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|
/*
* STi Mailbox
*
* Copyright (C) 2015 ST Microelectronics
*
* Author: Lee Jones <lee.jones@linaro.org> for ST Microelectronics
*
* Based on the original driver written by;
* Alexandre Torgue, Olivier Lebreton and Loic Pallardy
*
* 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/err.h>
#include <linux/interrupt.h>
#include <linux/io.h>
#include <linux/kernel.h>
#include <linux/mailbox_controller.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/of_device.h>
#include <linux/platform_device.h>
#include <linux/slab.h>
#include "mailbox.h"
#define STI_MBOX_INST_MAX 4 /* RAM saving: Max supported instances */
#define STI_MBOX_CHAN_MAX 20 /* RAM saving: Max supported channels */
#define STI_IRQ_VAL_OFFSET 0x04 /* Read interrupt status */
#define STI_IRQ_SET_OFFSET 0x24 /* Generate a Tx channel interrupt */
#define STI_IRQ_CLR_OFFSET 0x44 /* Clear pending Rx interrupts */
#define STI_ENA_VAL_OFFSET 0x64 /* Read enable status */
#define STI_ENA_SET_OFFSET 0x84 /* Enable a channel */
#define STI_ENA_CLR_OFFSET 0xa4 /* Disable a channel */
#define MBOX_BASE(mdev, inst) ((mdev)->base + ((inst) * 4))
/**
* STi Mailbox device data
*
* An IP Mailbox is currently composed of 4 instances
* Each instance is currently composed of 32 channels
* This means that we have 128 channels per Mailbox
* A channel an be used for TX or RX
*
* @dev: Device to which it is attached
* @mbox: Representation of a communication channel controller
* @base: Base address of the register mapping region
* @name: Name of the mailbox
* @enabled: Local copy of enabled channels
* @lock: Mutex protecting enabled status
*/
struct sti_mbox_device {
struct device *dev;
struct mbox_controller *mbox;
void __iomem *base;
const char *name;
u32 enabled[STI_MBOX_INST_MAX];
spinlock_t lock;
};
/**
* STi Mailbox platform specific configuration
*
* @num_inst: Maximum number of instances in one HW Mailbox
* @num_chan: Maximum number of channel per instance
*/
struct sti_mbox_pdata {
unsigned int num_inst;
unsigned int num_chan;
};
/**
* STi Mailbox allocated channel information
*
* @mdev: Pointer to parent Mailbox device
* @instance: Instance number channel resides in
* @channel: Channel number pertaining to this container
*/
struct sti_channel {
struct sti_mbox_device *mdev;
unsigned int instance;
unsigned int channel;
};
static inline bool sti_mbox_channel_is_enabled(struct mbox_chan *chan)
{
struct sti_channel *chan_info = chan->con_priv;
struct sti_mbox_device *mdev = chan_info->mdev;
unsigned int instance = chan_info->instance;
unsigned int channel = chan_info->channel;
return mdev->enabled[instance] & BIT(channel);
}
static inline
struct mbox_chan *sti_mbox_to_channel(struct mbox_controller *mbox,
unsigned int instance,
unsigned int channel)
{
struct sti_channel *chan_info;
int i;
for (i = 0; i < mbox->num_chans; i++) {
chan_info = mbox->chans[i].con_priv;
if (chan_info &&
chan_info->instance == instance &&
chan_info->channel == channel)
return &mbox->chans[i];
}
dev_err(mbox->dev,
"Channel not registered: instance: %d channel: %d\n",
instance, channel);
return NULL;
}
static void sti_mbox_enable_channel(struct mbox_chan *chan)
{
struct sti_channel *chan_info = chan->con_priv;
struct sti_mbox_device *mdev = chan_info->mdev;
unsigned int instance = chan_info->instance;
unsigned int channel = chan_info->channel;
unsigned long flags;
void __iomem *base = MBOX_BASE(mdev, instance);
spin_lock_irqsave(&mdev->lock, flags);
mdev->enabled[instance] |= BIT(channel);
writel_relaxed(BIT(channel), base + STI_ENA_SET_OFFSET);
spin_unlock_irqrestore(&mdev->lock, flags);
}
static void sti_mbox_disable_channel(struct mbox_chan *chan)
{
struct sti_channel *chan_info = chan->con_priv;
struct sti_mbox_device *mdev = chan_info->mdev;
unsigned int instance = chan_info->instance;
unsigned int channel = chan_info->channel;
unsigned long flags;
void __iomem *base = MBOX_BASE(mdev, instance);
spin_lock_irqsave(&mdev->lock, flags);
mdev->enabled[instance] &= ~BIT(channel);
writel_relaxed(BIT(channel), base + STI_ENA_CLR_OFFSET);
spin_unlock_irqrestore(&mdev->lock, flags);
}
static void sti_mbox_clear_irq(struct mbox_chan *chan)
{
struct sti_channel *chan_info = chan->con_priv;
struct sti_mbox_device *mdev = chan_info->mdev;
unsigned int instance = chan_info->instance;
unsigned int channel = chan_info->channel;
void __iomem *base = MBOX_BASE(mdev, instance);
writel_relaxed(BIT(channel), base + STI_IRQ_CLR_OFFSET);
}
static struct mbox_chan *sti_mbox_irq_to_channel(struct sti_mbox_device *mdev,
unsigned int instance)
{
struct mbox_controller *mbox = mdev->mbox;
struct mbox_chan *chan = NULL;
unsigned int channel;
unsigned long bits;
void __iomem *base = MBOX_BASE(mdev, instance);
bits = readl_relaxed(base + STI_IRQ_VAL_OFFSET);
if (!bits)
/* No IRQs fired in specified instance */
return NULL;
/* An IRQ has fired, find the associated channel */
for (channel = 0; bits; channel++) {
if (!test_and_clear_bit(channel, &bits))
continue;
chan = sti_mbox_to_channel(mbox, instance, channel);
if (chan) {
dev_dbg(mbox->dev,
"IRQ fired on instance: %d channel: %d\n",
instance, channel);
break;
}
}
return chan;
}
static irqreturn_t sti_mbox_thread_handler(int irq, void *data)
{
struct sti_mbox_device *mdev = data;
struct sti_mbox_pdata *pdata = dev_get_platdata(mdev->dev);
struct mbox_chan *chan;
unsigned int instance;
for (instance = 0; instance < pdata->num_inst; instance++) {
keep_looking:
chan = sti_mbox_irq_to_channel(mdev, instance);
if (!chan)
continue;
mbox_chan_received_data(chan, NULL);
sti_mbox_clear_irq(chan);
sti_mbox_enable_channel(chan);
goto keep_looking;
}
return IRQ_HANDLED;
}
static irqreturn_t sti_mbox_irq_handler(int irq, void *data)
{
struct sti_mbox_device *mdev = data;
struct sti_mbox_pdata *pdata = dev_get_platdata(mdev->dev);
struct sti_channel *chan_info;
struct mbox_chan *chan;
unsigned int instance;
int ret = IRQ_NONE;
for (instance = 0; instance < pdata->num_inst; instance++) {
chan = sti_mbox_irq_to_channel(mdev, instance);
if (!chan)
continue;
chan_info = chan->con_priv;
if (!sti_mbox_channel_is_enabled(chan)) {
dev_warn(mdev->dev,
"Unexpected IRQ: %s\n"
" instance: %d: channel: %d [enabled: %x]\n",
mdev->name, chan_info->instance,
chan_info->channel, mdev->enabled[instance]);
/* Only handle IRQ if no other valid IRQs were found */
if (ret == IRQ_NONE)
ret = IRQ_HANDLED;
continue;
}
sti_mbox_disable_channel(chan);
ret = IRQ_WAKE_THREAD;
}
if (ret == IRQ_NONE)
dev_err(mdev->dev, "Spurious IRQ - was a channel requested?\n");
return ret;
}
static bool sti_mbox_tx
|