All of lore.kernel.org
 help / color / mirror / Atom feed
From: Vignesh R <vigneshr@ti.com>
To: Mark Brown <broonie@kernel.org>
Cc: <linux-spi@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
	<linux-omap@vger.kernel.org>, Vignesh R <vigneshr@ti.com>
Subject: [PATCH v3 2/2] spi: spi-ti-qspi: Add DMA support for QSPI mmap read
Date: Tue, 7 Jun 2016 13:48:10 +0530	[thread overview]
Message-ID: <20160607081810.6640-3-vigneshr@ti.com> (raw)
In-Reply-To: <20160607081810.6640-1-vigneshr@ti.com>

Use mem-to-mem DMA to read from flash when reading in mmap mode. This
gives improved read performance and reduces CPU load.

With this patch the raw-read throughput is ~16MB/s on DRA74 EVM. And CPU
load is <20%. UBIFS read ~13 MB/s.

Signed-off-by: Vignesh R <vigneshr@ti.com>
---

v3: Cleanup code based on review comments for v2.
v2: Handle kmap'd buffers of JFFS2 FS.

 drivers/spi/spi-ti-qspi.c | 189 ++++++++++++++++++++++++++++++++++++++++++----
 1 file changed, 176 insertions(+), 13 deletions(-)

diff --git a/drivers/spi/spi-ti-qspi.c b/drivers/spi/spi-ti-qspi.c
index 29ea8d2f9824..1f6c59c29157 100644
--- a/drivers/spi/spi-ti-qspi.c
+++ b/drivers/spi/spi-ti-qspi.c
@@ -33,6 +33,7 @@
 #include <linux/pinctrl/consumer.h>
 #include <linux/mfd/syscon.h>
 #include <linux/regmap.h>
+#include <linux/highmem.h>
 
 #include <linux/spi/spi.h>
 
@@ -41,6 +42,8 @@ struct ti_qspi_regs {
 };
 
 struct ti_qspi {
+	struct completion	transfer_complete;
+
 	/* list synchronization */
 	struct mutex            list_lock;
 
@@ -54,6 +57,9 @@ struct ti_qspi {
 
 	struct ti_qspi_regs     ctx_reg;
 
+	dma_addr_t		mmap_phys_base;
+	struct dma_chan		*rx_chan;
+
 	u32 spi_max_frequency;
 	u32 cmd;
 	u32 dc;
@@ -379,6 +385,72 @@ static int qspi_transfer_msg(struct ti_qspi *qspi, struct spi_transfer *t,
 	return 0;
 }
 
+static void ti_qspi_dma_callback(void *param)
+{
+	struct ti_qspi *qspi = param;
+
+	complete(&qspi->transfer_complete);
+}
+
+static int ti_qspi_dma_xfer(struct ti_qspi *qspi, dma_addr_t dma_dst,
+			    dma_addr_t dma_src, size_t len)
+{
+	struct dma_chan *chan = qspi->rx_chan;
+	struct dma_device *dma_dev = chan->device;
+	dma_cookie_t cookie;
+	enum dma_ctrl_flags flags = DMA_CTRL_ACK | DMA_PREP_INTERRUPT;
+	struct dma_async_tx_descriptor *tx;
+	int ret;
+
+	tx = dma_dev->device_prep_dma_memcpy(chan, dma_dst, dma_src,
+					     len, flags);
+	if (!tx) {
+		dev_err(qspi->dev, "device_prep_dma_memcpy error\n");
+		return -EIO;
+	}
+
+	tx->callback = ti_qspi_dma_callback;
+	tx->callback_param = qspi;
+	cookie = tx->tx_submit(tx);
+
+	ret = dma_submit_error(cookie);
+	if (ret) {
+		dev_err(qspi->dev, "dma_submit_error %d\n", cookie);
+		return -EIO;
+	}
+
+	dma_async_issue_pending(chan);
+	ret = wait_for_completion_timeout(&qspi->transfer_complete,
+					  msecs_to_jiffies(len));
+	if (ret <= 0) {
+		dmaengine_terminate_sync(chan);
+		dev_err(qspi->dev, "DMA wait_for_completion_timeout\n");
+		return -ETIMEDOUT;
+	}
+
+	return 0;
+}
+
+static int ti_qspi_dma_xfer_sg(struct ti_qspi *qspi, struct sg_table rx_sg,
+			       loff_t from)
+{
+	struct scatterlist *sg;
+	dma_addr_t dma_src = qspi->mmap_phys_base + from;
+	dma_addr_t dma_dst;
+	int i, len, ret;
+
+	for_each_sg(rx_sg.sgl, sg, rx_sg.nents, i) {
+		dma_dst = sg_dma_address(sg);
+		len = sg_dma_len(sg);
+		ret = ti_qspi_dma_xfer(qspi, dma_dst, dma_src, len);
+		if (ret)
+			return ret;
+		dma_src += len;
+	}
+
+	return 0;
+}
+
 static void ti_qspi_enable_memory_map(struct spi_device *spi)
 {
 	struct ti_qspi  *qspi = spi_master_get_devdata(spi->master);
@@ -426,7 +498,40 @@ static void ti_qspi_setup_mmap_read(struct spi_device *spi,
 		      QSPI_SPI_SETUP_REG(spi->chip_select));
 }
 
-static int ti_qspi_spi_flash_read(struct  spi_device *spi,
+#ifdef CONFIG_HIGHMEM
+static int ti_qspi_map_buf(struct ti_qspi *qspi, void *buf,
+			   unsigned int len, struct sg_table *sgt)
+{
+	unsigned int max_seg_size =
+		dma_get_max_seg_size(qspi->rx_chan->device->dev);
+	unsigned int desc_len = min_t(int, max_seg_size, PAGE_SIZE);
+	int sgs = DIV_ROUND_UP(len + offset_in_page(buf), desc_len);
+	struct page *vm_page;
+	size_t min;
+	int i, ret;
+
+	ret = sg_alloc_table(sgt, sgs, GFP_KERNEL);
+	if (ret)
+		return ret;
+
+	for (i = 0; i < sgs; i++) {
+		min = min_t(size_t, len, desc_len -
+			    offset_in_page(buf));
+		vm_page = kmap_to_page(buf);
+		if (!vm_page) {
+			sg_free_table(sgt);
+			return -ENOMEM;
+		}
+		sg_set_page(&sgt->sgl[i], vm_page, min,
+			    offset_in_page(buf));
+		buf += min;
+		len -= min;
+	}
+	return 0;
+}
+#endif
+
+static int ti_qspi_spi_flash_read(struct spi_device *spi,
 				  struct spi_flash_read_message *msg)
 {
 	struct ti_qspi *qspi = spi_master_get_devdata(spi->master);
@@ -437,9 +542,46 @@ static int ti_qspi_spi_flash_read(struct  spi_device *spi,
 	if (!qspi->mmap_enabled)
 		ti_qspi_enable_memory_map(spi);
 	ti_qspi_setup_mmap_read(spi, msg);
-	memcpy_fromio(msg->buf, qspi->mmap_base + msg->from, msg->len);
+
+	if (qspi->rx_chan) {
+		struct device *dev = qspi->rx_chan->device->dev;
+		void *buf = msg->buf;
+		struct sg_table sgt;
+
+		if (msg->cur_msg_mapped) {
+			ret = ti_qspi_dma_xfer_sg(qspi, msg->rx_sg, msg->from);
+			if (ret)
+				goto err_unlock;
+#ifdef CONFIG_HIGHMEM
+		} else if ((unsigned long)buf >= PKMAP_BASE &&
+				(unsigned long)buf < (PKMAP_BASE +
+					(LAST_PKMAP * PAGE_SIZE))) {
+			/* Generate sg_table for kmap buffers */
+			ret = ti_qspi_map_buf(qspi, buf, msg->len, &sgt);
+			if (ret)
+				goto err_unlock;
+			ret = dma_map_sg(dev, sgt.sgl, sgt.nents,
+					 DMA_FROM_DEVICE);
+			if (!ret) {
+				ret = -ENOMEM;
+				goto err_unlock;
+			}
+			ret = ti_qspi_dma_xfer_sg(qspi, sgt, msg->from);
+			dma_unmap_sg(dev, sgt.sgl, sgt.orig_nents,
+				     DMA_FROM_DEVICE);
+			sg_free_table(&sgt);
+#endif
+		} else {
+			dev_err(qspi->dev, "Invalid address for DMA\n");
+			ret = -EIO;
+			goto err_unlock;
+		}
+	} else {
+		memcpy_fromio(msg->buf, qspi->mmap_base + msg->from, msg->len);
+	}
 	msg->retlen = msg->len;
 
+err_unlock:
 	mutex_unlock(&qspi->list_lock);
 
 	return ret;
@@ -536,6 +678,7 @@ static int ti_qspi_probe(struct platform_device *pdev)
 	struct device_node *np = pdev->dev.of_node;
 	u32 max_freq;
 	int ret = 0, num_cs, irq;
+	dma_cap_mask_t mask;
 
 	master = spi_alloc_master(&pdev->dev, sizeof(*qspi));
 	if (!master)
@@ -550,6 +693,7 @@ static int ti_qspi_probe(struct platform_device *pdev)
 	master->dev.of_node = pdev->dev.of_node;
 	master->bits_per_word_mask = SPI_BPW_MASK(32) | SPI_BPW_MASK(16) |
 				     SPI_BPW_MASK(8);
+	master->spi_flash_read = ti_qspi_spi_flash_read;
 
 	if (!of_property_read_u32(np, "num-cs", &num_cs))
 		master->num_chipselect = num_cs;
@@ -592,17 +736,6 @@ static int ti_qspi_probe(struct platform_device *pdev)
 		goto free_master;
 	}
 
-	if (res_mmap) {
-		qspi->mmap_base = devm_ioremap_resource(&pdev->dev,
-							res_mmap);
-		master->spi_flash_read = ti_qspi_spi_flash_read;
-		if (IS_ERR(qspi->mmap_base)) {
-			dev_err(&pdev->dev,
-				"falling back to PIO mode\n");
-			master->spi_flash_read = NULL;
-		}
-	}
-	qspi->mmap_enabled = false;
 
 	if (of_property_read_bool(np, "syscon-chipselects")) {
 		qspi->ctrl_base =
@@ -637,6 +770,33 @@ static int ti_qspi_probe(struct platform_device *pdev)
 	if (ret)
 		goto free_master;
 
+	dma_cap_zero(mask);
+	dma_cap_set(DMA_MEMCPY, mask);
+
+	qspi->rx_chan = dma_request_channel(mask, NULL, NULL);
+	if (!qspi->rx_chan) {
+		dev_err(qspi->dev,
+			"No Rx DMA available, trying mmap mode\n");
+		ret = 0;
+		goto no_dma;
+	}
+	master->dma_rx = qspi->rx_chan;
+	init_completion(&qspi->transfer_complete);
+	if (res_mmap)
+		qspi->mmap_phys_base = (dma_addr_t)res_mmap->start;
+
+no_dma:
+	if (!qspi->rx_chan && res_mmap) {
+		qspi->mmap_base = devm_ioremap_resource(&pdev->dev, res_mmap);
+		if (IS_ERR(qspi->mmap_base)) {
+			dev_info(&pdev->dev,
+				 "mmap failed with error %ld using PIO mode\n",
+				 PTR_ERR(qspi->mmap_base));
+			qspi->mmap_base = NULL;
+			master->spi_flash_read = NULL;
+		}
+	}
+	qspi->mmap_enabled = false;
 	return 0;
 
 free_master:
@@ -656,6 +816,9 @@ static int ti_qspi_remove(struct platform_device *pdev)
 	pm_runtime_put_sync(&pdev->dev);
 	pm_runtime_disable(&pdev->dev);
 
+	if (qspi->rx_chan)
+		dma_release_channel(qspi->rx_chan);
+
 	return 0;
 }
 
-- 
2.8.3

WARNING: multiple messages have this Message-ID (diff)
From: Vignesh R <vigneshr@ti.com>
To: Mark Brown <broonie@kernel.org>
Cc: linux-spi@vger.kernel.org, linux-kernel@vger.kernel.org,
	linux-omap@vger.kernel.org, Vignesh R <vigneshr@ti.com>
Subject: [PATCH v3 2/2] spi: spi-ti-qspi: Add DMA support for QSPI mmap read
Date: Tue, 7 Jun 2016 13:48:10 +0530	[thread overview]
Message-ID: <20160607081810.6640-3-vigneshr@ti.com> (raw)
In-Reply-To: <20160607081810.6640-1-vigneshr@ti.com>

Use mem-to-mem DMA to read from flash when reading in mmap mode. This
gives improved read performance and reduces CPU load.

With this patch the raw-read throughput is ~16MB/s on DRA74 EVM. And CPU
load is <20%. UBIFS read ~13 MB/s.

Signed-off-by: Vignesh R <vigneshr@ti.com>
---

v3: Cleanup code based on review comments for v2.
v2: Handle kmap'd buffers of JFFS2 FS.

 drivers/spi/spi-ti-qspi.c | 189 ++++++++++++++++++++++++++++++++++++++++++----
 1 file changed, 176 insertions(+), 13 deletions(-)

diff --git a/drivers/spi/spi-ti-qspi.c b/drivers/spi/spi-ti-qspi.c
index 29ea8d2f9824..1f6c59c29157 100644
--- a/drivers/spi/spi-ti-qspi.c
+++ b/drivers/spi/spi-ti-qspi.c
@@ -33,6 +33,7 @@
 #include <linux/pinctrl/consumer.h>
 #include <linux/mfd/syscon.h>
 #include <linux/regmap.h>
+#include <linux/highmem.h>
 
 #include <linux/spi/spi.h>
 
@@ -41,6 +42,8 @@ struct ti_qspi_regs {
 };
 
 struct ti_qspi {
+	struct completion	transfer_complete;
+
 	/* list synchronization */
 	struct mutex            list_lock;
 
@@ -54,6 +57,9 @@ struct ti_qspi {
 
 	struct ti_qspi_regs     ctx_reg;
 
+	dma_addr_t		mmap_phys_base;
+	struct dma_chan		*rx_chan;
+
 	u32 spi_max_frequency;
 	u32 cmd;
 	u32 dc;
@@ -379,6 +385,72 @@ static int qspi_transfer_msg(struct ti_qspi *qspi, struct spi_transfer *t,
 	return 0;
 }
 
+static void ti_qspi_dma_callback(void *param)
+{
+	struct ti_qspi *qspi = param;
+
+	complete(&qspi->transfer_complete);
+}
+
+static int ti_qspi_dma_xfer(struct ti_qspi *qspi, dma_addr_t dma_dst,
+			    dma_addr_t dma_src, size_t len)
+{
+	struct dma_chan *chan = qspi->rx_chan;
+	struct dma_device *dma_dev = chan->device;
+	dma_cookie_t cookie;
+	enum dma_ctrl_flags flags = DMA_CTRL_ACK | DMA_PREP_INTERRUPT;
+	struct dma_async_tx_descriptor *tx;
+	int ret;
+
+	tx = dma_dev->device_prep_dma_memcpy(chan, dma_dst, dma_src,
+					     len, flags);
+	if (!tx) {
+		dev_err(qspi->dev, "device_prep_dma_memcpy error\n");
+		return -EIO;
+	}
+
+	tx->callback = ti_qspi_dma_callback;
+	tx->callback_param = qspi;
+	cookie = tx->tx_submit(tx);
+
+	ret = dma_submit_error(cookie);
+	if (ret) {
+		dev_err(qspi->dev, "dma_submit_error %d\n", cookie);
+		return -EIO;
+	}
+
+	dma_async_issue_pending(chan);
+	ret = wait_for_completion_timeout(&qspi->transfer_complete,
+					  msecs_to_jiffies(len));
+	if (ret <= 0) {
+		dmaengine_terminate_sync(chan);
+		dev_err(qspi->dev, "DMA wait_for_completion_timeout\n");
+		return -ETIMEDOUT;
+	}
+
+	return 0;
+}
+
+static int ti_qspi_dma_xfer_sg(struct ti_qspi *qspi, struct sg_table rx_sg,
+			       loff_t from)
+{
+	struct scatterlist *sg;
+	dma_addr_t dma_src = qspi->mmap_phys_base + from;
+	dma_addr_t dma_dst;
+	int i, len, ret;
+
+	for_each_sg(rx_sg.sgl, sg, rx_sg.nents, i) {
+		dma_dst = sg_dma_address(sg);
+		len = sg_dma_len(sg);
+		ret = ti_qspi_dma_xfer(qspi, dma_dst, dma_src, len);
+		if (ret)
+			return ret;
+		dma_src += len;
+	}
+
+	return 0;
+}
+
 static void ti_qspi_enable_memory_map(struct spi_device *spi)
 {
 	struct ti_qspi  *qspi = spi_master_get_devdata(spi->master);
@@ -426,7 +498,40 @@ static void ti_qspi_setup_mmap_read(struct spi_device *spi,
 		      QSPI_SPI_SETUP_REG(spi->chip_select));
 }
 
-static int ti_qspi_spi_flash_read(struct  spi_device *spi,
+#ifdef CONFIG_HIGHMEM
+static int ti_qspi_map_buf(struct ti_qspi *qspi, void *buf,
+			   unsigned int len, struct sg_table *sgt)
+{
+	unsigned int max_seg_size =
+		dma_get_max_seg_size(qspi->rx_chan->device->dev);
+	unsigned int desc_len = min_t(int, max_seg_size, PAGE_SIZE);
+	int sgs = DIV_ROUND_UP(len + offset_in_page(buf), desc_len);
+	struct page *vm_page;
+	size_t min;
+	int i, ret;
+
+	ret = sg_alloc_table(sgt, sgs, GFP_KERNEL);
+	if (ret)
+		return ret;
+
+	for (i = 0; i < sgs; i++) {
+		min = min_t(size_t, len, desc_len -
+			    offset_in_page(buf));
+		vm_page = kmap_to_page(buf);
+		if (!vm_page) {
+			sg_free_table(sgt);
+			return -ENOMEM;
+		}
+		sg_set_page(&sgt->sgl[i], vm_page, min,
+			    offset_in_page(buf));
+		buf += min;
+		len -= min;
+	}
+	return 0;
+}
+#endif
+
+static int ti_qspi_spi_flash_read(struct spi_device *spi,
 				  struct spi_flash_read_message *msg)
 {
 	struct ti_qspi *qspi = spi_master_get_devdata(spi->master);
@@ -437,9 +542,46 @@ static int ti_qspi_spi_flash_read(struct  spi_device *spi,
 	if (!qspi->mmap_enabled)
 		ti_qspi_enable_memory_map(spi);
 	ti_qspi_setup_mmap_read(spi, msg);
-	memcpy_fromio(msg->buf, qspi->mmap_base + msg->from, msg->len);
+
+	if (qspi->rx_chan) {
+		struct device *dev = qspi->rx_chan->device->dev;
+		void *buf = msg->buf;
+		struct sg_table sgt;
+
+		if (msg->cur_msg_mapped) {
+			ret = ti_qspi_dma_xfer_sg(qspi, msg->rx_sg, msg->from);
+			if (ret)
+				goto err_unlock;
+#ifdef CONFIG_HIGHMEM
+		} else if ((unsigned long)buf >= PKMAP_BASE &&
+				(unsigned long)buf < (PKMAP_BASE +
+					(LAST_PKMAP * PAGE_SIZE))) {
+			/* Generate sg_table for kmap buffers */
+			ret = ti_qspi_map_buf(qspi, buf, msg->len, &sgt);
+			if (ret)
+				goto err_unlock;
+			ret = dma_map_sg(dev, sgt.sgl, sgt.nents,
+					 DMA_FROM_DEVICE);
+			if (!ret) {
+				ret = -ENOMEM;
+				goto err_unlock;
+			}
+			ret = ti_qspi_dma_xfer_sg(qspi, sgt, msg->from);
+			dma_unmap_sg(dev, sgt.sgl, sgt.orig_nents,
+				     DMA_FROM_DEVICE);
+			sg_free_table(&sgt);
+#endif
+		} else {
+			dev_err(qspi->dev, "Invalid address for DMA\n");
+			ret = -EIO;
+			goto err_unlock;
+		}
+	} else {
+		memcpy_fromio(msg->buf, qspi->mmap_base + msg->from, msg->len);
+	}
 	msg->retlen = msg->len;
 
+err_unlock:
 	mutex_unlock(&qspi->list_lock);
 
 	return ret;
@@ -536,6 +678,7 @@ static int ti_qspi_probe(struct platform_device *pdev)
 	struct device_node *np = pdev->dev.of_node;
 	u32 max_freq;
 	int ret = 0, num_cs, irq;
+	dma_cap_mask_t mask;
 
 	master = spi_alloc_master(&pdev->dev, sizeof(*qspi));
 	if (!master)
@@ -550,6 +693,7 @@ static int ti_qspi_probe(struct platform_device *pdev)
 	master->dev.of_node = pdev->dev.of_node;
 	master->bits_per_word_mask = SPI_BPW_MASK(32) | SPI_BPW_MASK(16) |
 				     SPI_BPW_MASK(8);
+	master->spi_flash_read = ti_qspi_spi_flash_read;
 
 	if (!of_property_read_u32(np, "num-cs", &num_cs))
 		master->num_chipselect = num_cs;
@@ -592,17 +736,6 @@ static int ti_qspi_probe(struct platform_device *pdev)
 		goto free_master;
 	}
 
-	if (res_mmap) {
-		qspi->mmap_base = devm_ioremap_resource(&pdev->dev,
-							res_mmap);
-		master->spi_flash_read = ti_qspi_spi_flash_read;
-		if (IS_ERR(qspi->mmap_base)) {
-			dev_err(&pdev->dev,
-				"falling back to PIO mode\n");
-			master->spi_flash_read = NULL;
-		}
-	}
-	qspi->mmap_enabled = false;
 
 	if (of_property_read_bool(np, "syscon-chipselects")) {
 		qspi->ctrl_base =
@@ -637,6 +770,33 @@ static int ti_qspi_probe(struct platform_device *pdev)
 	if (ret)
 		goto free_master;
 
+	dma_cap_zero(mask);
+	dma_cap_set(DMA_MEMCPY, mask);
+
+	qspi->rx_chan = dma_request_channel(mask, NULL, NULL);
+	if (!qspi->rx_chan) {
+		dev_err(qspi->dev,
+			"No Rx DMA available, trying mmap mode\n");
+		ret = 0;
+		goto no_dma;
+	}
+	master->dma_rx = qspi->rx_chan;
+	init_completion(&qspi->transfer_complete);
+	if (res_mmap)
+		qspi->mmap_phys_base = (dma_addr_t)res_mmap->start;
+
+no_dma:
+	if (!qspi->rx_chan && res_mmap) {
+		qspi->mmap_base = devm_ioremap_resource(&pdev->dev, res_mmap);
+		if (IS_ERR(qspi->mmap_base)) {
+			dev_info(&pdev->dev,
+				 "mmap failed with error %ld using PIO mode\n",
+				 PTR_ERR(qspi->mmap_base));
+			qspi->mmap_base = NULL;
+			master->spi_flash_read = NULL;
+		}
+	}
+	qspi->mmap_enabled = false;
 	return 0;
 
 free_master:
@@ -656,6 +816,9 @@ static int ti_qspi_remove(struct platform_device *pdev)
 	pm_runtime_put_sync(&pdev->dev);
 	pm_runtime_disable(&pdev->dev);
 
+	if (qspi->rx_chan)
+		dma_release_channel(qspi->rx_chan);
+
 	return 0;
 }
 
-- 
2.8.3

  parent reply	other threads:[~2016-06-07  8:18 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-06-07  8:18 [PATCH v3 0/2] spi: Add DMA support for ti-qspi Vignesh R
2016-06-07  8:18 ` Vignesh R
2016-06-07  8:18 ` Vignesh R
2016-06-07  8:18 ` [PATCH v3 1/2] spi: Add DMA support for spi_flash_read() Vignesh R
2016-06-07  8:18   ` Vignesh R
2016-06-07 22:29   ` kbuild test robot
2016-06-07 22:29     ` kbuild test robot
2016-06-08  6:51     ` Vignesh R
2016-06-07  8:18 ` Vignesh R [this message]
2016-06-07  8:18   ` [PATCH v3 2/2] spi: spi-ti-qspi: Add DMA support for QSPI mmap read Vignesh R
2016-06-07  9:17   ` Peter Ujfalusi
2016-06-07  9:17     ` Peter Ujfalusi
2016-06-08  6:53     ` Vignesh R
2016-06-08  6:53       ` Vignesh R
2016-06-07 10:00   ` kbuild test robot
2016-06-07 10:00     ` kbuild test robot

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20160607081810.6640-3-vigneshr@ti.com \
    --to=vigneshr@ti.com \
    --cc=broonie@kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-omap@vger.kernel.org \
    --cc=linux-spi@vger.kernel.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.