// SPDX-License-Identifier: GPL-2.0+ /* * Copyright 2019 Google Inc * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License * as published by the Free Software Foundation; either version * 2 of the License, or (at your option) any later version. * * Provides a simple driver to control the ASPEED P2A interface which allows * the host to read and write to various regions of the BMC's memory. */ #include <linux/fs.h> #include <linux/io.h> #include <linux/mfd/syscon.h> #include <linux/miscdevice.h> #include <linux/mm.h> #include <linux/module.h> #include <linux/mutex.h> #include <linux/of.h> #include <linux/of_address.h> #include <linux/platform_device.h> #include <linux/regmap.h> #include <linux/slab.h> #include <linux/uaccess.h> #include <linux/aspeed-p2a-ctrl.h> #define DEVICE_NAME … /* SCU2C is a Misc. Control Register. */ #define SCU2C … /* SCU180 is the PCIe Configuration Setting Control Register. */ #define SCU180 … /* Bit 1 controls the P2A bridge, while bit 0 controls the entire VGA device * on the PCI bus. */ #define SCU180_ENP2A … /* The ast2400/2500 both have six ranges. */ #define P2A_REGION_COUNT … struct region { … }; struct aspeed_p2a_model_data { … }; struct aspeed_p2a_ctrl { … }; struct aspeed_p2a_user { … }; static void aspeed_p2a_enable_bridge(struct aspeed_p2a_ctrl *p2a_ctrl) { … } static void aspeed_p2a_disable_bridge(struct aspeed_p2a_ctrl *p2a_ctrl) { … } static int aspeed_p2a_mmap(struct file *file, struct vm_area_struct *vma) { … } static bool aspeed_p2a_region_acquire(struct aspeed_p2a_user *priv, struct aspeed_p2a_ctrl *ctrl, struct aspeed_p2a_ctrl_mapping *map) { … } static long aspeed_p2a_ioctl(struct file *file, unsigned int cmd, unsigned long data) { … } /* * When a user opens this file, we create a structure to track their mappings. * * A user can map a region as read-only (bridge enabled), or read-write (bit * flipped, and bridge enabled). Either way, this tracking is used, s.t. when * they release the device references are handled. * * The bridge is not enabled until a user calls an ioctl to map a region, * simply opening the device does not enable it. */ static int aspeed_p2a_open(struct inode *inode, struct file *file) { … } /* * This will close the users mappings. It will go through what they had opened * for readwrite, and decrement those counts. If at the end, this is the last * user, it'll close the bridge. */ static int aspeed_p2a_release(struct inode *inode, struct file *file) { … } static const struct file_operations aspeed_p2a_ctrl_fops = …; /* The regions are controlled by SCU2C */ static void aspeed_p2a_disable_all(struct aspeed_p2a_ctrl *p2a_ctrl) { … } static int aspeed_p2a_ctrl_probe(struct platform_device *pdev) { … } static void aspeed_p2a_ctrl_remove(struct platform_device *pdev) { … } #define SCU2C_DRAM … #define SCU2C_SPI … #define SCU2C_SOC … #define SCU2C_FLASH … static const struct aspeed_p2a_model_data ast2400_model_data = …; static const struct aspeed_p2a_model_data ast2500_model_data = …; static const struct of_device_id aspeed_p2a_ctrl_match[] = …; static struct platform_driver aspeed_p2a_ctrl_driver = …; module_platform_driver(…) …; MODULE_DEVICE_TABLE(of, aspeed_p2a_ctrl_match); MODULE_LICENSE(…) …; MODULE_AUTHOR(…) …; MODULE_DESCRIPTION(…) …;
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