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Message-ID: <k139rl$gbm$2@ger.gmane.org>
Date: Wed, 22 Aug 2012 20:53:43 +0200
From: Koen Kooi <koen@...inion.thruhere.net>
To: linux-kernel@...r.kernel.org
Cc: spi-devel-general@...ts.sourceforge.net, linux-mmc@...r.kernel.org,
linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org
Subject: Re: [PATCH v2 2/3] mmc: davinci_mmc: convert to DMA engine API
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Op 21-08-12 20:43, Matt Porter schreef:
> Removes use of the DaVinci EDMA private DMA API and replaces it with use
> of the DMA engine API.
>
> Signed-off-by: Matt Porter <mporter@...com>
Runtime tested on hawkboard with 3.6.0-rc2 with rootfs on SD and running
bonnie++ on it.
Tested-by: Koen Kooi <koen@...inion.thruhere.net>
> --- drivers/mmc/host/davinci_mmc.c | 271
> ++++++++++++---------------------------- 1 file changed, 82
> insertions(+), 189 deletions(-)
>
> diff --git a/drivers/mmc/host/davinci_mmc.c
> b/drivers/mmc/host/davinci_mmc.c index 7cf6c62..c5e1eeb 100644 ---
> a/drivers/mmc/host/davinci_mmc.c +++ b/drivers/mmc/host/davinci_mmc.c @@
> -30,11 +30,12 @@ #include <linux/io.h> #include <linux/irq.h> #include
> <linux/delay.h> +#include <linux/dmaengine.h> #include
> <linux/dma-mapping.h> +#include <linux/edma.h> #include
> <linux/mmc/mmc.h>
>
> #include <mach/mmc.h> -#include <mach/edma.h>
>
> /* * Register Definitions @@ -200,21 +201,13 @@ struct mmc_davinci_host
> { u32 bytes_left;
>
> u32 rxdma, txdma; + struct dma_chan *dma_tx; + struct dma_chan *dma_rx;
> bool use_dma; bool do_dma; bool sdio_int; bool active_request;
>
> - /* 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; @@ -410,153
> +403,74 @@ static void mmc_davinci_start_command(struct mmc_davinci_host
> *host,
>
> static void davinci_abort_dma(struct mmc_davinci_host *host) { - int
> sync_dev; + struct dma_chan *sync_dev;
>
> if (host->data_dir == DAVINCI_MMC_DATADIR_READ) - sync_dev =
> host->rxdma; + sync_dev = host->dma_rx; 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); + sync_dev =
> host->dma_tx;
>
> - 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; +
> dmaengine_terminate_all(sync_dev); }
>
> -static void mmc_davinci_send_dma_request(struct mmc_davinci_host *host,
> +static int 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; + struct dma_chan *chan; + struct
> dma_async_tx_descriptor *desc; + int ret = 0;
>
> if (host->data_dir == DAVINCI_MMC_DATADIR_WRITE) { - template =
> &host->tx_template; - channel = host->txdma; + struct dma_slave_config
> dma_tx_conf = { + .direction = DMA_MEM_TO_DEV, + .dst_addr =
> host->mem_res->start + DAVINCI_MMCDXR, + .dst_addr_width =
> DMA_SLAVE_BUSWIDTH_4_BYTES, + .dst_maxburst = + rw_threshold /
> DMA_SLAVE_BUSWIDTH_4_BYTES, + }; + chan = host->dma_tx; +
> dmaengine_slave_config(host->dma_tx, &dma_tx_conf); + + desc =
> dmaengine_prep_slave_sg(host->dma_tx, + data->sg, + host->sg_len, +
> DMA_MEM_TO_DEV, + DMA_PREP_INTERRUPT | DMA_CTRL_ACK); + if (!desc) {
> + dev_dbg(mmc_dev(host->mmc), + "failed to allocate DMA TX
> descriptor"); + ret = -1; + goto out; + } } 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); + struct dma_slave_config dma_rx_conf =
> { + .direction = DMA_DEV_TO_MEM, + .src_addr = host->mem_res->start +
> DAVINCI_MMCDRR, + .src_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES, +
> .src_maxburst = + rw_threshold / DMA_SLAVE_BUSWIDTH_4_BYTES, + }; +
> chan = host->dma_rx; + dmaengine_slave_config(host->dma_rx,
> &dma_rx_conf); + + desc = dmaengine_prep_slave_sg(host->dma_rx, +
> data->sg, + host->sg_len, + DMA_DEV_TO_MEM, + DMA_PREP_INTERRUPT
> | DMA_CTRL_ACK); + if (!desc) { + dev_dbg(mmc_dev(host->mmc), +
> "failed to allocate DMA RX descriptor"); + ret = -1; + goto out; +
> } }
>
> - if (host->version == MMC_CTLR_VERSION_2) - edma_clear_event(channel);
> + dmaengine_submit(desc); + dma_async_issue_pending(chan);
>
> - edma_start(channel); +out: + return ret; }
>
> static int mmc_davinci_start_dma_transfer(struct mmc_davinci_host *host,
> @@ -564,6 +478,7 @@ static int mmc_davinci_start_dma_transfer(struct
> mmc_davinci_host *host, { int i; int mask = rw_threshold - 1; + int ret =
> 0;
>
> host->sg_len = dma_map_sg(mmc_dev(host->mmc), data->sg, data->sg_len,
> ((data->flags & MMC_DATA_WRITE) @@ -583,70 +498,48 @@ static int
> mmc_davinci_start_dma_transfer(struct mmc_davinci_host *host, }
>
> host->do_dma = 1; - mmc_davinci_send_dma_request(host, data); + ret =
> mmc_davinci_send_dma_request(host, data);
>
> - return 0; + return ret; }
>
> 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); +
> dma_release_channel(host->dma_tx); + dma_release_channel(host->dma_rx);
> }
>
> 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; + int r; + dma_cap_mask_t mask; + +
> dma_cap_zero(mask); + dma_cap_set(DMA_SLAVE, mask); + + host->dma_tx = +
> dma_request_channel(mask, edma_filter_fn, &host->txdma); + if
> (!host->dma_tx) { + dev_err(mmc_dev(host->mmc), "Can't get dma_tx
> channel\n"); + return -ENODEV; } - 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->dma_rx = + dma_request_channel(mask, edma_filter_fn,
> &host->rxdma); + if (!host->dma_rx) { + dev_err(mmc_dev(host->mmc),
> "Can't get dma_rx channel\n"); + r = -ENODEV; + goto
> free_master_write; } - host->n_link = i;
>
> return 0;
>
> free_master_write: - edma_free_channel(host->txdma); +
> dma_release_channel(host->dma_tx);
>
> return r; } @@ -1359,7 +1252,7 @@ static int __init
> davinci_mmcsd_probe(struct platform_device *pdev) * Each hw_seg uses one
> EDMA parameter RAM slot, always one * channel and then usually some
> linked slots. */ - mmc->max_segs = 1 + host->n_link; + mmc->max_segs =
> MAX_NR_SG;
>
> /* EDMA limit per hw segment (one or two MBytes) */ mmc->max_seg_size =
> MAX_CCNT * rw_threshold;
>
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