[PATCH] dma: tegra: add support for Tegra114 SoC

[Laxman Dewangan]

NVIDIA's Tegra114 has APB DMA controller which supports channel wise
pause control. The global pause is used for clock gating and hence
DMA registers are not accessible if DMAs are globally disabled.

Add support for use of channel wise pause feature for Tegra114 SOCs.

Signed-off-by: Laxman Dewangan <ldewangan@xxxxxxxxxx>
---
 drivers/dma/tegra20-apb-dma.c |   54 +++++++++++++++++++++++++++++++++++++----
 1 files changed, 49 insertions(+), 5 deletions(-)

diff --git a/drivers/dma/tegra20-apb-dma.c b/drivers/dma/tegra20-apb-dma.c
index c39e61b..d33c1ae 100644
--- a/drivers/dma/tegra20-apb-dma.c
+++ b/drivers/dma/tegra20-apb-dma.c
@@ -62,6 +62,9 @@
 #define TEGRA_APBDMA_STATUS_COUNT_SHIFT		2
 #define TEGRA_APBDMA_STATUS_COUNT_MASK		0xFFFC
 
+#define TEGRA_APBDMA_CHAN_CSRE			0x00C
+#define TEGRA_APBDMA_CHAN_CSRE_PAUSE		(1 << 31)
+
 /* AHB memory address */
 #define TEGRA_APBDMA_CHAN_AHBPTR		0x010
 
@@ -112,10 +115,12 @@ struct tegra_dma;
  * tegra_dma_chip_data Tegra chip specific DMA data
  * @nr_channels: Number of channels available in the controller.
  * @max_dma_count: Maximum DMA transfer count supported by DMA controller.
+ * @support_channel_pause: Support channel wise pause of dma.
  */
 struct tegra_dma_chip_data {
 	int nr_channels;
 	int max_dma_count;
+	bool support_channel_pause;
 };
 
 /* DMA channel registers */
@@ -353,6 +358,32 @@ static void tegra_dma_global_resume(struct tegra_dma_channel *tdc)
 	spin_unlock(&tdma->global_lock);
 }
 
+static void tegra_dma_pause(struct tegra_dma_channel *tdc,
+	bool wait_for_burst_complete)
+{
+	struct tegra_dma *tdma = tdc->tdma;
+
+	if (tdma->chip_data->support_channel_pause) {
+		tdc_write(tdc, TEGRA_APBDMA_CHAN_CSRE,
+				TEGRA_APBDMA_CHAN_CSRE_PAUSE);
+		if (wait_for_burst_complete)
+			udelay(TEGRA_APBDMA_BURST_COMPLETE_TIME);
+	} else {
+		tegra_dma_global_pause(tdc, wait_for_burst_complete);
+	}
+}
+
+static void tegra_dma_resume(struct tegra_dma_channel *tdc)
+{
+	struct tegra_dma *tdma = tdc->tdma;
+
+	if (tdma->chip_data->support_channel_pause) {
+		tdc_write(tdc, TEGRA_APBDMA_CHAN_CSRE, 0);
+	} else {
+		tegra_dma_global_resume(tdc);
+	}
+}
+
 static void tegra_dma_stop(struct tegra_dma_channel *tdc)
 {
 	u32 csr;
@@ -408,7 +439,7 @@ static void tegra_dma_configure_for_next(struct tegra_dma_channel *tdc,
 	 * If there is already IEC status then interrupt handler need to
 	 * load new configuration.
 	 */
-	tegra_dma_global_pause(tdc, false);
+	tegra_dma_pause(tdc, false);
 	status  = tdc_read(tdc, TEGRA_APBDMA_CHAN_STATUS);
 
 	/*
@@ -418,7 +449,7 @@ static void tegra_dma_configure_for_next(struct tegra_dma_channel *tdc,
 	if (status & TEGRA_APBDMA_STATUS_ISE_EOC) {
 		dev_err(tdc2dev(tdc),
 			"Skipping new configuration as interrupt is pending\n");
-		tegra_dma_global_resume(tdc);
+		tegra_dma_resume(tdc);
 		return;
 	}
 
@@ -429,7 +460,7 @@ static void tegra_dma_configure_for_next(struct tegra_dma_channel *tdc,
 				nsg_req->ch_regs.csr | TEGRA_APBDMA_CSR_ENB);
 	nsg_req->configured = true;
 
-	tegra_dma_global_resume(tdc);
+	tegra_dma_resume(tdc);
 }
 
 static void tdc_start_head_req(struct tegra_dma_channel *tdc)
@@ -690,7 +721,7 @@ static void tegra_dma_terminate_all(struct dma_chan *dc)
 		goto skip_dma_stop;
 
 	/* Pause DMA before checking the queue status */
-	tegra_dma_global_pause(tdc, true);
+	tegra_dma_pause(tdc, true);
 
 	status = tdc_read(tdc, TEGRA_APBDMA_CHAN_STATUS);
 	if (status & TEGRA_APBDMA_STATUS_ISE_EOC) {
@@ -708,7 +739,7 @@ static void tegra_dma_terminate_all(struct dma_chan *dc)
 		sgreq->dma_desc->bytes_transferred +=
 				get_current_xferred_count(tdc, sgreq, status);
 	}
-	tegra_dma_global_resume(tdc);
+	tegra_dma_resume(tdc);
 
 skip_dma_stop:
 	tegra_dma_abort_all(tdc);
@@ -1175,6 +1206,7 @@ static void tegra_dma_free_chan_resources(struct dma_chan *dc)
 static const struct tegra_dma_chip_data tegra20_dma_chip_data = {
 	.nr_channels		= 16,
 	.max_dma_count		= 1024UL * 64,
+	.support_channel_pause	= false,
 };
 
 #if defined(CONFIG_OF)
@@ -1182,10 +1214,22 @@ static const struct tegra_dma_chip_data tegra20_dma_chip_data = {
 static const struct tegra_dma_chip_data tegra30_dma_chip_data = {
 	.nr_channels		= 32,
 	.max_dma_count		= 1024UL * 64,
+	.support_channel_pause	= false,
 };
 
+/* Tegra114 specific DMA controller information */
+static const struct tegra_dma_chip_data tegra114_dma_chip_data = {
+	.nr_channels		= 32,
+	.max_dma_count		= 1024UL * 64,
+	.support_channel_pause	= true,
+};
+
+
 static const struct of_device_id tegra_dma_of_match[] = {
 	{
+		.compatible = "nvidia,tegra114-apbdma",
+		.data = &tegra114_dma_chip_data,
+	}, {
 		.compatible = "nvidia,tegra30-apbdma",
 		.data = &tegra30_dma_chip_data,
 	}, {
-- 
1.7.1.1

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