0055-VIMs-add-gpiomem-support.patch

From 0c998d213c23664f632657308fdeea90960b805b Mon Sep 17 00:00:00 2001
From: Nick Xie <nick@khadas.com>
Date: Sat, 15 May 2021 16:39:23 +0800
Subject: [PATCH 55/67] VIMs: add gpiomem support

Signed-off-by: Nick Xie <nick@khadas.com>
---
 .../amlogic/meson-gxl-s905x-khadas-vim.dts    |  14 +
 .../dts/amlogic/meson-gxm-khadas-vim2.dts     |  14 +
 .../boot/dts/amlogic/meson-khadas-vim3.dtsi   |  14 +
 drivers/char/Kconfig                          |   9 +
 drivers/char/Makefile                         |   1 +
 drivers/char/aml-gpiomem.c                    | 298 ++++++++++++++++++
 6 files changed, 350 insertions(+)
 create mode 100644 drivers/char/aml-gpiomem.c

diff --git a/arch/arm64/boot/dts/amlogic/meson-gxl-s905x-khadas-vim.dts b/arch/arm64/boot/dts/amlogic/meson-gxl-s905x-khadas-vim.dts
index 02473c9e35a6..60d4d0e6aaa4 100644
--- a/arch/arm64/boot/dts/amlogic/meson-gxl-s905x-khadas-vim.dts
+++ b/arch/arm64/boot/dts/amlogic/meson-gxl-s905x-khadas-vim.dts
@@ -44,6 +44,20 @@ power-button {
 		};
 	};
 
+	gpiomem {
+		compatible = "amlogic, gpiomem";
+		reg = <0x0 0xda834000 0x0 0x1000>;
+		dev_name = "gpiomem";
+		status = "okay";
+	};
+
+	gpiomem_ao {
+		compatible = "amlogic, gpiomem";
+		reg = <0x0 0xc8100000 0x0 0x1000>;
+		dev_name = "gpiomem-ao";
+		status = "okay";
+	};
+
 	led-controller {
 		compatible = "pwm-leds";
 
diff --git a/arch/arm64/boot/dts/amlogic/meson-gxm-khadas-vim2.dts b/arch/arm64/boot/dts/amlogic/meson-gxm-khadas-vim2.dts
index f3c5c4a0f160..012fc6723596 100644
--- a/arch/arm64/boot/dts/amlogic/meson-gxm-khadas-vim2.dts
+++ b/arch/arm64/boot/dts/amlogic/meson-gxm-khadas-vim2.dts
@@ -71,6 +71,20 @@ power-button {
 		};
 	};
 
+	gpiomem {
+		compatible = "amlogic, gpiomem";
+		reg = <0x0 0xda834000 0x0 0x1000>;
+		dev_name = "gpiomem";
+		status = "okay";
+	};
+
+	gpiomem_ao {
+		compatible = "amlogic, gpiomem";
+		reg = <0x0 0xc8100000 0x0 0x1000>;
+		dev_name = "gpiomem-ao";
+		status = "okay";
+	};
+
 	hdmi-connector {
 		compatible = "hdmi-connector";
 		type = "a";
diff --git a/arch/arm64/boot/dts/amlogic/meson-khadas-vim3.dtsi b/arch/arm64/boot/dts/amlogic/meson-khadas-vim3.dtsi
index c84bed336d06..7fa1dc10da7e 100644
--- a/arch/arm64/boot/dts/amlogic/meson-khadas-vim3.dtsi
+++ b/arch/arm64/boot/dts/amlogic/meson-khadas-vim3.dtsi
@@ -40,6 +40,20 @@ button-function {
 		};
 	};
 
+	gpiomem {
+		compatible = "amlogic, gpiomem";
+		reg = <0x0 0xff634000 0x0 0x1000>;
+		dev_name = "gpiomem";
+		status = "okay";
+	};
+
+	gpiomem_ao {
+		compatible = "amlogic, gpiomem";
+		reg = <0x0 0xff800000 0x0 0x1000>;
+		dev_name = "gpiomem-ao";
+		status = "okay";
+	};
+
 	leds {
 		compatible = "gpio-leds";
 
diff --git a/drivers/char/Kconfig b/drivers/char/Kconfig
index d229a2d0c017..97890e9697b7 100644
--- a/drivers/char/Kconfig
+++ b/drivers/char/Kconfig
@@ -471,6 +471,15 @@ config ADI
 	  and SSM (Silicon Secured Memory).  Intended consumers of this
 	  driver include crash and makedumpfile.
 
+config AMLOGIC_GPIOMEM
+    tristate "/dev/gpiomem rootless GPIO access via mmap() on the Amlogic"
+    default y
+    help
+      Provides users with root-free access to the GPIO registers
+      on Meson platform. Calling mmap(/dev/gpiomem) will map the GPIO
+      register page to the user's pointer. This drvier can allow to access
+      gpio memory area in user account.
+
 endmenu
 
 config RANDOM_TRUST_CPU
diff --git a/drivers/char/Makefile b/drivers/char/Makefile
index ffce287ef415..063431b3d763 100644
--- a/drivers/char/Makefile
+++ b/drivers/char/Makefile
@@ -47,3 +47,4 @@ obj-$(CONFIG_PS3_FLASH)		+= ps3flash.o
 obj-$(CONFIG_XILLYBUS)		+= xillybus/
 obj-$(CONFIG_POWERNV_OP_PANEL)	+= powernv-op-panel.o
 obj-$(CONFIG_ADI)		+= adi.o
+obj-$(CONFIG_AMLOGIC_GPIOMEM)   += aml-gpiomem.o
diff --git a/drivers/char/aml-gpiomem.c b/drivers/char/aml-gpiomem.c
new file mode 100644
index 000000000000..5c71560acc69
--- /dev/null
+++ b/drivers/char/aml-gpiomem.c
@@ -0,0 +1,298 @@
+/**
+ * GPIO memory device driver
+ *
+ * Creates a chardev /dev/gpiomem which will provide user access to
+ * the Meson's GPIO registers when it is mmap()'d.
+ * No longer need root for user GPIO access, but without relaxing permissions
+ * on /dev/mem.
+ *
+ * Copyright (c) 2019 Wesion Co., Ltd.
+ *
+ * This driver is based on bcm2835-gpiomem.c:
+ * Written by Luke Wren <luke@raspberrypi.org>
+ * Copyright (c) 2015, Raspberry Pi (Trading) Ltd.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions, and the following disclaimer,
+ *    without modification.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. The names of the above-listed copyright holders may not be used
+ *    to endorse or promote products derived from this software without
+ *    specific prior written permission.
+ *
+ * ALTERNATIVELY, this software may be distributed under the terms of the
+ * GNU General Public License ("GPL") version 2, as published by the Free
+ * Software Foundation.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
+ * IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
+ * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+ * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
+ * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+ * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+ * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
+ * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
+ * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/mm.h>
+#include <linux/slab.h>
+#include <linux/cdev.h>
+#include <linux/pagemap.h>
+#include <linux/io.h>
+
+#define DEVICE_NAME "aml-gpiomem"
+#define DRIVER_NAME "gpiomem-aml"
+#define DEVICE_MINOR 0
+
+#define DEVICE_NUM_MAX 2
+
+struct aml_gpiomem_instance {
+	unsigned long gpio_regs_phys;
+	struct device *dev;
+	char dev_name[32];
+	int major;
+};
+
+static struct cdev aml_gpiomem_cdev;
+static dev_t aml_gpiomem_devid;
+static struct class *aml_gpiomem_class;
+static struct device *aml_gpiomem_dev;
+//static struct aml_gpiomem_instance *inst;
+static struct aml_gpiomem_instance *gpiomem_instances[DEVICE_NUM_MAX];
+static int instance_num = 0;
+
+/****************************************************************************
+*
+*   GPIO mem chardev file ops
+*
+***************************************************************************/
+
+static int aml_gpiomem_open(struct inode *inode, struct file *file)
+{
+	int dev = iminor(inode);
+	int major = imajor(inode);
+	int ret = 0;
+	int i = 0;
+	struct aml_gpiomem_instance *inst = NULL;
+
+	for (i=0; i<DEVICE_NUM_MAX; i++) {
+		if (major == gpiomem_instances[i]->major) {
+			inst = gpiomem_instances[i];
+			file->private_data = gpiomem_instances[i];
+		}
+	}
+
+	if (!inst)
+		return -ENXIO;
+
+	if (dev != DEVICE_MINOR) {
+		dev_err(inst->dev, "Unknown minor device: %d", dev);
+		ret = -ENXIO;
+	}
+	return ret;
+}
+
+static int aml_gpiomem_release(struct inode *inode, struct file *file)
+{
+	int dev = iminor(inode);
+	int ret = 0;
+	struct aml_gpiomem_instance *inst = file->private_data;
+
+	if (dev != DEVICE_MINOR) {
+		dev_err(inst->dev, "Unknown minor device %d", dev);
+		ret = -ENXIO;
+	}
+	return ret;
+}
+
+static const struct vm_operations_struct aml_gpiomem_vm_ops = {
+#ifdef CONFIG_HAVE_IOREMAP_PROT
+	.access = generic_access_phys
+#endif
+};
+
+static int aml_gpiomem_mmap(struct file *file, struct vm_area_struct *vma)
+{
+	/* Ignore what the user says - they're getting the GPIO regs
+	   whether they like it or not! */
+	struct aml_gpiomem_instance *inst = file->private_data;
+	unsigned long gpio_page = inst->gpio_regs_phys >> PAGE_SHIFT;
+
+	vma->vm_page_prot = phys_mem_access_prot(file, gpio_page,
+						 PAGE_SIZE,
+						 vma->vm_page_prot);
+	vma->vm_ops = &aml_gpiomem_vm_ops;
+	if (remap_pfn_range(vma, vma->vm_start,
+			gpio_page,
+			PAGE_SIZE,
+			vma->vm_page_prot)) {
+		return -EAGAIN;
+	}
+	return 0;
+}
+
+static const struct file_operations
+aml_gpiomem_fops = {
+	.owner = THIS_MODULE,
+	.open = aml_gpiomem_open,
+	.release = aml_gpiomem_release,
+	.mmap = aml_gpiomem_mmap,
+};
+
+
+ /****************************************************************************
+*
+*   Probe and remove functions
+*
+***************************************************************************/
+
+
+static int aml_gpiomem_probe(struct platform_device *pdev)
+{
+	int err;
+	void *ptr_err;
+	struct device *dev = &pdev->dev;
+	struct resource *ioresource;
+	const char *str;
+	char tmp[64];
+	struct aml_gpiomem_instance *inst = NULL;
+
+	/* Allocate buffers and instance data */
+	inst = kzalloc(sizeof(struct aml_gpiomem_instance), GFP_KERNEL);
+
+	if (!inst) {
+		err = -ENOMEM;
+		goto failed_inst_alloc;
+	}
+
+	inst->dev = dev;
+
+	platform_set_drvdata(pdev, inst);
+
+	ioresource = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	if (ioresource) {
+		inst->gpio_regs_phys = ioresource->start;
+	} else {
+		dev_err(inst->dev, "failed to get IO resource");
+		err = -ENOENT;
+		goto failed_get_resource;
+	}
+
+	err = of_property_read_string(dev->of_node, "dev_name", &str);
+	if (err) {
+		dev_err(inst->dev, "failed to get device name\n");
+		err = -ENOENT;
+		goto failed_get_device_name;
+	}
+	strncpy(inst->dev_name, str, 32);
+	inst->dev_name[31] = '\0';
+
+	/* Create character device entries */
+	sprintf(tmp, "aml-%s", inst->dev_name);
+	err = alloc_chrdev_region(&aml_gpiomem_devid,
+				  DEVICE_MINOR, 1, tmp);
+	if (err != 0) {
+		dev_err(inst->dev, "unable to allocate device number");
+		goto failed_alloc_chrdev;
+	}
+	cdev_init(&aml_gpiomem_cdev, &aml_gpiomem_fops);
+	aml_gpiomem_cdev.owner = THIS_MODULE;
+	err = cdev_add(&aml_gpiomem_cdev, aml_gpiomem_devid, 1);
+	if (err != 0) {
+		dev_err(inst->dev, "unable to register device");
+		goto failed_cdev_add;
+	}
+
+	/* Create sysfs entries */
+	aml_gpiomem_class = class_create(THIS_MODULE, tmp);
+	ptr_err = aml_gpiomem_class;
+	if (IS_ERR(ptr_err))
+		goto failed_class_create;
+
+	aml_gpiomem_dev = device_create(aml_gpiomem_class, NULL,
+					aml_gpiomem_devid, NULL,
+					inst->dev_name);
+	ptr_err = aml_gpiomem_dev;
+	if (IS_ERR(ptr_err))
+		goto failed_device_create;
+
+	inst->major = MAJOR(aml_gpiomem_devid);
+	gpiomem_instances[instance_num++] = inst;
+
+	dev_info(inst->dev, "Initialised: Registers at 0x%08lx\n",
+		inst->gpio_regs_phys);
+
+	return 0;
+
+failed_device_create:
+	class_destroy(aml_gpiomem_class);
+failed_class_create:
+	cdev_del(&aml_gpiomem_cdev);
+	err = PTR_ERR(ptr_err);
+failed_cdev_add:
+	unregister_chrdev_region(aml_gpiomem_devid, 1);
+failed_alloc_chrdev:
+failed_get_device_name:
+failed_get_resource:
+	kfree(inst);
+failed_inst_alloc:
+	dev_err(inst->dev, "could not load aml_gpiomem");
+	return err;
+}
+
+static int aml_gpiomem_remove(struct platform_device *pdev)
+{
+	struct aml_gpiomem_instance *inst = platform_get_drvdata(pdev);
+	struct device *dev = inst->dev;
+
+	kfree(inst);
+	device_destroy(aml_gpiomem_class, aml_gpiomem_devid);
+	class_destroy(aml_gpiomem_class);
+	cdev_del(&aml_gpiomem_cdev);
+	unregister_chrdev_region(aml_gpiomem_devid, 1);
+
+	dev_info(dev, "GPIO mem driver removed - OK");
+	return 0;
+}
+
+ /****************************************************************************
+*
+*   Register the driver with device tree
+*
+***************************************************************************/
+
+static const struct of_device_id aml_gpiomem_of_match[] = {
+	{.compatible = "amlogic, gpiomem",},
+	{ /* sentinel */ },
+};
+
+MODULE_DEVICE_TABLE(of, aml_gpiomem_of_match);
+
+static struct platform_driver aml_gpiomem_driver = {
+	.probe = aml_gpiomem_probe,
+	.remove = aml_gpiomem_remove,
+	.driver = {
+		.name = DRIVER_NAME,
+		.owner = THIS_MODULE,
+		.of_match_table = aml_gpiomem_of_match,
+	},
+};
+
+module_platform_driver(aml_gpiomem_driver);
+
+MODULE_ALIAS("platform:gpiomem-aml");
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("gpiomem driver for accessing GPIO from userspace");
+MODULE_AUTHOR("Nick Xie <nick@khadas.com>");
-- 
2.25.1