--- /dev/null
--- /dev/null
++// 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_address.h>
++#include <linux/of_device.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 "aspeed-p2a-ctrl"
++
++/* SCU2C is a Misc. Control Register. */
++#define SCU2C 0x2c
++/* SCU180 is the PCIe Configuration Setting Control Register. */
++#define SCU180 0x180
++/* Bit 1 controls the P2A bridge, while bit 0 controls the entire VGA device
++ * on the PCI bus.
++ */
++#define SCU180_ENP2A BIT(1)
++
++/* The ast2400/2500 both have six ranges. */
++#define P2A_REGION_COUNT 6
++
++struct region {
++ u64 min;
++ u64 max;
++ u32 bit;
++};
++
++struct aspeed_p2a_model_data {
++ /* min, max, bit */
++ struct region regions[P2A_REGION_COUNT];
++};
++
++struct aspeed_p2a_ctrl {
++ struct miscdevice miscdev;
++ struct regmap *regmap;
++
++ const struct aspeed_p2a_model_data *config;
++
++ /* Access to these needs to be locked, held via probe, mapping ioctl,
++ * and release, remove.
++ */
++ struct mutex tracking;
++ u32 readers;
++ u32 readerwriters[P2A_REGION_COUNT];
++
++ phys_addr_t mem_base;
++ resource_size_t mem_size;
++};
++
++struct aspeed_p2a_user {
++ struct file *file;
++ struct aspeed_p2a_ctrl *parent;
++
++ /* The entire memory space is opened for reading once the bridge is
++ * enabled, therefore this needs only to be tracked once per user.
++ * If any user has it open for read, the bridge must stay enabled.
++ */
++ u32 read;
++
++ /* Each entry of the array corresponds to a P2A Region. If the user
++ * opens for read or readwrite, the reference goes up here. On
++ * release, this array is walked and references adjusted accordingly.
++ */
++ u32 readwrite[P2A_REGION_COUNT];
++};
++
++static void aspeed_p2a_enable_bridge(struct aspeed_p2a_ctrl *p2a_ctrl)
++{
++ regmap_update_bits(p2a_ctrl->regmap,
++ SCU180, SCU180_ENP2A, SCU180_ENP2A);
++}
++
++static void aspeed_p2a_disable_bridge(struct aspeed_p2a_ctrl *p2a_ctrl)
++{
++ regmap_update_bits(p2a_ctrl->regmap, SCU180, SCU180_ENP2A, 0);
++}
++
++static int aspeed_p2a_mmap(struct file *file, struct vm_area_struct *vma)
++{
++ unsigned long vsize;
++ pgprot_t prot;
++ struct aspeed_p2a_user *priv = file->private_data;
++ struct aspeed_p2a_ctrl *ctrl = priv->parent;
++
++ if (ctrl->mem_base == 0 && ctrl->mem_size == 0)
++ return -EINVAL;
++
++ vsize = vma->vm_end - vma->vm_start;
++ prot = vma->vm_page_prot;
++
++ if (vma->vm_pgoff + vsize > ctrl->mem_base + ctrl->mem_size)
++ return -EINVAL;
++
++ /* ast2400/2500 AHB accesses are not cache coherent */
++ prot = pgprot_noncached(prot);
++
++ if (remap_pfn_range(vma, vma->vm_start,
++ (ctrl->mem_base >> PAGE_SHIFT) + vma->vm_pgoff,
++ vsize, prot))
++ return -EAGAIN;
++
++ return 0;
++}
++
++static bool aspeed_p2a_region_acquire(struct aspeed_p2a_user *priv,
++ struct aspeed_p2a_ctrl *ctrl,
++ struct aspeed_p2a_ctrl_mapping *map)
++{
++ int i;
++ u64 base, end;
++ bool matched = false;
++
++ base = map->addr;
++ end = map->addr + (map->length - 1);
++
++ /* If the value is a legal u32, it will find a match. */
++ for (i = 0; i < P2A_REGION_COUNT; i++) {
++ const struct region *curr = &ctrl->config->regions[i];
++
++ /* If the top of this region is lower than your base, skip it.
++ */
++ if (curr->max < base)
++ continue;
++
++ /* If the bottom of this region is higher than your end, bail.
++ */
++ if (curr->min > end)
++ break;
++
++ /* Lock this and update it, therefore it someone else is
++ * closing their file out, this'll preserve the increment.
++ */
++ mutex_lock(&ctrl->tracking);
++ ctrl->readerwriters[i] += 1;
++ mutex_unlock(&ctrl->tracking);
++
++ /* Track with the user, so when they close their file, we can
++ * decrement properly.
++ */
++ priv->readwrite[i] += 1;
++
++ /* Enable the region as read-write. */
++ regmap_update_bits(ctrl->regmap, SCU2C, curr->bit, 0);
++ matched = true;
++ }
++
++ return matched;
++}
++
++static long aspeed_p2a_ioctl(struct file *file, unsigned int cmd,
++ unsigned long data)
++{
++ struct aspeed_p2a_user *priv = file->private_data;
++ struct aspeed_p2a_ctrl *ctrl = priv->parent;
++ void __user *arg = (void __user *)data;
++ struct aspeed_p2a_ctrl_mapping map;
++
++ if (copy_from_user(&map, arg, sizeof(map)))
++ return -EFAULT;
++
++ switch (cmd) {
++ case ASPEED_P2A_CTRL_IOCTL_SET_WINDOW:
++ /* If they want a region to be read-only, since the entire
++ * region is read-only once enabled, we just need to track this
++ * user wants to read from the bridge, and if it's not enabled.
++ * Enable it.
++ */
++ if (map.flags == ASPEED_P2A_CTRL_READ_ONLY) {
++ mutex_lock(&ctrl->tracking);
++ ctrl->readers += 1;
++ mutex_unlock(&ctrl->tracking);
++
++ /* Track with the user, so when they close their file,
++ * we can decrement properly.
++ */
++ priv->read += 1;
++ } else if (map.flags == ASPEED_P2A_CTRL_READWRITE) {
++ /* If we don't acquire any region return error. */
++ if (!aspeed_p2a_region_acquire(priv, ctrl, &map)) {
++ return -EINVAL;
++ }
++ } else {
++ /* Invalid map flags. */
++ return -EINVAL;
++ }
++
++ aspeed_p2a_enable_bridge(ctrl);
++ return 0;
++ case ASPEED_P2A_CTRL_IOCTL_GET_MEMORY_CONFIG:
++ /* This is a request for the memory-region and corresponding
++ * length that is used by the driver for mmap.
++ */
++
++ map.flags = 0;
++ map.addr = ctrl->mem_base;
++ map.length = ctrl->mem_size;
++
++ return copy_to_user(arg, &map, sizeof(map)) ? -EFAULT : 0;
++ }
++
++ return -EINVAL;
++}
++
++
++/*
++ * 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)
++{
++ struct aspeed_p2a_user *priv;
++
++ priv = kmalloc(sizeof(*priv), GFP_KERNEL);
++ if (!priv)
++ return -ENOMEM;
++
++ priv->file = file;
++ priv->read = 0;
++ memset(priv->readwrite, 0, sizeof(priv->readwrite));
++
++ /* The file's private_data is initialized to the p2a_ctrl. */
++ priv->parent = file->private_data;
++
++ /* Set the file's private_data to the user's data. */
++ file->private_data = priv;
++
++ return 0;
++}
++
++/*
++ * 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)
++{
++ int i;
++ u32 bits = 0;
++ bool open_regions = false;
++ struct aspeed_p2a_user *priv = file->private_data;
++
++ /* Lock others from changing these values until everything is updated
++ * in one pass.
++ */
++ mutex_lock(&priv->parent->tracking);
++
++ priv->parent->readers -= priv->read;
++
++ for (i = 0; i < P2A_REGION_COUNT; i++) {
++ priv->parent->readerwriters[i] -= priv->readwrite[i];
++
++ if (priv->parent->readerwriters[i] > 0)
++ open_regions = true;
++ else
++ bits |= priv->parent->config->regions[i].bit;
++ }
++
++ /* Setting a bit to 1 disables the region, so let's just OR with the
++ * above to disable any.
++ */
++
++ /* Note, if another user is trying to ioctl, they can't grab tracking,
++ * and therefore can't grab either register mutex.
++ * If another user is trying to close, they can't grab tracking either.
++ */
++ regmap_update_bits(priv->parent->regmap, SCU2C, bits, bits);
++
++ /* If parent->readers is zero and open windows is 0, disable the
++ * bridge.
++ */
++ if (!open_regions && priv->parent->readers == 0)
++ aspeed_p2a_disable_bridge(priv->parent);
++
++ mutex_unlock(&priv->parent->tracking);
++
++ kfree(priv);
++
++ return 0;
++}
++
++static const struct file_operations aspeed_p2a_ctrl_fops = {
++ .owner = THIS_MODULE,
++ .mmap = aspeed_p2a_mmap,
++ .unlocked_ioctl = aspeed_p2a_ioctl,
++ .open = aspeed_p2a_open,
++ .release = aspeed_p2a_release,
++};
++
++/* The regions are controlled by SCU2C */
++static void aspeed_p2a_disable_all(struct aspeed_p2a_ctrl *p2a_ctrl)
++{
++ int i;
++ u32 value = 0;
++
++ for (i = 0; i < P2A_REGION_COUNT; i++)
++ value |= p2a_ctrl->config->regions[i].bit;
++
++ regmap_update_bits(p2a_ctrl->regmap, SCU2C, value, value);
++
++ /* Disable the bridge. */
++ aspeed_p2a_disable_bridge(p2a_ctrl);
++}
++
++static int aspeed_p2a_ctrl_probe(struct platform_device *pdev)
++{
++ struct aspeed_p2a_ctrl *misc_ctrl;
++ struct device *dev;
++ struct resource resm;
++ struct device_node *node;
++ int rc = 0;
++
++ dev = &pdev->dev;
++
++ misc_ctrl = devm_kzalloc(dev, sizeof(*misc_ctrl), GFP_KERNEL);
++ if (!misc_ctrl)
++ return -ENOMEM;
++
++ mutex_init(&misc_ctrl->tracking);
++
++ /* optional. */
++ node = of_parse_phandle(dev->of_node, "memory-region", 0);
++ if (node) {
++ rc = of_address_to_resource(node, 0, &resm);
++ of_node_put(node);
++ if (rc) {
++ dev_err(dev, "Couldn't address to resource for reserved memory\n");
++ return -ENODEV;
++ }
++
++ misc_ctrl->mem_size = resource_size(&resm);
++ misc_ctrl->mem_base = resm.start;
++ }
++
++ misc_ctrl->regmap = syscon_node_to_regmap(pdev->dev.parent->of_node);
++ if (IS_ERR(misc_ctrl->regmap)) {
++ dev_err(dev, "Couldn't get regmap\n");
++ return -ENODEV;
++ }
++
++ misc_ctrl->config = of_device_get_match_data(dev);
++
++ dev_set_drvdata(&pdev->dev, misc_ctrl);
++
++ aspeed_p2a_disable_all(misc_ctrl);
++
++ misc_ctrl->miscdev.minor = MISC_DYNAMIC_MINOR;
++ misc_ctrl->miscdev.name = DEVICE_NAME;
++ misc_ctrl->miscdev.fops = &aspeed_p2a_ctrl_fops;
++ misc_ctrl->miscdev.parent = dev;
++
++ rc = misc_register(&misc_ctrl->miscdev);
++ if (rc)
++ dev_err(dev, "Unable to register device\n");
++
++ return rc;
++}
++
++static int aspeed_p2a_ctrl_remove(struct platform_device *pdev)
++{
++ struct aspeed_p2a_ctrl *p2a_ctrl = dev_get_drvdata(&pdev->dev);
++
++ misc_deregister(&p2a_ctrl->miscdev);
++
++ return 0;
++}
++
++#define SCU2C_DRAM BIT(25)
++#define SCU2C_SPI BIT(24)
++#define SCU2C_SOC BIT(23)
++#define SCU2C_FLASH BIT(22)
++
++static const struct aspeed_p2a_model_data ast2400_model_data = {
++ .regions = {
++ {0x00000000, 0x17FFFFFF, SCU2C_FLASH},
++ {0x18000000, 0x1FFFFFFF, SCU2C_SOC},
++ {0x20000000, 0x2FFFFFFF, SCU2C_FLASH},
++ {0x30000000, 0x3FFFFFFF, SCU2C_SPI},
++ {0x40000000, 0x5FFFFFFF, SCU2C_DRAM},
++ {0x60000000, 0xFFFFFFFF, SCU2C_SOC},
++ }
++};
++
++static const struct aspeed_p2a_model_data ast2500_model_data = {
++ .regions = {
++ {0x00000000, 0x0FFFFFFF, SCU2C_FLASH},
++ {0x10000000, 0x1FFFFFFF, SCU2C_SOC},
++ {0x20000000, 0x3FFFFFFF, SCU2C_FLASH},
++ {0x40000000, 0x5FFFFFFF, SCU2C_SOC},
++ {0x60000000, 0x7FFFFFFF, SCU2C_SPI},
++ {0x80000000, 0xFFFFFFFF, SCU2C_DRAM},
++ }
++};
++
++static const struct of_device_id aspeed_p2a_ctrl_match[] = {
++ { .compatible = "aspeed,ast2400-p2a-ctrl",
++ .data = &ast2400_model_data },
++ { .compatible = "aspeed,ast2500-p2a-ctrl",
++ .data = &ast2500_model_data },
++ { },
++};
++
++static struct platform_driver aspeed_p2a_ctrl_driver = {
++ .driver = {
++ .name = DEVICE_NAME,
++ .of_match_table = aspeed_p2a_ctrl_match,
++ },
++ .probe = aspeed_p2a_ctrl_probe,
++ .remove = aspeed_p2a_ctrl_remove,
++};
++
++module_platform_driver(aspeed_p2a_ctrl_driver);
++
++MODULE_DEVICE_TABLE(of, aspeed_p2a_ctrl_match);
++MODULE_LICENSE("GPL");
++MODULE_AUTHOR("Patrick Venture <venture@google.com>");
++MODULE_DESCRIPTION("Control for aspeed 2400/2500 P2A VGA HOST to BMC mappings");
projects / linux-2.6-microblaze.git / commitdiff