[PATCH 04/22] mmc: omap hsmmc: adaptation of sdma descriptor

From: Adrian Hunter <adrian.hunter@nokia.com>
Cc: Madhusudhan Chikkature <madhu.cr@ti.com>,
	linux-omap Mailing List <linux-omap@vger.kernel.org>,
	linux-mmc Mailing List <linux-mmc@vger.kernel.org>,
	linux-arm Mailing List <linux-arm-kernel@lists.infradead.org>,
	Venkatraman S <svenkatr@ti.com>,
	Shilimkar Santosh <santosh.shilimkar@ti.com>,
	Tony Lindgren <tony@atomide.com>,
	Adrian Hunter <adrian.hunter@nokia.com>
Subject: [PATCH 04/22] mmc: omap hsmmc: adaptation of sdma descriptor
Date: Thu,  5 May 2011 14:51:04 +0300	[thread overview]
Message-ID: <1304596282-4095-5-git-send-email-adrian.hunter@nokia.com> (raw)
In-Reply-To: <1304596282-4095-1-git-send-email-adrian.hunter@nokia.com>

From: Venkatraman S <svenkatr@ti.com>

autoloading feature

Start to use the sDMA descriptor autoloading feature.
For large datablocks, the MMC driver has to repeatedly setup,
program and teardown the dma channel for each element of the
sglist received in omap_hsmmc_request.

By using descriptor autoloading, transfers from / to each element of
the sglist is pre programmed into a linked list. The sDMA driver
completes the entire transaction and provides a single interrupt.

Due to this, number of dma interrupts for a typical 100MB transfer on the MMC is
reduced from 25000 to about 400 (approximate). Transfer speeds are improved by ~5%.
(Though it varies on the size of read / write & improves on huge transfers)

Descriptor autoloading is available only in 3630 and 4430 (as of now).
Hence normal DMA mode is also retained.

Signed-off-by: Venkatraman S <svenkatr@ti.com>
CC: Madhusudhan C <madhu.cr@ti.com>
CC: Shilimkar Santosh <santosh.shilimkar@ti.com>
CC: Tony Lindgren <tony@atomide.com>
Signed-off-by: Adrian Hunter <adrian.hunter@nokia.com>
---
 drivers/mmc/host/omap_hsmmc.c |  147 ++++++++++++++++++++++++++++++++++------
 1 files changed, 125 insertions(+), 22 deletions(-)

diff --git a/drivers/mmc/host/omap_hsmmc.c b/drivers/mmc/host/omap_hsmmc.c
index 259ece0..ebcef31 100644
--- a/drivers/mmc/host/omap_hsmmc.c
+++ b/drivers/mmc/host/omap_hsmmc.c
@@ -104,6 +104,8 @@
 #define SRD			(1 << 26)
 #define SOFTRESET		(1 << 1)
 #define RESETDONE		(1 << 0)
+/* End of superblock indicator for sglist transfers */
+#define DMA_ICR_SGLIST_END	0x4D00
 
 /*
  * FIXME: Most likely all the data using these _DEVID defines should come
@@ -120,6 +122,12 @@
 #define OMAP_MMC_MASTER_CLOCK	96000000
 #define DRIVER_NAME		"omap_hsmmc"
 
+#define DMA_TYPE_NODMA	0
+#define DMA_TYPE_SDMA	1
+#define DMA_TYPE_SDMA_DLOAD 2
+
+#define DMA_CTRL_BUF_SIZE	(PAGE_SIZE * 3)
+
 /* Timeouts for entering power saving states on inactivity, msec */
 #define OMAP_MMC_DISABLED_TIMEOUT	100
 #define OMAP_MMC_SLEEP_TIMEOUT		1000
@@ -172,7 +180,11 @@ struct omap_hsmmc_host {
 	u32			bytesleft;
 	int			suspended;
 	int			irq;
-	int			use_dma, dma_ch;
+	int			dma_caps;
+	int			dma_in_use;
+	int			dma_ch;
+	void			*dma_ctrl_buf;
+	dma_addr_t		dma_ctrl_buf_phy;
 	int			dma_line_tx, dma_line_rx;
 	int			slot_id;
 	int			got_dbclk;
@@ -561,7 +573,7 @@ static void omap_hsmmc_enable_irq(struct omap_hsmmc_host *host,
 {
 	unsigned int irq_mask;
 
-	if (host->use_dma)
+	if (host->dma_in_use)
 		irq_mask = INT_EN_MASK & ~(BRR_ENABLE | BWR_ENABLE);
 	else
 		irq_mask = INT_EN_MASK;
@@ -851,7 +863,7 @@ omap_hsmmc_start_command(struct omap_hsmmc_host *host, struct mmc_command *cmd,
 			cmdreg &= ~(DDIR);
 	}
 
-	if (host->use_dma)
+	if (host->dma_in_use)
 		cmdreg |= DMA_EN;
 
 	host->req_in_progress = 1;
@@ -880,7 +892,7 @@ static void omap_hsmmc_request_done(struct omap_hsmmc_host *host, struct mmc_req
 
 	omap_hsmmc_disable_irq(host);
 	/* Do not complete the request if DMA is still in progress */
-	if (mrq->data && host->use_dma && dma_ch != -1)
+	if (mrq->data && host->dma_in_use && dma_ch != -1)
 		return;
 	host->mrq = NULL;
 	mmc_request_done(host->mmc, mrq);
@@ -958,7 +970,7 @@ static void omap_hsmmc_dma_cleanup(struct omap_hsmmc_host *host, int errno)
 	host->dma_ch = -1;
 	spin_unlock(&host->irq_lock);
 
-	if (host->use_dma && dma_ch != -1) {
+	if (host->dma_in_use && dma_ch != -1) {
 		dma_unmap_sg(mmc_dev(host->mmc), host->data->sg, host->dma_len,
 			omap_hsmmc_get_dma_dir(host, host->data));
 		omap_free_dma(dma_ch);
@@ -1310,7 +1322,6 @@ static void omap_hsmmc_config_dma_params(struct omap_hsmmc_host *host,
 			omap_hsmmc_get_dma_sync_dev(host, data),
 			!(data->flags & MMC_DATA_WRITE));
 
-	omap_start_dma(dma_ch);
 }
 
 /*
@@ -1334,13 +1345,16 @@ static void omap_hsmmc_dma_cb(int lch, u16 ch_status, void *cb_data)
 		return;
 	}
 
-	host->dma_sg_idx++;
-	if (host->dma_sg_idx < host->dma_len) {
-		/* Fire up the next transfer. */
-		omap_hsmmc_config_dma_params(host, data,
-					   data->sg + host->dma_sg_idx);
-		spin_unlock(&host->irq_lock);
-		return;
+	if (host->dma_in_use == DMA_TYPE_SDMA) {
+		host->dma_sg_idx++;
+		if (host->dma_sg_idx < host->dma_len) {
+			/* Fire up the next transfer. */
+			omap_hsmmc_config_dma_params(host, data,
+						   data->sg + host->dma_sg_idx);
+			omap_start_dma(host->dma_ch);
+			spin_unlock(&host->irq_lock);
+			return;
+		}
 	}
 
 	dma_unmap_sg(mmc_dev(host->mmc), data->sg, host->dma_len,
@@ -1362,10 +1376,19 @@ static void omap_hsmmc_dma_cb(int lch, u16 ch_status, void *cb_data)
 	}
 }
 
+static int omap_hsmmc_start_dma_transfer(struct omap_hsmmc_host *host)
+{
+	if (host->dma_in_use == DMA_TYPE_SDMA)
+		omap_start_dma(host->dma_ch);
+	else if (host->dma_in_use == DMA_TYPE_SDMA_DLOAD)
+		return omap_start_dma_sglist_transfers(host->dma_ch, -1);
+
+	return 0;
+}
 /*
- * Routine to configure and start DMA for the MMC card
+ * Routine to configure DMA for the MMC card
  */
-static int omap_hsmmc_start_dma_transfer(struct omap_hsmmc_host *host,
+static int omap_hsmmc_configure_sdma(struct omap_hsmmc_host *host,
 					struct mmc_request *req)
 {
 	int dma_ch = 0, ret = 0, i;
@@ -1406,6 +1429,56 @@ static int omap_hsmmc_start_dma_transfer(struct omap_hsmmc_host *host,
 	return 0;
 }
 
+static int omap_hsmmc_configure_sdma_sglist(struct omap_hsmmc_host *host,
+		struct mmc_request *req)
+{
+	int i;
+	struct omap_dma_sglist_node *sglist, *snode;
+	struct mmc_data *data = req->data;
+	int blksz;
+	int dmadir = omap_hsmmc_get_dma_dir(host, data);
+	struct omap_dma_sglist_type2a_params *t2p;
+
+	sglist = (struct omap_dma_sglist_node *) host->dma_ctrl_buf;
+	snode = sglist;
+	blksz = host->data->blksz;
+
+	if ((host->dma_len * sizeof(*snode)) > DMA_CTRL_BUF_SIZE) {
+		dev_err(mmc_dev(host->mmc), "not enough sglist memory %d\n",
+			host->dma_len);
+		return -ENOMEM;
+	}
+	for (i = 0; i < host->dma_len; snode++, i++) {
+		snode->desc_type = OMAP_DMA_SGLIST_DESCRIPTOR_TYPE2a;
+		snode->num_of_elem = blksz / 4;
+		t2p = &snode->sg_node.t2a;
+
+		if (dmadir == DMA_FROM_DEVICE) {
+			t2p->src_addr = host->mapbase + OMAP_HSMMC_DATA;
+			t2p->dst_addr = sg_dma_address(data->sg + i);
+		} else {
+			t2p->dst_addr = host->mapbase + OMAP_HSMMC_DATA;
+			t2p->src_addr = sg_dma_address(data->sg + i);
+		}
+		snode->flags =
+			OMAP_DMA_LIST_DST_VALID | OMAP_DMA_LIST_SRC_VALID;
+
+		t2p->cfn_fn = sg_dma_len(data->sg + i) / host->data->blksz;
+		t2p->cicr = DMA_ICR_SGLIST_END;
+
+		t2p->dst_frame_idx_or_pkt_size = 0;
+		t2p->src_frame_idx_or_pkt_size = 0;
+		t2p->dst_elem_idx = 0;
+		t2p->src_elem_idx = 0;
+	}
+	dev_dbg(mmc_dev(host->mmc), "new sglist %x len =%d\n",
+			host->dma_ctrl_buf_phy, i);
+	omap_set_dma_sglist_mode(host->dma_ch, sglist,
+			host->dma_ctrl_buf_phy, i, NULL);
+	omap_dma_set_sglist_fastmode(host->dma_ch, 1);
+	return 0;
+}
+
 static void set_data_timeout(struct omap_hsmmc_host *host,
 			     unsigned int timeout_ns,
 			     unsigned int timeout_clks)
@@ -1467,14 +1540,23 @@ omap_hsmmc_prepare_data(struct omap_hsmmc_host *host, struct mmc_request *req)
 					| (req->data->blocks << 16));
 	set_data_timeout(host, req->data->timeout_ns, req->data->timeout_clks);
 
-	if (host->use_dma) {
-		ret = omap_hsmmc_start_dma_transfer(host, req);
-		if (ret != 0) {
-			dev_dbg(mmc_dev(host->mmc), "MMC start dma failure\n");
+	if (host->dma_caps & DMA_TYPE_SDMA) {
+		ret = omap_hsmmc_configure_sdma(host, req);
+		if (ret)
 			return ret;
-		}
+		host->dma_in_use = DMA_TYPE_SDMA;
 	}
-	return 0;
+	if ((host->dma_caps & DMA_TYPE_SDMA_DLOAD) &&
+		host->data->sg_len > 4) {
+		ret = omap_hsmmc_configure_sdma_sglist(host, req);
+		if (ret)
+			return ret;
+		host->dma_in_use = DMA_TYPE_SDMA_DLOAD;
+
+	}
+	ret = omap_hsmmc_start_dma_transfer(host);
+	return ret;
+
 }
 
 /*
@@ -2065,7 +2147,9 @@ static int __init omap_hsmmc_probe(struct platform_device *pdev)
 	host->mmc	= mmc;
 	host->pdata	= pdata;
 	host->dev	= &pdev->dev;
-	host->use_dma	= 1;
+	host->dma_caps	= DMA_TYPE_SDMA;
+	host->dma_in_use	= DMA_TYPE_NODMA;
+	host->dma_ctrl_buf = NULL;
 	host->dev->dma_mask = &pdata->dma_mask;
 	host->dma_ch	= -1;
 	host->irq	= irq;
@@ -2146,6 +2230,15 @@ static int __init omap_hsmmc_probe(struct platform_device *pdev)
 							" clk failed\n");
 	}
 
+	if (cpu_is_omap44xx() || cpu_is_omap3630()) {
+		host->dma_ctrl_buf = dma_alloc_coherent(NULL,
+					DMA_CTRL_BUF_SIZE,
+					&host->dma_ctrl_buf_phy,
+					0);
+		if (host->dma_ctrl_buf != NULL)
+			host->dma_caps |= DMA_TYPE_SDMA_DLOAD;
+	}
+
 	/* Since we do only SG emulation, we can have as many segs
 	 * as we want. */
 	mmc->max_segs = 1024;
@@ -2271,6 +2364,10 @@ err_reg:
 err_irq_cd_init:
 	free_irq(host->irq, host);
 err_irq:
+	if (host->dma_ctrl_buf)
+		dma_free_coherent(NULL, DMA_CTRL_BUF_SIZE,
+				host->dma_ctrl_buf,
+				host->dma_ctrl_buf_phy);
 	mmc_host_disable(host->mmc);
 	clk_disable(host->iclk);
 	clk_put(host->fclk);
@@ -2298,6 +2395,12 @@ static int omap_hsmmc_remove(struct platform_device *pdev)
 	if (host) {
 		mmc_host_enable(host->mmc);
 		mmc_remove_host(host->mmc);
+
+		if (host->dma_ctrl_buf != NULL) {
+			dma_free_coherent(NULL, DMA_CTRL_BUF_SIZE,
+				host->dma_ctrl_buf,
+				host->dma_ctrl_buf_phy);
+		}
 		if (host->use_reg)
 			omap_hsmmc_reg_put(host);
 		if (host->pdata->cleanup)
-- 
1.7.0.4

