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linux/drivers/mmc/host/tmio_mmc_dma.c
Guennadi Liakhovetski e6ee7182c3 mmc: Add runtime and system-wide PM to the TMIO MMC driver 
Add runtime and system-wide power management to the TMIO MMC driver
in PIO and DMA modes, allowing it to properly save and restore its
state during system suspend. Runtime PM is very crude ATM, because
the controller has to be powered on all the time to detect card
hotplug events.

Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Signed-off-by: Chris Ball <cjb@laptop.org>
2011-05-24 23:53:51 -04:00

321 lines
7.7 KiB
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/*
* linux/drivers/mmc/tmio_mmc_dma.c
*
* Copyright (C) 2010-2011 Guennadi Liakhovetski
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
* DMA function for TMIO MMC implementations
*/
#include <linux/device.h>
#include <linux/dmaengine.h>
#include <linux/mfd/tmio.h>
#include <linux/mmc/host.h>
#include <linux/mmc/tmio.h>
#include <linux/pagemap.h>
#include <linux/scatterlist.h>
#include "tmio_mmc.h"
#define TMIO_MMC_MIN_DMA_LEN 8
static void tmio_mmc_enable_dma(struct tmio_mmc_host *host, bool enable)
{
#if defined(CONFIG_SUPERH) || defined(CONFIG_ARCH_SHMOBILE)
/* Switch DMA mode on or off - SuperH specific? */
writew(enable ? 2 : 0, host->ctl + (0xd8 << host->bus_shift));
#endif
}
static void tmio_mmc_start_dma_rx(struct tmio_mmc_host *host)
{
struct scatterlist *sg = host->sg_ptr, *sg_tmp;
struct dma_async_tx_descriptor *desc = NULL;
struct dma_chan *chan = host->chan_rx;
struct tmio_mmc_data *pdata = host->pdata;
dma_cookie_t cookie;
int ret, i;
bool aligned = true, multiple = true;
unsigned int align = (1 << pdata->dma->alignment_shift) - 1;
for_each_sg(sg, sg_tmp, host->sg_len, i) {
if (sg_tmp->offset & align)
aligned = false;
if (sg_tmp->length & align) {
multiple = false;
break;
}
}
if ((!aligned && (host->sg_len > 1 || sg->length > PAGE_CACHE_SIZE ||
(align & PAGE_MASK))) || !multiple) {
ret = -EINVAL;
goto pio;
}
if (sg->length < TMIO_MMC_MIN_DMA_LEN) {
host->force_pio = true;
return;
}
tmio_mmc_disable_mmc_irqs(host, TMIO_STAT_RXRDY);
/* The only sg element can be unaligned, use our bounce buffer then */
if (!aligned) {
sg_init_one(&host->bounce_sg, host->bounce_buf, sg->length);
host->sg_ptr = &host->bounce_sg;
sg = host->sg_ptr;
}
ret = dma_map_sg(chan->device->dev, sg, host->sg_len, DMA_FROM_DEVICE);
if (ret > 0)
desc = chan->device->device_prep_slave_sg(chan, sg, ret,
DMA_FROM_DEVICE, DMA_CTRL_ACK);
if (desc) {
cookie = dmaengine_submit(desc);
if (cookie < 0) {
desc = NULL;
ret = cookie;
}
}
dev_dbg(&host->pdev->dev, "%s(): mapped %d -> %d, cookie %d, rq %p\n",
__func__, host->sg_len, ret, cookie, host->mrq);
pio:
if (!desc) {
/* DMA failed, fall back to PIO */
if (ret >= 0)
ret = -EIO;
host->chan_rx = NULL;
dma_release_channel(chan);
/* Free the Tx channel too */
chan = host->chan_tx;
if (chan) {
host->chan_tx = NULL;
dma_release_channel(chan);
}
dev_warn(&host->pdev->dev,
"DMA failed: %d, falling back to PIO\n", ret);
tmio_mmc_enable_dma(host, false);
}
dev_dbg(&host->pdev->dev, "%s(): desc %p, cookie %d, sg[%d]\n", __func__,
desc, cookie, host->sg_len);
}
static void tmio_mmc_start_dma_tx(struct tmio_mmc_host *host)
{
struct scatterlist *sg = host->sg_ptr, *sg_tmp;
struct dma_async_tx_descriptor *desc = NULL;
struct dma_chan *chan = host->chan_tx;
struct tmio_mmc_data *pdata = host->pdata;
dma_cookie_t cookie;
int ret, i;
bool aligned = true, multiple = true;
unsigned int align = (1 << pdata->dma->alignment_shift) - 1;
for_each_sg(sg, sg_tmp, host->sg_len, i) {
if (sg_tmp->offset & align)
aligned = false;
if (sg_tmp->length & align) {
multiple = false;
break;
}
}
if ((!aligned && (host->sg_len > 1 || sg->length > PAGE_CACHE_SIZE ||
(align & PAGE_MASK))) || !multiple) {
ret = -EINVAL;
goto pio;
}
if (sg->length < TMIO_MMC_MIN_DMA_LEN) {
host->force_pio = true;
return;
}
tmio_mmc_disable_mmc_irqs(host, TMIO_STAT_TXRQ);
/* The only sg element can be unaligned, use our bounce buffer then */
if (!aligned) {
unsigned long flags;
void *sg_vaddr = tmio_mmc_kmap_atomic(sg, &flags);
sg_init_one(&host->bounce_sg, host->bounce_buf, sg->length);
memcpy(host->bounce_buf, sg_vaddr, host->bounce_sg.length);
tmio_mmc_kunmap_atomic(sg, &flags, sg_vaddr);
host->sg_ptr = &host->bounce_sg;
sg = host->sg_ptr;
}
ret = dma_map_sg(chan->device->dev, sg, host->sg_len, DMA_TO_DEVICE);
if (ret > 0)
desc = chan->device->device_prep_slave_sg(chan, sg, ret,
DMA_TO_DEVICE, DMA_CTRL_ACK);
if (desc) {
cookie = dmaengine_submit(desc);
if (cookie < 0) {
desc = NULL;
ret = cookie;
}
}
dev_dbg(&host->pdev->dev, "%s(): mapped %d -> %d, cookie %d, rq %p\n",
__func__, host->sg_len, ret, cookie, host->mrq);
pio:
if (!desc) {
/* DMA failed, fall back to PIO */
if (ret >= 0)
ret = -EIO;
host->chan_tx = NULL;
dma_release_channel(chan);
/* Free the Rx channel too */
chan = host->chan_rx;
if (chan) {
host->chan_rx = NULL;
dma_release_channel(chan);
}
dev_warn(&host->pdev->dev,
"DMA failed: %d, falling back to PIO\n", ret);
tmio_mmc_enable_dma(host, false);
}
dev_dbg(&host->pdev->dev, "%s(): desc %p, cookie %d\n", __func__,
desc, cookie);
}
void tmio_mmc_start_dma(struct tmio_mmc_host *host,
struct mmc_data *data)
{
if (data->flags & MMC_DATA_READ) {
if (host->chan_rx)
tmio_mmc_start_dma_rx(host);
} else {
if (host->chan_tx)
tmio_mmc_start_dma_tx(host);
}
}
static void tmio_mmc_issue_tasklet_fn(unsigned long priv)
{
struct tmio_mmc_host *host = (struct tmio_mmc_host *)priv;
struct dma_chan *chan = NULL;
spin_lock_irq(&host->lock);
if (host && host->data) {
if (host->data->flags & MMC_DATA_READ)
chan = host->chan_rx;
else
chan = host->chan_tx;
}
spin_unlock_irq(&host->lock);
tmio_mmc_enable_mmc_irqs(host, TMIO_STAT_DATAEND);
if (chan)
dma_async_issue_pending(chan);
}
static void tmio_mmc_tasklet_fn(unsigned long arg)
{
struct tmio_mmc_host *host = (struct tmio_mmc_host *)arg;
spin_lock_irq(&host->lock);
if (!host->data)
goto out;
if (host->data->flags & MMC_DATA_READ)
dma_unmap_sg(host->chan_rx->device->dev,
host->sg_ptr, host->sg_len,
DMA_FROM_DEVICE);
else
dma_unmap_sg(host->chan_tx->device->dev,
host->sg_ptr, host->sg_len,
DMA_TO_DEVICE);
tmio_mmc_do_data_irq(host);
out:
spin_unlock_irq(&host->lock);
}
/* It might be necessary to make filter MFD specific */
static bool tmio_mmc_filter(struct dma_chan *chan, void *arg)
{
dev_dbg(chan->device->dev, "%s: slave data %p\n", __func__, arg);
chan->private = arg;
return true;
}
void tmio_mmc_request_dma(struct tmio_mmc_host *host, struct tmio_mmc_data *pdata)
{
/* We can only either use DMA for both Tx and Rx or not use it at all */
if (!pdata->dma)
return;
if (!host->chan_tx && !host->chan_rx) {
dma_cap_mask_t mask;
dma_cap_zero(mask);
dma_cap_set(DMA_SLAVE, mask);
host->chan_tx = dma_request_channel(mask, tmio_mmc_filter,
pdata->dma->chan_priv_tx);
dev_dbg(&host->pdev->dev, "%s: TX: got channel %p\n", __func__,
host->chan_tx);
if (!host->chan_tx)
return;
host->chan_rx = dma_request_channel(mask, tmio_mmc_filter,
pdata->dma->chan_priv_rx);
dev_dbg(&host->pdev->dev, "%s: RX: got channel %p\n", __func__,
host->chan_rx);
if (!host->chan_rx)
goto ereqrx;
host->bounce_buf = (u8 *)__get_free_page(GFP_KERNEL | GFP_DMA);
if (!host->bounce_buf)
goto ebouncebuf;
tasklet_init(&host->dma_complete, tmio_mmc_tasklet_fn, (unsigned long)host);
tasklet_init(&host->dma_issue, tmio_mmc_issue_tasklet_fn, (unsigned long)host);
}
tmio_mmc_enable_dma(host, true);
return;
ebouncebuf:
dma_release_channel(host->chan_rx);
host->chan_rx = NULL;
ereqrx:
dma_release_channel(host->chan_tx);
host->chan_tx = NULL;
}
void tmio_mmc_release_dma(struct tmio_mmc_host *host)
{
if (host->chan_tx) {
struct dma_chan *chan = host->chan_tx;
host->chan_tx = NULL;
dma_release_channel(chan);
}
if (host->chan_rx) {
struct dma_chan *chan = host->chan_rx;
host->chan_rx = NULL;
dma_release_channel(chan);
}
if (host->bounce_buf) {
free_pages((unsigned long)host->bounce_buf, 0);
host->bounce_buf = NULL;
}
}
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