From: Benjamin Fair <benjaminf...@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.

Signed-off-by: Benjamin Fair <benjaminf...@google.com>
Signed-off-by: Brendan Higgins <brendanhigg...@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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