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path: root/drivers/char/ipmi/bt-bmc.c
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Diffstat (limited to 'drivers/char/ipmi/bt-bmc.c')
-rw-r--r--drivers/char/ipmi/bt-bmc.c533
1 files changed, 533 insertions, 0 deletions
diff --git a/drivers/char/ipmi/bt-bmc.c b/drivers/char/ipmi/bt-bmc.c
new file mode 100644
index 000000000..40b9927c0
--- /dev/null
+++ b/drivers/char/ipmi/bt-bmc.c
@@ -0,0 +1,533 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (c) 2015-2016, IBM Corporation.
+ */
+
+#include <linux/atomic.h>
+#include <linux/bt-bmc.h>
+#include <linux/errno.h>
+#include <linux/interrupt.h>
+#include <linux/io.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 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
+
+#define BT_BMC_BUFFER_SIZE 256
+
+struct bt_bmc {
+ struct device dev;
+ struct miscdevice miscdev;
+ struct regmap *map;
+ int offset;
+ int irq;
+ wait_queue_head_t queue;
+ struct timer_list poll_timer;
+ struct mutex mutex;
+};
+
+static atomic_t open_count = ATOMIC_INIT(0);
+
+static const struct regmap_config bt_regmap_cfg = {
+ .reg_bits = 32,
+ .val_bits = 32,
+ .reg_stride = 4,
+};
+
+static u8 bt_inb(struct bt_bmc *bt_bmc, int reg)
+{
+ uint32_t val = 0;
+ int rc;
+
+ rc = regmap_read(bt_bmc->map, bt_bmc->offset + reg, &val);
+ WARN(rc != 0, "regmap_read() failed: %d\n", rc);
+
+ return rc == 0 ? (u8) val : 0;
+}
+
+static void bt_outb(struct bt_bmc *bt_bmc, u8 data, int reg)
+{
+ int rc;
+
+ rc = regmap_write(bt_bmc->map, bt_bmc->offset + reg, data);
+ WARN(rc != 0, "regmap_write() failed: %d\n", rc);
+}
+
+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);
+
+ if (atomic_inc_return(&open_count) == 1) {
+ clr_b_busy(bt_bmc);
+ return 0;
+ }
+
+ atomic_dec(&open_count);
+ return -EBUSY;
+}
+
+/*
+ * The BT (Block Transfer) interface means that entire messages are
+ * buffered by the host before a notification is sent to the BMC that
+ * there is data to be read. The first byte is the length and the
+ * message data follows. The read operation just tries to capture the
+ * whole before returning it to userspace.
+ *
+ * BT Message format :
+ *
+ * Byte 1 Byte 2 Byte 3 Byte 4 Byte 5:N
+ * Length NetFn/LUN Seq Cmd Data
+ *
+ */
+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;
+
+ 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;
+ }
+
+ 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;
+ }
+
+ clr_b_busy(bt_bmc);
+
+out_unlock:
+ mutex_unlock(&bt_bmc->mutex);
+ return ret;
+}
+
+/*
+ * BT Message response format :
+ *
+ * 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)
+{
+ struct bt_bmc *bt_bmc = file_bt_bmc(file);
+ u8 kbuffer[BT_BMC_BUFFER_SIZE];
+ ssize_t ret = 0;
+ ssize_t nwritten;
+
+ /*
+ * send a minimum response size
+ */
+ if (count < 5)
+ return -EINVAL;
+
+ 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;
+ }
+
+ 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);
+
+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);
+ return 0;
+}
+
+static __poll_t bt_bmc_poll(struct file *file, poll_table *wait)
+{
+ struct bt_bmc *bt_bmc = file_bt_bmc(file);
+ __poll_t 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 |= EPOLLIN;
+
+ if (!(ctrl & (BT_CTRL_H_BUSY | BT_CTRL_B2H_ATN)))
+ mask |= EPOLLOUT;
+
+ 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(struct timer_list *t)
+{
+ struct bt_bmc *bt_bmc = from_timer(bt_bmc, t, poll_timer);
+
+ 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;
+ u32 reg;
+ int rc;
+
+ rc = regmap_read(bt_bmc->map, bt_bmc->offset + BT_CR2, &reg);
+ if (rc)
+ return IRQ_NONE;
+
+ reg &= BT_CR2_IRQ_H2B | BT_CR2_IRQ_HBUSY;
+ if (!reg)
+ return IRQ_NONE;
+
+ /* ack pending IRQs */
+ regmap_write(bt_bmc->map, bt_bmc->offset + BT_CR2, reg);
+
+ 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;
+ 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
+ */
+ rc = regmap_update_bits(bt_bmc->map, bt_bmc->offset + BT_CR1,
+ (BT_CR1_IRQ_H2B | BT_CR1_IRQ_HBUSY),
+ (BT_CR1_IRQ_H2B | BT_CR1_IRQ_HBUSY));
+
+ return rc;
+}
+
+static int bt_bmc_probe(struct platform_device *pdev)
+{
+ struct bt_bmc *bt_bmc;
+ struct device *dev;
+ 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);
+
+ bt_bmc->map = syscon_node_to_regmap(pdev->dev.parent->of_node);
+ if (IS_ERR(bt_bmc->map)) {
+ struct resource *res;
+ void __iomem *base;
+
+ /*
+ * Assume it's not the MFD-based devicetree description, in
+ * which case generate a regmap ourselves
+ */
+ res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ base = devm_ioremap_resource(&pdev->dev, res);
+ if (IS_ERR(base))
+ return PTR_ERR(base);
+
+ bt_bmc->map = devm_regmap_init_mmio(dev, base, &bt_regmap_cfg);
+ bt_bmc->offset = 0;
+ } else {
+ rc = of_property_read_u32(dev->of_node, "reg", &bt_bmc->offset);
+ if (rc)
+ return rc;
+ }
+
+ mutex_init(&bt_bmc->mutex);
+ 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 misc device\n");
+ return rc;
+ }
+
+ 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");
+ timer_setup(&bt_bmc->poll_timer, poll_timer, 0);
+ bt_bmc->poll_timer.expires = jiffies + msecs_to_jiffies(10);
+ add_timer(&bt_bmc->poll_timer);
+ }
+
+ regmap_write(bt_bmc->map, bt_bmc->offset + BT_CR0,
+ (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);
+
+ clr_b_busy(bt_bmc);
+
+ return 0;
+}
+
+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);
+ return 0;
+}
+
+static const struct of_device_id bt_bmc_match[] = {
+ { .compatible = "aspeed,ast2400-ibt-bmc" },
+ { .compatible = "aspeed,ast2500-ibt-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@popple.id.au>");
+MODULE_DESCRIPTION("Linux device interface to the IPMI BT interface");
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-25 15:03:43 +0000