mtd: nand: pxa3xx-nand: switch to dmaengine

Now pxa architecture has a dmaengine driver, remove the access to direct
dma registers in favor of the more generic dmaengine code.

This should be also applicable for mmp and orion, provided they work in
device-tree environment.

This patch also removes the previous hack which was necessary to make
the driver work in a devicetree environment.
Signed-off-by: Robert Jarzmik <robert.jarzmik@free.fr>
Reviewed-by: Ezequiel Garcia <ezequiel@vanguardiasur.com.ar>
Tested-by: Ezequiel Garcia <ezequiel@vanguardiasur.com.ar>
[Brian: fixup use of 'enum dma_transfer_direction']
Signed-off-by: Brian Norris <computersforpeace@gmail.com>

drivers/mtd/nand/pxa3xx_nand.c

@@ -15,7 +15,9 @@
 #include <linux/module.h>
 #include <linux/interrupt.h>
 #include <linux/platform_device.h>
+#include <linux/dmaengine.h>
 #include <linux/dma-mapping.h>
+#include <linux/dma/pxa-dma.h>
 #include <linux/delay.h>
 #include <linux/clk.h>
 #include <linux/mtd/mtd.h>
@@ -33,10 +35,6 @@
 #define ARCH_HAS_DMA
 #endif
 
-#ifdef ARCH_HAS_DMA
-#include <mach/dma.h>
-#endif
-
 #include <linux/platform_data/mtd-nand-pxa3xx.h>
 
 #define	CHIP_DELAY_TIMEOUT	msecs_to_jiffies(200)
@@ -201,6 +199,10 @@ struct pxa3xx_nand_info {
 	unsigned int		oob_buff_pos;
 
 	/* DMA information */
+	struct scatterlist	sg;
+	enum dma_data_direction	dma_dir;
+	struct dma_chan		*dma_chan;
+	dma_cookie_t		dma_cookie;
 	int			drcmr_dat;
 	int			drcmr_cmd;
 
@@ -208,8 +210,6 @@ struct pxa3xx_nand_info {
 	unsigned char		*oob_buff;
 	dma_addr_t 		data_buff_phys;
 	int 			data_dma_ch;
-	struct pxa_dma_desc	*data_desc;
-	dma_addr_t 		data_desc_addr;
 
 	struct pxa3xx_nand_host *host[NUM_CHIP_SELECT];
 	unsigned int		state;
@@ -492,6 +492,9 @@ static void pxa3xx_nand_stop(struct pxa3xx_nand_info *info)
 		ndcr &= ~NDCR_ND_RUN;
 		nand_writel(info, NDCR, ndcr);
 	}
+	if (info->dma_chan)
+		dmaengine_terminate_all(info->dma_chan);
+
 	/* clear status bits */
 	nand_writel(info, NDSR, NDSR_MASK);
 }
@@ -583,57 +586,61 @@ static void handle_data_pio(struct pxa3xx_nand_info *info)
 	info->data_size -= do_bytes;
 }
 
-#ifdef ARCH_HAS_DMA
-static void start_data_dma(struct pxa3xx_nand_info *info)
+static void pxa3xx_nand_data_dma_irq(void *data)
 {
-	struct pxa_dma_desc *desc = info->data_desc;
-	int dma_len = ALIGN(info->data_size + info->oob_size, 32);
+	struct pxa3xx_nand_info *info = data;
+	struct dma_tx_state state;
+	enum dma_status status;
 
-	desc->ddadr = DDADR_STOP;
-	desc->dcmd = DCMD_ENDIRQEN | DCMD_WIDTH4 | DCMD_BURST32 | dma_len;
+	status = dmaengine_tx_status(info->dma_chan, info->dma_cookie, &state);
+	if (likely(status == DMA_COMPLETE)) {
+		info->state = STATE_DMA_DONE;
+	} else {
+		dev_err(&info->pdev->dev, "DMA error on data channel\n");
+		info->retcode = ERR_DMABUSERR;
+	}
+	dma_unmap_sg(info->dma_chan->device->dev, &info->sg, 1, info->dma_dir);
+
+	nand_writel(info, NDSR, NDSR_WRDREQ | NDSR_RDDREQ);
+	enable_int(info, NDCR_INT_MASK);
+}
+
+static void start_data_dma(struct pxa3xx_nand_info *info)
+{
+	enum dma_transfer_direction direction;
+	struct dma_async_tx_descriptor *tx;
 
 	switch (info->state) {
 	case STATE_DMA_WRITING:
-		desc->dsadr = info->data_buff_phys;
-		desc->dtadr = info->mmio_phys + NDDB;
-		desc->dcmd |= DCMD_INCSRCADDR | DCMD_FLOWTRG;
+		info->dma_dir = DMA_TO_DEVICE;
+		direction = DMA_MEM_TO_DEV;
 		break;
 	case STATE_DMA_READING:
-		desc->dtadr = info->data_buff_phys;
-		desc->dsadr = info->mmio_phys + NDDB;
-		desc->dcmd |= DCMD_INCTRGADDR | DCMD_FLOWSRC;
+		info->dma_dir = DMA_FROM_DEVICE;
+		direction = DMA_DEV_TO_MEM;
 		break;
 	default:
 		dev_err(&info->pdev->dev, "%s: invalid state %d\n", __func__,
 				info->state);
 		BUG();
 	}
+	info->sg.length = info->data_size +
+		(info->oob_size ? info->spare_size + info->ecc_size : 0);
+	dma_map_sg(info->dma_chan->device->dev, &info->sg, 1, info->dma_dir);
 
-	DRCMR(info->drcmr_dat) = DRCMR_MAPVLD | info->data_dma_ch;
-	DDADR(info->data_dma_ch) = info->data_desc_addr;
-	DCSR(info->data_dma_ch) |= DCSR_RUN;
-}
-
-static void pxa3xx_nand_data_dma_irq(int channel, void *data)
-{
-	struct pxa3xx_nand_info *info = data;
-	uint32_t dcsr;
-
-	dcsr = DCSR(channel);
-	DCSR(channel) = dcsr;
-
-	if (dcsr & DCSR_BUSERR) {
-		info->retcode = ERR_DMABUSERR;
+	tx = dmaengine_prep_slave_sg(info->dma_chan, &info->sg, 1, direction,
+				     DMA_PREP_INTERRUPT);
+	if (!tx) {
+		dev_err(&info->pdev->dev, "prep_slave_sg() failed\n");
+		return;
 	}
-
-	info->state = STATE_DMA_DONE;
-	enable_int(info, NDCR_INT_MASK);
-	nand_writel(info, NDSR, NDSR_WRDREQ | NDSR_RDDREQ);
+	tx->callback = pxa3xx_nand_data_dma_irq;
+	tx->callback_param = info;
+	info->dma_cookie = dmaengine_submit(tx);
+	dma_async_issue_pending(info->dma_chan);
+	dev_dbg(&info->pdev->dev, "%s(dir=%d cookie=%x size=%u)\n",
+		__func__, direction, info->dma_cookie, info->sg.length);
 }
-#else
-static void start_data_dma(struct pxa3xx_nand_info *info)
-{}
-#endif
 
 static irqreturn_t pxa3xx_nand_irq_thread(int irq, void *data)
 {
@@ -1319,36 +1326,50 @@ static int pxa3xx_nand_detect_config(struct pxa3xx_nand_info *info)
 	return 0;
 }
 
-#ifdef ARCH_HAS_DMA
 static int pxa3xx_nand_init_buff(struct pxa3xx_nand_info *info)
 {
 	struct platform_device *pdev = info->pdev;
-	int data_desc_offset = info->buf_size - sizeof(struct pxa_dma_desc);
+	struct dma_slave_config	config;
+	dma_cap_mask_t mask;
+	struct pxad_param param;
+	int ret;
 
-	if (use_dma == 0) {
 	info->data_buff = kmalloc(info->buf_size, GFP_KERNEL);
 	if (info->data_buff == NULL)
 		return -ENOMEM;
+	if (use_dma == 0)
 		return 0;
-	}
 
-	info->data_buff = dma_alloc_coherent(&pdev->dev, info->buf_size,
-				&info->data_buff_phys, GFP_KERNEL);
-	if (info->data_buff == NULL) {
-		dev_err(&pdev->dev, "failed to allocate dma buffer\n");
-		return -ENOMEM;
-	}
+	ret = dma_set_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(32));
+	if (ret)
+		return ret;
 
-	info->data_desc = (void *)info->data_buff + data_desc_offset;
-	info->data_desc_addr = info->data_buff_phys + data_desc_offset;
+	sg_init_one(&info->sg, info->data_buff, info->buf_size);
+	dma_cap_zero(mask);
+	dma_cap_set(DMA_SLAVE, mask);
+	param.prio = PXAD_PRIO_LOWEST;
+	param.drcmr = info->drcmr_dat;
+	info->dma_chan = dma_request_slave_channel_compat(mask, pxad_filter_fn,
+							  &param, &pdev->dev,
+							  "data");
+	if (!info->dma_chan) {
+		dev_err(&pdev->dev, "unable to request data dma channel\n");
+		return -ENODEV;
+	}
 
-	info->data_dma_ch = pxa_request_dma("nand-data", DMA_PRIO_LOW,
-				pxa3xx_nand_data_dma_irq, info);
-	if (info->data_dma_ch < 0) {
-		dev_err(&pdev->dev, "failed to request data dma\n");
-		dma_free_coherent(&pdev->dev, info->buf_size,
-				info->data_buff, info->data_buff_phys);
-		return info->data_dma_ch;
+	memset(&config, 0, sizeof(config));
+	config.src_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
+	config.dst_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
+	config.src_addr = info->mmio_phys + NDDB;
+	config.dst_addr = info->mmio_phys + NDDB;
+	config.src_maxburst = 32;
+	config.dst_maxburst = 32;
+	ret = dmaengine_slave_config(info->dma_chan, &config);
+	if (ret < 0) {
+		dev_err(&info->pdev->dev,
+			"dma channel configuration failed: %d\n",
+			ret);
+		return ret;
 	}
 
 	/*
@@ -1361,29 +1382,12 @@ static int pxa3xx_nand_init_buff(struct pxa3xx_nand_info *info)
 
 static void pxa3xx_nand_free_buff(struct pxa3xx_nand_info *info)
 {
-	struct platform_device *pdev = info->pdev;
 	if (info->use_dma) {
-		pxa_free_dma(info->data_dma_ch);
-		dma_free_coherent(&pdev->dev, info->buf_size,
-				  info->data_buff, info->data_buff_phys);
-	} else {
-		kfree(info->data_buff);
+		dmaengine_terminate_all(info->dma_chan);
+		dma_release_channel(info->dma_chan);
 	}
-}
-#else
-static int pxa3xx_nand_init_buff(struct pxa3xx_nand_info *info)
-{
-	info->data_buff = kmalloc(info->buf_size, GFP_KERNEL);
-	if (info->data_buff == NULL)
-		return -ENOMEM;
-	return 0;
-}
-
-static void pxa3xx_nand_free_buff(struct pxa3xx_nand_info *info)
-{
 	kfree(info->data_buff);
 }
-#endif
 
 static int pxa3xx_nand_sensing(struct pxa3xx_nand_info *info)
 {
@@ -1683,16 +1687,6 @@ static int alloc_nand_resource(struct platform_device *pdev)
 		return ret;
 
 	if (use_dma) {
-		/*
-		 * This is a dirty hack to make this driver work from
-		 * devicetree bindings. It can be removed once we have
-		 * a prober DMA controller framework for DT.
-		 */
-		if (pdev->dev.of_node &&
-		    of_machine_is_compatible("marvell,pxa3xx")) {
-			info->drcmr_dat = 97;
-			info->drcmr_cmd = 99;
-		} else {
 		r = platform_get_resource(pdev, IORESOURCE_DMA, 0);
 		if (r == NULL) {
 			dev_err(&pdev->dev,
@@ -1711,7 +1705,6 @@ static int alloc_nand_resource(struct platform_device *pdev)
 		}
 		info->drcmr_cmd = r->start;
 	}
-	}
 
 	irq = platform_get_irq(pdev, 0);
 	if (irq < 0) {
@@ -1821,15 +1814,16 @@ static int pxa3xx_nand_probe(struct platform_device *pdev)
 	struct pxa3xx_nand_platform_data *pdata;
 	struct mtd_part_parser_data ppdata = {};
 	struct pxa3xx_nand_info *info;
-	int ret, cs, probe_success;
+	int ret, cs, probe_success, dma_available;
 
-#ifndef ARCH_HAS_DMA
-	if (use_dma) {
+	dma_available = IS_ENABLED(CONFIG_ARM) &&
+		(IS_ENABLED(CONFIG_ARCH_PXA) || IS_ENABLED(CONFIG_ARCH_MMP));
+	if (use_dma && !dma_available) {
 		use_dma = 0;
 		dev_warn(&pdev->dev,
 			 "This platform can't do DMA on this device\n");
 	}
-#endif
+
 	ret = pxa3xx_nand_probe_dt(pdev);
 	if (ret)
 		return ret;