Commit f62092f6 authored by Ley Foon Tan's avatar Ley Foon Tan Committed by Jassi Brar

mailbox: Add Altera mailbox driver

The Altera mailbox allows for interprocessor communication. It supports
only one channel and work as either sender or receiver.
Signed-off-by: default avatarLey Foon Tan <lftan@altera.com>
parent 01340df8
Altera Mailbox Driver
=====================
Required properties:
- compatible : "altr,mailbox-1.0".
- reg : physical base address of the mailbox and length of
memory mapped region.
- #mbox-cells: Common mailbox binding property to identify the number
of cells required for the mailbox specifier. Should be 1.
Optional properties:
- interrupt-parent : interrupt source phandle.
- interrupts : interrupt number. The interrupt specifier format
depends on the interrupt controller parent.
Example:
mbox_tx: mailbox@0x100 {
compatible = "altr,mailbox-1.0";
reg = <0x100 0x8>;
interrupt-parent = < &gic_0 >;
interrupts = <5>;
#mbox-cells = <1>;
};
mbox_rx: mailbox@0x200 {
compatible = "altr,mailbox-1.0";
reg = <0x200 0x8>;
interrupt-parent = < &gic_0 >;
interrupts = <6>;
#mbox-cells = <1>;
};
Mailbox client
===============
"mboxes" and the optional "mbox-names" (please see
Documentation/devicetree/bindings/mailbox/mailbox.txt for details). Each value
of the mboxes property should contain a phandle to the mailbox controller
device node and second argument is the channel index. It must be 0 (hardware
support only one channel).The equivalent "mbox-names" property value can be
used to give a name to the communication channel to be used by the client user.
Example:
mclient0: mclient0@0x400 {
compatible = "client-1.0";
reg = <0x400 0x10>;
mbox-names = "mbox-tx", "mbox-rx";
mboxes = <&mbox_tx 0>,
<&mbox_rx 0>;
};
......@@ -563,6 +563,12 @@ S: Odd Fixes
L: linux-alpha@vger.kernel.org
F: arch/alpha/
ALTERA MAILBOX DRIVER
M: Ley Foon Tan <lftan@altera.com>
L: nios2-dev@lists.rocketboards.org (moderated for non-subscribers)
S: Maintained
F: drivers/mailbox/mailbox-altera.c
ALTERA TRIPLE SPEED ETHERNET DRIVER
M: Vince Bridgers <vbridger@opensource.altera.com>
L: netdev@vger.kernel.org
......
......@@ -45,4 +45,10 @@ config PCC
states). Select this driver if your platform implements the
PCC clients mentioned above.
config ALTERA_MBOX
tristate "Altera Mailbox"
help
An implementation of the Altera Mailbox soft core. It is used
to send message between processors. Say Y here if you want to use the
Altera mailbox support.
endif
......@@ -7,3 +7,5 @@ obj-$(CONFIG_PL320_MBOX) += pl320-ipc.o
obj-$(CONFIG_OMAP2PLUS_MBOX) += omap-mailbox.o
obj-$(CONFIG_PCC) += pcc.o
obj-$(CONFIG_ALTERA_MBOX) += mailbox-altera.o
/*
* Copyright Altera Corporation (C) 2013-2014. All rights reserved
*
* This program is free software; you can redistribute it and/or modify it
* under the terms and conditions of the GNU General Public License,
* version 2, as published by the Free Software Foundation.
*
* This program is distributed in the hope it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
* more details.
*
* You should have received a copy of the GNU General Public License along with
* this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include <linux/device.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/platform_device.h>
#define DRIVER_NAME "altera-mailbox"
#define MAILBOX_CMD_REG 0x00
#define MAILBOX_PTR_REG 0x04
#define MAILBOX_STS_REG 0x08
#define MAILBOX_INTMASK_REG 0x0C
#define INT_PENDING_MSK 0x1
#define INT_SPACE_MSK 0x2
#define STS_PENDING_MSK 0x1
#define STS_FULL_MSK 0x2
#define STS_FULL_OFT 0x1
#define MBOX_PENDING(status) (((status) & STS_PENDING_MSK))
#define MBOX_FULL(status) (((status) & STS_FULL_MSK) >> STS_FULL_OFT)
enum altera_mbox_msg {
MBOX_CMD = 0,
MBOX_PTR,
};
#define MBOX_POLLING_MS 5 /* polling interval 5ms */
struct altera_mbox {
bool is_sender; /* 1-sender, 0-receiver */
bool intr_mode;
int irq;
void __iomem *mbox_base;
struct device *dev;
struct mbox_controller controller;
/* If the controller supports only RX polling mode */
struct timer_list rxpoll_timer;
};
static struct altera_mbox *mbox_chan_to_altera_mbox(struct mbox_chan *chan)
{
if (!chan || !chan->con_priv)
return NULL;
return (struct altera_mbox *)chan->con_priv;
}
static inline int altera_mbox_full(struct altera_mbox *mbox)
{
u32 status;
status = readl_relaxed(mbox->mbox_base + MAILBOX_STS_REG);
return MBOX_FULL(status);
}
static inline int altera_mbox_pending(struct altera_mbox *mbox)
{
u32 status;
status = readl_relaxed(mbox->mbox_base + MAILBOX_STS_REG);
return MBOX_PENDING(status);
}
static void altera_mbox_rx_intmask(struct altera_mbox *mbox, bool enable)
{
u32 mask;
mask = readl_relaxed(mbox->mbox_base + MAILBOX_INTMASK_REG);
if (enable)
mask |= INT_PENDING_MSK;
else
mask &= ~INT_PENDING_MSK;
writel_relaxed(mask, mbox->mbox_base + MAILBOX_INTMASK_REG);
}
static void altera_mbox_tx_intmask(struct altera_mbox *mbox, bool enable)
{
u32 mask;
mask = readl_relaxed(mbox->mbox_base + MAILBOX_INTMASK_REG);
if (enable)
mask |= INT_SPACE_MSK;
else
mask &= ~INT_SPACE_MSK;
writel_relaxed(mask, mbox->mbox_base + MAILBOX_INTMASK_REG);
}
static bool altera_mbox_is_sender(struct altera_mbox *mbox)
{
u32 reg;
/* Write a magic number to PTR register and read back this register.
* This register is read-write if it is a sender.
*/
#define MBOX_MAGIC 0xA5A5AA55
writel_relaxed(MBOX_MAGIC, mbox->mbox_base + MAILBOX_PTR_REG);
reg = readl_relaxed(mbox->mbox_base + MAILBOX_PTR_REG);
if (reg == MBOX_MAGIC) {
/* Clear to 0 */
writel_relaxed(0, mbox->mbox_base + MAILBOX_PTR_REG);
return true;
}
return false;
}
static void altera_mbox_rx_data(struct mbox_chan *chan)
{
struct altera_mbox *mbox = mbox_chan_to_altera_mbox(chan);
u32 data[2];
if (altera_mbox_pending(mbox)) {
data[MBOX_PTR] =
readl_relaxed(mbox->mbox_base + MAILBOX_PTR_REG);
data[MBOX_CMD] =
readl_relaxed(mbox->mbox_base + MAILBOX_CMD_REG);
mbox_chan_received_data(chan, (void *)data);
}
}
static void altera_mbox_poll_rx(unsigned long data)
{
struct mbox_chan *chan = (struct mbox_chan *)data;
struct altera_mbox *mbox = mbox_chan_to_altera_mbox(chan);
altera_mbox_rx_data(chan);
mod_timer(&mbox->rxpoll_timer,
jiffies + msecs_to_jiffies(MBOX_POLLING_MS));
}
static irqreturn_t altera_mbox_tx_interrupt(int irq, void *p)
{
struct mbox_chan *chan = (struct mbox_chan *)p;
struct altera_mbox *mbox = mbox_chan_to_altera_mbox(chan);
altera_mbox_tx_intmask(mbox, false);
mbox_chan_txdone(chan, 0);
return IRQ_HANDLED;
}
static irqreturn_t altera_mbox_rx_interrupt(int irq, void *p)
{
struct mbox_chan *chan = (struct mbox_chan *)p;
altera_mbox_rx_data(chan);
return IRQ_HANDLED;
}
static int altera_mbox_startup_sender(struct mbox_chan *chan)
{
int ret;
struct altera_mbox *mbox = mbox_chan_to_altera_mbox(chan);
if (mbox->intr_mode) {
ret = request_irq(mbox->irq, altera_mbox_tx_interrupt, 0,
DRIVER_NAME, chan);
if (unlikely(ret)) {
dev_err(mbox->dev,
"failed to register mailbox interrupt:%d\n",
ret);
return ret;
}
}
return 0;
}
static int altera_mbox_startup_receiver(struct mbox_chan *chan)
{
int ret;
struct altera_mbox *mbox = mbox_chan_to_altera_mbox(chan);
if (mbox->intr_mode) {
ret = request_irq(mbox->irq, altera_mbox_rx_interrupt, 0,
DRIVER_NAME, chan);
if (unlikely(ret)) {
mbox->intr_mode = false;
goto polling; /* use polling if failed */
}
altera_mbox_rx_intmask(mbox, true);
return 0;
}
polling:
/* Setup polling timer */
setup_timer(&mbox->rxpoll_timer, altera_mbox_poll_rx,
(unsigned long)chan);
mod_timer(&mbox->rxpoll_timer,
jiffies + msecs_to_jiffies(MBOX_POLLING_MS));
return 0;
}
static int altera_mbox_send_data(struct mbox_chan *chan, void *data)
{
struct altera_mbox *mbox = mbox_chan_to_altera_mbox(chan);
u32 *udata = (u32 *)data;
if (!mbox || !data)
return -EINVAL;
if (!mbox->is_sender) {
dev_warn(mbox->dev,
"failed to send. This is receiver mailbox.\n");
return -EINVAL;
}
if (altera_mbox_full(mbox))
return -EBUSY;
/* Enable interrupt before send */
if (mbox->intr_mode)
altera_mbox_tx_intmask(mbox, true);
/* Pointer register must write before command register */
writel_relaxed(udata[MBOX_PTR], mbox->mbox_base + MAILBOX_PTR_REG);
writel_relaxed(udata[MBOX_CMD], mbox->mbox_base + MAILBOX_CMD_REG);
return 0;
}
static bool altera_mbox_last_tx_done(struct mbox_chan *chan)
{
struct altera_mbox *mbox = mbox_chan_to_altera_mbox(chan);
/* Return false if mailbox is full */
return altera_mbox_full(mbox) ? false : true;
}
static bool altera_mbox_peek_data(struct mbox_chan *chan)
{
struct altera_mbox *mbox = mbox_chan_to_altera_mbox(chan);
return altera_mbox_pending(mbox) ? true : false;
}
static int altera_mbox_startup(struct mbox_chan *chan)
{
struct altera_mbox *mbox = mbox_chan_to_altera_mbox(chan);
int ret = 0;
if (!mbox)
return -EINVAL;
if (mbox->is_sender)
ret = altera_mbox_startup_sender(chan);
else
ret = altera_mbox_startup_receiver(chan);
return ret;
}
static void altera_mbox_shutdown(struct mbox_chan *chan)
{
struct altera_mbox *mbox = mbox_chan_to_altera_mbox(chan);
if (mbox->intr_mode) {
/* Unmask all interrupt masks */
writel_relaxed(~0, mbox->mbox_base + MAILBOX_INTMASK_REG);
free_irq(mbox->irq, chan);
} else if (!mbox->is_sender) {
del_timer_sync(&mbox->rxpoll_timer);
}
}
static struct mbox_chan_ops altera_mbox_ops = {
.send_data = altera_mbox_send_data,
.startup = altera_mbox_startup,
.shutdown = altera_mbox_shutdown,
.last_tx_done = altera_mbox_last_tx_done,
.peek_data = altera_mbox_peek_data,
};
static int altera_mbox_probe(struct platform_device *pdev)
{
struct altera_mbox *mbox;
struct resource *regs;
struct mbox_chan *chans;
int ret;
mbox = devm_kzalloc(&pdev->dev, sizeof(*mbox),
GFP_KERNEL);
if (!mbox)
return -ENOMEM;
/* Allocated one channel */
chans = devm_kzalloc(&pdev->dev, sizeof(*chans), GFP_KERNEL);
if (!chans)
return -ENOMEM;
regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
mbox->mbox_base = devm_ioremap_resource(&pdev->dev, regs);
if (IS_ERR(mbox->mbox_base))
return PTR_ERR(mbox->mbox_base);
/* Check is it a sender or receiver? */
mbox->is_sender = altera_mbox_is_sender(mbox);
mbox->irq = platform_get_irq(pdev, 0);
if (mbox->irq >= 0)
mbox->intr_mode = true;
mbox->dev = &pdev->dev;
/* Hardware supports only one channel. */
chans[0].con_priv = mbox;
mbox->controller.dev = mbox->dev;
mbox->controller.num_chans = 1;
mbox->controller.chans = chans;
mbox->controller.ops = &altera_mbox_ops;
if (mbox->is_sender) {
if (mbox->intr_mode) {
mbox->controller.txdone_irq = true;
} else {
mbox->controller.txdone_poll = true;
mbox->controller.txpoll_period = MBOX_POLLING_MS;
}
}
ret = mbox_controller_register(&mbox->controller);
if (ret) {
dev_err(&pdev->dev, "Register mailbox failed\n");
goto err;
}
platform_set_drvdata(pdev, mbox);
err:
return ret;
}
static int altera_mbox_remove(struct platform_device *pdev)
{
struct altera_mbox *mbox = platform_get_drvdata(pdev);
if (!mbox)
return -EINVAL;
mbox_controller_unregister(&mbox->controller);
return 0;
}
static const struct of_device_id altera_mbox_match[] = {
{ .compatible = "altr,mailbox-1.0" },
{ /* Sentinel */ }
};
MODULE_DEVICE_TABLE(of, altera_mbox_match);
static struct platform_driver altera_mbox_driver = {
.probe = altera_mbox_probe,
.remove = altera_mbox_remove,
.driver = {
.name = DRIVER_NAME,
.of_match_table = altera_mbox_match,
},
};
module_platform_driver(altera_mbox_driver);
MODULE_LICENSE("GPL v2");
MODULE_DESCRIPTION("Altera mailbox specific functions");
MODULE_AUTHOR("Ley Foon Tan <lftan@altera.com>");
MODULE_ALIAS("platform:altera-mailbox");
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