[PATCH 3/4] drivers/misc: Add ASpeed LPC control driver
Cyril Bur
cyrilbur at gmail.com
Thu Jan 12 11:29:09 AEDT 2017
This driver exposes a reserved chunk of BMC ram to userspace as well as
an ioctl interface to control the BMC<->HOST mapping of the LPC bus.
This allows for a communication channel between the BMC and the host
Signed-off-by: Cyril Bur <cyrilbur at gmail.com>
---
drivers/misc/Kconfig | 9 ++
drivers/misc/Makefile | 1 +
drivers/misc/aspeed-lpc-ctrl.c | 269 +++++++++++++++++++++++++++++++++++
include/uapi/linux/aspeed-lpc-ctrl.h | 25 ++++
4 files changed, 304 insertions(+)
create mode 100644 drivers/misc/aspeed-lpc-ctrl.c
create mode 100644 include/uapi/linux/aspeed-lpc-ctrl.h
diff --git a/drivers/misc/Kconfig b/drivers/misc/Kconfig
index 64971baf11fa..8696627ce9d2 100644
--- a/drivers/misc/Kconfig
+++ b/drivers/misc/Kconfig
@@ -766,6 +766,15 @@ config PANEL_BOOT_MESSAGE
An empty message will only clear the display at driver init time. Any other
printf()-formatted message is valid with newline and escape codes.
+config ASPEED_LPC_CTRL
+ depends on (ARCH_ASPEED || COMPILE_TEST) && REGMAP && MFD_SYSCON
+ bool "Build a driver to control the BMC to HOST LPC bus"
+ default "y"
+ ---help---
+ Provides a driver to control BMC to HOST LPC mappings through
+ ioctl()s, the driver aso provides a read/write interface to a BMC ram
+ region where host LPC can be buffered.
+
source "drivers/misc/c2port/Kconfig"
source "drivers/misc/eeprom/Kconfig"
source "drivers/misc/cb710/Kconfig"
diff --git a/drivers/misc/Makefile b/drivers/misc/Makefile
index 31983366090a..de1925a9c80b 100644
--- a/drivers/misc/Makefile
+++ b/drivers/misc/Makefile
@@ -53,6 +53,7 @@ obj-$(CONFIG_ECHO) += echo/
obj-$(CONFIG_VEXPRESS_SYSCFG) += vexpress-syscfg.o
obj-$(CONFIG_CXL_BASE) += cxl/
obj-$(CONFIG_PANEL) += panel.o
+obj-$(CONFIG_ASPEED_LPC_CTRL) += aspeed-lpc-ctrl.o
lkdtm-$(CONFIG_LKDTM) += lkdtm_core.o
lkdtm-$(CONFIG_LKDTM) += lkdtm_bugs.o
diff --git a/drivers/misc/aspeed-lpc-ctrl.c b/drivers/misc/aspeed-lpc-ctrl.c
new file mode 100644
index 000000000000..36ab718681a5
--- /dev/null
+++ b/drivers/misc/aspeed-lpc-ctrl.c
@@ -0,0 +1,269 @@
+/*
+ * Copyright 2016 IBM Corporation
+ *
+ * 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.
+ */
+
+#include <linux/mfd/syscon.h>
+#include <linux/miscdevice.h>
+#include <linux/mm.h>
+#include <linux/module.h>
+#include <linux/of_address.h>
+#include <linux/platform_device.h>
+#include <linux/poll.h>
+#include <linux/regmap.h>
+
+#include <linux/aspeed-lpc-ctrl.h>
+
+#define DEVICE_NAME "aspeed-lpc-ctrl"
+
+#define HICR7 0x8
+#define HICR8 0xc
+
+struct lpc_ctrl {
+ struct miscdevice miscdev;
+ struct regmap *regmap;
+ phys_addr_t base;
+ resource_size_t size;
+ uint32_t pnor_size;
+ uint32_t pnor_base;
+};
+
+static atomic_t lpc_ctrl_open_count = ATOMIC_INIT(0);
+
+static struct lpc_ctrl *file_lpc_ctrl(struct file *file)
+{
+ return container_of(file->private_data, struct lpc_ctrl, miscdev);
+}
+
+static int lpc_ctrl_mmap(struct file *file, struct vm_area_struct *vma)
+{
+ struct lpc_ctrl *lpc_ctrl = file_lpc_ctrl(file);
+ unsigned long vsize = vma->vm_end - vma->vm_start;
+
+ if (vma->vm_pgoff + vsize > lpc_ctrl->base + lpc_ctrl->size)
+ return -EINVAL;
+
+ /* Other checks? */
+
+ if (remap_pfn_range(vma, vma->vm_start,
+ (lpc_ctrl->base >> PAGE_SHIFT) + vma->vm_pgoff,
+ vsize, vma->vm_page_prot))
+ return -EAGAIN;
+
+ return 0;
+}
+
+static int lpc_ctrl_open(struct inode *inode, struct file *file)
+{
+ if (atomic_inc_return(&lpc_ctrl_open_count) == 1)
+ return 0;
+
+ atomic_dec(&lpc_ctrl_open_count);
+ return -EBUSY;
+}
+
+static ssize_t lpc_ctrl_read(struct file *file, char __user *buf,
+ size_t count, loff_t *ppos)
+{
+ if (!access_ok(VERIFY_WRITE, buf, count))
+ return -EFAULT;
+
+ return -EPERM;
+}
+
+static ssize_t lpc_ctrl_write(struct file *file, const char __user *buf,
+ size_t count, loff_t *ppos)
+{
+ if (!access_ok(VERIFY_READ, buf, count))
+ return -EFAULT;
+
+ return -EPERM;
+}
+
+static long lpc_ctrl_ioctl(struct file *file, unsigned int cmd,
+ unsigned long param)
+{
+ long rc;
+ struct lpc_mapping map;
+ struct lpc_ctrl *lpc_ctrl = file_lpc_ctrl(file);
+ void __user *p = (void __user *)param;
+
+ switch (cmd) {
+ case LPC_CTRL_IOCTL_SIZE:
+ return copy_to_user(p, &lpc_ctrl->size,
+ sizeof(lpc_ctrl->size)) ? -EFAULT : 0;
+ case LPC_CTRL_IOCTL_MAP:
+ if (copy_from_user(&map, p, sizeof(map)))
+ return -EFAULT;
+
+
+ /*
+ * The top half of HICR7 is the MSB of the BMC address of the
+ * mapping.
+ * The bottom half of HICR7 is the MSB of the HOST LPC
+ * firmware space address of the mapping.
+ *
+ * The 1 bits in the top of half of HICR8 represent the bits
+ * (in the requested address) that should be ignored and
+ * replaced with those from the top half of HICR7.
+ * The 1 bits in the bottom half of HICR8 represent the bits
+ * (in the requested address) that should be kept and pass
+ * into the BMC address space.
+ */
+
+ rc = regmap_write(lpc_ctrl->regmap, HICR7,
+ (lpc_ctrl->base | (map.hostaddr >> 16)));
+ if (rc)
+ return rc;
+
+ rc = regmap_write(lpc_ctrl->regmap, HICR8,
+ (~(map.size - 1)) | ((map.size >> 16) - 1));
+ return rc;
+ case LPC_CTRL_IOCTL_UNMAP:
+ /*
+ * The top nibble in host lpc addresses references which
+ * firmware space, use space zero hence the & 0x0fff
+ */
+
+ rc = regmap_write(lpc_ctrl->regmap, HICR7,
+ lpc_ctrl->pnor_base | (((-lpc_ctrl->pnor_size) >> 16) & 0x0fff));
+ if (rc)
+ return rc;
+
+ rc = regmap_write(lpc_ctrl->regmap, HICR8,
+ (~(lpc_ctrl->pnor_size - 1)) | ((lpc_ctrl->pnor_size >> 16) - 1));
+ return rc;
+ }
+
+ return -EINVAL;
+}
+
+static int lpc_ctrl_release(struct inode *inode, struct file *file)
+{
+ atomic_dec(&lpc_ctrl_open_count);
+ return 0;
+}
+
+static const struct file_operations lpc_ctrl_fops = {
+ .owner = THIS_MODULE,
+ .mmap = lpc_ctrl_mmap,
+ .open = lpc_ctrl_open,
+ .read = lpc_ctrl_read,
+ .write = lpc_ctrl_write,
+ .release = lpc_ctrl_release,
+ .unlocked_ioctl = lpc_ctrl_ioctl,
+};
+
+static int lpc_ctrl_probe(struct platform_device *pdev)
+{
+ struct lpc_ctrl *lpc_ctrl;
+ struct device *dev;
+ struct device_node *node;
+ struct resource resm;
+ int rc;
+
+ if (!pdev || !pdev->dev.of_node)
+ return -ENODEV;
+
+ dev = &pdev->dev;
+
+ lpc_ctrl = devm_kzalloc(dev, sizeof(*lpc_ctrl), GFP_KERNEL);
+ if (!lpc_ctrl)
+ return -ENOMEM;
+
+ node = of_parse_phandle(dev->of_node, "flash", 0);
+ if (!node) {
+ dev_err(dev, "Didn't find host pnor flash node\n");
+ rc = -ENODEV;
+ goto out;
+ }
+
+ rc = of_property_read_u32_index(node, "reg", 3,
+ &lpc_ctrl->pnor_size);
+ if (rc)
+ return rc;
+ rc = of_property_read_u32_index(node, "reg", 2,
+ &lpc_ctrl->pnor_base);
+ if (rc)
+ return rc;
+
+ dev_info(dev, "Host PNOR base: 0x%08x size: 0x%08x\n",
+ lpc_ctrl->pnor_base, lpc_ctrl->pnor_size);
+
+ dev_set_drvdata(&pdev->dev, lpc_ctrl);
+
+ node = of_parse_phandle(dev->of_node, "memory-region", 0);
+ if (!node) {
+ dev_err(dev, "Didn't find reserved memory\n");
+ rc = -EINVAL;
+ goto out;
+ }
+
+ rc = of_address_to_resource(node, 0, &resm);
+ of_node_put(node);
+ if (rc) {
+ dev_err(dev, "Could address to resource\n");
+ rc = -ENOMEM;
+ goto out;
+ }
+
+ lpc_ctrl->size = resource_size(&resm);
+ lpc_ctrl->base = resm.start;
+
+ lpc_ctrl->regmap = syscon_node_to_regmap(
+ pdev->dev.parent->of_node);
+ if (IS_ERR(lpc_ctrl->regmap)) {
+ dev_err(dev, "Couldn't get regmap\n");
+ rc = -ENODEV;
+ goto out;
+ }
+
+ lpc_ctrl->miscdev.minor = MISC_DYNAMIC_MINOR;
+ lpc_ctrl->miscdev.name = DEVICE_NAME;
+ lpc_ctrl->miscdev.fops = &lpc_ctrl_fops;
+ lpc_ctrl->miscdev.parent = dev;
+ rc = misc_register(&lpc_ctrl->miscdev);
+ if (rc)
+ dev_err(dev, "Unable to register device\n");
+ else
+ dev_info(dev, "Loaded at 0x%08x (0x%08x)\n",
+ lpc_ctrl->base, lpc_ctrl->size);
+
+out:
+ return rc;
+}
+
+static int lpc_ctrl_remove(struct platform_device *pdev)
+{
+ struct lpc_ctrl *lpc_ctrl = dev_get_drvdata(&pdev->dev);
+
+ misc_deregister(&lpc_ctrl->miscdev);
+ lpc_ctrl = NULL;
+
+ return 0;
+}
+
+static const struct of_device_id lpc_ctrl_match[] = {
+ { .compatible = "aspeed,ast2400-lpc-ctrl" },
+ { },
+};
+
+static struct platform_driver lpc_ctrl_driver = {
+ .driver = {
+ .name = DEVICE_NAME,
+ .of_match_table = lpc_ctrl_match,
+ },
+ .probe = lpc_ctrl_probe,
+ .remove = lpc_ctrl_remove,
+};
+
+module_platform_driver(lpc_ctrl_driver);
+
+MODULE_DEVICE_TABLE(of, lpc_ctrl_match);
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Cyril Bur <cyrilbur at gmail.com>");
+MODULE_DESCRIPTION("Linux device interface to control LPC bus");
diff --git a/include/uapi/linux/aspeed-lpc-ctrl.h b/include/uapi/linux/aspeed-lpc-ctrl.h
new file mode 100644
index 000000000000..c5f1caf827ac
--- /dev/null
+++ b/include/uapi/linux/aspeed-lpc-ctrl.h
@@ -0,0 +1,25 @@
+/*
+ * Copyright 2016 IBM Corp.
+ *
+ * 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.
+ */
+
+#ifndef _UAPI_LINUX_LPC_CTRL_H
+#define _UAPI_LINUX_LPC_CTRL_H
+
+#include <linux/ioctl.h>
+
+struct lpc_mapping {
+ uint32_t hostaddr;
+ uint32_t size;
+};
+
+#define __LPC_CTRL_IOCTL_MAGIC 0xb2
+#define LPC_CTRL_IOCTL_SIZE _IOR(__LPC_CTRL_IOCTL_MAGIC, 0x00, uint32_t)
+#define LPC_CTRL_IOCTL_MAP _IOW(__LPC_CTRL_IOCTL_MAGIC, 0x01, struct lpc_mapping)
+#define LPC_CTRL_IOCTL_UNMAP _IO(__LPC_CTRL_IOCTL_MAGIC, 0x02)
+
+#endif /* _UAPI_LINUX_LPC_CTRL_H */
--
2.11.0
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