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Message-Id: <1350615088-14562-4-git-send-email-mporter@ti.com>
Date: Thu, 18 Oct 2012 22:51:28 -0400
From: Matt Porter <mporter@...com>
To: Vinod Koul <vinod.koul@...el.com>
Cc: Dan Williams <djbw@...com>, Chris Ball <cjb@...top.org>,
Linux DaVinci Kernel List
<davinci-linux-open-source@...ux.davincidsp.com>,
Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
Linux MMC List <linux-mmc@...r.kernel.org>
Subject: [RFC PATCH 3/3] mmc: davinci: get SG segment limits with dma_get_channel_caps()
Replace the hardcoded values used to set max_segs/max_seg_size with
a dma_get_channel_caps() query to the dmaengine driver.
Signed-off-by: Matt Porter <mporter@...com>
---
drivers/mmc/host/davinci_mmc.c | 66 +++++++++--------------------
include/linux/platform_data/mmc-davinci.h | 3 --
2 files changed, 21 insertions(+), 48 deletions(-)
diff --git a/drivers/mmc/host/davinci_mmc.c b/drivers/mmc/host/davinci_mmc.c
index f5d46ea..d1efacc 100644
--- a/drivers/mmc/host/davinci_mmc.c
+++ b/drivers/mmc/host/davinci_mmc.c
@@ -145,18 +145,6 @@
/* 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_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,
@@ -217,8 +205,6 @@ struct mmc_davinci_host {
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
@@ -422,16 +408,7 @@ static int mmc_davinci_send_dma_request(struct mmc_davinci_host *host,
int ret = 0;
if (host->data_dir == DAVINCI_MMC_DATADIR_WRITE) {
- 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,
@@ -444,16 +421,7 @@ static int mmc_davinci_send_dma_request(struct mmc_davinci_host *host,
goto out;
}
} else {
- 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,
@@ -1166,6 +1134,7 @@ static int __init davinci_mmcsd_probe(struct platform_device *pdev)
struct resource *r, *mem = NULL;
int ret = 0, irq = 0;
size_t mem_size;
+ struct dmaengine_chan_caps *dma_chan_caps;
/* REVISIT: when we're fully converted, fail if pdata is NULL */
@@ -1215,12 +1184,6 @@ static int __init davinci_mmcsd_probe(struct platform_device *pdev)
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->mmc_irq = irq;
host->sdio_irq = platform_get_irq(pdev, 1);
@@ -1249,14 +1212,27 @@ static int __init davinci_mmcsd_probe(struct platform_device *pdev)
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_segs = MAX_NR_SG;
+ {
+ struct dma_slave_config dma_txrx_conf = {
+ .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,
+ .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,
+ };
+ dmaengine_slave_config(host->dma_tx, &dma_txrx_conf);
+ dmaengine_slave_config(host->dma_rx, &dma_txrx_conf);
+ }
- /* EDMA limit per hw segment (one or two MBytes) */
- mmc->max_seg_size = MAX_CCNT * rw_threshold;
+ /* Just check one channel for the DMA SG limits */
+ dma_chan_caps = dma_get_channel_caps(host->dma_tx, DMA_MEM_TO_DEV);
+ if (dma_chan_caps) {
+ mmc->max_segs = dma_chan_caps->seg_nr;
+ mmc->max_seg_size = dma_chan_caps->seg_len;
+ }
/* MMC/SD controller limits for multiblock requests */
mmc->max_blk_size = 4095; /* BLEN is 12 bits */
diff --git a/include/linux/platform_data/mmc-davinci.h b/include/linux/platform_data/mmc-davinci.h
index 5ba6b22..6910209 100644
--- a/include/linux/platform_data/mmc-davinci.h
+++ b/include/linux/platform_data/mmc-davinci.h
@@ -25,9 +25,6 @@ struct davinci_mmc_config {
/* Version of the MMC/SD controller */
u8 version;
-
- /* Number of sg segments */
- u8 nr_sg;
};
void davinci_setup_mmc(int module, struct davinci_mmc_config *config);
--
1.7.9.5
--
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