[PATCH v4 2/3] spi: mediatek: add spi slave for Mediatek MT2712

[Leilk Liu <leilk.liu@mediatek.com>]

This patch adds basic spi slave for MT2712.

Signed-off-by: Leilk Liu <leilk.liu@mediatek.com>
---
 drivers/spi/Kconfig            |   10 +
 drivers/spi/Makefile           |    1 +
 drivers/spi/spi-slave-mt27xx.c |  554 ++++++++++++++++++++++++++++++++++++++++
 3 files changed, 565 insertions(+)
 create mode 100644 drivers/spi/spi-slave-mt27xx.c

diff --git a/drivers/spi/Kconfig b/drivers/spi/Kconfig
index 671d078..60b13c6 100644
--- a/drivers/spi/Kconfig
+++ b/drivers/spi/Kconfig
@@ -596,6 +596,16 @@ config SPI_SIRF
 	help
 	  SPI driver for CSR SiRFprimaII SoCs
 
+config SPI_SLAVE_MT27XX
+	tristate "MediaTek SPI slave device"
+	depends on ARCH_MEDIATEK || COMPILE_TEST
+	depends on SPI_SLAVE
+	help
+	  This selects the MediaTek(R) SPI slave device driver.
+	  If you want to use MediaTek(R) SPI slave interface,
+	  say Y or M here.If you are not sure, say N.
+	  SPI slave drivers for Mediatek MT27XX series ARM SoCs.
+
 config SPI_SPRD_ADI
 	tristate "Spreadtrum ADI controller"
 	depends on ARCH_SPRD || COMPILE_TEST
diff --git a/drivers/spi/Makefile b/drivers/spi/Makefile
index a90d559..3b469fa 100644
--- a/drivers/spi/Makefile
+++ b/drivers/spi/Makefile
@@ -88,6 +88,7 @@ obj-$(CONFIG_SPI_SH_HSPI)		+= spi-sh-hspi.o
 obj-$(CONFIG_SPI_SH_MSIOF)		+= spi-sh-msiof.o
 obj-$(CONFIG_SPI_SH_SCI)		+= spi-sh-sci.o
 obj-$(CONFIG_SPI_SIRF)		+= spi-sirf.o
+obj-$(CONFIG_SPI_SLAVE_MT27XX)          += spi-slave-mt27xx.o
 obj-$(CONFIG_SPI_SPRD_ADI)		+= spi-sprd-adi.o
 obj-$(CONFIG_SPI_STM32) 		+= spi-stm32.o
 obj-$(CONFIG_SPI_ST_SSC4)		+= spi-st-ssc4.o
diff --git a/drivers/spi/spi-slave-mt27xx.c b/drivers/spi/spi-slave-mt27xx.c
new file mode 100644
index 0000000..d1075433
--- /dev/null
+++ b/drivers/spi/spi-slave-mt27xx.c
@@ -0,0 +1,554 @@
+// SPDX-License-Identifier: GPL-2.0+
+// Copyright (c) 2018 MediaTek Inc.
+
+#include <linux/clk.h>
+#include <linux/device.h>
+#include <linux/dma-mapping.h>
+#include <linux/err.h>
+#include <linux/interrupt.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/pm_runtime.h>
+#include <linux/spi/spi.h>
+
+#define SPIS_IRQ_EN_REG		0x0
+#define SPIS_IRQ_CLR_REG	0x4
+#define SPIS_IRQ_ST_REG		0x8
+#define SPIS_IRQ_MASK_REG	0xc
+#define SPIS_CFG_REG		0x10
+#define SPIS_RX_DATA_REG	0x14
+#define SPIS_TX_DATA_REG	0x18
+#define SPIS_RX_DST_REG		0x1c
+#define SPIS_TX_SRC_REG		0x20
+#define SPIS_DMA_CFG_REG	0x30
+#define SPIS_SOFT_RST_REG	0x40
+
+/* SPIS_IRQ_EN_REG */
+#define DMA_DONE_EN		BIT(7)
+#define DATA_DONE_EN		BIT(2)
+#define RSTA_DONE_EN		BIT(1)
+#define CMD_INVALID_EN		BIT(0)
+
+/* SPIS_IRQ_ST_REG */
+#define DMA_DONE_ST		BIT(7)
+#define DATA_DONE_ST		BIT(2)
+#define RSTA_DONE_ST		BIT(1)
+#define CMD_INVALID_ST		BIT(0)
+
+/* SPIS_IRQ_MASK_REG */
+#define DMA_DONE_MASK		BIT(7)
+#define DATA_DONE_MASK		BIT(2)
+#define RSTA_DONE_MASK		BIT(1)
+#define CMD_INVALID_MASK	BIT(0)
+
+/* SPIS_CFG_REG */
+#define SPIS_TX_ENDIAN		BIT(7)
+#define SPIS_RX_ENDIAN		BIT(6)
+#define SPIS_TXMSBF		BIT(5)
+#define SPIS_RXMSBF		BIT(4)
+#define SPIS_CPHA		BIT(3)
+#define SPIS_CPOL		BIT(2)
+#define SPIS_TX_EN		BIT(1)
+#define SPIS_RX_EN		BIT(0)
+
+/* SPIS_DMA_CFG_REG */
+#define TX_DMA_TRIG_EN		BIT(31)
+#define TX_DMA_EN		BIT(30)
+#define RX_DMA_EN		BIT(29)
+#define TX_DMA_LEN		0xfffff
+
+/* SPIS_SOFT_RST_REG */
+#define SPIS_DMA_ADDR_EN	BIT(1)
+#define SPIS_SOFT_RST		BIT(0)
+
+#define MTK_SPI_SLAVE_MAX_FIFO_SIZE 512U
+
+struct mtk_spi_slave {
+	struct device *dev;
+	void __iomem *base;
+	struct clk *spi_clk;
+	struct completion xfer_done;
+	struct spi_transfer *cur_transfer;
+	bool slave_aborted;
+};
+
+static const struct of_device_id mtk_spi_slave_of_match[] = {
+	{ .compatible = "mediatek,mt2712-spi-slave", },
+	{}
+};
+MODULE_DEVICE_TABLE(of, mtk_spi_slave_of_match);
+
+static void mtk_spi_slave_disable_dma(struct mtk_spi_slave *mdata)
+{
+	u32 reg_val;
+
+	reg_val = readl(mdata->base + SPIS_DMA_CFG_REG);
+	reg_val &= ~RX_DMA_EN;
+	reg_val &= ~TX_DMA_EN;
+	writel(reg_val, mdata->base + SPIS_DMA_CFG_REG);
+}
+
+static void mtk_spi_slave_disable_xfer(struct mtk_spi_slave *mdata)
+{
+	u32 reg_val;
+
+	reg_val = readl(mdata->base + SPIS_CFG_REG);
+	reg_val &= ~SPIS_TX_EN;
+	reg_val &= ~SPIS_RX_EN;
+	writel(reg_val, mdata->base + SPIS_CFG_REG);
+}
+
+static int mtk_spi_slave_wait_for_completion(struct mtk_spi_slave *mdata)
+{
+	if (wait_for_completion_interruptible(&mdata->xfer_done) ||
+	    mdata->slave_aborted) {
+		dev_err(mdata->dev, "interrupted\n");
+		return -EINTR;
+	}
+
+	return 0;
+}
+
+static int mtk_spi_slave_prepare_message(struct spi_controller *ctlr,
+					 struct spi_message *msg)
+{
+	struct mtk_spi_slave *mdata = spi_controller_get_devdata(ctlr);
+	struct spi_device *spi = msg->spi;
+	bool cpha, cpol;
+	u32 reg_val;
+
+	cpha = spi->mode & SPI_CPHA ? 1 : 0;
+	cpol = spi->mode & SPI_CPOL ? 1 : 0;
+
+	reg_val = readl(mdata->base + SPIS_CFG_REG);
+	if (cpha)
+		reg_val |= SPIS_CPHA;
+	else
+		reg_val &= ~SPIS_CPHA;
+	if (cpol)
+		reg_val |= SPIS_CPOL;
+	else
+		reg_val &= ~SPIS_CPOL;
+
+	if (spi->mode & SPI_LSB_FIRST)
+		reg_val &= ~(SPIS_TXMSBF | SPIS_RXMSBF);
+	else
+		reg_val |= SPIS_TXMSBF | SPIS_RXMSBF;
+
+	reg_val &= ~SPIS_TX_ENDIAN;
+	reg_val &= ~SPIS_RX_ENDIAN;
+	writel(reg_val, mdata->base + SPIS_CFG_REG);
+
+	return 0;
+}
+
+static int mtk_spi_slave_fifo_transfer(struct spi_controller *ctlr,
+				       struct spi_device *spi,
+				       struct spi_transfer *xfer)
+{
+	struct mtk_spi_slave *mdata = spi_controller_get_devdata(ctlr);
+	int reg_val, cnt, remainder, ret;
+
+	writel(SPIS_SOFT_RST, mdata->base + SPIS_SOFT_RST_REG);
+
+	reg_val = readl(mdata->base + SPIS_CFG_REG);
+	if (xfer->rx_buf)
+		reg_val |= SPIS_RX_EN;
+	if (xfer->tx_buf)
+		reg_val |= SPIS_TX_EN;
+	writel(reg_val, mdata->base + SPIS_CFG_REG);
+
+	cnt = xfer->len / 4;
+	if (xfer->tx_buf)
+		iowrite32_rep(mdata->base + SPIS_TX_DATA_REG,
+			      xfer->tx_buf, cnt);
+
+	remainder = xfer->len % 4;
+	if (xfer->tx_buf && remainder > 0) {
+		reg_val = 0;
+		memcpy(&reg_val, xfer->tx_buf + cnt * 4, remainder);
+		writel(reg_val, mdata->base + SPIS_TX_DATA_REG);
+	}
+
+	ret = mtk_spi_slave_wait_for_completion(mdata);
+	if (ret) {
+		mtk_spi_slave_disable_xfer(mdata);
+		writel(SPIS_SOFT_RST, mdata->base + SPIS_SOFT_RST_REG);
+	}
+
+	return ret;
+}
+
+static int mtk_spi_slave_dma_transfer(struct spi_controller *ctlr,
+				      struct spi_device *spi,
+				      struct spi_transfer *xfer)
+{
+	struct mtk_spi_slave *mdata = spi_controller_get_devdata(ctlr);
+	struct device *dev = mdata->dev;
+	int reg_val, ret;
+
+	writel(SPIS_SOFT_RST, mdata->base + SPIS_SOFT_RST_REG);
+
+	if (xfer->tx_buf) {
+		/* tx_buf is a const void* where we need a void * for
+		 * the dma mapping
+		 */
+		void *nonconst_tx = (void *)xfer->tx_buf;
+
+		xfer->tx_dma = dma_map_single(dev, nonconst_tx,
+					      xfer->len, DMA_TO_DEVICE);
+		if (dma_mapping_error(dev, xfer->tx_dma)) {
+			ret = -ENOMEM;
+			goto disable_transfer;
+		}
+	}
+
+	if (xfer->rx_buf) {
+		xfer->rx_dma = dma_map_single(dev, xfer->rx_buf,
+					      xfer->len, DMA_FROM_DEVICE);
+		if (dma_mapping_error(dev, xfer->rx_dma)) {
+			ret = -ENOMEM;
+			goto unmap_txdma;
+		}
+	}
+
+	writel(xfer->tx_dma, mdata->base + SPIS_TX_SRC_REG);
+	writel(xfer->rx_dma, mdata->base + SPIS_RX_DST_REG);
+
+	writel(SPIS_DMA_ADDR_EN, mdata->base + SPIS_SOFT_RST_REG);
+
+	/* enable config reg tx rx_enable */
+	reg_val = readl(mdata->base + SPIS_CFG_REG);
+	if (xfer->tx_buf)
+		reg_val |= SPIS_TX_EN;
+	if (xfer->rx_buf)
+		reg_val |= SPIS_RX_EN;
+	writel(reg_val, mdata->base + SPIS_CFG_REG);
+
+	/* config dma */
+	reg_val = 0;
+	reg_val |= (xfer->len - 1) & TX_DMA_LEN;
+	writel(reg_val, mdata->base + SPIS_DMA_CFG_REG);
+
+	reg_val = readl(mdata->base + SPIS_DMA_CFG_REG);
+	if (xfer->tx_buf)
+		reg_val |= TX_DMA_EN;
+	if (xfer->rx_buf)
+		reg_val |= RX_DMA_EN;
+	reg_val |= TX_DMA_TRIG_EN;
+	writel(reg_val, mdata->base + SPIS_DMA_CFG_REG);
+
+	ret = mtk_spi_slave_wait_for_completion(mdata);
+	if (ret)
+		goto unmap_rxdma;
+
+	return 0;
+
+unmap_rxdma:
+	if (xfer->rx_buf)
+		dma_unmap_single(dev, xfer->rx_dma,
+				 xfer->len, DMA_FROM_DEVICE);
+
+unmap_txdma:
+	if (xfer->tx_buf)
+		dma_unmap_single(dev, xfer->tx_dma,
+				 xfer->len, DMA_TO_DEVICE);
+
+disable_transfer:
+	mtk_spi_slave_disable_dma(mdata);
+	mtk_spi_slave_disable_xfer(mdata);
+	writel(SPIS_SOFT_RST, mdata->base + SPIS_SOFT_RST_REG);
+
+	return ret;
+}
+
+static int mtk_spi_slave_transfer_one(struct spi_controller *ctlr,
+				      struct spi_device *spi,
+				      struct spi_transfer *xfer)
+{
+	struct mtk_spi_slave *mdata = spi_controller_get_devdata(ctlr);
+
+	reinit_completion(&mdata->xfer_done);
+	mdata->slave_aborted = false;
+	mdata->cur_transfer = xfer;
+
+	if (xfer->len > MTK_SPI_SLAVE_MAX_FIFO_SIZE)
+		return mtk_spi_slave_dma_transfer(ctlr, spi, xfer);
+	else
+		return mtk_spi_slave_fifo_transfer(ctlr, spi, xfer);
+}
+
+static int mtk_spi_slave_setup(struct spi_device *spi)
+{
+	struct mtk_spi_slave *mdata = spi_controller_get_devdata(spi->master);
+	u32 reg_val;
+
+	reg_val = DMA_DONE_EN | DATA_DONE_EN |
+		  RSTA_DONE_EN | CMD_INVALID_EN;
+	writel(reg_val, mdata->base + SPIS_IRQ_EN_REG);
+
+	reg_val = DMA_DONE_MASK | DATA_DONE_MASK |
+		  RSTA_DONE_MASK | CMD_INVALID_MASK;
+	writel(reg_val, mdata->base + SPIS_IRQ_MASK_REG);
+
+	mtk_spi_slave_disable_dma(mdata);
+	mtk_spi_slave_disable_xfer(mdata);
+
+	return 0;
+}
+
+static int mtk_slave_abort(struct spi_controller *ctlr)
+{
+	struct mtk_spi_slave *mdata = spi_controller_get_devdata(ctlr);
+
+	mdata->slave_aborted = true;
+	complete(&mdata->xfer_done);
+
+	return 0;
+}
+
+static irqreturn_t mtk_spi_slave_interrupt(int irq, void *dev_id)
+{
+	struct spi_controller *ctlr = dev_id;
+	struct mtk_spi_slave *mdata = spi_controller_get_devdata(ctlr);
+	struct spi_transfer *trans = mdata->cur_transfer;
+	u32 int_status, reg_val, cnt, remainder;
+
+	int_status = readl(mdata->base + SPIS_IRQ_ST_REG);
+	writel(int_status, mdata->base + SPIS_IRQ_CLR_REG);
+
+	if (!trans)
+		return IRQ_NONE;
+
+	if ((int_status & DMA_DONE_ST) &&
+	    ((int_status & DATA_DONE_ST) ||
+	    (int_status & RSTA_DONE_ST))) {
+		writel(SPIS_SOFT_RST, mdata->base + SPIS_SOFT_RST_REG);
+
+		if (trans->tx_buf)
+			dma_unmap_single(mdata->dev, trans->tx_dma,
+					 trans->len, DMA_TO_DEVICE);
+		if (trans->rx_buf)
+			dma_unmap_single(mdata->dev, trans->rx_dma,
+					 trans->len, DMA_FROM_DEVICE);
+
+		mtk_spi_slave_disable_dma(mdata);
+		mtk_spi_slave_disable_xfer(mdata);
+	}
+
+	if ((!(int_status & DMA_DONE_ST)) &&
+	    ((int_status & DATA_DONE_ST) ||
+	    (int_status & RSTA_DONE_ST))) {
+		cnt = trans->len / 4;
+		if (trans->rx_buf)
+			ioread32_rep(mdata->base + SPIS_RX_DATA_REG,
+				     trans->rx_buf, cnt);
+		remainder = trans->len % 4;
+		if (trans->rx_buf && remainder > 0) {
+			reg_val = readl(mdata->base + SPIS_RX_DATA_REG);
+			memcpy(trans->rx_buf + (cnt * 4),
+			       &reg_val, remainder);
+		}
+
+		mtk_spi_slave_disable_xfer(mdata);
+	}
+
+	if (int_status & CMD_INVALID_ST) {
+		dev_warn(&ctlr->dev, "cmd invalid\n");
+		return IRQ_NONE;
+	}
+
+	mdata->cur_transfer = NULL;
+	complete(&mdata->xfer_done);
+
+	return IRQ_HANDLED;
+}
+
+static int mtk_spi_slave_probe(struct platform_device *pdev)
+{
+	struct spi_controller *ctlr;
+	struct mtk_spi_slave *mdata;
+	struct resource *res;
+	int irq, ret;
+
+	ctlr = spi_alloc_slave(&pdev->dev, sizeof(*mdata));
+	if (!ctlr) {
+		dev_err(&pdev->dev, "failed to alloc spi slave\n");
+		return -ENOMEM;
+	}
+
+	ctlr->auto_runtime_pm = true;
+	ctlr->dev.of_node = pdev->dev.of_node;
+	ctlr->mode_bits = SPI_CPOL | SPI_CPHA;
+	ctlr->mode_bits |= SPI_LSB_FIRST;
+
+	ctlr->prepare_message = mtk_spi_slave_prepare_message;
+	ctlr->transfer_one = mtk_spi_slave_transfer_one;
+	ctlr->setup = mtk_spi_slave_setup;
+	ctlr->slave_abort = mtk_slave_abort;
+
+	mdata = spi_controller_get_devdata(ctlr);
+
+	platform_set_drvdata(pdev, ctlr);
+
+	init_completion(&mdata->xfer_done);
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	if (!res) {
+		ret = -ENODEV;
+		dev_err(&pdev->dev, "failed to determine base address\n");
+		goto err_put_ctlr;
+	}
+
+	mdata->dev = &pdev->dev;
+
+	mdata->base = devm_ioremap_resource(&pdev->dev, res);
+	if (IS_ERR(mdata->base)) {
+		ret = PTR_ERR(mdata->base);
+		goto err_put_ctlr;
+	}
+
+	irq = platform_get_irq(pdev, 0);
+	if (irq < 0) {
+		dev_err(&pdev->dev, "failed to get irq (%d)\n", irq);
+		ret = irq;
+		goto err_put_ctlr;
+	}
+
+	ret = devm_request_irq(&pdev->dev, irq, mtk_spi_slave_interrupt,
+			       IRQF_TRIGGER_NONE, dev_name(&pdev->dev), ctlr);
+	if (ret) {
+		dev_err(&pdev->dev, "failed to register irq (%d)\n", ret);
+		goto err_put_ctlr;
+	}
+
+	mdata->spi_clk = devm_clk_get(&pdev->dev, "spi");
+	if (IS_ERR(mdata->spi_clk)) {
+		ret = PTR_ERR(mdata->spi_clk);
+		dev_err(&pdev->dev, "failed to get spi-clk: %d\n", ret);
+		goto err_put_ctlr;
+	}
+
+	ret = clk_prepare_enable(mdata->spi_clk);
+	if (ret < 0) {
+		dev_err(&pdev->dev, "failed to enable spi_clk (%d)\n", ret);
+		goto err_put_ctlr;
+	}
+
+	pm_runtime_enable(&pdev->dev);
+
+	ret = devm_spi_register_controller(&pdev->dev, ctlr);
+	if (ret) {
+		dev_err(&pdev->dev,
+			"failed to register slave controller(%d)\n", ret);
+		clk_disable_unprepare(mdata->spi_clk);
+		goto err_disable_runtime_pm;
+	}
+
+	clk_disable_unprepare(mdata->spi_clk);
+
+	return 0;
+
+err_disable_runtime_pm:
+	pm_runtime_disable(&pdev->dev);
+err_put_ctlr:
+	spi_controller_put(ctlr);
+
+	return ret;
+}
+
+static int mtk_spi_slave_remove(struct platform_device *pdev)
+{
+	pm_runtime_disable(&pdev->dev);
+
+	return 0;
+}
+
+#ifdef CONFIG_PM_SLEEP
+static int mtk_spi_slave_suspend(struct device *dev)
+{
+	struct spi_controller *ctlr = dev_get_drvdata(dev);
+	struct mtk_spi_slave *mdata = spi_controller_get_devdata(ctlr);
+	int ret;
+
+	ret = spi_controller_suspend(ctlr);
+	if (ret)
+		return ret;
+
+	if (!pm_runtime_suspended(dev))
+		clk_disable_unprepare(mdata->spi_clk);
+
+	return ret;
+}
+
+static int mtk_spi_slave_resume(struct device *dev)
+{
+	struct spi_controller *ctlr = dev_get_drvdata(dev);
+	struct mtk_spi_slave *mdata = spi_controller_get_devdata(ctlr);
+	int ret;
+
+	if (!pm_runtime_suspended(dev)) {
+		ret = clk_prepare_enable(mdata->spi_clk);
+		if (ret < 0) {
+			dev_err(dev, "failed to enable spi_clk (%d)\n", ret);
+			return ret;
+		}
+	}
+
+	ret = spi_controller_resume(ctlr);
+	if (ret < 0)
+		clk_disable_unprepare(mdata->spi_clk);
+
+	return ret;
+}
+#endif /* CONFIG_PM_SLEEP */
+
+#ifdef CONFIG_PM
+static int mtk_spi_slave_runtime_suspend(struct device *dev)
+{
+	struct spi_controller *ctlr = dev_get_drvdata(dev);
+	struct mtk_spi_slave *mdata = spi_controller_get_devdata(ctlr);
+
+	clk_disable_unprepare(mdata->spi_clk);
+
+	return 0;
+}
+
+static int mtk_spi_slave_runtime_resume(struct device *dev)
+{
+	struct spi_controller *ctlr = dev_get_drvdata(dev);
+	struct mtk_spi_slave *mdata = spi_controller_get_devdata(ctlr);
+	int ret;
+
+	ret = clk_prepare_enable(mdata->spi_clk);
+	if (ret < 0) {
+		dev_err(dev, "failed to enable spi_clk (%d)\n", ret);
+		return ret;
+	}
+
+	return 0;
+}
+#endif /* CONFIG_PM */
+
+static const struct dev_pm_ops mtk_spi_slave_pm = {
+	SET_SYSTEM_SLEEP_PM_OPS(mtk_spi_slave_suspend, mtk_spi_slave_resume)
+	SET_RUNTIME_PM_OPS(mtk_spi_slave_runtime_suspend,
+			   mtk_spi_slave_runtime_resume, NULL)
+};
+
+static struct platform_driver mtk_spi_slave_driver = {
+	.driver = {
+		.name = "mtk-spi-slave",
+		.pm	= &mtk_spi_slave_pm,
+		.of_match_table = mtk_spi_slave_of_match,
+	},
+	.probe = mtk_spi_slave_probe,
+	.remove = mtk_spi_slave_remove,
+};
+
+module_platform_driver(mtk_spi_slave_driver);
+
+MODULE_DESCRIPTION("MTK SPI Slave Controller driver");
+MODULE_AUTHOR("Leilk Liu <leilk.liu@mediatek.com>");
+MODULE_LICENSE("GPL v2");
+MODULE_ALIAS("platform:mtk-spi-slave");
-- 
1.7.9.5