[RFC PATCH linux dev-4.7 4/6] misc: Add Aspeed BT IPMI BMC driver
Joel Stanley
joel at jms.id.au
Thu Sep 15 17:09:28 AEST 2016
On Thu, Sep 15, 2016 at 4:02 PM, Cédric Le Goater <clg at kaod.org> wrote:
> From: Alistair Popple <alistair at popple.id.au>
>
> This patch adds a simple device driver to expose the iBT interface on
> Aspeed SOCs (AST2400 and AST2500) as a character device :
> /dev/ipmi-bt-bmc.
>
> The BT (Block Transfer) interface is used to perform in-band IPMI
> communication from a BMC to the host. Entire messages are buffered
> before sending a notification to the host, or the BMC when on the
> other side, that there is data to be read. The driver implements the
> BMC side of the BT interface.
>
> 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: - did some checkpatch fixes
> - added a devicetree binding documentation
> - renamed 'bt_host' to 'bt_bmc' to reflect that the driver is
> the BMC side of the IPMI BT interface
> - remaned the device name to 'ipmi-bt-bmc'
I'm not sure there. When I open /dev/ttyUSB0 I'm talking to the USB0
serial device. When I open /dev/mtd0, I'm talking to the mtd0 device.
So when I open /dev/ipmi-bt-bmc, I would expect to talk to the BMC
device?
> - introduced a temporary buffer to copy_{to,from}_user
> - used platform_get_irq()
> - move the driver under drivers/char/ipmi/ ]
> Signed-off-by: Cédric Le Goater <clg at kaod.org>
> ---
> .../bindings/char/ipmi/aspeed,bt-bmc.txt | 19 +
> drivers/char/ipmi/Kconfig | 7 +
> drivers/char/ipmi/Makefile | 1 +
> drivers/char/ipmi/bt-bmc.c | 475 +++++++++++++++++++++
> include/uapi/linux/Kbuild | 1 +
> include/uapi/linux/bt-bmc.h | 18 +
> 6 files changed, 521 insertions(+)
> create mode 100644 Documentation/devicetree/bindings/char/ipmi/aspeed,bt-bmc.txt
> create mode 100644 drivers/char/ipmi/bt-bmc.c
> create mode 100644 include/uapi/linux/bt-bmc.h
>
> diff --git a/Documentation/devicetree/bindings/char/ipmi/aspeed,bt-bmc.txt b/Documentation/devicetree/bindings/char/ipmi/aspeed,bt-bmc.txt
> new file mode 100644
> index 000000000000..551323606f6e
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/char/ipmi/aspeed,bt-bmc.txt
> @@ -0,0 +1,19 @@
> +* Aspeed BT IPMI interface
> +
> +Required properties:
> +
> +- compatible : should be "aspeed,bt-bmc"
> +- 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-bmc";
> + reg = <0x1e789140 0x18>;
> + interrupts = <8>;
> + };
> diff --git a/drivers/char/ipmi/Kconfig b/drivers/char/ipmi/Kconfig
> index 6ed9e9fe5233..f0cf4889ba66 100644
> --- a/drivers/char/ipmi/Kconfig
> +++ b/drivers/char/ipmi/Kconfig
> @@ -88,3 +88,10 @@ config IPMI_POWEROFF
> the IPMI management controller is capable of this.
>
> endif # IPMI_HANDLER
> +
> +config ASPEED_BT_IPMI_BMC
> + tristate "BT IPMI bmc driver"
> + help
> + Provides a driver for the BT IPMI interface found on Aspeed
> + SOCs (AST2400 and AST2500). The driver implements the BMC
> + side of the BT interface.
> diff --git a/drivers/char/ipmi/Makefile b/drivers/char/ipmi/Makefile
> index f3ffde1f5f1f..0d98cd91def1 100644
> --- a/drivers/char/ipmi/Makefile
> +++ b/drivers/char/ipmi/Makefile
> @@ -11,3 +11,4 @@ obj-$(CONFIG_IPMI_SSIF) += ipmi_ssif.o
> obj-$(CONFIG_IPMI_POWERNV) += ipmi_powernv.o
> obj-$(CONFIG_IPMI_WATCHDOG) += ipmi_watchdog.o
> obj-$(CONFIG_IPMI_POWEROFF) += ipmi_poweroff.o
> +obj-$(CONFIG_ASPEED_BT_IPMI_BMC) += bt-bmc.o
> diff --git a/drivers/char/ipmi/bt-bmc.c b/drivers/char/ipmi/bt-bmc.c
> new file mode 100644
> index 000000000000..5069ed6f0646
> --- /dev/null
> +++ b/drivers/char/ipmi/bt-bmc.c
> @@ -0,0 +1,475 @@
> +/*
> + * 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-bmc.h>
> +
> +#define DEVICE_NAME "ipmi-bt-bmc"
> +
> +#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_bmc {
> + 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_bmc *bt_bmc, int reg)
> +{
> + return ioread8(bt_bmc->base + reg);
> +}
> +
> +static void bt_outb(struct bt_bmc *bt_bmc, u8 data, int reg)
> +{
> + iowrite8(data, bt_bmc->base + reg);
> +}
> +
> +static void clr_rd_ptr(struct bt_bmc *bt_bmc)
> +{
> + bt_outb(bt_bmc, BT_CTRL_CLR_RD_PTR, BT_CTRL);
> +}
> +
> +static void clr_wr_ptr(struct bt_bmc *bt_bmc)
> +{
> + bt_outb(bt_bmc, BT_CTRL_CLR_WR_PTR, BT_CTRL);
> +}
> +
> +static void clr_h2b_atn(struct bt_bmc *bt_bmc)
> +{
> + bt_outb(bt_bmc, BT_CTRL_H2B_ATN, BT_CTRL);
> +}
> +
> +static void set_b_busy(struct bt_bmc *bt_bmc)
> +{
> + if (!(bt_inb(bt_bmc, BT_CTRL) & BT_CTRL_B_BUSY))
> + bt_outb(bt_bmc, BT_CTRL_B_BUSY, BT_CTRL);
> +}
> +
> +static void clr_b_busy(struct bt_bmc *bt_bmc)
> +{
> + if (bt_inb(bt_bmc, BT_CTRL) & BT_CTRL_B_BUSY)
> + bt_outb(bt_bmc, BT_CTRL_B_BUSY, BT_CTRL);
> +}
> +
> +static void set_b2h_atn(struct bt_bmc *bt_bmc)
> +{
> + bt_outb(bt_bmc, BT_CTRL_B2H_ATN, BT_CTRL);
> +}
> +
> +static u8 bt_read(struct bt_bmc *bt_bmc)
> +{
> + return bt_inb(bt_bmc, BT_BMC2HOST);
> +}
> +
> +static ssize_t bt_readn(struct bt_bmc *bt_bmc, u8 *buf, size_t n)
> +{
> + int i;
> +
> + for (i = 0; i < n; i++)
> + buf[i] = bt_read(bt_bmc);
> + return n;
> +}
> +
> +static void bt_write(struct bt_bmc *bt_bmc, u8 c)
> +{
> + bt_outb(bt_bmc, c, BT_BMC2HOST);
> +}
> +
> +static ssize_t bt_writen(struct bt_bmc *bt_bmc, u8 *buf, size_t n)
> +{
> + int i;
> +
> + for (i = 0; i < n; i++)
> + bt_write(bt_bmc, buf[i]);
> + return n;
> +}
> +
> +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)
> +{
> + return container_of(file->private_data, struct bt_bmc, miscdev);
> +}
> +
> +static int bt_bmc_open(struct inode *inode, struct file *file)
> +{
> + struct bt_bmc *bt_bmc = file_bt_bmc(file);
> +
> + clr_b_busy(bt_bmc);
> +
> + return 0;
> +}
> +
> +#define BT_BMC_BUFFER_SIZE 256
> +
> +static ssize_t bt_bmc_read(struct file *file, char __user *buf,
> + size_t count, loff_t *ppos)
> +{
> + 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;
> +
> + if (!access_ok(VERIFY_WRITE, buf, count))
> + return -EFAULT;
> +
> + WARN_ON(*ppos);
> +
> + if (wait_event_interruptible(bt_bmc->queue,
> + bt_inb(bt_bmc, BT_CTRL) & BT_CTRL_H2B_ATN))
> + return -ERESTARTSYS;
> +
> + set_b_busy(bt_bmc);
> + clr_h2b_atn(bt_bmc);
> + clr_rd_ptr(bt_bmc);
> +
> + /* The BT frames start with the message length, not including
> + * the length byte
> + */
> + kbuffer[0] = bt_read(bt_bmc);
> + len = kbuffer[0];
> +
> + /* We pass the length back 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;
> + }
> +
> + clr_b_busy(bt_bmc);
> +
> + return ret;
> +}
> +
> +static ssize_t bt_bmc_write(struct file *file, const char __user *buf,
> + size_t count, loff_t *ppos)
> +{
> + struct bt_bmc *bt_bmc = file_bt_bmc(file);
> + u8 kbuffer[BT_BMC_BUFFER_SIZE];
> + ssize_t ret = 0;
> + ssize_t nwritten;
> +
> + 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;
> +
> + 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;
> + }
> +
> + set_b2h_atn(bt_bmc);
> +
> + 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);
> +
> + set_b_busy(bt_bmc);
> + 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;
> + uint8_t 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);
> + add_timer(&bt_bmc->poll_timer);
> +}
> +
> +static irqreturn_t bt_bmc_irq(int irq, void *arg)
> +{
> + struct bt_bmc *bt_bmc = arg;
> + uint32_t reg;
> +
> + reg = ioread32(bt_bmc->base + BT_CR2);
> + reg &= BT_CR2_IRQ_H2B | BT_CR2_IRQ_HBUSY;
> + if (!reg)
> + return IRQ_NONE;
> +
> + /* ack pending IRQs */
> + iowrite32(reg, bt_bmc->base + BT_CR2);
> +
> + wake_up(&bt_bmc->queue);
> + return IRQ_HANDLED;
> +}
> +
> +static int bt_bmc_config_irq(struct bt_bmc *bt_bmc,
> + struct platform_device *pdev)
> +{
> + struct device *dev = &pdev->dev;
> + uint32_t reg;
> + int rc;
> +
> + bt_bmc->irq = platform_get_irq(pdev, 0);
> + if (!bt_bmc->irq)
> + return -ENODEV;
> +
> + rc = devm_request_irq(dev, bt_bmc->irq, bt_bmc_irq, IRQF_SHARED,
> + DEVICE_NAME, bt_bmc);
> + if (rc < 0) {
> + dev_warn(dev, "Unable to request IRQ %d\n", bt_bmc->irq);
> + bt_bmc->irq = 0;
> + return rc;
> + }
> +
> + /* Configure IRQs on the bmc clearing the H2B and HBUSY bits;
> + * H2B will be asserted when the bmc 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_bmc->base + BT_CR1);
> + reg |= BT_CR1_IRQ_H2B | BT_CR1_IRQ_HBUSY;
> + iowrite32(reg, bt_bmc->base + BT_CR1);
> +
> + return 0;
> +}
> +
> +static int bt_bmc_probe(struct platform_device *pdev)
> +{
> + struct bt_bmc *bt_bmc;
> + struct device *dev;
> + struct resource *res;
> + int rc;
> +
> + if (!pdev || !pdev->dev.of_node)
> + return -ENODEV;
> +
> + dev = &pdev->dev;
> + dev_info(dev, "Found bt bmc device\n");
> +
> + bt_bmc = devm_kzalloc(dev, sizeof(*bt_bmc), GFP_KERNEL);
> + if (!bt_bmc)
> + return -ENOMEM;
> +
> + dev_set_drvdata(&pdev->dev, bt_bmc);
> +
> + res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> + if (!res) {
> + dev_err(dev, "Unable to find resources\n");
> + rc = -ENXIO;
> + goto out_free;
> + }
> +
> + bt_bmc->base = devm_ioremap_resource(&pdev->dev, res);
> + if (!bt_bmc->base) {
> + rc = -ENOMEM;
> + goto out_free;
> + }
> +
> + init_waitqueue_head(&bt_bmc->queue);
> +
> + 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);
> + if (rc) {
> + dev_err(dev, "Unable to register device\n");
> + goto out_unmap;
> + }
> +
> + bt_bmc_config_irq(bt_bmc, pdev);
> +
> + if (bt_bmc->irq) {
> + dev_info(dev, "Using IRQ %d\n", bt_bmc->irq);
> + } else {
> + dev_info(dev, "No IRQ; using timer\n");
> + setup_timer(&bt_bmc->poll_timer, poll_timer,
> + (unsigned long)bt_bmc);
> + bt_bmc->poll_timer.expires = jiffies + msecs_to_jiffies(10);
> + add_timer(&bt_bmc->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_bmc->base + BT_CR0);
> +
> + clr_b_busy(bt_bmc);
> +
> + return 0;
> +
> +out_unmap:
> + devm_iounmap(&pdev->dev, bt_bmc->base);
> +
> +out_free:
> + devm_kfree(dev, bt_bmc);
> + return rc;
> +
> +}
> +
> +static int bt_bmc_remove(struct platform_device *pdev)
> +{
> + struct bt_bmc *bt_bmc = dev_get_drvdata(&pdev->dev);
> +
> + misc_deregister(&bt_bmc->miscdev);
> + if (!bt_bmc->irq)
> + del_timer_sync(&bt_bmc->poll_timer);
> + devm_iounmap(&pdev->dev, bt_bmc->base);
> + devm_kfree(&pdev->dev, bt_bmc);
> + bt_bmc = NULL;
> +
> + return 0;
> +}
> +
> +static const struct of_device_id bt_bmc_match[] = {
> + { .compatible = "aspeed,bt-bmc" },
> + { },
> +};
> +
> +static struct platform_driver bt_bmc_driver = {
> + .driver = {
> + .name = DEVICE_NAME,
> + .of_match_table = bt_bmc_match,
> + },
> + .probe = bt_bmc_probe,
> + .remove = bt_bmc_remove,
> +};
> +
> +module_platform_driver(bt_bmc_driver);
> +
> +MODULE_DEVICE_TABLE(of, bt_bmc_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 ec10cfef166a..9493842de93b 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-bmc.h
> header-y += btrfs.h
> header-y += can.h
> header-y += capability.h
> diff --git a/include/uapi/linux/bt-bmc.h b/include/uapi/linux/bt-bmc.h
> new file mode 100644
> index 000000000000..d9ec766a63d0
> --- /dev/null
> +++ b/include/uapi/linux/bt-bmc.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_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 */
> --
> 2.7.4
>
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