Re: [PATCH v10 1/3] dmaengine: 8250_mtk_dma: add MediaTek uart DMA support

On 18/01/2019 04:10, Long Cheng wrote:

In DMA engine framework, add 8250 uart dma to support MediaTek uart.
If MediaTek uart enabled(SERIAL_8250_MT6577), and want to improve
the performance, can enable the function.

Signed-off-by: Long Cheng <redacted>
---
 drivers/dma/mediatek/Kconfig          |   11 +
 drivers/dma/mediatek/Makefile         |    1 +
 drivers/dma/mediatek/mtk-uart-apdma.c |  669 +++++++++++++++++++++++++++++++++
 3 files changed, 681 insertions(+)
 create mode 100644 drivers/dma/mediatek/mtk-uart-apdma.c

[...]

+
+static int mtk_uart_apdma_probe(struct platform_device *pdev)
+{
+	struct device_node *np = pdev->dev.of_node;
+	struct mtk_uart_apdmadev *mtkd;
+	struct resource *res;
+	struct mtk_chan *c;
+	int bit_mask = 32, rc;
+	unsigned int i;
+
+	mtkd = devm_kzalloc(&pdev->dev, sizeof(*mtkd), GFP_KERNEL);
+	if (!mtkd)
+		return -ENOMEM;
+
+	mtkd->clk = devm_clk_get(&pdev->dev, NULL);
+	if (IS_ERR(mtkd->clk)) {
+		dev_err(&pdev->dev, "No clock specified\n");
+		rc = PTR_ERR(mtkd->clk);
+		return rc;
+	}
+
+	if (of_property_read_bool(np, "dma-33bits"))
+		mtkd->support_33bits = true;

dma-33bits not defined in the binding description.

+
+	if (mtkd->support_33bits)
+		bit_mask = 33;
+
+	rc = dma_set_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(bit_mask));
+	if (rc)
+		return rc;
+
+	dma_cap_set(DMA_SLAVE, mtkd->ddev.cap_mask);
+	mtkd->ddev.device_alloc_chan_resources =
+				mtk_uart_apdma_alloc_chan_resources;
+	mtkd->ddev.device_free_chan_resources =
+				mtk_uart_apdma_free_chan_resources;
+	mtkd->ddev.device_tx_status = mtk_uart_apdma_tx_status;
+	mtkd->ddev.device_issue_pending = mtk_uart_apdma_issue_pending;
+	mtkd->ddev.device_prep_slave_sg = mtk_uart_apdma_prep_slave_sg;
+	mtkd->ddev.device_config = mtk_uart_apdma_slave_config;
+	mtkd->ddev.device_pause = mtk_uart_apdma_device_pause;
+	mtkd->ddev.device_terminate_all = mtk_uart_apdma_terminate_all;
+	mtkd->ddev.src_addr_widths = BIT(DMA_SLAVE_BUSWIDTH_1_BYTE);
+	mtkd->ddev.dst_addr_widths = BIT(DMA_SLAVE_BUSWIDTH_1_BYTE);
+	mtkd->ddev.directions = BIT(DMA_DEV_TO_MEM) | BIT(DMA_MEM_TO_DEV);
+	mtkd->ddev.residue_granularity = DMA_RESIDUE_GRANULARITY_SEGMENT;
+	mtkd->ddev.dev = &pdev->dev;
+	INIT_LIST_HEAD(&mtkd->ddev.channels);
+
+	mtkd->dma_requests = MTK_UART_APDMA_NR_VCHANS;

Do this if dma-requests property is not present.

+	if (of_property_read_u32(np, "dma-requests", &mtkd->dma_requests)) {

It's quite obvious what this does, but IMHO it should be reflected in the binding.

Regards,
Matthias

+		dev_info(&pdev->dev,
+			 "Using %u as missing dma-requests property\n",
+			 MTK_UART_APDMA_NR_VCHANS);
+	}
+
+	mtkd->dma_irq = devm_kcalloc(&pdev->dev, mtkd->dma_requests,
+				 sizeof(*mtkd->dma_irq), GFP_KERNEL);
+	if (!mtkd->dma_irq)
+		return -ENOMEM;
+
+	for (i = 0; i < mtkd->dma_requests; i++) {
+		c = devm_kzalloc(mtkd->ddev.dev, sizeof(*c), GFP_KERNEL);
+		if (!c) {
+			rc = -ENODEV;
+			goto err_no_dma;
+		}
+
+		res = platform_get_resource(pdev, IORESOURCE_MEM, i);
+		if (!res) {
+			rc = -ENODEV;
+			goto err_no_dma;
+		}
+
+		c->base = devm_ioremap_resource(&pdev->dev, res);
+		if (IS_ERR(c->base)) {
+			rc = PTR_ERR(c->base);
+			goto err_no_dma;
+		}
+		c->requested = false;
+		c->vc.desc_free = mtk_uart_apdma_desc_free;
+		vchan_init(&c->vc, &mtkd->ddev);
+
+		mtkd->dma_irq[i] = platform_get_irq(pdev, i);
+		if ((int)mtkd->dma_irq[i] < 0) {
+			dev_err(&pdev->dev, "failed to get IRQ[%d]\n", i);
+			rc = -EINVAL;
+			goto err_no_dma;
+		}
+	}
+
+	pm_runtime_enable(&pdev->dev);
+	pm_runtime_set_active(&pdev->dev);
+
+	rc = dma_async_device_register(&mtkd->ddev);
+	if (rc)
+		goto rpm_disable;
+
+	platform_set_drvdata(pdev, mtkd);
+
+	/* Device-tree DMA controller registration */
+	rc = of_dma_controller_register(np, of_dma_xlate_by_chan_id, mtkd);
+	if (rc)
+		goto dma_remove;
+
+	return rc;
+
+dma_remove:
+	dma_async_device_unregister(&mtkd->ddev);
+rpm_disable:
+	pm_runtime_disable(&pdev->dev);
+err_no_dma:
+	mtk_uart_apdma_free(mtkd);
+	return rc;
+}
+
+static int mtk_uart_apdma_remove(struct platform_device *pdev)
+{
+	struct mtk_uart_apdmadev *mtkd = platform_get_drvdata(pdev);
+
+	if (pdev->dev.of_node)
+		of_dma_controller_free(pdev->dev.of_node);
+
+	pm_runtime_disable(&pdev->dev);
+	pm_runtime_put_noidle(&pdev->dev);
+
+	dma_async_device_unregister(&mtkd->ddev);
+	mtk_uart_apdma_free(mtkd);
+
+	return 0;
+}
+
+#ifdef CONFIG_PM_SLEEP
+static int mtk_uart_apdma_suspend(struct device *dev)
+{
+	struct mtk_uart_apdmadev *mtkd = dev_get_drvdata(dev);
+
+	if (!pm_runtime_suspended(dev))
+		clk_disable_unprepare(mtkd->clk);
+
+	return 0;
+}
+
+static int mtk_uart_apdma_resume(struct device *dev)
+{
+	int ret;
+	struct mtk_uart_apdmadev *mtkd = dev_get_drvdata(dev);
+
+	if (!pm_runtime_suspended(dev)) {
+		ret = clk_prepare_enable(mtkd->clk);
+		if (ret)
+			return ret;
+	}
+
+	return 0;
+}
+#endif /* CONFIG_PM_SLEEP */
+
+#ifdef CONFIG_PM
+static int mtk_uart_apdma_runtime_suspend(struct device *dev)
+{
+	struct mtk_uart_apdmadev *mtkd = dev_get_drvdata(dev);
+
+	clk_disable_unprepare(mtkd->clk);
+
+	return 0;
+}
+
+static int mtk_uart_apdma_runtime_resume(struct device *dev)
+{
+	int ret;
+	struct mtk_uart_apdmadev *mtkd = dev_get_drvdata(dev);
+
+	ret = clk_prepare_enable(mtkd->clk);
+	if (ret)
+		return ret;
+
+	return 0;
+}
+#endif /* CONFIG_PM */
+
+static const struct dev_pm_ops mtk_uart_apdma_pm_ops = {
+	SET_SYSTEM_SLEEP_PM_OPS(mtk_uart_apdma_suspend, mtk_uart_apdma_resume)
+	SET_RUNTIME_PM_OPS(mtk_uart_apdma_runtime_suspend,
+			   mtk_uart_apdma_runtime_resume, NULL)
+};
+
+static struct platform_driver mtk_uart_apdma_driver = {
+	.probe	= mtk_uart_apdma_probe,
+	.remove	= mtk_uart_apdma_remove,
+	.driver = {
+		.name		= KBUILD_MODNAME,
+		.pm		= &mtk_uart_apdma_pm_ops,
+		.of_match_table = of_match_ptr(mtk_uart_apdma_match),
+	},
+};
+
+module_platform_driver(mtk_uart_apdma_driver);
+
+MODULE_DESCRIPTION("MediaTek UART APDMA Controller Driver");
+MODULE_AUTHOR("Long Cheng [off-list ref]");
+MODULE_LICENSE("GPL v2");
+