[PATCH v2 4/5] drivers/mailbox: Add aspeed ast2400/ast2500 mbox driver
Cyril Bur
cyrilbur at gmail.com
Thu Dec 22 17:06:09 AEDT 2016
This provides access to the mbox registers on the ast2400 and ast2500 boards.
An ioctl() is used to allow users to write to a specific register with a specific
value. This is useful as the other end have configured the mbox registers to
provide an interrupt when a specific regster gets written to.
Signed-off-by: Cyril Bur <cyrilbur at gmail.com>
---
drivers/mailbox/Kconfig | 9 +
drivers/mailbox/Makefile | 3 +
drivers/mailbox/aspeed-mbox.c | 354 +++++++++++++++++++++++++++++++++++++++
include/uapi/linux/aspeed-mbox.h | 23 +++
4 files changed, 389 insertions(+)
create mode 100644 drivers/mailbox/aspeed-mbox.c
create mode 100644 include/uapi/linux/aspeed-mbox.h
diff --git a/drivers/mailbox/Kconfig b/drivers/mailbox/Kconfig
index 5305923752d2..815cfe852dea 100644
--- a/drivers/mailbox/Kconfig
+++ b/drivers/mailbox/Kconfig
@@ -123,4 +123,13 @@ config XGENE_SLIMPRO_MBOX
It is used to send short messages between ARM64-bit cores and
the SLIMpro Management Engine, primarily for PM. Say Y here if you
want to use the APM X-Gene SLIMpro IPCM support.
+
+config ASPEED_MBOX
+ depends on ARCH_ASPEED || COMPILE_TEST
+ bool "Aspeed ast2400/2500 Mailbox Controller"
+ default "y"
+ ---help---
+ Provides a driver for the MBOX regsiters found on Aspeed SOCs
+ (AST2400 and AST2500). This driver provides a device for aspeed
+ mbox registers
endif
diff --git a/drivers/mailbox/Makefile b/drivers/mailbox/Makefile
index 0be3e742bb7d..99d17f3b9552 100644
--- a/drivers/mailbox/Makefile
+++ b/drivers/mailbox/Makefile
@@ -25,3 +25,6 @@ obj-$(CONFIG_TI_MESSAGE_MANAGER) += ti-msgmgr.o
obj-$(CONFIG_XGENE_SLIMPRO_MBOX) += mailbox-xgene-slimpro.o
obj-$(CONFIG_HI6220_MBOX) += hi6220-mailbox.o
+
+obj-$(CONFIG_ASPEED_MBOX) += aspeed-mbox.o
+
diff --git a/drivers/mailbox/aspeed-mbox.c b/drivers/mailbox/aspeed-mbox.c
new file mode 100644
index 000000000000..a5da7fc0fd23
--- /dev/null
+++ b/drivers/mailbox/aspeed-mbox.c
@@ -0,0 +1,354 @@
+/*
+ * Copyright 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/mfd/syscon.h>
+#include <linux/regmap.h>
+#include <linux/aspeed-mbox.h>
+
+#define DEVICE_NAME "aspeed-mbox"
+
+#define MBOX_NUM_REGS 16
+#define MBOX_NUM_DATA_REGS 14
+
+#define MBOX_DATA_0 0x00
+#define MBOX_STATUS_0 0x40
+#define MBOX_STATUS_1 0x44
+#define MBOX_BMC_CTRL 0x48
+#define MBOX_CTRL_RECV BIT(7)
+#define MBOX_CTRL_MASK BIT(1)
+#define MBOX_CTRL_SEND BIT(0)
+#define MBOX_HOST_CTRL 0x4c
+#define MBOX_INTERRUPT_0 0x50
+#define MBOX_INTERRUPT_1 0x54
+
+struct mbox {
+ struct miscdevice miscdev;
+ struct regmap *regmap;
+ unsigned int base;
+ int irq;
+ wait_queue_head_t queue;
+ struct timer_list poll_timer;
+};
+
+static atomic_t mbox_open_count = ATOMIC_INIT(0);
+
+static u8 mbox_inb(struct mbox *mbox, int reg)
+{
+ /*
+ * The mbox registers are actually only 1 byte but are addressed 4
+ * bytes appart. The other three bytes are marked 'reserved', they
+ * *should* be zero but lets not rely on it.
+ * I am going to rely on the fact we can casually read/write to them...
+ */
+ unsigned int val = 0xff; /* If regmap throws an error return 0xff */
+ regmap_read(mbox->regmap, mbox->base + reg, &val);
+ return val & 0xff;
+}
+
+static void mbox_outb(struct mbox *mbox, u8 data, int reg)
+{
+ regmap_write(mbox->regmap, mbox->base + reg, data);
+}
+
+static struct mbox *file_mbox(struct file *file)
+{
+ return container_of(file->private_data, struct mbox, miscdev);
+}
+
+static int mbox_open(struct inode *inode, struct file *file)
+{
+ struct mbox *mbox = file_mbox(file);
+
+ if (atomic_inc_return(&mbox_open_count) == 1) {
+ /*
+ * Clear the interrupt status bit if it was left on and unmask
+ * interrupts.
+ * MBOX_CTRL_RECV bit is W1C, this also unmasks in 1 step
+ */
+ mbox_outb(mbox, MBOX_CTRL_RECV, MBOX_BMC_CTRL);
+ return 0;
+ }
+
+ atomic_dec(&mbox_open_count);
+ return -EBUSY;
+}
+
+static ssize_t mbox_read(struct file *file, char __user *buf,
+ size_t count, loff_t *ppos)
+{
+ struct mbox *mbox = file_mbox(file);
+ char __user *p = buf;
+ int i;
+
+ if (!access_ok(VERIFY_WRITE, buf, count))
+ return -EFAULT;
+
+ WARN_ON(*ppos);
+
+ if (wait_event_interruptible(mbox->queue,
+ mbox_inb(mbox, MBOX_BMC_CTRL) & MBOX_CTRL_RECV))
+ return -ERESTARTSYS;
+
+ for (i = 0; i < MBOX_NUM_DATA_REGS; i++)
+ if (__put_user(mbox_inb(mbox, MBOX_DATA_0 + (i * 4)), p++))
+ return -EFAULT;
+
+ /* MBOX_CTRL_RECV bit is W1C, this also unmasks in 1 step */
+ mbox_outb(mbox, MBOX_CTRL_RECV, MBOX_BMC_CTRL);
+ return p - buf;
+}
+
+static ssize_t mbox_write(struct file *file, const char __user *buf,
+ size_t count, loff_t *ppos)
+{
+ struct mbox *mbox = file_mbox(file);
+ const char __user *p = buf;
+ char c;
+ int i;
+
+ if (!access_ok(VERIFY_READ, buf, count))
+ return -EFAULT;
+
+ WARN_ON(*ppos);
+
+ for (i = 0; i < MBOX_NUM_DATA_REGS; i++) {
+ if (__get_user(c, p))
+ return -EFAULT;
+
+ mbox_outb(mbox, c, MBOX_DATA_0 + (i * 4));
+ p++;
+ }
+
+ mbox_outb(mbox, MBOX_CTRL_SEND, MBOX_BMC_CTRL);
+
+ return p - buf;
+}
+
+static long mbox_ioctl(struct file *file, unsigned int cmd,
+ unsigned long param)
+{
+ struct aspeed_mbox_atn atn;
+ struct mbox *mbox = file_mbox(file);
+ void __user *p = (void __user *)param;
+
+ switch (cmd) {
+ case ASPEED_MBOX_IOCTL_ATN:
+ if (copy_from_user(&atn, p, sizeof(atn)))
+ return -EFAULT;
+ if (atn.reg > 15)
+ return -EINVAL;
+
+ mbox_outb(mbox, atn.val, atn.reg);
+ return 0;
+ }
+
+ return -EINVAL;
+}
+
+static unsigned int mbox_poll(struct file *file, poll_table *wait)
+{
+ struct mbox *mbox = file_mbox(file);
+ unsigned int mask = 0;
+
+ poll_wait(file, &mbox->queue, wait);
+
+ if (mbox_inb(mbox, MBOX_BMC_CTRL) & MBOX_CTRL_RECV)
+ mask |= POLLIN;
+
+ return mask;
+}
+
+static int mbox_release(struct inode *inode, struct file *file)
+{
+ atomic_dec(&mbox_open_count);
+ return 0;
+}
+
+static const struct file_operations mbox_fops = {
+ .owner = THIS_MODULE,
+ .open = mbox_open,
+ .read = mbox_read,
+ .write = mbox_write,
+ .release = mbox_release,
+ .poll = mbox_poll,
+ .unlocked_ioctl = mbox_ioctl,
+};
+
+static void poll_timer(unsigned long data)
+{
+ struct mbox *mbox = (void *)data;
+
+ mbox->poll_timer.expires += msecs_to_jiffies(500);
+ wake_up(&mbox->queue);
+ add_timer(&mbox->poll_timer);
+}
+
+static irqreturn_t mbox_irq(int irq, void *arg)
+{
+ struct mbox *mbox = arg;
+
+ if (!(mbox_inb(mbox, MBOX_BMC_CTRL) & MBOX_CTRL_RECV))
+ return IRQ_NONE;
+
+ /*
+ * Leave the status bit set so that we know the data is for us,
+ * clear it once it has been read.
+ */
+
+ /* Mask it off, we'll clear it when we the data gets read */
+ mbox_outb(mbox, MBOX_CTRL_MASK, MBOX_BMC_CTRL);
+
+ wake_up(&mbox->queue);
+ return IRQ_HANDLED;
+}
+
+static int mbox_config_irq(struct mbox *mbox,
+ struct platform_device *pdev)
+{
+ struct device *dev = &pdev->dev;
+ int rc;
+
+ mbox->irq = irq_of_parse_and_map(dev->of_node, 0);
+ if (!mbox->irq)
+ return -ENODEV;
+
+ rc = devm_request_irq(dev, mbox->irq, mbox_irq, IRQF_SHARED,
+ DEVICE_NAME, mbox);
+ if (rc < 0) {
+ dev_warn(dev, "Unable to request IRQ %d\n", mbox->irq);
+ mbox->irq = 0;
+ return rc;
+ }
+
+ /*
+ * Disable all register based interrupts, we'll have to change
+ * this, protocol seemingly will require regs 0 and 15
+ */
+ mbox_outb(mbox, 0x00, MBOX_INTERRUPT_0); /* regs 0 - 7 */
+ mbox_outb(mbox, 0x00, MBOX_INTERRUPT_1); /* regs 8 - 15 */
+
+ /* W1C */
+ mbox_outb(mbox, 0xff, MBOX_STATUS_0);
+ mbox_outb(mbox, 0xff, MBOX_STATUS_1);
+
+ mbox_outb(mbox, MBOX_CTRL_RECV, MBOX_BMC_CTRL);
+ return 0;
+}
+
+static int mbox_probe(struct platform_device *pdev)
+{
+ struct mbox *mbox;
+ struct device *dev;
+ int rc;
+
+ if (!pdev || !pdev->dev.of_node)
+ return -ENODEV;
+
+ dev = &pdev->dev;
+ dev_info(dev, "Found mbox host device\n");
+
+ mbox = devm_kzalloc(dev, sizeof(*mbox), GFP_KERNEL);
+ if (!mbox)
+ return -ENOMEM;
+
+ dev_set_drvdata(&pdev->dev, mbox);
+
+ rc = of_property_read_u32(dev->of_node, "reg", &mbox->base);
+ if (rc) {
+ dev_err(dev, "Couldn't read reg device-tree property\n");
+ goto out;
+ }
+
+ mbox->regmap = syscon_node_to_regmap(
+ pdev->dev.parent->of_node);
+ if (IS_ERR(mbox->regmap)) {
+ dev_err(dev, "Couldn't get regmap\n");
+ rc = -ENODEV;
+ goto out;
+ }
+
+ init_waitqueue_head(&mbox->queue);
+
+ mbox->miscdev.minor = MISC_DYNAMIC_MINOR;
+ mbox->miscdev.name = DEVICE_NAME;
+ mbox->miscdev.fops = &mbox_fops;
+ mbox->miscdev.parent = dev;
+ rc = misc_register(&mbox->miscdev);
+ if (rc) {
+ dev_err(dev, "Unable to register device\n");
+ goto out;
+ }
+
+ mbox_config_irq(mbox, pdev);
+
+ if (mbox->irq) {
+ dev_info(dev, "Using IRQ %d\n", mbox->irq);
+ } else {
+ dev_info(dev, "No IRQ; using timer\n");
+ setup_timer(&mbox->poll_timer, poll_timer,
+ (unsigned long)mbox);
+ mbox->poll_timer.expires = jiffies + msecs_to_jiffies(10);
+ add_timer(&mbox->poll_timer);
+ }
+
+out:
+ return rc;
+
+}
+
+static int mbox_remove(struct platform_device *pdev)
+{
+ struct mbox *mbox = dev_get_drvdata(&pdev->dev);
+
+ misc_deregister(&mbox->miscdev);
+ if (!mbox->irq)
+ del_timer_sync(&mbox->poll_timer);
+ mbox = NULL;
+
+ return 0;
+}
+
+static const struct of_device_id mbox_match[] = {
+ { .compatible = "aspeed,ast2400-mbox" },
+ { },
+};
+
+static struct platform_driver mbox_driver = {
+ .driver = {
+ .name = DEVICE_NAME,
+ .of_match_table = mbox_match,
+ },
+ .probe = mbox_probe,
+ .remove = mbox_remove,
+};
+
+module_platform_driver(mbox_driver);
+
+MODULE_DEVICE_TABLE(of, mbox_match);
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Cyril Bur <cyrilbur at gmail.com>");
+MODULE_DESCRIPTION("Linux device interface to the Aspeed MBOX registers");
diff --git a/include/uapi/linux/aspeed-mbox.h b/include/uapi/linux/aspeed-mbox.h
new file mode 100644
index 000000000000..f4e6a9242fd0
--- /dev/null
+++ b/include/uapi/linux/aspeed-mbox.h
@@ -0,0 +1,23 @@
+/*
+ * Copyright 2016 IBM Corp.
+ *
+ * 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_MBOX_HOST_H
+#define _UAPI_LINUX_MBOX_HOST_H
+
+#include <linux/ioctl.h>
+
+struct aspeed_mbox_atn {
+ uint8_t reg;
+ uint8_t val;
+};
+
+#define __ASPEED_MBOX_IOCTL_MAGIC 0xb1
+#define ASPEED_MBOX_IOCTL_ATN _IOW(__ASPEED_MBOX_IOCTL_MAGIC, 0x00, struct aspeed_mbox_atn)
+
+#endif /* _UAPI_LINUX_MBOX_HOST_H */
--
2.11.0
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