[PATCH 1/3] misc: Add Aspeed BT IPMI host driver
Cédric Le Goater
clg at kaod.org
Wed Aug 31 10:24:17 PDT 2016
From: Alistair Popple <alistair at popple.id.au>
This patch adds a simple device driver to expose the iBT interface on
Aspeed chips as a character device (/dev/bt).
The iBT interface is used to perform in-band IPMI communication from a
BMC to the host.
Signed-off-by: Alistair Popple <alistair at popple.id.au>
Signed-off-by: Jeremy Kerr <jk at ozlabs.org>
Signed-off-by: Joel Stanley <joel at jms.id.au>
[clg: checkpatch fixes
devicetree binding documentation]
Signed-off-by: Cédric Le Goater <clg at kaod.org>
---
.../devicetree/bindings/misc/aspeed,bt-host.txt | 19 +
drivers/misc/Kconfig | 5 +
drivers/misc/Makefile | 1 +
drivers/misc/bt-host.c | 433 +++++++++++++++++++++
include/uapi/linux/Kbuild | 1 +
include/uapi/linux/bt-host.h | 18 +
6 files changed, 477 insertions(+)
create mode 100644 Documentation/devicetree/bindings/misc/aspeed,bt-host.txt
create mode 100644 drivers/misc/bt-host.c
create mode 100644 include/uapi/linux/bt-host.h
diff --git a/Documentation/devicetree/bindings/misc/aspeed,bt-host.txt b/Documentation/devicetree/bindings/misc/aspeed,bt-host.txt
new file mode 100644
index 000000000000..938c5998c331
--- /dev/null
+++ b/Documentation/devicetree/bindings/misc/aspeed,bt-host.txt
@@ -0,0 +1,19 @@
+* Aspeed BT IPMI interface
+
+Required properties:
+
+- compatible : should be "aspeed,bt-host"
+- reg: physical address and size of the registers
+
+Optional properties:
+
+- interrupts: interrupt generated by the BT interface. without an
+ interrupt, the driver will operate in poll mode.
+
+Example:
+
+ ibt at 1e789140 {
+ compatible = "aspeed,bt-host";
+ reg = <0x1e789140 0x18>;
+ interrupts = <8>;
+ };
diff --git a/drivers/misc/Kconfig b/drivers/misc/Kconfig
index a216b4667742..47f761861120 100644
--- a/drivers/misc/Kconfig
+++ b/drivers/misc/Kconfig
@@ -804,6 +804,11 @@ 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_BT_IPMI_HOST
+ tristate "BT IPMI host driver"
+ help
+ Support for the Aspeed BT IPMI host.
+
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 7410c6d9a34d..71a7b9feb0f0 100644
--- a/drivers/misc/Makefile
+++ b/drivers/misc/Makefile
@@ -57,6 +57,7 @@ obj-$(CONFIG_ECHO) += echo/
obj-$(CONFIG_VEXPRESS_SYSCFG) += vexpress-syscfg.o
obj-$(CONFIG_CXL_BASE) += cxl/
obj-$(CONFIG_PANEL) += panel.o
+obj-$(CONFIG_ASPEED_BT_IPMI_HOST) += bt-host.o
lkdtm-$(CONFIG_LKDTM) += lkdtm_core.o
lkdtm-$(CONFIG_LKDTM) += lkdtm_bugs.o
diff --git a/drivers/misc/bt-host.c b/drivers/misc/bt-host.c
new file mode 100644
index 000000000000..3d9bfbaa8940
--- /dev/null
+++ b/drivers/misc/bt-host.c
@@ -0,0 +1,433 @@
+/*
+ * 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.
+ */
+
+#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_irq.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/bt-host.h>
+
+#define DEVICE_NAME "bt-host"
+
+#define BT_IO_BASE 0xe4
+#define BT_IRQ 10
+
+#define BT_CR0 0x0
+#define BT_CR0_IO_BASE 16
+#define BT_CR0_IRQ 12
+#define BT_CR0_EN_CLR_SLV_RDP 0x8
+#define BT_CR0_EN_CLR_SLV_WRP 0x4
+#define BT_CR0_ENABLE_IBT 0x1
+#define BT_CR1 0x4
+#define BT_CR1_IRQ_H2B 0x01
+#define BT_CR1_IRQ_HBUSY 0x40
+#define BT_CR2 0x8
+#define BT_CR2_IRQ_H2B 0x01
+#define BT_CR2_IRQ_HBUSY 0x40
+#define BT_CR3 0xc
+#define BT_CTRL 0x10
+#define BT_CTRL_B_BUSY 0x80
+#define BT_CTRL_H_BUSY 0x40
+#define BT_CTRL_OEM0 0x20
+#define BT_CTRL_SMS_ATN 0x10
+#define BT_CTRL_B2H_ATN 0x08
+#define BT_CTRL_H2B_ATN 0x04
+#define BT_CTRL_CLR_RD_PTR 0x02
+#define BT_CTRL_CLR_WR_PTR 0x01
+#define BT_BMC2HOST 0x14
+#define BT_INTMASK 0x18
+#define BT_INTMASK_B2H_IRQEN 0x01
+#define BT_INTMASK_B2H_IRQ 0x02
+#define BT_INTMASK_BMC_HWRST 0x80
+
+struct bt_host {
+ struct device dev;
+ struct miscdevice miscdev;
+ void __iomem *base;
+ int open_count;
+ int irq;
+ wait_queue_head_t queue;
+ struct timer_list poll_timer;
+};
+
+static u8 bt_inb(struct bt_host *bt_host, int reg)
+{
+ return ioread8(bt_host->base + reg);
+}
+
+static void bt_outb(struct bt_host *bt_host, u8 data, int reg)
+{
+ iowrite8(data, bt_host->base + reg);
+}
+
+static void clr_rd_ptr(struct bt_host *bt_host)
+{
+ bt_outb(bt_host, BT_CTRL_CLR_RD_PTR, BT_CTRL);
+}
+
+static void clr_wr_ptr(struct bt_host *bt_host)
+{
+ bt_outb(bt_host, BT_CTRL_CLR_WR_PTR, BT_CTRL);
+}
+
+static void clr_h2b_atn(struct bt_host *bt_host)
+{
+ bt_outb(bt_host, BT_CTRL_H2B_ATN, BT_CTRL);
+}
+
+static void set_b_busy(struct bt_host *bt_host)
+{
+ if (!(bt_inb(bt_host, BT_CTRL) & BT_CTRL_B_BUSY))
+ bt_outb(bt_host, BT_CTRL_B_BUSY, BT_CTRL);
+}
+
+static void clr_b_busy(struct bt_host *bt_host)
+{
+ if (bt_inb(bt_host, BT_CTRL) & BT_CTRL_B_BUSY)
+ bt_outb(bt_host, BT_CTRL_B_BUSY, BT_CTRL);
+}
+
+static void set_b2h_atn(struct bt_host *bt_host)
+{
+ bt_outb(bt_host, BT_CTRL_B2H_ATN, BT_CTRL);
+}
+
+static u8 bt_read(struct bt_host *bt_host)
+{
+ return bt_inb(bt_host, BT_BMC2HOST);
+}
+
+static void bt_write(struct bt_host *bt_host, u8 c)
+{
+ bt_outb(bt_host, c, BT_BMC2HOST);
+}
+
+static void set_sms_atn(struct bt_host *bt_host)
+{
+ bt_outb(bt_host, BT_CTRL_SMS_ATN, BT_CTRL);
+}
+
+static struct bt_host *file_bt_host(struct file *file)
+{
+ return container_of(file->private_data, struct bt_host, miscdev);
+}
+
+static int bt_host_open(struct inode *inode, struct file *file)
+{
+ struct bt_host *bt_host = file_bt_host(file);
+
+ clr_b_busy(bt_host);
+
+ return 0;
+}
+
+static ssize_t bt_host_read(struct file *file, char __user *buf,
+ size_t count, loff_t *ppos)
+{
+ struct bt_host *bt_host = file_bt_host(file);
+ char __user *p = buf;
+ u8 len;
+
+ if (!access_ok(VERIFY_WRITE, buf, count))
+ return -EFAULT;
+
+ WARN_ON(*ppos);
+
+ if (wait_event_interruptible(bt_host->queue,
+ bt_inb(bt_host, BT_CTRL) & BT_CTRL_H2B_ATN))
+ return -ERESTARTSYS;
+
+ set_b_busy(bt_host);
+ clr_h2b_atn(bt_host);
+ clr_rd_ptr(bt_host);
+
+ len = bt_read(bt_host);
+ __put_user(len, p++);
+
+ /* We pass the length back as well */
+ if (len + 1 > count)
+ len = count - 1;
+
+ while (len) {
+ if (__put_user(bt_read(bt_host), p))
+ return -EFAULT;
+ len--; p++;
+ }
+
+ clr_b_busy(bt_host);
+
+ return p - buf;
+}
+
+static ssize_t bt_host_write(struct file *file, const char __user *buf,
+ size_t count, loff_t *ppos)
+{
+ struct bt_host *bt_host = file_bt_host(file);
+ const char __user *p = buf;
+ u8 c;
+
+ if (!access_ok(VERIFY_READ, buf, count))
+ return -EFAULT;
+
+ WARN_ON(*ppos);
+
+ /* There's no interrupt for clearing host busy so we have to
+ * poll
+ */
+ if (wait_event_interruptible(bt_host->queue,
+ !(bt_inb(bt_host, BT_CTRL) &
+ (BT_CTRL_H_BUSY | BT_CTRL_B2H_ATN))))
+ return -ERESTARTSYS;
+
+ clr_wr_ptr(bt_host);
+
+ while (count) {
+ if (__get_user(c, p))
+ return -EFAULT;
+
+ bt_write(bt_host, c);
+ count--; p++;
+ }
+
+ set_b2h_atn(bt_host);
+
+ return p - buf;
+}
+
+static long bt_host_ioctl(struct file *file, unsigned int cmd,
+ unsigned long param)
+{
+ struct bt_host *bt_host = file_bt_host(file);
+
+ switch (cmd) {
+ case BT_HOST_IOCTL_SMS_ATN:
+ set_sms_atn(bt_host);
+ return 0;
+ }
+ return -EINVAL;
+}
+
+static int bt_host_release(struct inode *inode, struct file *file)
+{
+ struct bt_host *bt_host = file_bt_host(file);
+
+ set_b_busy(bt_host);
+ return 0;
+}
+
+static unsigned int bt_host_poll(struct file *file, poll_table *wait)
+{
+ struct bt_host *bt_host = file_bt_host(file);
+ unsigned int mask = 0;
+ uint8_t ctrl;
+
+ poll_wait(file, &bt_host->queue, wait);
+
+ ctrl = bt_inb(bt_host, 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_host_fops = {
+ .owner = THIS_MODULE,
+ .open = bt_host_open,
+ .read = bt_host_read,
+ .write = bt_host_write,
+ .release = bt_host_release,
+ .poll = bt_host_poll,
+ .unlocked_ioctl = bt_host_ioctl,
+};
+
+static void poll_timer(unsigned long data)
+{
+ struct bt_host *bt_host = (void *)data;
+
+ bt_host->poll_timer.expires += msecs_to_jiffies(500);
+ wake_up(&bt_host->queue);
+ add_timer(&bt_host->poll_timer);
+}
+
+static irqreturn_t bt_host_irq(int irq, void *arg)
+{
+ struct bt_host *bt_host = arg;
+ uint32_t reg;
+
+ reg = ioread32(bt_host->base + BT_CR2);
+ reg &= BT_CR2_IRQ_H2B | BT_CR2_IRQ_HBUSY;
+ if (!reg)
+ return IRQ_NONE;
+
+ /* ack pending IRQs */
+ iowrite32(reg, bt_host->base + BT_CR2);
+
+ wake_up(&bt_host->queue);
+ return IRQ_HANDLED;
+}
+
+static int bt_host_config_irq(struct bt_host *bt_host,
+ struct platform_device *pdev)
+{
+ struct device *dev = &pdev->dev;
+ uint32_t reg;
+ int rc;
+
+ bt_host->irq = irq_of_parse_and_map(dev->of_node, 0);
+ if (!bt_host->irq)
+ return -ENODEV;
+
+ rc = devm_request_irq(dev, bt_host->irq, bt_host_irq, IRQF_SHARED,
+ DEVICE_NAME, bt_host);
+ if (rc < 0) {
+ dev_warn(dev, "Unable to request IRQ %d\n", bt_host->irq);
+ bt_host->irq = 0;
+ return rc;
+ }
+
+ /* Configure IRQs on the host clearing the H2B and HBUSY bits;
+ * H2B will be asserted when the host has data for us; HBUSY
+ * will be cleared (along with B2H) when we can write the next
+ * message to the BT buffer
+ */
+ reg = ioread32(bt_host->base + BT_CR1);
+ reg |= BT_CR1_IRQ_H2B | BT_CR1_IRQ_HBUSY;
+ iowrite32(reg, bt_host->base + BT_CR1);
+
+ return 0;
+}
+
+static int bt_host_probe(struct platform_device *pdev)
+{
+ struct bt_host *bt_host;
+ struct device *dev;
+ struct resource *res;
+ int rc;
+
+ if (!pdev || !pdev->dev.of_node)
+ return -ENODEV;
+
+ dev = &pdev->dev;
+ dev_info(dev, "Found bt host device\n");
+
+ bt_host = devm_kzalloc(dev, sizeof(*bt_host), GFP_KERNEL);
+ if (!bt_host)
+ return -ENOMEM;
+
+ dev_set_drvdata(&pdev->dev, bt_host);
+
+ res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ if (!res) {
+ dev_err(dev, "Unable to find resources\n");
+ rc = -ENXIO;
+ goto out_free;
+ }
+
+ bt_host->base = devm_ioremap_resource(&pdev->dev, res);
+ if (!bt_host->base) {
+ rc = -ENOMEM;
+ goto out_free;
+ }
+
+ init_waitqueue_head(&bt_host->queue);
+
+ bt_host->miscdev.minor = MISC_DYNAMIC_MINOR,
+ bt_host->miscdev.name = DEVICE_NAME,
+ bt_host->miscdev.fops = &bt_host_fops,
+ bt_host->miscdev.parent = dev;
+ rc = misc_register(&bt_host->miscdev);
+ if (rc) {
+ dev_err(dev, "Unable to register device\n");
+ goto out_unmap;
+ }
+
+ bt_host_config_irq(bt_host, pdev);
+
+ if (bt_host->irq) {
+ dev_info(dev, "Using IRQ %d\n", bt_host->irq);
+ } else {
+ dev_info(dev, "No IRQ; using timer\n");
+ setup_timer(&bt_host->poll_timer, poll_timer,
+ (unsigned long)bt_host);
+ bt_host->poll_timer.expires = jiffies + msecs_to_jiffies(10);
+ add_timer(&bt_host->poll_timer);
+ }
+
+ iowrite32((BT_IO_BASE << BT_CR0_IO_BASE) |
+ (BT_IRQ << BT_CR0_IRQ) |
+ BT_CR0_EN_CLR_SLV_RDP |
+ BT_CR0_EN_CLR_SLV_WRP |
+ BT_CR0_ENABLE_IBT,
+ bt_host->base + BT_CR0);
+
+ clr_b_busy(bt_host);
+
+ return 0;
+
+out_unmap:
+ devm_iounmap(&pdev->dev, bt_host->base);
+
+out_free:
+ devm_kfree(dev, bt_host);
+ return rc;
+
+}
+
+static int bt_host_remove(struct platform_device *pdev)
+{
+ struct bt_host *bt_host = dev_get_drvdata(&pdev->dev);
+
+ misc_deregister(&bt_host->miscdev);
+ if (!bt_host->irq)
+ del_timer_sync(&bt_host->poll_timer);
+ devm_iounmap(&pdev->dev, bt_host->base);
+ devm_kfree(&pdev->dev, bt_host);
+ bt_host = NULL;
+
+ return 0;
+}
+
+static const struct of_device_id bt_host_match[] = {
+ { .compatible = "aspeed,bt-host" },
+ { },
+};
+
+static struct platform_driver bt_host_driver = {
+ .driver = {
+ .name = DEVICE_NAME,
+ .of_match_table = bt_host_match,
+ },
+ .probe = bt_host_probe,
+ .remove = bt_host_remove,
+};
+
+module_platform_driver(bt_host_driver);
+
+MODULE_DEVICE_TABLE(of, bt_host_match);
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Alistair Popple <alistair at popple.id.au>");
+MODULE_DESCRIPTION("Linux device interface to the BT interface");
diff --git a/include/uapi/linux/Kbuild b/include/uapi/linux/Kbuild
index 185f8ea2702f..c763a35c2147 100644
--- a/include/uapi/linux/Kbuild
+++ b/include/uapi/linux/Kbuild
@@ -74,6 +74,7 @@ header-y += bpf_common.h
header-y += bpf.h
header-y += bpqether.h
header-y += bsg.h
+header-y += bt-host.h
header-y += btrfs.h
header-y += can.h
header-y += capability.h
diff --git a/include/uapi/linux/bt-host.h b/include/uapi/linux/bt-host.h
new file mode 100644
index 000000000000..e2aedddf0bf4
--- /dev/null
+++ b/include/uapi/linux/bt-host.h
@@ -0,0 +1,18 @@
+/*
+ * 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_HOST_H
+#define _UAPI_LINUX_BT_HOST_H
+
+#include <linux/ioctl.h>
+
+#define __BT_HOST_IOCTL_MAGIC 0xb1
+#define BT_HOST_IOCTL_SMS_ATN _IO(__BT_HOST_IOCTL_MAGIC, 0x00)
+
+#endif /* _UAPI_LINUX_BT_HOST_H */
--
2.7.4
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