[PATCH v2 4/5] drivers/mailbox: Add aspeed ast2400/ast2500 mbox driver
Cyril Bur
cyrilbur at gmail.com
Fri Dec 23 18:56:35 AEDT 2016
On Fri, 2016-12-23 at 13:12 +1030, Andrew Jeffery wrote:
> Hi Cyril,
>
> This looks good to me. A couple of minor comments below.
>
> On Thu, 2016-12-22 at 17:06 +1100, Cyril Bur wrote:
> > 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);
>
> We could use regmap_update_bits() here, but ultimately it's not going
> to matter. Should we say something if regmap_write() fails (it
> shouldn't, but if it does that's extra concerning)?
regmap_update_bits() to about touching the reserved section? Probs a
good idea.
Yeah I thought about putting a dev_err() in there. I'm not opposed, I
sort of though, we'll you never see them or when you do something
really bad has happened you'll probably notice everything broke...
Still in the incredibly unlikely event that a print proves useful I'm
happy to add it.
>
> > +}
> > +
> > +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:
>
> I think we should rename the IOCTL as what we do below doesn't
> necessarily raise an interrupt.
>
Agreed, taking unput :). ASPEED_MBOX_IOCTL_WRITE_BYTE ?
Thanks,
Cyril
> > + 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 */
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