[V3] spi: Add HiSilicon SPI Controller Driver for Kunpeng SoCs

diff --git a/MAINTAINERS b/MAINTAINERS
index 546aa66..ced2731 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -8080,6 +8080,13 @@  F:	drivers/crypto/hisilicon/sec2/sec_crypto.c
 F:	drivers/crypto/hisilicon/sec2/sec_crypto.h
 F:	drivers/crypto/hisilicon/sec2/sec_main.c
 
+HISILICON SPI Controller DRIVER FOR KUNPENG SOCS
+M:	Jay Fang <f.fangjian@huawei.com>
+L:	linux-spi@vger.kernel.org
+S:	Maintained
+W:	http://www.hisilicon.com
+F:	drivers/spi/spi-hisi-kunpeng.c
+
 HISILICON STAGING DRIVERS FOR HIKEY 960/970
 M:	Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
 L:	devel@driverdev.osuosl.org
diff --git a/drivers/spi/Kconfig b/drivers/spi/Kconfig
index aadaea0..2e284ca 100644
--- a/drivers/spi/Kconfig
+++ b/drivers/spi/Kconfig
@@ -339,6 +339,16 @@  config SPI_FSL_QUADSPI
 	  This controller does not support generic SPI messages. It only
 	  supports the high-level SPI memory interface.
 
+config SPI_HISI_KUNPENG
+	tristate "HiSilicon SPI Controller for Kunpeng SoCs"
+	depends on (ARM64 && ACPI) || COMPILE_TEST
+	help
+	  This enables support for HiSilicon SPI controller found on
+	  Kunpeng SoCs.
+
+	  This driver can also be built as a module. If so, the module
+	  will be called hisi-kunpeng-spi.
+
 config SPI_HISI_SFC_V3XX
 	tristate "HiSilicon SPI NOR Flash Controller for Hi16XX chipsets"
 	depends on (ARM64 && ACPI) || COMPILE_TEST
diff --git a/drivers/spi/Makefile b/drivers/spi/Makefile
index 6fea582..04291ff 100644
--- a/drivers/spi/Makefile
+++ b/drivers/spi/Makefile
@@ -54,6 +54,7 @@  obj-$(CONFIG_SPI_FSL_LPSPI)		+= spi-fsl-lpspi.o
 obj-$(CONFIG_SPI_FSL_QUADSPI)		+= spi-fsl-qspi.o
 obj-$(CONFIG_SPI_FSL_SPI)		+= spi-fsl-spi.o
 obj-$(CONFIG_SPI_GPIO)			+= spi-gpio.o
+obj-$(CONFIG_SPI_HISI_KUNPENG)		+= spi-hisi-kunpeng.o
 obj-$(CONFIG_SPI_HISI_SFC_V3XX)		+= spi-hisi-sfc-v3xx.o
 obj-$(CONFIG_SPI_IMG_SPFI)		+= spi-img-spfi.o
 obj-$(CONFIG_SPI_IMX)			+= spi-imx.o
diff --git a/drivers/spi/spi-hisi-kunpeng.c b/drivers/spi/spi-hisi-kunpeng.c
new file mode 100644
index 00000000..abc0cd5
--- /dev/null
+++ b/drivers/spi/spi-hisi-kunpeng.c
@@ -0,0 +1,505 @@ 
+// SPDX-License-Identifier: GPL-2.0-only
+//
+// HiSilicon SPI Controller Driver for Kunpeng SoCs
+//
+// Copyright (c) 2021 HiSilicon Technologies Co., Ltd.
+// Author: Jay Fang <f.fangjian@huawei.com>
+//
+// This code is based on spi-dw-core.c.
+
+#include <linux/acpi.h>
+#include <linux/bitfield.h>
+#include <linux/delay.h>
+#include <linux/err.h>
+#include <linux/interrupt.h>
+#include <linux/module.h>
+#include <linux/property.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+#include <linux/spi/spi.h>
+
+/* Register offsets */
+#define HISI_SPI_CSCR		0x00	/* cs control register */
+#define HISI_SPI_CR		0x04	/* spi common control register */
+#define HISI_SPI_ENR		0x08	/* spi enable register */
+#define HISI_SPI_FIFOC		0x0c	/* fifo level control register */
+#define HISI_SPI_IMR		0x10	/* interrupt mask register */
+#define HISI_SPI_DIN		0x14	/* data in register */
+#define HISI_SPI_DOUT		0x18	/* data out register */
+#define HISI_SPI_SR		0x1c	/* status register */
+#define HISI_SPI_RISR		0x20	/* raw interrupt status register */
+#define HISI_SPI_ISR		0x24	/* interrupt status register */
+#define HISI_SPI_ICR		0x28	/* interrupt clear register */
+#define HISI_SPI_VERSION	0xe0	/* version register */
+
+/* Bit fields in HISI_SPI_CR */
+#define CR_LOOP_MASK		GENMASK(1, 1)
+#define CR_CPOL_MASK		GENMASK(2, 2)
+#define CR_CPHA_MASK		GENMASK(3, 3)
+#define CR_DIV_PRE_MASK		GENMASK(11, 4)
+#define CR_DIV_POST_MASK	GENMASK(19, 12)
+#define CR_BPW_MASK		GENMASK(24, 20)
+#define CR_SPD_MODE_MASK	GENMASK(25, 25)
+
+/* Bit fields in HISI_SPI_FIFOC */
+#define FIFOC_TX_MASK		GENMASK(5, 3)
+#define FIFOC_RX_MASK		GENMASK(11, 9)
+
+/* Bit fields in HISI_SPI_IMR, 4 bits */
+#define IMR_RXOF		BIT(0)		/* Receive Overflow */
+#define IMR_RXTO		BIT(1)		/* Receive Timeout */
+#define IMR_RX			BIT(2)		/* Receive */
+#define IMR_TX			BIT(3)		/* Transmit */
+#define IMR_MASK		(IMR_RXOF | IMR_RXTO | IMR_RX | IMR_TX)
+
+/* Bit fields in HISI_SPI_SR, 5 bits */
+#define SR_TXE			BIT(0)		/* Transmit FIFO empty */
+#define SR_TXNF			BIT(1)		/* Transmit FIFO not full */
+#define SR_RXNE			BIT(2)		/* Receive FIFO not empty */
+#define SR_RXF			BIT(3)		/* Receive FIFO full */
+#define SR_BUSY			BIT(4)		/* Busy Flag */
+
+/* Bit fields in HISI_SPI_ISR, 4 bits */
+#define ISR_RXOF		BIT(0)		/* Receive Overflow */
+#define ISR_RXTO		BIT(1)		/* Receive Timeout */
+#define ISR_RX			BIT(2)		/* Receive */
+#define ISR_TX			BIT(3)		/* Transmit */
+#define ISR_MASK		(ISR_RXOF | ISR_RXTO | ISR_RX | ISR_TX)
+
+/* Bit fields in HISI_SPI_ICR, 2 bits */
+#define ICR_RXOF		BIT(0)		/* Receive Overflow */
+#define ICR_RXTO		BIT(1)		/* Receive Timeout */
+#define ICR_MASK		(ICR_RXOF | ICR_RXTO)
+
+#define DIV_POST_MAX		0xFF
+#define DIV_POST_MIN		0x00
+#define DIV_PRE_MAX		0xFE
+#define DIV_PRE_MIN		0x02
+#define CLK_DIV_MAX		((1 + DIV_POST_MAX) * DIV_PRE_MAX)
+#define CLK_DIV_MIN		((1 + DIV_POST_MIN) * DIV_PRE_MIN)
+
+#define DEFAULT_NUM_CS		1
+
+#define HISI_SPI_WAIT_TIMEOUT_MS	10UL
+
+enum hisi_spi_rx_level_trig {
+	HISI_SPI_RX_1,
+	HISI_SPI_RX_4,
+	HISI_SPI_RX_8,
+	HISI_SPI_RX_16,
+	HISI_SPI_RX_32,
+	HISI_SPI_RX_64,
+	HISI_SPI_RX_128
+};
+
+enum hisi_spi_tx_level_trig {
+	HISI_SPI_TX_1_OR_LESS,
+	HISI_SPI_TX_4_OR_LESS,
+	HISI_SPI_TX_8_OR_LESS,
+	HISI_SPI_TX_16_OR_LESS,
+	HISI_SPI_TX_32_OR_LESS,
+	HISI_SPI_TX_64_OR_LESS,
+	HISI_SPI_TX_128_OR_LESS
+};
+
+enum hisi_spi_frame_n_bytes {
+	HISI_SPI_N_BYTES_NULL,
+	HISI_SPI_N_BYTES_U8,
+	HISI_SPI_N_BYTES_U16,
+	HISI_SPI_N_BYTES_U32 = 4
+};
+
+/* Slave spi_dev related */
+struct hisi_chip_data {
+	u32 cr;
+	u32 speed_hz;	/* baud rate */
+	u16 clk_div;	/* baud rate divider */
+
+	/* clk_div = (1 + div_post) * div_pre */
+	u8 div_post;	/* value from 0 to 255 */
+	u8 div_pre;	/* value from 2 to 254 (even only!) */
+};
+
+struct hisi_spi {
+	struct device		*dev;
+
+	void __iomem		*regs;
+	int			irq;
+	u32			fifo_len; /* depth of the FIFO buffer */
+
+	/* Current message transfer state info */
+	const void		*tx;
+	unsigned int		tx_len;
+	void			*rx;
+	unsigned int		rx_len;
+	u8			n_bytes; /* current is a 1/2/4 bytes op */
+};
+
+static u32 hisi_spi_busy(struct hisi_spi *hs)
+{
+	return readl(hs->regs + HISI_SPI_SR) & SR_BUSY;
+}
+
+static u32 hisi_spi_rx_not_empty(struct hisi_spi *hs)
+{
+	return readl(hs->regs + HISI_SPI_SR) & SR_RXNE;
+}
+
+static u32 hisi_spi_tx_not_full(struct hisi_spi *hs)
+{
+	return readl(hs->regs + HISI_SPI_SR) & SR_TXNF;
+}
+
+static void hisi_spi_flush_fifo(struct hisi_spi *hs)
+{
+	unsigned long limit = loops_per_jiffy << 1;
+
+	do {
+		while (hisi_spi_rx_not_empty(hs))
+			readl(hs->regs + HISI_SPI_DOUT);
+	} while (hisi_spi_busy(hs) && limit--);
+}
+
+/* Disable the controller and all interrupts */
+static void hisi_spi_disable(struct hisi_spi *hs)
+{
+	writel(0, hs->regs + HISI_SPI_ENR);
+	writel(IMR_MASK, hs->regs + HISI_SPI_IMR);
+	writel(ICR_MASK, hs->regs + HISI_SPI_ICR);
+}
+
+static u8 hisi_spi_n_bytes(struct spi_transfer *transfer)
+{
+	if (transfer->bits_per_word <= 8)
+		return HISI_SPI_N_BYTES_U8;
+	else if (transfer->bits_per_word <= 16)
+		return HISI_SPI_N_BYTES_U16;
+	else
+		return HISI_SPI_N_BYTES_U32;
+}
+
+static void hisi_spi_reader(struct hisi_spi *hs)
+{
+	u32 max = min_t(u32, hs->rx_len, hs->fifo_len);
+	u32 rxw;
+
+	while (hisi_spi_rx_not_empty(hs) && max--) {
+		rxw = readl(hs->regs + HISI_SPI_DOUT);
+		/* Check the transfer's original "rx" is not null */
+		if (hs->rx) {
+			switch (hs->n_bytes) {
+			case HISI_SPI_N_BYTES_U8:
+				*(u8 *)(hs->rx) = rxw;
+				break;
+			case HISI_SPI_N_BYTES_U16:
+				*(u16 *)(hs->rx) = rxw;
+				break;
+			case HISI_SPI_N_BYTES_U32:
+				*(u32 *)(hs->rx) = rxw;
+				break;
+			}
+			hs->rx += hs->n_bytes;
+		}
+		--hs->rx_len;
+	}
+}
+
+static void hisi_spi_writer(struct hisi_spi *hs)
+{
+	u32 max = min_t(u32, hs->tx_len, hs->fifo_len);
+	u32 txw = 0;
+
+	while (hisi_spi_tx_not_full(hs) && max--) {
+		/* Check the transfer's original "tx" is not null */
+		if (hs->tx) {
+			switch (hs->n_bytes) {
+			case HISI_SPI_N_BYTES_U8:
+				txw = *(u8 *)(hs->tx);
+				break;
+			case HISI_SPI_N_BYTES_U16:
+				txw = *(u16 *)(hs->tx);
+				break;
+			case HISI_SPI_N_BYTES_U32:
+				txw = *(u32 *)(hs->tx);
+				break;
+			}
+			hs->tx += hs->n_bytes;
+		}
+		writel(txw, hs->regs + HISI_SPI_DIN);
+		--hs->tx_len;
+	}
+}
+
+static void __hisi_calc_div_reg(struct hisi_chip_data *chip)
+{
+	chip->div_pre = DIV_PRE_MAX;
+	while (chip->div_pre >= DIV_PRE_MIN) {
+		if (chip->clk_div % chip->div_pre == 0)
+			break;
+
+		chip->div_pre -= 2;
+	}
+
+	if (chip->div_pre > chip->clk_div)
+		chip->div_pre = chip->clk_div;
+
+	chip->div_post = (chip->clk_div / chip->div_pre) - 1;
+}
+
+static u32 hisi_calc_effective_speed(struct spi_controller *master,
+			struct hisi_chip_data *chip, u32 speed_hz)
+{
+	u32 effective_speed;
+
+	/* Note clock divider doesn't support odd numbers */
+	chip->clk_div = DIV_ROUND_UP(master->max_speed_hz, speed_hz) + 1;
+	chip->clk_div &= 0xfffe;
+	if (chip->clk_div > CLK_DIV_MAX)
+		chip->clk_div = CLK_DIV_MAX;
+
+	effective_speed = master->max_speed_hz / chip->clk_div;
+	if (chip->speed_hz != effective_speed) {
+		__hisi_calc_div_reg(chip);
+		chip->speed_hz = effective_speed;
+	}
+
+	return effective_speed;
+}
+
+static u32 hisi_spi_prepare_cr(struct spi_device *spi)
+{
+	u32 cr = FIELD_PREP(CR_SPD_MODE_MASK, 1);
+
+	cr |= FIELD_PREP(CR_CPHA_MASK, (spi->mode & SPI_CPHA) ? 1 : 0);
+	cr |= FIELD_PREP(CR_CPOL_MASK, (spi->mode & SPI_CPOL) ? 1 : 0);
+	cr |= FIELD_PREP(CR_LOOP_MASK, (spi->mode & SPI_LOOP) ? 1 : 0);
+
+	return cr;
+}
+
+static void hisi_spi_hw_init(struct hisi_spi *hs)
+{
+	hisi_spi_disable(hs);
+
+	/* FIFO default config */
+	writel(FIELD_PREP(FIFOC_TX_MASK, HISI_SPI_TX_64_OR_LESS) |
+		FIELD_PREP(FIFOC_RX_MASK, HISI_SPI_RX_16),
+		hs->regs + HISI_SPI_FIFOC);
+
+	hs->fifo_len = 256;
+}
+
+static irqreturn_t hisi_spi_irq(int irq, void *dev_id)
+{
+	struct spi_controller *master = dev_id;
+	struct hisi_spi *hs = spi_controller_get_devdata(master);
+	u32 irq_status = readl(hs->regs + HISI_SPI_ISR) & ISR_MASK;
+
+	if (!irq_status)
+		return IRQ_NONE;
+
+	if (!master->cur_msg)
+		return IRQ_HANDLED;
+
+	/* Error handling */
+	if (irq_status & ISR_RXOF) {
+		dev_err(hs->dev, "interrupt_transfer: fifo overflow\n");
+		master->cur_msg->status = -EIO;
+		goto finalize_transfer;
+	}
+
+	/*
+	 * Read data from the Rx FIFO every time. If there is
+	 * nothing left to receive, finalize the transfer.
+	 */
+	hisi_spi_reader(hs);
+	if (!hs->rx_len)
+		goto finalize_transfer;
+
+	/* Send data out when Tx FIFO IRQ triggered */
+	if (irq_status & ISR_TX)
+		hisi_spi_writer(hs);
+
+	return IRQ_HANDLED;
+
+finalize_transfer:
+	hisi_spi_disable(hs);
+	spi_finalize_current_transfer(master);
+	return IRQ_HANDLED;
+}
+
+static int hisi_spi_transfer_one(struct spi_controller *master,
+		struct spi_device *spi, struct spi_transfer *transfer)
+{
+	struct hisi_spi *hs = spi_controller_get_devdata(master);
+	struct hisi_chip_data *chip = spi_get_ctldata(spi);
+	u32 cr = chip->cr;
+
+	/* Update per transfer options for speed and bpw */
+	transfer->effective_speed_hz =
+		hisi_calc_effective_speed(master, chip, transfer->speed_hz);
+	cr |= FIELD_PREP(CR_DIV_PRE_MASK, chip->div_pre);
+	cr |= FIELD_PREP(CR_DIV_POST_MASK, chip->div_post);
+	cr |= FIELD_PREP(CR_BPW_MASK, transfer->bits_per_word - 1);
+	writel(cr, hs->regs + HISI_SPI_CR);
+
+	hisi_spi_flush_fifo(hs);
+
+	hs->n_bytes = hisi_spi_n_bytes(transfer);
+	hs->tx = transfer->tx_buf;
+	hs->tx_len = transfer->len / hs->n_bytes;
+	hs->rx = transfer->rx_buf;
+	hs->rx_len = hs->tx_len;
+
+	/*
+	 * Ensure that the transfer data above has been updated
+	 * before the interrupt to start.
+	 */
+	smp_mb();
+
+	/* Enable all interrupts and the controller */
+	writel(~IMR_MASK, hs->regs + HISI_SPI_IMR);
+	writel(1, hs->regs + HISI_SPI_ENR);
+
+	return 1;
+}
+
+static void hisi_spi_handle_err(struct spi_controller *master,
+		struct spi_message *msg)
+{
+	struct hisi_spi *hs = spi_controller_get_devdata(master);
+
+	hisi_spi_disable(hs);
+
+	/*
+	 * Wait for interrupt handler that is
+	 * already in timeout to complete.
+	 */
+	msleep(HISI_SPI_WAIT_TIMEOUT_MS);
+}
+
+static int hisi_spi_setup(struct spi_device *spi)
+{
+	struct hisi_chip_data *chip;
+
+	/* Only alloc on first setup */
+	chip = spi_get_ctldata(spi);
+	if (!chip) {
+		chip = kzalloc(sizeof(*chip), GFP_KERNEL);
+		if (!chip)
+			return -ENOMEM;
+		spi_set_ctldata(spi, chip);
+	}
+
+	chip->cr = hisi_spi_prepare_cr(spi);
+
+	return 0;
+}
+
+static void hisi_spi_cleanup(struct spi_device *spi)
+{
+	struct hisi_chip_data *chip = spi_get_ctldata(spi);
+
+	kfree(chip);
+	spi_set_ctldata(spi, NULL);
+}
+
+static int hisi_spi_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct spi_controller *master;
+	struct hisi_spi *hs;
+	int ret, irq;
+
+	irq = platform_get_irq(pdev, 0);
+	if (irq < 0)
+		return irq;
+
+	master = devm_spi_alloc_master(dev, sizeof(*hs));
+	if (!master)
+		return -ENOMEM;
+
+	platform_set_drvdata(pdev, master);
+
+	hs = spi_controller_get_devdata(master);
+	hs->dev = dev;
+	hs->irq = irq;
+
+	hs->regs = devm_platform_ioremap_resource(pdev, 0);
+	if (IS_ERR(hs->regs))
+		return PTR_ERR(hs->regs);
+
+	/* Specify maximum SPI clocking speed (master only) by firmware */
+	ret = device_property_read_u32(dev, "spi-max-frequency",
+					&master->max_speed_hz);
+	if (ret) {
+		dev_err(dev, "failed to get max SPI clocking speed, ret=%d\n",
+			ret);
+		return -EINVAL;
+	}
+
+	ret = device_property_read_u16(dev, "num-cs",
+					&master->num_chipselect);
+	if (ret)
+		master->num_chipselect = DEFAULT_NUM_CS;
+
+	master->use_gpio_descriptors = true;
+	master->mode_bits = SPI_CPOL | SPI_CPHA | SPI_CS_HIGH | SPI_LOOP;
+	master->bits_per_word_mask = SPI_BPW_RANGE_MASK(4, 32);
+	master->bus_num = pdev->id;
+	master->setup = hisi_spi_setup;
+	master->cleanup = hisi_spi_cleanup;
+	master->transfer_one = hisi_spi_transfer_one;
+	master->handle_err = hisi_spi_handle_err;
+	master->dev.fwnode = dev->fwnode;
+
+	hisi_spi_hw_init(hs);
+
+	ret = devm_request_irq(dev, hs->irq, hisi_spi_irq, 0, dev_name(dev),
+			master);
+	if (ret < 0) {
+		dev_err(dev, "failed to get IRQ=%d, ret=%d\n", hs->irq, ret);
+		return ret;
+	}
+
+	ret = spi_register_controller(master);
+	if (ret) {
+		dev_err(dev, "failed to register spi master, ret=%d\n", ret);
+		return ret;
+	}
+
+	dev_info(dev, "hw version:0x%x max-freq:%u kHz\n",
+		readl(hs->regs + HISI_SPI_VERSION),
+		master->max_speed_hz / 1000);
+
+	return 0;
+}
+
+static int hisi_spi_remove(struct platform_device *pdev)
+{
+	struct spi_controller *master = platform_get_drvdata(pdev);
+
+	spi_unregister_controller(master);
+
+	return 0;
+}
+
+static const struct acpi_device_id hisi_spi_acpi_match[] = {
+	{"HISI03E1", 0},
+	{}
+};
+MODULE_DEVICE_TABLE(acpi, hisi_spi_acpi_match);
+
+static struct platform_driver hisi_spi_driver = {
+	.probe		= hisi_spi_probe,
+	.remove		= hisi_spi_remove,
+	.driver		= {
+		.name	= "hisi-kunpeng-spi",
+		.acpi_match_table = hisi_spi_acpi_match,
+	},
+};
+module_platform_driver(hisi_spi_driver);
+
+MODULE_AUTHOR("Jay Fang <f.fangjian@huawei.com>");
+MODULE_DESCRIPTION("HiSilicon SPI Controller Driver for Kunpeng SoCs");
+MODULE_LICENSE("GPL v2");