&davinci_mmcsd_driver);
}
module_exit(davinci_mmcsd_exit);
MODULE_AUTHOR("Texas Instruments India");
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("MMC/SD driver for Davinci MMC controller");