Message-Id: <20220722172335.33404-2-nick.hawkins@hpe.com>
Date:   Fri, 22 Jul 2022 12:23:31 -0500
From:   nick.hawkins@....com
To:     nick.hawkins@....com
Cc:     broonie@...nel.org, robh+dt@...nel.org,
        krzysztof.kozlowski+dt@...aro.org, verdun@....com,
        linux@...linux.org.uk, linux-spi@...r.kernel.org,
        devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org, arnd@...db.de, joel@....id.au
Subject: [PATCH v2 1/5] spi: spi-gxp: Add support for HPE GXP SoCs

From: Nick Hawkins <nick.hawkins@....com>

The GXP supports 3 separate SPI interfaces to accommodate the system
flash, core flash, and other functions. The SPI engine supports variable
clock frequency, selectable 3-byte or 4-byte addressing and a
configurable x1, x2, and x4 command/address/data modes. The memory
buffer for reading and writing ranges between 256 bytes and 8KB. This
driver supports access to the core flash and bios part.

Signed-off-by: Nick Hawkins <nick.hawkins@....com>

---

v2:
 *Removed repeated include file
 *Removed unnecessary initialization of ret variable
 *Removed conditional variable checks where failure is impossible
 *Removed unecessary variable cs and instead used in the initialization
 *Removed blank gxp_spifi_remove function
 *Fixed error messages so they are not repetitive
---
 drivers/spi/Kconfig   |   7 +
 drivers/spi/Makefile  |   1 +
 drivers/spi/spi-gxp.c | 325 ++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 333 insertions(+)
 create mode 100644 drivers/spi/spi-gxp.c

diff --git a/drivers/spi/Kconfig b/drivers/spi/Kconfig
index 3b1044ebc400..543e4a5b5ffa 100644
--- a/drivers/spi/Kconfig
+++ b/drivers/spi/Kconfig
@@ -371,6 +371,13 @@ config SPI_FSL_QUADSPI
 	  This controller does not support generic SPI messages. It only
 	  supports the high-level SPI memory interface.
 
+config SPI_GXP
+	tristate "GXP SPI driver"
+	depends on ARCH_HPE || COMPILE_TEST
+	help
+	 This enables support for the driver for GXP bus attached SPI
+	 controllers.
+
 config SPI_HISI_KUNPENG
 	tristate "HiSilicon SPI Controller for Kunpeng SoCs"
 	depends on (ARM64 && ACPI) || COMPILE_TEST
diff --git a/drivers/spi/Makefile b/drivers/spi/Makefile
index 0f44eb6083a5..ca5f204017ee 100644
--- a/drivers/spi/Makefile
+++ b/drivers/spi/Makefile
@@ -57,6 +57,7 @@ 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-$(CONFIG_SPI_GXP)			+= spi-gxp.o
 obj-$(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
diff --git a/drivers/spi/spi-gxp.c b/drivers/spi/spi-gxp.c
new file mode 100644
index 000000000000..9ea355f7d64f
--- /dev/null
+++ b/drivers/spi/spi-gxp.c
@@ -0,0 +1,325 @@
+// SPDX-License-Identifier: GPL-2.0=or-later
+/* Copyright (C) 2022 Hewlett-Packard Development Company, L.P. */
+
+#include <linux/iopoll.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/platform_device.h>
+#include <linux/spi/spi.h>
+#include <linux/spi/spi-mem.h>
+
+#define GXP_SPI0_MAX_CHIPSELECT	2
+#define GXP_SPI_SLEEP_TIME	1
+#define GXP_SPI_TIMEOUT (130 * 1000000 / GXP_SPI_SLEEP_TIME)
+
+#define MANUAL_MODE		0
+#define DIRECT_MODE		1
+#define SPILDAT_LEN		256
+
+#define OFFSET_SPIMCFG		0x0
+#define OFFSET_SPIMCTRL		0x4
+#define OFFSET_SPICMD		0x5
+#define OFFSET_SPIDCNT		0x6
+#define OFFSET_SPIADDR		0x8
+#define OFFSET_SPIINTSTS	0xc
+
+#define SPIMCTRL_START		0x01
+#define SPIMCTRL_BUSY		0x02
+#define SPIMCTRL_DIR		0x08
+
+struct gxp_spi;
+
+struct gxp_spi_chip {
+	struct gxp_spi *spifi;
+	u32 cs;
+};
+
+struct gxp_spi_data {
+	u32 max_cs;
+	u32 mode_bits;
+};
+
+struct gxp_spi {
+	const struct gxp_spi_data *data;
+	void __iomem *reg_base;
+	void __iomem *dat_base;
+	void __iomem *dir_base;
+	struct device *dev;
+	struct gxp_spi_chip chips[GXP_SPI0_MAX_CHIPSELECT];
+};
+
+static void gxp_spi_set_mode(struct gxp_spi *spifi, int mode)
+{
+	u8 value;
+	void __iomem *reg_base = spifi->reg_base;
+
+	value = readb(reg_base + OFFSET_SPIMCTRL);
+
+	if (mode == MANUAL_MODE) {
+		writeb(0x55, reg_base + OFFSET_SPICMD);
+		writeb(0xaa, reg_base + OFFSET_SPICMD);
+		value &= ~0x30;
+	} else {
+		value |= 0x30;
+	}
+	writeb(value, reg_base + OFFSET_SPIMCTRL);
+}
+
+static int gxp_spi_read_reg(struct gxp_spi_chip *chip, const struct spi_mem_op *op)
+{
+	int ret;
+	struct gxp_spi *spifi = chip->spifi;
+	void __iomem *reg_base = spifi->reg_base;
+	u32 value;
+
+	value = readl(reg_base + OFFSET_SPIMCFG);
+	value &= ~(1 << 24);
+	value |= (chip->cs << 24);
+	value &= ~(0x07 << 16);
+	value &= ~(0x1f << 19);
+	writel(value, reg_base + OFFSET_SPIMCFG);
+
+	writel(0, reg_base + OFFSET_SPIADDR);
+
+	writeb(op->cmd.opcode, reg_base + OFFSET_SPICMD);
+
+	writew(op->data.nbytes, reg_base + OFFSET_SPIDCNT);
+
+	value = readb(reg_base + OFFSET_SPIMCTRL);
+	value &= ~SPIMCTRL_DIR;
+	value |= SPIMCTRL_START;
+
+	writeb(value, reg_base + OFFSET_SPIMCTRL);
+
+	ret = readb_poll_timeout(reg_base + OFFSET_SPIMCTRL, value,
+				 !(value & SPIMCTRL_BUSY),
+				 GXP_SPI_SLEEP_TIME, GXP_SPI_TIMEOUT);
+	if (ret) {
+		dev_warn(spifi->dev, "read reg busy time out\n");
+		return ret;
+	}
+
+	memcpy_fromio(op->data.buf.in, spifi->dat_base, op->data.nbytes);
+	return ret;
+}
+
+static int gxp_spi_write_reg(struct gxp_spi_chip *chip, const struct spi_mem_op *op)
+{
+	int ret;
+	struct gxp_spi *spifi = chip->spifi;
+	void __iomem *reg_base = spifi->reg_base;
+	u32 value;
+
+	value = readl(reg_base + OFFSET_SPIMCFG);
+	value &= ~(1 << 24);
+	value |= (chip->cs << 24);
+	value &= ~(0x07 << 16);
+	value &= ~(0x1f << 19);
+	writel(value, reg_base + OFFSET_SPIMCFG);
+
+	writel(0, reg_base + OFFSET_SPIADDR);
+
+	writeb(op->cmd.opcode, reg_base + OFFSET_SPICMD);
+
+	memcpy_toio(spifi->dat_base, op->data.buf.in, op->data.nbytes);
+
+	writew(op->data.nbytes, reg_base + OFFSET_SPIDCNT);
+
+	value = readb(reg_base + OFFSET_SPIMCTRL);
+	value |= SPIMCTRL_DIR;
+	value |= SPIMCTRL_START;
+
+	writeb(value, reg_base + OFFSET_SPIMCTRL);
+
+	ret = readb_poll_timeout(reg_base + OFFSET_SPIMCTRL, value,
+				 !(value & SPIMCTRL_BUSY),
+				 GXP_SPI_SLEEP_TIME, GXP_SPI_TIMEOUT);
+	if (ret)
+		dev_warn(spifi->dev, "write reg busy time out\n");
+
+	return ret;
+}
+
+static ssize_t gxp_spi_read(struct gxp_spi_chip *chip, const struct spi_mem_op *op)
+{
+	struct gxp_spi *spifi = chip->spifi;
+	u32 offset = op->addr.val;
+
+	if (chip->cs == 0)
+		offset += 0x4000000;
+
+	memcpy_fromio(op->data.buf.in, spifi->dir_base + offset, op->data.nbytes);
+
+	return 0;
+}
+
+static ssize_t gxp_spi_write(struct gxp_spi_chip *chip, const struct spi_mem_op *op)
+{
+	struct gxp_spi *spifi = chip->spifi;
+	void __iomem *reg_base = spifi->reg_base;
+	u32 write_len;
+	u32 value;
+	int ret;
+
+	write_len = op->data.nbytes;
+	if (write_len > SPILDAT_LEN)
+		write_len = SPILDAT_LEN;
+
+	value = readl(reg_base + OFFSET_SPIMCFG);
+	value &= ~(1 << 24);
+	value |= (chip->cs << 24);
+	value &= ~(0x07 << 16);
+	value |= (op->addr.nbytes << 16);
+	value &= ~(0x1f << 19);
+	writel(value, reg_base + OFFSET_SPIMCFG);
+
+	writel(op->addr.val, reg_base + OFFSET_SPIADDR);
+
+	writeb(op->cmd.opcode, reg_base + OFFSET_SPICMD);
+
+	writew(write_len, reg_base + OFFSET_SPIDCNT);
+
+	memcpy_toio(spifi->dat_base, op->data.buf.in, write_len);
+
+	value = readb(reg_base + OFFSET_SPIMCTRL);
+	value |= SPIMCTRL_DIR;
+	value |= SPIMCTRL_START;
+
+	writeb(value, reg_base + OFFSET_SPIMCTRL);
+
+	ret = readb_poll_timeout(reg_base + OFFSET_SPIMCTRL, value,
+				 !(value & SPIMCTRL_BUSY),
+				 GXP_SPI_SLEEP_TIME, GXP_SPI_TIMEOUT);
+	if (ret) {
+		dev_warn(spifi->dev, "write busy time out\n");
+		return ret;
+	}
+
+	return write_len;
+}
+
+static int do_gxp_exec_mem_op(struct spi_mem *mem, const struct spi_mem_op *op)
+{
+	struct gxp_spi *spifi = spi_controller_get_devdata(mem->spi->master);
+	struct gxp_spi_chip *chip = &spifi->chips[mem->spi->chip_select];
+	int ret;
+
+	if (op->data.dir == SPI_MEM_DATA_IN) {
+		if (!op->addr.nbytes)
+			ret = gxp_spi_read_reg(chip, op);
+		else
+			ret = gxp_spi_read(chip, op);
+	} else {
+		if (!op->addr.nbytes)
+			ret = gxp_spi_write_reg(chip, op);
+		else
+			ret = gxp_spi_write(chip, op);
+	}
+
+	return ret;
+}
+
+static int gxp_exec_mem_op(struct spi_mem *mem, const struct spi_mem_op *op)
+{
+	int ret;
+
+	ret = do_gxp_exec_mem_op(mem, op);
+	if (ret)
+		dev_err(&mem->spi->dev, "operation failed: %d", ret);
+
+	return ret;
+}
+
+static const struct spi_controller_mem_ops gxp_spi_mem_ops = {
+	.exec_op = gxp_exec_mem_op,
+};
+
+static int gxp_spi_setup(struct spi_device *spi)
+{
+	struct gxp_spi *spifi = spi_controller_get_devdata(spi->master);
+	unsigned int cs = spi->chip_select;
+	struct gxp_spi_chip *chip = &spifi->chips[cs];
+
+	chip->spifi = spifi;
+	chip->cs = cs;
+
+	gxp_spi_set_mode(spifi, MANUAL_MODE);
+
+	return 0;
+}
+
+static int gxp_spifi_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	const struct gxp_spi_data *data;
+	struct spi_controller *ctlr;
+	struct gxp_spi *spifi;
+	struct resource *res;
+	int ret;
+
+	data = of_device_get_match_data(&pdev->dev);
+
+	ctlr = devm_spi_alloc_master(dev, sizeof(*spifi));
+	if (!ctlr)
+		return -ENOMEM;
+
+	spifi = spi_controller_get_devdata(ctlr);
+
+	platform_set_drvdata(pdev, spifi);
+	spifi->data = data;
+	spifi->dev = dev;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	spifi->reg_base = devm_ioremap_resource(&pdev->dev, res);
+	if (IS_ERR(spifi->reg_base))
+		return PTR_ERR(spifi->reg_base);
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 1);
+	spifi->dat_base = devm_ioremap_resource(&pdev->dev, res);
+	if (IS_ERR(spifi->dat_base))
+		return PTR_ERR(spifi->dat_base);
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 2);
+	spifi->dir_base = devm_ioremap_resource(&pdev->dev, res);
+	if (IS_ERR(spifi->dir_base))
+		return PTR_ERR(spifi->dir_base);
+
+	ctlr->mode_bits = data->mode_bits;
+	ctlr->bus_num = pdev->id;
+	ctlr->mem_ops = &gxp_spi_mem_ops;
+	ctlr->setup = gxp_spi_setup;
+	ctlr->num_chipselect = data->max_cs;
+	ctlr->dev.of_node = dev->of_node;
+
+	ret = devm_spi_register_controller(dev, ctlr);
+	if (ret) {
+		return dev_err_probe(&pdev->dev, ret,
+				     "failed to register spi controller\n");
+	}
+
+	return 0;
+}
+
+static const struct gxp_spi_data gxp_spifi_data = {
+	.max_cs	= 2,
+	.mode_bits = 0,
+};
+
+static const struct of_device_id gxp_spifi_match[] = {
+	{.compatible = "hpe,gxp-spifi", .data = &gxp_spifi_data },
+	{ /* null */ }
+};
+MODULE_DEVICE_TABLE(of, gxp_spifi_match);
+
+static struct platform_driver gxp_spifi_driver = {
+	.probe = gxp_spifi_probe,
+	.driver = {
+		.name = "gxp-spifi",
+		.of_match_table = gxp_spifi_match,
+	},
+};
+module_platform_driver(gxp_spifi_driver);
+
+MODULE_DESCRIPTION("HPE GXP SPI Flash Interface driver");
+MODULE_AUTHOR("Nick Hawkins <nick.hawkins@....com>");
+MODULE_LICENSE("GPL");
-- 
2.17.1

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