[PATCH linux 3/3] drivers/misc: Add aspeed lpc controlling driver
Joel Stanley
joel at jms.id.au
Tue Dec 13 11:51:28 AEDT 2016
Hi Cyril,
On Fri, Dec 9, 2016 at 4:43 PM, Cyril Bur <cyrilbur at gmail.com> wrote:
> 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
Jagha and Andrew are both interested in a LPC Host Controller driver.
I like your ioctl approach.
Is the register layout generic to many LPC Host Controllers, or is it
specific to the Aspeed chips? If it's specific then perhaps we should
add the aspeed_ prefix to the filename, kconfig symbol and functions.
Andrew has recently sent device tree bindings upstream for the LPC
address space. You should review them to make sure they describe the
hardware well enough for your purposes:
http://patchwork.ozlabs.org/patch/693032/
With these bindings you will need to perform the memory accesses
through regmap, instead of directly mapping the address space
yourself.
Cheers,
Joel
>
> Signed-off-by: Cyril Bur <cyrilbur at gmail.com>
> ---
> drivers/misc/Kconfig | 7 ++
> drivers/misc/Makefile | 2 +-
> drivers/misc/lpc-ctrl.c | 251 ++++++++++++++++++++++++++++++++++++++++++
> include/uapi/linux/lpc-ctrl.h | 25 +++++
> 4 files changed, 284 insertions(+), 1 deletion(-)
> create mode 100644 drivers/misc/lpc-ctrl.c
> create mode 100644 include/uapi/linux/lpc-ctrl.h
>
> diff --git a/drivers/misc/Kconfig b/drivers/misc/Kconfig
> index 44f191d..2bd3f92 100644
> --- a/drivers/misc/Kconfig
> +++ b/drivers/misc/Kconfig
> @@ -811,6 +811,13 @@ config MBOX_HOST
> ---help---
> Build the MBOX driver
>
> +config LPC_CTRL
> + depends on ARCH_ASPEED
> + bool "Build a driver to control the BMC to HOST LPC bus"
> + default "n"
> + ---help---
> + This will also use a BMC ram region defined in the device tree
> +
> 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 7bcaf30..e8502de 100644
> --- a/drivers/misc/Makefile
> +++ b/drivers/misc/Makefile
> @@ -58,4 +58,4 @@ obj-$(CONFIG_VEXPRESS_SYSCFG) += vexpress-syscfg.o
> obj-$(CONFIG_CXL_BASE) += cxl/
> obj-$(CONFIG_PANEL) += panel.o
> obj-$(CONFIG_MBOX_HOST) += mbox-host.o
> ->>>>>>> 6252f95... fixup! drivers/misc: Add aspeed mbox driver
> +obj-$(CONFIG_LPC_CTRL) += lpc-ctrl.o
> diff --git a/drivers/misc/lpc-ctrl.c b/drivers/misc/lpc-ctrl.c
> new file mode 100644
> index 0000000..f72f44f
> --- /dev/null
> +++ b/drivers/misc/lpc-ctrl.c
> @@ -0,0 +1,251 @@
> +/*
> + * 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/mm.h>
> +#include <linux/module.h>
> +#include <linux/moduleparam.h>
> +#include <linux/errno.h>
> +#include <linux/poll.h>
> +#include <linux/sched.h>
> +#include <linux/spinlock.h>
> +#include <linux/slab.h>
> +#include <linux/init.h>
> +#include <linux/device.h>
> +#include <linux/of.h>
> +#include <linux/of_address.h>
> +#include <linux/platform_device.h>
> +#include <linux/io.h>
> +#include <linux/interrupt.h>
> +#include <linux/delay.h>
> +#include <linux/miscdevice.h>
> +#include <linux/timer.h>
> +#include <linux/jiffies.h>
> +#include <linux/lpc-ctrl.h>
> +
> +#define DEVICE_NAME "lpc-ctrl"
> +
> +#define LPC_HICR7 0x88
> +#define LPC_HICR8 0x8c
> +
> +struct lpc_ctrl {
> + struct miscdevice miscdev;
> + void __iomem *ctrl;
> + phys_addr_t base;
> + resource_size_t size;
> +};
> +
> +
> +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)
> +{
> + return 0;
> +}
> +
> +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;
> +
> + WARN_ON(*ppos);
> +
> + 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;
> +
> + WARN_ON(*ppos);
> +
> + return -EPERM;
> +}
> +
> +static long lpc_ctrl_ioctl(struct file *file, unsigned int cmd,
> + unsigned long param)
> +{
> + 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;
> +
> + iowrite32(lpc_ctrl->base | (map.hostaddr >> 16),
> + lpc_ctrl->ctrl + LPC_HICR7);
> + iowrite32((~(map.size - 1)) | ((map.size >> 16) - 1),
> + lpc_ctrl->ctrl + LPC_HICR8);
> + return 0;
> + case LPC_CTRL_IOCTL_UNMAP:
> + if (copy_from_user(&map, p, sizeof(map)))
> + return -EFAULT;
> +
> + iowrite32((0x3000 << 16) | (0x0e00),
> + lpc_ctrl->ctrl + LPC_HICR7);
> + iowrite32(((~(0x0200 - 1)) << 16) | ((0x0200) - 1),
> + lpc_ctrl->ctrl + LPC_HICR8);
> + return 0;
> + }
> +
> + return -EINVAL;
> +}
> +
> +static int lpc_ctrl_release(struct inode *inode, struct file *file)
> +{
> + 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 *res;
> + 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;
> +
> + dev_set_drvdata(&pdev->dev, lpc_ctrl);
> +
> + res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> + if (!res) {
> + dev_err(dev, "Unable to find resources\n");
> + rc = -ENXIO;
> + goto out_free;
> + }
> +
> + /* Todo unmap this on fail cases and exit */
> + lpc_ctrl->ctrl = devm_ioremap_resource(&pdev->dev, res);
> + if (!lpc_ctrl->ctrl) {
> + rc = -ENOMEM;
> + goto out_free;
> + }
> +
> + node = of_parse_phandle(dev->of_node, "memory-region", 0);
> + if (!node) {
> + /*
> + * Should probaby handle this by allocating 4-64k now and
> + * using that
> + */
> + 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->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");
> + goto out;
> + }
> +
> + dev_info(dev, "Loaded at 0x%08x (0x%08x)\n",
> + lpc_ctrl->base, lpc_ctrl->size);
> + return 0;
> +
> +out:
> + devm_iounmap(&pdev->dev, lpc_ctrl->ctrl);
> +out_free:
> + devm_kfree(dev, lpc_ctrl);
> + 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);
> + devm_iounmap(&pdev->dev, lpc_ctrl->ctrl);
> + devm_kfree(&pdev->dev, lpc_ctrl);
> + lpc_ctrl = NULL;
> +
> + return 0;
> +}
> +
> +static const struct of_device_id lpc_ctrl_match[] = {
> + { .compatible = "aspeed,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/lpc-ctrl.h b/include/uapi/linux/lpc-ctrl.h
> new file mode 100644
> index 0000000..c5f1caf
> --- /dev/null
> +++ b/include/uapi/linux/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 */
> --
> 2.10.2
>
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