[RFC v1 4/4] ipmi_bmc: bt-aspeed: port driver to IPMI BMC framework
Chris Austen
austenc at us.ibm.com
Wed Aug 9 00:14:59 AEST 2017
"openbmc" <openbmc-bounces+austenc=us.ibm.com at lists.ozlabs.org> wrote on
08/07/2017 10:53:01 PM:
> From: Brendan Higgins <brendanhiggins at google.com>
> To: minyard at acm.org, benjaminfair at google.com, clg at kaod.org,
> joel at jms.id.au, andrew at aj.id.au
> Cc: openipmi-developer at lists.sourceforge.net, Brendan Higgins
> <brendanhiggins at google.com>, openbmc at lists.ozlabs.org, linux-
> kernel at vger.kernel.org
> Date: 08/07/2017 10:55 PM
> Subject: [RFC v1 4/4] ipmi_bmc: bt-aspeed: port driver to IPMI BMC
framework
> Sent by: "openbmc" <openbmc-bounces+austenc=us.ibm.com at lists.ozlabs.org>
>
> From: Benjamin Fair <benjaminfair at google.com>
>
> The driver was handling interaction with userspace on its own. This
> patch changes it to use the functionality of the ipmi_bmc framework
> instead.
>
> Note that this removes the ability for the BMC to set SMS_ATN by making
> an ioctl. If this functionality is required, it can be added back in
> with a later patch.
Isn't SMS_ATN the way a BMC initiates an IPMI message to the OS? Say for
instance a request to shutdown?
>
> Signed-off-by: Benjamin Fair <benjaminfair at google.com>
> Signed-off-by: Brendan Higgins <brendanhiggins at google.com>
> ---
> drivers/char/ipmi_bmc/ipmi_bmc_bt_aspeed.c | 258 ++++++++
> +--------------------
> include/uapi/linux/bt-bmc.h | 18 --
> 2 files changed, 74 insertions(+), 202 deletions(-)
> delete mode 100644 include/uapi/linux/bt-bmc.h
>
> diff --git a/drivers/char/ipmi_bmc/ipmi_bmc_bt_aspeed.c b/drivers/
> char/ipmi_bmc/ipmi_bmc_bt_aspeed.c
> index 70d434bc1cbf..7c8082c511ee 100644
> --- a/drivers/char/ipmi_bmc/ipmi_bmc_bt_aspeed.c
> +++ b/drivers/char/ipmi_bmc/ipmi_bmc_bt_aspeed.c
> @@ -7,25 +7,19 @@
> * 2 of the License, or (at your option) any later version.
> */
>
> -#include <linux/atomic.h>
> -#include <linux/bt-bmc.h>
> #include <linux/errno.h>
> #include <linux/interrupt.h>
> #include <linux/io.h>
> +#include <linux/ipmi_bmc.h>
> #include <linux/mfd/syscon.h>
> -#include <linux/miscdevice.h>
> #include <linux/module.h>
> #include <linux/of.h>
> #include <linux/platform_device.h>
> -#include <linux/poll.h>
> #include <linux/regmap.h>
> #include <linux/sched.h>
> #include <linux/timer.h>
>
> -/*
> - * This is a BMC device used to communicate to the host
> - */
> -#define DEVICE_NAME "ipmi-bt-host"
> +#define DEVICE_NAME "ipmi-bmc-bt-aspeed"
>
> #define BT_IO_BASE 0xe4
> #define BT_IRQ 10
> @@ -61,18 +55,17 @@
> #define BT_BMC_BUFFER_SIZE 256
>
> struct bt_bmc {
> + struct ipmi_bmc_bus bus;
> struct device dev;
> - struct miscdevice miscdev;
> + struct ipmi_bmc_ctx *bmc_ctx;
> + struct bt_msg request;
> struct regmap *map;
> int offset;
> int irq;
> - wait_queue_head_t queue;
> struct timer_list poll_timer;
> - struct mutex mutex;
> + spinlock_t lock;
> };
>
> -static atomic_t open_count = ATOMIC_INIT(0);
> -
> static const struct regmap_config bt_regmap_cfg = {
> .reg_bits = 32,
> .val_bits = 32,
> @@ -158,27 +151,28 @@ static ssize_t bt_writen(struct bt_bmc
> *bt_bmc, u8 *buf, size_t n)
> return n;
> }
>
> +/* TODO(benjaminfair): support ioctl BT_BMC_IOCTL_SMS_ATN */
> static void set_sms_atn(struct bt_bmc *bt_bmc)
> {
> bt_outb(bt_bmc, BT_CTRL_SMS_ATN, BT_CTRL);
> }
>
> -static struct bt_bmc *file_bt_bmc(struct file *file)
> +/* Called with bt_bmc->lock held */
> +static bool __is_request_avail(struct bt_bmc *bt_bmc)
> {
> - return container_of(file->private_data, struct bt_bmc, miscdev);
> + return bt_inb(bt_bmc, BT_CTRL) & BT_CTRL_H2B_ATN;
> }
>
> -static int bt_bmc_open(struct inode *inode, struct file *file)
> +static bool is_request_avail(struct bt_bmc *bt_bmc)
> {
> - struct bt_bmc *bt_bmc = file_bt_bmc(file);
> + unsigned long flags;
> + bool result;
>
> - if (atomic_inc_return(&open_count) == 1) {
> - clr_b_busy(bt_bmc);
> - return 0;
> - }
> + spin_lock_irqsave(&bt_bmc->lock, flags);
> + result = __is_request_avail(bt_bmc);
> + spin_unlock_irqrestore(&bt_bmc->lock, flags);
>
> - atomic_dec(&open_count);
> - return -EBUSY;
> + return result;
> }
>
> /*
> @@ -194,67 +188,43 @@ static int bt_bmc_open(struct inode *inode,
> struct file *file)
> * Length NetFn/LUN Seq Cmd Data
> *
> */
> -static ssize_t bt_bmc_read(struct file *file, char __user *buf,
> - size_t count, loff_t *ppos)
> +static void get_request(struct bt_bmc *bt_bmc)
> {
> - struct bt_bmc *bt_bmc = file_bt_bmc(file);
> - u8 len;
> - int len_byte = 1;
> - u8 kbuffer[BT_BMC_BUFFER_SIZE];
> - ssize_t ret = 0;
> - ssize_t nread;
> + u8 *request_buf = (u8 *) &bt_bmc->request;
> + unsigned long flags;
>
> - if (!access_ok(VERIFY_WRITE, buf, count))
> - return -EFAULT;
> + spin_lock_irqsave(&bt_bmc->lock, flags);
>
> - WARN_ON(*ppos);
> -
> - if (wait_event_interruptible(bt_bmc->queue,
> - bt_inb(bt_bmc, BT_CTRL) & BT_CTRL_H2B_ATN))
> - return -ERESTARTSYS;
> -
> - mutex_lock(&bt_bmc->mutex);
> -
> - if (unlikely(!(bt_inb(bt_bmc, BT_CTRL) & BT_CTRL_H2B_ATN))) {
> - ret = -EIO;
> - goto out_unlock;
> + if (!__is_request_avail(bt_bmc)) {
> + spin_unlock_irqrestore(&bt_bmc->lock, flags);
> + return;
> }
>
> set_b_busy(bt_bmc);
> clr_h2b_atn(bt_bmc);
> clr_rd_ptr(bt_bmc);
>
> - /*
> - * The BT frames start with the message length, which does not
> - * include the length byte.
> - */
> - kbuffer[0] = bt_read(bt_bmc);
> - len = kbuffer[0];
> -
> - /* We pass the length back to userspace as well */
> - if (len + 1 > count)
> - len = count - 1;
> -
> - while (len) {
> - nread = min_t(ssize_t, len, sizeof(kbuffer) - len_byte);
> -
> - bt_readn(bt_bmc, kbuffer + len_byte, nread);
> -
> - if (copy_to_user(buf, kbuffer, nread + len_byte)) {
> - ret = -EFAULT;
> - break;
> - }
> - len -= nread;
> - buf += nread + len_byte;
> - ret += nread + len_byte;
> - len_byte = 0;
> - }
> + bt_bmc->request.len = bt_read(bt_bmc);
> + bt_readn(bt_bmc, request_buf + 1, bt_bmc->request.len);
>
> clr_b_busy(bt_bmc);
> + ipmi_bmc_handle_request(bt_bmc->bmc_ctx, &bt_bmc->request);
> +
> + spin_unlock_irqrestore(&bt_bmc->lock, flags);
> +}
> +
> +static bool bt_bmc_is_response_open(struct ipmi_bmc_bus *bus)
> +{
> + struct bt_bmc *bt_bmc = container_of(bus, struct bt_bmc, bus);
> + bool response_in_progress;
> + unsigned long flags;
> +
> + spin_lock_irqsave(&bt_bmc->lock, flags);
> + response_in_progress = bt_inb(bt_bmc, BT_CTRL) & (BT_CTRL_H_BUSY |
> + BT_CTRL_B2H_ATN);
> + spin_unlock_irqrestore(&bt_bmc->lock, flags);
>
> -out_unlock:
> - mutex_unlock(&bt_bmc->mutex);
> - return ret;
> + return !response_in_progress;
> }
>
> /*
> @@ -263,122 +233,38 @@ static ssize_t bt_bmc_read(struct file *file,
> char __user *buf,
> * Byte 1 Byte 2 Byte 3 Byte 4 Byte 5 Byte 6:N
> * Length NetFn/LUN Seq Cmd Code Data
> */
> -static ssize_t bt_bmc_write(struct file *file, const char __user *buf,
> - size_t count, loff_t *ppos)
> +static int bt_bmc_send_response(struct ipmi_bmc_bus *bus,
> + struct bt_msg *bt_response)
> {
> - struct bt_bmc *bt_bmc = file_bt_bmc(file);
> - u8 kbuffer[BT_BMC_BUFFER_SIZE];
> - ssize_t ret = 0;
> - ssize_t nwritten;
> + struct bt_bmc *bt_bmc = container_of(bus, struct bt_bmc, bus);
> + unsigned long flags;
>
> - /*
> - * send a minimum response size
> - */
> - if (count < 5)
> - return -EINVAL;
> -
> - if (!access_ok(VERIFY_READ, buf, count))
> - return -EFAULT;
> -
> - WARN_ON(*ppos);
> -
> - /*
> - * There's no interrupt for clearing bmc busy so we have to
> - * poll
> - */
> - if (wait_event_interruptible(bt_bmc->queue,
> - !(bt_inb(bt_bmc, BT_CTRL) &
> - (BT_CTRL_H_BUSY | BT_CTRL_B2H_ATN))))
> - return -ERESTARTSYS;
> -
> - mutex_lock(&bt_bmc->mutex);
> -
> - if (unlikely(bt_inb(bt_bmc, BT_CTRL) &
> - (BT_CTRL_H_BUSY | BT_CTRL_B2H_ATN))) {
> - ret = -EIO;
> - goto out_unlock;
> + spin_lock_irqsave(&bt_bmc->lock, flags);
> + if (!bt_bmc_is_response_open(bus)) {
> + spin_unlock_irqrestore(&bt_bmc->lock, flags);
> + return -EAGAIN;
> }
>
> clr_wr_ptr(bt_bmc);
> -
> - while (count) {
> - nwritten = min_t(ssize_t, count, sizeof(kbuffer));
> - if (copy_from_user(&kbuffer, buf, nwritten)) {
> - ret = -EFAULT;
> - break;
> - }
> -
> - bt_writen(bt_bmc, kbuffer, nwritten);
> -
> - count -= nwritten;
> - buf += nwritten;
> - ret += nwritten;
> - }
> -
> + bt_writen(bt_bmc, (u8 *) bt_response, bt_msg_len(bt_response));
> set_b2h_atn(bt_bmc);
>
> -out_unlock:
> - mutex_unlock(&bt_bmc->mutex);
> - return ret;
> -}
> -
> -static long bt_bmc_ioctl(struct file *file, unsigned int cmd,
> - unsigned long param)
> -{
> - struct bt_bmc *bt_bmc = file_bt_bmc(file);
> -
> - switch (cmd) {
> - case BT_BMC_IOCTL_SMS_ATN:
> - set_sms_atn(bt_bmc);
> - return 0;
> - }
> - return -EINVAL;
> -}
> -
> -static int bt_bmc_release(struct inode *inode, struct file *file)
> -{
> - struct bt_bmc *bt_bmc = file_bt_bmc(file);
> -
> - atomic_dec(&open_count);
> - set_b_busy(bt_bmc);
> + spin_unlock_irqrestore(&bt_bmc->lock, flags);
> return 0;
> }
>
> -static unsigned int bt_bmc_poll(struct file *file, poll_table *wait)
> -{
> - struct bt_bmc *bt_bmc = file_bt_bmc(file);
> - unsigned int mask = 0;
> - u8 ctrl;
> -
> - poll_wait(file, &bt_bmc->queue, wait);
> -
> - ctrl = bt_inb(bt_bmc, BT_CTRL);
> -
> - if (ctrl & BT_CTRL_H2B_ATN)
> - mask |= POLLIN;
> -
> - if (!(ctrl & (BT_CTRL_H_BUSY | BT_CTRL_B2H_ATN)))
> - mask |= POLLOUT;
> -
> - return mask;
> -}
> -
> -static const struct file_operations bt_bmc_fops = {
> - .owner = THIS_MODULE,
> - .open = bt_bmc_open,
> - .read = bt_bmc_read,
> - .write = bt_bmc_write,
> - .release = bt_bmc_release,
> - .poll = bt_bmc_poll,
> - .unlocked_ioctl = bt_bmc_ioctl,
> -};
> -
> static void poll_timer(unsigned long data)
> {
> struct bt_bmc *bt_bmc = (void *)data;
>
> bt_bmc->poll_timer.expires += msecs_to_jiffies(500);
> - wake_up(&bt_bmc->queue);
> +
> + if (bt_bmc_is_response_open(&bt_bmc->bus))
> + ipmi_bmc_signal_response_open(bt_bmc->bmc_ctx);
> +
> + if (is_request_avail(bt_bmc))
> + get_request(bt_bmc);
> +
> add_timer(&bt_bmc->poll_timer);
> }
>
> @@ -399,7 +285,12 @@ static irqreturn_t bt_bmc_irq(int irq, void *arg)
> /* ack pending IRQs */
> regmap_write(bt_bmc->map, bt_bmc->offset + BT_CR2, reg);
>
> - wake_up(&bt_bmc->queue);
> + if (bt_bmc_is_response_open(&bt_bmc->bus))
> + ipmi_bmc_signal_response_open(bt_bmc->bmc_ctx);
> +
> + if (is_request_avail(bt_bmc))
> + get_request(bt_bmc);
> +
> return IRQ_HANDLED;
> }
>
> @@ -474,16 +365,14 @@ static int bt_bmc_probe(struct platform_device
*pdev)
> return rc;
> }
>
> - mutex_init(&bt_bmc->mutex);
> - init_waitqueue_head(&bt_bmc->queue);
> + spin_lock_init(&bt_bmc->lock);
> + bt_bmc->bus.send_response = bt_bmc_send_response;
> + bt_bmc->bus.is_response_open = bt_bmc_is_response_open;
> + bt_bmc->bmc_ctx = ipmi_bmc_get_global_ctx();
>
> - bt_bmc->miscdev.minor = MISC_DYNAMIC_MINOR,
> - bt_bmc->miscdev.name = DEVICE_NAME,
> - bt_bmc->miscdev.fops = &bt_bmc_fops,
> - bt_bmc->miscdev.parent = dev;
> - rc = misc_register(&bt_bmc->miscdev);
> + rc = ipmi_bmc_register_bus(bt_bmc->bmc_ctx, &bt_bmc->bus);
> if (rc) {
> - dev_err(dev, "Unable to register misc device\n");
> + dev_err(dev, "Unable to register IPMI BMC bus\n");
> return rc;
> }
>
> @@ -514,11 +403,12 @@ static int bt_bmc_probe(struct platform_device
*pdev)
> static int bt_bmc_remove(struct platform_device *pdev)
> {
> struct bt_bmc *bt_bmc = dev_get_drvdata(&pdev->dev);
> + int rc;
>
> - misc_deregister(&bt_bmc->miscdev);
> + rc = ipmi_bmc_unregister_bus(bt_bmc->bmc_ctx, &bt_bmc->bus);
> if (!bt_bmc->irq)
> del_timer_sync(&bt_bmc->poll_timer);
> - return 0;
> + return rc;
> }
>
> static const struct of_device_id bt_bmc_match[] = {
> diff --git a/include/uapi/linux/bt-bmc.h b/include/uapi/linux/bt-bmc.h
> deleted file mode 100644
> index d9ec766a63d0..000000000000
> --- a/include/uapi/linux/bt-bmc.h
> +++ /dev/null
> @@ -1,18 +0,0 @@
> -/*
> - * Copyright (c) 2015-2016, 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.
> - */
> -
> -#ifndef _UAPI_LINUX_BT_BMC_H
> -#define _UAPI_LINUX_BT_BMC_H
> -
> -#include <linux/ioctl.h>
> -
> -#define __BT_BMC_IOCTL_MAGIC 0xb1
> -#define BT_BMC_IOCTL_SMS_ATN _IO(__BT_BMC_IOCTL_MAGIC, 0x00)
> -
> -#endif /* _UAPI_LINUX_BT_BMC_H */
> --
> 2.14.0.rc1.383.gd1ce394fe2-goog
>
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