[PATCH v4 3/3] dmaengine: vdma: Add clock support

[Kedareswara rao Appana]

Added basic clock support for axi dma's.
The clocks are requested at probe and released at remove.

Reviewed-by: Shubhrajyoti Datta <shubhraj@xxxxxxxxxx>
Signed-off-by: Kedareswara rao Appana <appanad@xxxxxxxxxx>
---
Changes for v4:
---> Documented struct members as suggested by Soren.
---> Fixed required clock according to binding but a failure is ignored
in the cdma case as suggested by Soren.
---> Removed unnecessary IS_ERR checks during disabling the clocks.
Changes for v3:
---> Added clock support for all the AXI DMA's.
---> Fixed clk_unprepare leak during probe fail as suggested by Moritz.
---> Fixed comment driver specifically asks for the clocks it needs and return
an error if a mandatory clock is missing as suggested by soren.
Changes for v2:
---> None.

 drivers/dma/xilinx/xilinx_vdma.c | 226 ++++++++++++++++++++++++++++++++++++++-
 1 file changed, 224 insertions(+), 2 deletions(-)

diff --git a/drivers/dma/xilinx/xilinx_vdma.c b/drivers/dma/xilinx/xilinx_vdma.c
index 255cdca..51c633f 100644
--- a/drivers/dma/xilinx/xilinx_vdma.c
+++ b/drivers/dma/xilinx/xilinx_vdma.c
@@ -44,6 +44,7 @@
 #include <linux/of_platform.h>
 #include <linux/of_irq.h>
 #include <linux/slab.h>
+#include <linux/clk.h>
 
 #include "../dmaengine.h"
 
@@ -344,6 +345,9 @@ struct xilinx_dma_chan {
 
 struct dma_config {
 	enum xdma_ip_type dmatype;
+	int (*clk_init)(struct platform_device *pdev, struct clk **axi_clk,
+			struct clk **tx_clk, struct clk **txs_clk,
+			struct clk **rx_clk, struct clk **rxs_clk);
 };
 
 /**
@@ -355,7 +359,13 @@ struct dma_config {
  * @has_sg: Specifies whether Scatter-Gather is present or not
  * @flush_on_fsync: Flush on frame sync
  * @ext_addr: Indicates 64 bit addressing is supported by dma device
+ * @pdev: Platform device structure pointer
  * @dma_config: DMA config structure
+ * @axi_clk: DMA Axi4-lite interace clock
+ * @tx_clk: DMA mm2s clock
+ * @txs_clk: DMA mm2s stream clock
+ * @rx_clk: DMA s2mm clock
+ * @rxs_clk: DMA s2mm stream clock
  */
 struct xilinx_dma_device {
 	void __iomem *regs;
@@ -365,7 +375,13 @@ struct xilinx_dma_device {
 	bool has_sg;
 	u32 flush_on_fsync;
 	bool ext_addr;
+	struct platform_device  *pdev;
 	const struct dma_config *dma_config;
+	struct clk *axi_clk;
+	struct clk *tx_clk;
+	struct clk *txs_clk;
+	struct clk *rx_clk;
+	struct clk *rxs_clk;
 };
 
 /* Macros */
@@ -1757,6 +1773,195 @@ static void xilinx_dma_chan_remove(struct xilinx_dma_chan *chan)
 	list_del(&chan->common.device_node);
 }
 
+static int axidma_clk_init(struct platform_device *pdev, struct clk **axi_clk,
+			    struct clk **tx_clk, struct clk **rx_clk,
+			    struct clk **sg_clk, struct clk **tmp_clk)
+{
+	int err;
+
+	*tmp_clk = NULL;
+
+	*axi_clk = devm_clk_get(&pdev->dev, "s_axi_lite_aclk");
+	if (IS_ERR(*axi_clk)) {
+		err = PTR_ERR(*axi_clk);
+		dev_err(&pdev->dev, "failed to get axi_aclk (%u)\n", err);
+		return err;
+	}
+
+	*tx_clk = devm_clk_get(&pdev->dev, "m_axi_mm2s_aclk");
+	if (IS_ERR(*tx_clk))
+		*tx_clk = NULL;
+
+	*rx_clk = devm_clk_get(&pdev->dev, "m_axi_s2mm_aclk");
+	if (IS_ERR(*rx_clk))
+		*rx_clk = NULL;
+
+	*sg_clk = devm_clk_get(&pdev->dev, "m_axi_sg_aclk");
+	if (IS_ERR(*sg_clk))
+		*sg_clk = NULL;
+
+	err = clk_prepare_enable(*axi_clk);
+	if (err) {
+		dev_err(&pdev->dev, "failed to enable axi_clk (%u)\n", err);
+		return err;
+	}
+
+	err = clk_prepare_enable(*tx_clk);
+	if (err) {
+		dev_err(&pdev->dev, "failed to enable tx_clk (%u)\n", err);
+		goto err_disable_axiclk;
+	}
+
+	err = clk_prepare_enable(*rx_clk);
+	if (err) {
+		dev_err(&pdev->dev, "failed to enable rx_clk (%u)\n", err);
+		goto err_disable_txclk;
+	}
+
+	err = clk_prepare_enable(*sg_clk);
+	if (err) {
+		dev_err(&pdev->dev, "failed to enable sg_clk (%u)\n", err);
+		goto err_disable_rxclk;
+	}
+
+	return 0;
+
+err_disable_rxclk:
+	clk_disable_unprepare(*rx_clk);
+err_disable_txclk:
+	clk_disable_unprepare(*tx_clk);
+err_disable_axiclk:
+	clk_disable_unprepare(*axi_clk);
+
+	return err;
+}
+
+static int axicdma_clk_init(struct platform_device *pdev, struct clk **axi_clk,
+			    struct clk **dev_clk, struct clk **tmp_clk,
+			    struct clk **tmp1_clk, struct clk **tmp2_clk)
+{
+	int err;
+
+	*tmp_clk = NULL;
+	*tmp1_clk = NULL;
+	*tmp2_clk = NULL;
+
+	*axi_clk = devm_clk_get(&pdev->dev, "s_axi_lite_aclk");
+	if (IS_ERR(*axi_clk)) {
+		err = PTR_ERR(*axi_clk);
+		dev_err(&pdev->dev, "failed to get axi_clk (%u)\n", err);
+		return err;
+	}
+
+	*dev_clk = devm_clk_get(&pdev->dev, "m_axi_aclk");
+	if (IS_ERR(*dev_clk)) {
+		err = PTR_ERR(*dev_clk);
+		dev_err(&pdev->dev, "failed to get dev_clk (%u)\n", err);
+		return err;
+	}
+
+	err = clk_prepare_enable(*axi_clk);
+	if (err) {
+		dev_err(&pdev->dev, "failed to enable axi_clk (%u)\n", err);
+		return err;
+	}
+
+	err = clk_prepare_enable(*dev_clk);
+	if (err) {
+		dev_err(&pdev->dev, "failed to enable dev_clk (%u)\n", err);
+		goto err_disable_axiclk;
+	}
+
+	return 0;
+
+err_disable_axiclk:
+	clk_disable_unprepare(*axi_clk);
+
+	return err;
+}
+
+static int axivdma_clk_init(struct platform_device *pdev, struct clk **axi_clk,
+			    struct clk **tx_clk, struct clk **txs_clk,
+			    struct clk **rx_clk, struct clk **rxs_clk)
+{
+	int err;
+
+	*axi_clk = devm_clk_get(&pdev->dev, "s_axi_lite_aclk");
+	if (IS_ERR(*axi_clk)) {
+		err = PTR_ERR(*axi_clk);
+		dev_err(&pdev->dev, "failed to get axi_aclk (%u)\n", err);
+		return err;
+	}
+
+	*tx_clk = devm_clk_get(&pdev->dev, "m_axi_mm2s_aclk");
+	if (IS_ERR(*tx_clk))
+		*tx_clk = NULL;
+
+	*txs_clk = devm_clk_get(&pdev->dev, "m_axis_mm2s_aclk");
+	if (IS_ERR(*txs_clk))
+		*txs_clk = NULL;
+
+	*rx_clk = devm_clk_get(&pdev->dev, "m_axi_s2mm_aclk");
+	if (IS_ERR(*rx_clk))
+		*rx_clk = NULL;
+
+	*rxs_clk = devm_clk_get(&pdev->dev, "s_axis_s2mm_aclk");
+	if (IS_ERR(*rxs_clk))
+		*rxs_clk = NULL;
+
+	err = clk_prepare_enable(*axi_clk);
+	if (err) {
+		dev_err(&pdev->dev, "failed to enable axi_clk (%u)\n", err);
+		return err;
+	}
+
+	err = clk_prepare_enable(*tx_clk);
+	if (err) {
+		dev_err(&pdev->dev, "failed to enable tx_clk (%u)\n", err);
+		goto err_disable_axiclk;
+	}
+
+	err = clk_prepare_enable(*txs_clk);
+	if (err) {
+		dev_err(&pdev->dev, "failed to enable txs_clk (%u)\n", err);
+		goto err_disable_txclk;
+	}
+
+	err = clk_prepare_enable(*rx_clk);
+	if (err) {
+		dev_err(&pdev->dev, "failed to enable rx_clk (%u)\n", err);
+		goto err_disable_txsclk;
+	}
+
+	err = clk_prepare_enable(*rxs_clk);
+	if (err) {
+		dev_err(&pdev->dev, "failed to enable rxs_clk (%u)\n", err);
+		goto err_disable_rxclk;
+	}
+
+	return 0;
+
+err_disable_rxclk:
+	clk_disable_unprepare(*rx_clk);
+err_disable_txsclk:
+	clk_disable_unprepare(*txs_clk);
+err_disable_txclk:
+	clk_disable_unprepare(*tx_clk);
+err_disable_axiclk:
+	clk_disable_unprepare(*axi_clk);
+
+	return err;
+}
+
+static void xdma_disable_allclks(struct xilinx_dma_device *xdev)
+{
+	clk_disable_unprepare(xdev->rxs_clk);
+	clk_disable_unprepare(xdev->rx_clk);
+	clk_disable_unprepare(xdev->txs_clk);
+	clk_disable_unprepare(xdev->tx_clk);
+	clk_disable_unprepare(xdev->axi_clk);
+}
+
 /**
  * xilinx_dma_chan_probe - Per Channel Probing
  * It get channel features from the device tree entry and
@@ -1900,14 +2105,17 @@ static struct dma_chan *of_dma_xilinx_xlate(struct of_phandle_args *dma_spec,
 
 static const struct dma_config axidma_config = {
 	.dmatype = XDMA_TYPE_AXIDMA,
+	.clk_init = axidma_clk_init,
 };
 
 static const struct dma_config axicdma_config = {
 	.dmatype = XDMA_TYPE_CDMA,
+	.clk_init = axicdma_clk_init,
 };
 
 static const struct dma_config axivdma_config = {
 	.dmatype = XDMA_TYPE_VDMA,
+	.clk_init = axivdma_clk_init,
 };
 
 static const struct of_device_id xilinx_dma_of_ids[] = {
@@ -1926,6 +2134,9 @@ MODULE_DEVICE_TABLE(of, xilinx_dma_of_ids);
  */
 static int xilinx_dma_probe(struct platform_device *pdev)
 {
+	int (*clk_init)(struct platform_device *, struct clk **, struct clk **,
+			struct clk **, struct clk **, struct clk **)
+					= axivdma_clk_init;
 	struct device_node *node = pdev->dev.of_node;
 	struct xilinx_dma_device *xdev;
 	struct device_node *child, *np = pdev->dev.of_node;
@@ -1943,10 +2154,17 @@ static int xilinx_dma_probe(struct platform_device *pdev)
 		const struct of_device_id *match;
 
 		match = of_match_node(xilinx_dma_of_ids, np);
-		if (match && match->data)
+		if (match && match->data) {
 			xdev->dma_config = match->data;
+			clk_init = xdev->dma_config->clk_init;
+		}
 	}
 
+	err = clk_init(pdev, &xdev->axi_clk, &xdev->tx_clk, &xdev->txs_clk,
+		       &xdev->rx_clk, &xdev->rxs_clk);
+	if (err)
+		return err;
+
 	/* Request and map I/O memory */
 	io = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 	xdev->regs = devm_ioremap_resource(&pdev->dev, io);
@@ -2019,7 +2237,7 @@ static int xilinx_dma_probe(struct platform_device *pdev)
 	for_each_child_of_node(node, child) {
 		err = xilinx_dma_chan_probe(xdev, child);
 		if (err < 0)
-			goto error;
+			goto disable_clks;
 	}
 
 	if (xdev->dma_config->dmatype == XDMA_TYPE_VDMA) {
@@ -2043,6 +2261,8 @@ static int xilinx_dma_probe(struct platform_device *pdev)
 
 	return 0;
 
+disable_clks:
+	xdma_disable_allclks(xdev);
 error:
 	for (i = 0; i < XILINX_DMA_MAX_CHANS_PER_DEVICE; i++)
 		if (xdev->chan[i])
@@ -2070,6 +2290,8 @@ static int xilinx_dma_remove(struct platform_device *pdev)
 		if (xdev->chan[i])
 			xilinx_dma_chan_remove(xdev->chan[i]);
 
+	xdma_disable_allclks(xdev);
+
 	return 0;
 }
 
-- 
2.1.2