From b6147490e6aac82fa2f4b9d7fce925d9891ebe8f Mon Sep 17 00:00:00 2001 From: Guennadi Liakhovetski Date: Wed, 23 Mar 2011 12:42:44 +0100 Subject: mmc: tmio: split core functionality, DMA and MFD glue TMIO MMC chips contain an SD / SDIO IP core from Panasonic, similar to the one, used in MN5774 and other MN57xx controllers. These IP cores are included in many multifunction devices, in sh-mobile chips from Renesas, in the latter case they can also use DMA. Some sh-mobile implementations also have some other specialities, that MFD-based solutions don't have. This makes supporting all these features in a monolithic driver inconveniet and error-prone. This patch splits the driver into 3 parts: the core, the MFD glue and the DMA support. In case of a modular build, two modules will be built: mmc_tmio_core and mmc_tmio. Signed-off-by: Guennadi Liakhovetski Acked-by: Paul Mundt Signed-off-by: Chris Ball --- drivers/mmc/host/tmio_mmc_dma.c | 316 ++++++++++++++++++++++++++++++++++++++++ 1 file changed, 316 insertions(+) create mode 100644 drivers/mmc/host/tmio_mmc_dma.c (limited to 'drivers/mmc/host/tmio_mmc_dma.c') diff --git a/drivers/mmc/host/tmio_mmc_dma.c b/drivers/mmc/host/tmio_mmc_dma.c new file mode 100644 index 000000000000..c505278be43f --- /dev/null +++ b/drivers/mmc/host/tmio_mmc_dma.c @@ -0,0 +1,316 @@ +/* + * 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 +#include +#include +#include +#include +#include + +#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) { + 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; + return; + } +} + +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; + } +} -- cgit v1.2.3