soc: aspeed: Add eSPI driver

The Aspeed eSPI controller is slave device to communicate with
the master through the Enhanced Serial Peripheral Interface (eSPI).
All of the four eSPI channels, namely peripheral, virtual wire,
out-of-band, and flash are supported.

Signed-off-by: Chia-Wei Wang <chiawei_wang@aspeedtech.com>

drivers/soc/aspeed/Kconfig

@@ -42,6 +42,17 @@ config ASPEED_SOCINFO
 	help
 	  Say yes to support decoding of ASPEED BMC information.
 
+config ASPEED_ESPI
+	bool "ASPEED eSPI slave driver"
+	select REGMAP
+	select MFD_SYSCON
+	default n
+	help
+	  Enable driver support for the Aspeed eSPI engine. The eSPI engine
+	  plays as a slave device in BMC to communicate with the Host over
+	  the eSPI interface. The four eSPI channels, namely peripheral,
+	  virtual wire, out-of-band, and flash are supported.
+
 endmenu
 
 endif

drivers/soc/aspeed/Makefile

@@ -3,3 +3,4 @@ obj-$(CONFIG_ASPEED_LPC_CTRL)	+= aspeed-lpc-ctrl.o
 obj-$(CONFIG_ASPEED_LPC_SNOOP)	+= aspeed-lpc-snoop.o
 obj-$(CONFIG_ASPEED_P2A_CTRL)	+= aspeed-p2a-ctrl.o
 obj-$(CONFIG_ASPEED_SOCINFO)	+= aspeed-socinfo.o
+obj-$(CONFIG_ASPEED_ESPI)	+= aspeed-espi-ctrl.o

drivers/soc/aspeed/aspeed-espi-ctrl.c

@@ -0,0 +1,206 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright 2021 Aspeed Technology Inc.
+ */
+#include <linux/io.h>
+#include <linux/irq.h>
+#include <linux/clk.h>
+#include <linux/module.h>
+#include <linux/of_device.h>
+#include <linux/interrupt.h>
+#include <linux/platform_device.h>
+#include <linux/miscdevice.h>
+#include <linux/dma-mapping.h>
+#include <linux/mfd/syscon.h>
+#include <linux/regmap.h>
+#include <linux/uaccess.h>
+#include "aspeed-espi-ioc.h"
+#include "aspeed-espi-ctrl.h"
+
+/* include alloc/free/event/ioctl handlers of the eSPI 4 channels */
+#include "aspeed-espi-perif.h"
+#include "aspeed-espi-vw.h"
+#include "aspeed-espi-oob.h"
+#include "aspeed-espi-flash.h"
+
+#define DEVICE_NAME "aspeed-espi-ctrl"
+
+static irqreturn_t aspeed_espi_ctrl_isr(int irq, void *arg)
+{
+	uint32_t sts;
+	struct aspeed_espi_ctrl *espi_ctrl = (struct aspeed_espi_ctrl *)arg;
+
+	regmap_read(espi_ctrl->map, ESPI_INT_STS, &sts);
+
+	if (sts & ESPI_INT_STS_PERIF_BITS) {
+		aspeed_espi_perif_event(sts, espi_ctrl->perif);
+		regmap_write(espi_ctrl->map, ESPI_INT_STS, sts & ESPI_INT_STS_PERIF_BITS);
+	}
+
+	if (sts & ESPI_INT_STS_VW_BITS) {
+		aspeed_espi_vw_event(sts, espi_ctrl->vw);
+		regmap_write(espi_ctrl->map, ESPI_INT_STS, sts & ESPI_INT_STS_VW_BITS);
+	}
+
+	if (sts & (ESPI_INT_STS_OOB_BITS)) {
+		aspeed_espi_oob_event(sts, espi_ctrl->oob);
+		regmap_write(espi_ctrl->map, ESPI_INT_STS, sts & ESPI_INT_STS_OOB_BITS);
+	}
+
+	if (sts & ESPI_INT_STS_FLASH_BITS) {
+		aspeed_espi_flash_event(sts, espi_ctrl->flash);
+		regmap_write(espi_ctrl->map, ESPI_INT_STS, sts & ESPI_INT_STS_FLASH_BITS);
+	}
+
+	if (sts & ESPI_INT_STS_HW_RST_DEASSERT) {
+		aspeed_espi_perif_enable(espi_ctrl->perif);
+		aspeed_espi_vw_enable(espi_ctrl->vw);
+		aspeed_espi_oob_enable(espi_ctrl->oob);
+		aspeed_espi_flash_enable(espi_ctrl->flash);
+
+		regmap_write(espi_ctrl->map, ESPI_SYSEVT_INT_T0, 0x0);
+		regmap_write(espi_ctrl->map, ESPI_SYSEVT_INT_T1, 0x0);
+		regmap_write(espi_ctrl->map, ESPI_SYSEVT_INT_EN, 0xffffffff);
+
+		regmap_write(espi_ctrl->map, ESPI_SYSEVT1_INT_T0, 0x1);
+		regmap_write(espi_ctrl->map, ESPI_SYSEVT1_INT_EN, 0x1);
+
+		if (espi_ctrl->version == ESPI_AST2500)
+			regmap_write(espi_ctrl->map, ESPI_SYSEVT_INT_T2,
+				     ESPI_SYSEVT_INT_T2_HOST_RST_WARN |
+				     ESPI_SYSEVT_INT_T2_OOB_RST_WARN);
+
+		regmap_update_bits(espi_ctrl->map, ESPI_INT_EN,
+				   ESPI_INT_EN_HW_RST_DEASSERT,
+				   ESPI_INT_EN_HW_RST_DEASSERT);
+
+		regmap_update_bits(espi_ctrl->map, ESPI_SYSEVT,
+				   ESPI_SYSEVT_SLV_BOOT_STS | ESPI_SYSEVT_SLV_BOOT_DONE,
+				   ESPI_SYSEVT_SLV_BOOT_STS | ESPI_SYSEVT_SLV_BOOT_DONE);
+
+		regmap_write(espi_ctrl->map, ESPI_INT_STS, ESPI_INT_STS_HW_RST_DEASSERT);
+	}
+
+	return IRQ_HANDLED;
+}
+
+static int aspeed_espi_ctrl_probe(struct platform_device *pdev)
+{
+	int rc = 0;
+	uint32_t reg;
+	struct aspeed_espi_ctrl *espi_ctrl;
+	struct device *dev = &pdev->dev;
+	struct regmap *scu;
+
+	espi_ctrl = devm_kzalloc(dev, sizeof(*espi_ctrl), GFP_KERNEL);
+	if (!espi_ctrl)
+		return -ENOMEM;
+
+	espi_ctrl->version = (uint32_t)of_device_get_match_data(dev);
+
+	espi_ctrl->map = syscon_node_to_regmap(dev->parent->of_node);
+	if (IS_ERR(espi_ctrl->map)) {
+		dev_err(dev, "cannot get remap\n");
+		return -ENODEV;
+	}
+
+	espi_ctrl->irq = platform_get_irq(pdev, 0);
+	if (espi_ctrl->irq < 0)
+		return espi_ctrl->irq;
+
+	espi_ctrl->clk = devm_clk_get(dev, NULL);
+	if (IS_ERR(espi_ctrl->clk)) {
+		dev_err(dev, "cannot get clock\n");
+		return -ENODEV;
+	}
+
+	rc = clk_prepare_enable(espi_ctrl->clk);
+	if (rc) {
+		dev_err(dev, "cannot enable clock\n");
+		return rc;
+	}
+
+	espi_ctrl->perif = aspeed_espi_perif_alloc(dev, espi_ctrl);
+	if (IS_ERR(espi_ctrl->perif)) {
+		dev_err(dev, "failed to allocate peripheral channel\n");
+		return PTR_ERR(espi_ctrl->perif);
+	}
+
+	espi_ctrl->vw = aspeed_espi_vw_alloc(dev, espi_ctrl);
+	if (IS_ERR(espi_ctrl->vw)) {
+		dev_err(dev, "failed to allocate virtual wire channel\n");
+		return PTR_ERR(espi_ctrl->vw);
+	}
+
+	espi_ctrl->oob = aspeed_espi_oob_alloc(dev, espi_ctrl);
+	if (IS_ERR(espi_ctrl->oob)) {
+		dev_err(dev, "failed to allocate out-of-band channel\n");
+		return PTR_ERR(espi_ctrl->oob);
+	}
+
+	espi_ctrl->flash = aspeed_espi_flash_alloc(dev, espi_ctrl);
+	if (rc) {
+		dev_err(dev, "failed to allocate flash channel\n");
+		return PTR_ERR(espi_ctrl->flash);
+	}
+
+	regmap_write(espi_ctrl->map, ESPI_SYSEVT_INT_T0, 0x0);
+	regmap_write(espi_ctrl->map, ESPI_SYSEVT_INT_T1, 0x0);
+	regmap_write(espi_ctrl->map, ESPI_SYSEVT_INT_EN, 0xffffffff);
+
+	regmap_write(espi_ctrl->map, ESPI_SYSEVT1_INT_T0, 0x1);
+	regmap_write(espi_ctrl->map, ESPI_SYSEVT1_INT_EN, 0x1);
+
+	rc = devm_request_irq(dev, espi_ctrl->irq,
+			      aspeed_espi_ctrl_isr,
+			      0, DEVICE_NAME, espi_ctrl);
+	if (rc) {
+		dev_err(dev, "failed to request IRQ\n");
+		return rc;
+	}
+
+	regmap_update_bits(espi_ctrl->map, ESPI_INT_EN,
+			   ESPI_INT_EN_HW_RST_DEASSERT,
+			   ESPI_INT_EN_HW_RST_DEASSERT);
+
+	dev_set_drvdata(dev, espi_ctrl);
+
+	dev_info(dev, "module loaded\n");
+
+	return 0;
+}
+
+static int aspeed_espi_ctrl_remove(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct aspeed_espi_ctrl *espi_ctrl = dev_get_drvdata(dev);
+
+	aspeed_espi_perif_free(dev, espi_ctrl->perif);
+	aspeed_espi_vw_free(dev, espi_ctrl->vw);
+	aspeed_espi_oob_free(dev, espi_ctrl->oob);
+	aspeed_espi_flash_free(dev, espi_ctrl->flash);
+
+	return 0;
+}
+
+static const struct of_device_id aspeed_espi_ctrl_of_matches[] = {
+	{ .compatible = "aspeed,ast2500-espi-ctrl", .data = (void *)ESPI_AST2500 },
+	{ .compatible = "aspeed,ast2600-espi-ctrl", .data = (void *)ESPI_AST2600 },
+	{ },
+};
+
+static struct platform_driver aspeed_espi_ctrl_driver = {
+	.driver = {
+		.name = DEVICE_NAME,
+		.of_match_table = aspeed_espi_ctrl_of_matches,
+	},
+	.probe = aspeed_espi_ctrl_probe,
+	.remove = aspeed_espi_ctrl_remove,
+};
+
+module_platform_driver(aspeed_espi_ctrl_driver);
+
+MODULE_AUTHOR("Chia-Wei Wang <chiawei_wang@aspeedtech.com>");
+MODULE_AUTHOR("Ryan Chen <ryan_chen@aspeedtech.com>");
+MODULE_DESCRIPTION("Control of Aspeed eSPI Slave Device");
+MODULE_LICENSE("GPL v2");