// SPDX-License-Identifier: GPL-2.0-only
/*
* Copyright (C) 2013-2015 Fujitsu Semiconductor Ltd.
* Copyright (C) 2015 Linaro Ltd.
* Based on ARM MHU driver by Jassi Brar <[email protected]>
* Copyright (C) 2020 ARM Ltd.
*/
#include <linux/amba/bus.h>
#include <linux/device.h>
#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>
#define INTR_STAT_OFS 0x0
#define INTR_SET_OFS 0x8
#define INTR_CLR_OFS 0x10
#define MHU_LP_OFFSET 0x0
#define MHU_HP_OFFSET 0x20
#define MHU_SEC_OFFSET 0x200
#define TX_REG_OFFSET 0x100
#define MHU_CHANS 3 /* Secure, Non-Secure High and Low Priority */
#define MHU_CHAN_MAX 20 /* Max channels to save on unused RAM */
#define MHU_NUM_DOORBELLS 32
struct mhu_db_link {
unsigned int irq;
void __iomem *tx_reg;
void __iomem *rx_reg;
};
struct arm_mhu {
void __iomem *base;
struct mhu_db_link mlink[MHU_CHANS];
struct mbox_controller mbox;
struct device *dev;
};
/**
* struct mhu_db_channel - ARM MHU Mailbox allocated channel information
*
* @mhu: Pointer to parent mailbox device
* @pchan: Physical channel within which this doorbell resides in
* @doorbell: doorbell number pertaining to this channel
*/
struct mhu_db_channel {
struct arm_mhu *mhu;
unsigned int pchan;
unsigned int doorbell;
};
static inline struct mbox_chan *
mhu_db_mbox_to_channel(struct mbox_controller *mbox, unsigned int pchan,
unsigned int doorbell)
{
int i;
struct mhu_db_channel *chan_info;
for (i = 0; i < mbox->num_chans; i++) {
chan_info = mbox->chans[i].con_priv;
if (chan_info && chan_info->pchan == pchan &&
chan_info->doorbell == doorbell)
return &mbox->chans[i];
}
return NULL;
}
static void mhu_db_mbox_clear_irq(struct mbox_chan *chan)
{
struct mhu_db_channel *chan_info = chan->con_priv;
void __iomem *base = chan_info->mhu->mlink[chan_info->pchan].rx_reg;
writel_relaxed(BIT(chan_info->doorbell), base + INTR_CLR_OFS);
}
static unsigned int mhu_db_mbox_irq_to_pchan_num(struct arm_mhu *mhu, int irq)
{
unsigned int pchan;
for (pchan = 0; pchan < MHU_CHANS; pchan++)
if (mhu->mlink[pchan].irq == irq)
break;
return pchan;
}
static struct mbox_chan *
mhu_db_mbox_irq_to_channel(struct arm_mhu *mhu, unsigned int pchan)
{
unsigned long bits;
unsigned int doorbell;
struct mbox_chan *chan = NULL;
struct mbox_controller *mbox = &mhu->mbox;
void __iomem *base = mhu->mlink[pchan].rx_reg;
bits = readl_relaxed(base + INTR_STAT_OFS);
if (!bits)
/* No IRQs fired in specified physical channel */
return NULL;
/* An IRQ has fired, find the associated channel */
for (doorbell = 0; bits; doorbell++) {
if (!test_and_clear_bit(doorbell, &bits))
continue;
chan = mhu_db_mbox_to_channel(mbox, pchan, doorbell);
if (chan)
break;
dev_err(mbox->dev,
"Channel not registered: pchan: %d doorbell: %d\n",
pchan, doorbell);
}
return chan;
}
static irqreturn_t mhu_db_mbox_rx_handler(int irq, void *data)
{
struct mbox_chan *chan;
struct arm_mhu *mhu = data;
unsigned int pchan = mhu_db_mbox_irq_to_pchan_num(mhu, irq);
while (NULL != (chan = mhu_db_mbox_irq_to_channel(mhu, pchan))) {
mbox_chan_received_data(chan, NULL);
mhu_db_mbox_clear_irq(chan);
}
return IRQ_HANDLED;
}
static bool mhu_db_last_tx_done(struct mbox_chan *chan)
{
struct mhu_db_channel *chan_info = chan->con_priv;
void __iomem *base = chan_info->mhu->mlink[chan_info->pchan].tx_reg;
if (readl_relaxed(base + INTR_STAT_OFS) & BIT(chan_info->doorbell))
return false;
return true;
}
static int mhu_db_send_data(struct mbox_chan *chan, void *data)
{
struct mhu_db_channel *chan_info = chan->con_priv;
void __iomem *base = chan_info->mhu->mlink[chan_info->pchan].tx_reg;
/* Send event to co-processor */
writel_relaxed(BIT(chan_info->doorbell), base + INTR_SET_OFS);
return 0;
}
static int mhu_db_startup(struct mbox_chan *chan)
{
mhu_db_mbox_clear_irq(chan);
return 0;
}
static void mhu_db_shutdown(struct mbox_chan *chan)
{
struct mhu_db_channel *chan_info = chan->con_priv;
struct mbox_controller *mbox = &chan_info->mhu->mbox;
int i;
for (i = 0; i < mbox->num_chans; i++)
if (chan == &mbox->chans[i])
break;
if (mbox->num_chans == i) {
dev_warn(mbox->dev, "Request to free non-existent channel\n");
return;
}
/* Reset channel */
mhu_db_mbox_clear_irq(chan);
devm_kfree(mbox->dev, chan->con_priv);
chan->con_priv = NULL;
}
static struct mbox_chan *mhu_db_mbox_xlate(struct mbox_controller *mbox,
const struct of_phandle_args *spec)
{
struct arm_mhu *mhu = dev_get_drvdata(mbox->dev);
struct mhu_db_channel *chan_info;
struct mbox_chan *chan;
unsigned int pchan = spec->args[0];
unsigned int doorbell = spec->args[1];
int i;
/* Bounds checking */
if (pchan >= MHU_CHANS || doorbell >= MHU_NUM_DOORBELLS) {
dev_err(mbox->dev,
"Invalid channel requested pchan: %d doorbell: %d\n",
pchan, doorbell);
return ERR_PTR(-EINVAL);
}
/* Is requested channel free? */
chan = mhu_db_mbox_to_channel(mbox, pchan, doorbell);
if (chan) {
dev_err(mbox->dev, "Channel in use: pchan: %d doorbell: %d\n",
pchan, doorbell);
return ERR_PTR(-EBUSY);
}
/* Find the first free slot */
for (i = 0; i < mbox->num_chans; i++)
if (!mbox->chans[i].con_priv)
break;
if (mbox->num_chans == i) {
dev_err(mbox->dev, "No free channels left\n");
return ERR_PTR(-EBUSY);
}
chan = &mbox->chans[i];
chan_info = devm_kzalloc(mbox->dev, sizeof(*chan_info), GFP_KERNEL);
if (!chan_info)
return ERR_PTR(-ENOMEM);
chan_info->mhu = mhu;
chan_info->pchan = pchan;
chan_info->doorbell = doorbell;
chan->con_priv = chan_info;
dev_dbg(mbox->dev, "mbox: created channel phys: %d doorbell: %d\n",
pchan, doorbell);
return chan;
}
static const struct mbox_chan_ops mhu_db_ops = {
.send_data = mhu_db_send_data,
.startup = mhu_db_startup,
.shutdown = mhu_db_shutdown,
.last_tx_done = mhu_db_last_tx_done,
};
static int mhu_db_probe(struct amba_device *adev, const struct amba_id *id)
{
u32 cell_count;
int i, err, max_chans;
struct arm_mhu *mhu;
struct mbox_chan *chans;
struct device *dev = &adev->dev;
struct device_node *np = dev->of_node;
int mhu_reg[MHU_CHANS] = {
MHU_LP_OFFSET, MHU_HP_OFFSET, MHU_SEC_OFFSET,
};
if (!of_device_is_compatible(np, "arm,mhu-doorbell"))
return -ENODEV;
err = of_property_read_u32(np, "#mbox-cells", &cell_count);
if (err) {
dev_err(dev, "failed to read #mbox-cells in '%pOF'\n", np);
return err;
}
if (cell_count == 2) {
max_chans = MHU_CHAN_MAX;
} else {
dev_err(dev, "incorrect value of #mbox-cells in '%pOF'\n", np);
return -EINVAL;
}
mhu = devm_kzalloc(dev, sizeof(*mhu), GFP_KERNEL);
if (!mhu)
return -ENOMEM;
mhu->base = devm_ioremap_resource(dev, &adev->res);
if (IS_ERR(mhu->base))
return PTR_ERR(mhu->base);
chans = devm_kcalloc(dev, max_chans, sizeof(*chans), GFP_KERNEL);
if (!chans)
return -ENOMEM;
mhu->dev = dev;
mhu->mbox.dev = dev;
mhu->mbox.chans = chans;
mhu->mbox.num_chans = max_chans;
mhu->mbox.txdone_irq = false;
mhu->mbox.txdone_poll = true;
mhu->mbox.txpoll_period = 1;
mhu->mbox.of_xlate = mhu_db_mbox_xlate;
amba_set_drvdata(adev, mhu);
mhu->mbox.ops = &mhu_db_ops;
err = devm_mbox_controller_register(dev, &mhu->mbox);
if (err) {
dev_err(dev, "Failed to register mailboxes %d\n", err);
return err;
}
for (i = 0; i < MHU_CHANS; i++) {
int irq = mhu->mlink[i].irq = adev->irq[i];
if (irq <= 0) {
dev_dbg(dev, "No IRQ found for Channel %d\n", i);
continue;
}
mhu->mlink[i].rx_reg = mhu->base + mhu_reg[i];
mhu->mlink[i].tx_reg = mhu->mlink[i].rx_reg + TX_REG_OFFSET;
err = devm_request_threaded_irq(dev, irq, NULL,
mhu_db_mbox_rx_handler,
IRQF_ONESHOT, "mhu_db_link", mhu);
if (err) {
dev_err(dev, "Can't claim IRQ %d\n", irq);
mbox_controller_unregister(&mhu->mbox);
return err;
}
}
dev_info(dev, "ARM MHU Doorbell mailbox registered\n");
return 0;
}
static struct amba_id mhu_ids[] = {
{
.id = 0x1bb098,
.mask = 0xffffff,
},
{ 0, 0 },
};
MODULE_DEVICE_TABLE(amba, mhu_ids);
static struct amba_driver arm_mhu_db_driver = {
.drv = {
.name = "mhu-doorbell",
},
.id_table = mhu_ids,
.probe = mhu_db_probe,
};
module_amba_driver(arm_mhu_db_driver);
MODULE_LICENSE("GPL v2");
MODULE_DESCRIPTION("ARM MHU Doorbell Driver");
MODULE_AUTHOR("Sudeep Holla <[email protected]>");
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