[PATCH 3/6] mailbox: Add support for ST's Mailbox IP

Lee Jones
2015-07-17T12:04:25Z

ST's platforms currently support a maximum of 5 Mailboxes, one for
each of the supported co-processors situated on the platform. Each
Mailbox is divided up into 4 instances which consist of 32 channels.
Messages are passed between the application and co-processors using
shared memory areas. It is the Client's responsibility to manage
these areas.

Signed-off-by: Lee Jones <lee.jones@linaro.org>
---
drivers/mailbox/Kconfig | 7 +
drivers/mailbox/Makefile | 2 +
drivers/mailbox/mailbox-sti.c | 562 ++++++++++++++++++++++++++++++++++++++++++
3 files changed, 571 insertions(+)
create mode 100644 drivers/mailbox/mailbox-sti.c

diff --git a/drivers/mailbox/Kconfig b/drivers/mailbox/Kconfig
index e269f08..2cc4c39 100644
--- a/drivers/mailbox/Kconfig
+++ b/drivers/mailbox/Kconfig
@@ -70,4 +70,11 @@ config BCM2835_MBOX
the services of the Videocore. Say Y here if you want to use the
BCM2835 Mailbox.

+config STI_MBOX
+ tristate "STI Mailbox framework support"
+ depends on ARCH_STI && OF
+ help
+ Mailbox implementation for STMicroelectonics family chips with
+ hardware for interprocessor communication.
+
endif
diff --git a/drivers/mailbox/Makefile b/drivers/mailbox/Makefile
index 8e6d822..7cb4766 100644
--- a/drivers/mailbox/Makefile
+++ b/drivers/mailbox/Makefile
@@ -13,3 +13,5 @@ obj-$(CONFIG_PCC) += pcc.o
obj-$(CONFIG_ALTERA_MBOX) += mailbox-altera.o

obj-$(CONFIG_BCM2835_MBOX) += bcm2835-mailbox.o
+
+obj-$(CONFIG_STI_MBOX) += mailbox-sti.o
diff --git a/drivers/mailbox/mailbox-sti.c b/drivers/mailbox/mailbox-sti.c
new file mode 100644
index 0000000..0c82f7b
--- /dev/null
+++ b/drivers/mailbox/mailbox-sti.c
@@ -0,0 +1,562 @@
+/*
+ * 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 <dt-bindings/mailbox/mailbox.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 */
+
+static DEFINE_SPINLOCK(sti_mbox_chan_lock);
+
+/**
+ * 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
+ */
+struct sti_mbox_device {
+ struct device *dev;
+ struct mbox_controller *mbox;
+ void __iomem *base;
+ const char *name;
+ u32 enabled[STI_MBOX_INST_MAX];
+};
+
+/**
+ * STi Mailbox platform specfic configuration
+ *
+ * @num_inst: Maximum number of instances in one HW Mailbox
+ * @num_chan: Maximum number of channel per instance
+ * @irq_val: Register offset to read interrupt status
+ * @irq_set: Register offset to generate a Tx channel interrupt
+ * @irq_clr: Register offset to clear pending Rx interrupts
+ * @ena_val: Register offset to read enable status
+ * @ena_set: Register offset to enable a channel
+ * @ena_clr: Register offset to disable a channel
+ */
+struct sti_mbox_pdata {
+ unsigned int num_inst;
+ unsigned int num_chan;
+ unsigned int irq_val;
+ unsigned int irq_set;
+ unsigned int irq_clr;
+ unsigned int ena_val;
+ unsigned int ena_set;
+ unsigned int ena_clr;
+};
+
+/**
+ * STi Mailbox allocated channel information
+ *
+ * @mdev: Pointer to parent Mailbox device
+ * @instance: Instance number channel resides in
+ * @channel: Channel number pertaining to this container
+ * @direction: Direction which data will travel in through the channel (Tx/Rx)
+ */
+struct sti_channel {
+ struct sti_mbox_device *mdev;
+ unsigned int instance;
+ unsigned int channel;
+ unsigned int direction;
+};
+
+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;
+ struct sti_mbox_pdata *pdata = dev_get_platdata(mdev->dev);
+ unsigned int instance = chan_info->instance;
+ unsigned int channel = chan_info->channel;
+ unsigned long flags;
+ void __iomem *base;
+
+ base = mdev->base + (instance * sizeof(u32));
+
+ spin_lock_irqsave(&sti_mbox_chan_lock, flags);
+ mdev->enabled[instance] |= BIT(channel);
+ writel_relaxed(BIT(channel), base + pdata->ena_set);
+ spin_unlock_irqrestore(&sti_mbox_chan_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;
+ struct sti_mbox_pdata *pdata = dev_get_platdata(mdev->dev);
+ unsigned int instance = chan_info->instance;
+ unsigned int channel = chan_info->channel;
+ unsigned long flags;
+ void __iomem *base;
+
+ base = mdev->base + (instance * sizeof(u32));
+
+ spin_lock_irqsave(&sti_mbox_chan_lock, flags);
+ mdev->enabled[instance] &= ~BIT(channel);
+ writel_relaxed(BIT(channel), base + pdata->ena_clr);
+ spin_unlock_irqrestore(&sti_mbox_chan_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;
+ struct sti_mbox_pdata *pdata = dev_get_platdata(mdev->dev);
+ unsigned int instance = chan_info->instance;
+ unsigned int channel = chan_info->channel;
+ void __iomem *base;
+
+ base = mdev->base + (instance * sizeof(u32));
+
+ writel_relaxed(BIT(channel), base + pdata->irq_clr);
+}
+
+static struct mbox_chan *sti_mbox_irq_to_channel(struct sti_mbox_device *mdev,
+ unsigned int instance)
+{
+ struct mbox_controller *mbox = mdev->mbox;
+ struct sti_mbox_pdata *pdata = dev_get_platdata(mdev->dev);
+ struct mbox_chan *chan = NULL;
+ unsigned int channel;
+ unsigned long bits;
+ void __iomem *base;
+
+ base = mdev->base + (instance * sizeof(u32));
+
+ bits = readl_relaxed(base + pdata->irq_val);
+ 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]);
+ 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_is_ready(struct mbox_chan *chan)
+{
+ struct sti_channel *chan_info = chan->con_priv;
+ struct sti_mbox_device *mdev = chan_info->mdev;
+ struct sti_mbox_pdata *pdata = dev_get_platdata(mdev->dev);
+ unsigned int instance = chan_info->instance;
+ unsigned int channel = chan_info->channel;
+ void __iomem *base;
+
+ base = mdev->base + (instance * sizeof(u32));
+
+ if (!(chan_info->direction & MBOX_TX))
+ return false;
+
+ if (!(readl_relaxed(base + pdata->ena_val) & BIT(channel))) {
+ dev_dbg(mdev->dev, "Mbox: %s: inst: %d, chan: %d disabled\n",
+ mdev->name, instance, channel);
+ return false;
+ }
+
+ if (readl_relaxed(base + pdata->irq_val) & BIT(channel)) {
+ dev_dbg(mdev->dev, "Mbox: %s: inst: %d, chan: %d not ready\n",
+ mdev->name, instance, channel);
+ return false;
+ }
+
+ return true;
+}
+
+static int sti_mbox_send_data(struct mbox_chan *chan, void *data)
+{
+ struct sti_channel *chan_info = chan->con_priv;
+ struct sti_mbox_device *mdev = chan_info->mdev;
+ struct sti_mbox_pdata *pdata = dev_get_platdata(mdev->dev);
+ unsigned int instance = chan_info->instance;
+ unsigned int channel = chan_info->channel;
+ void __iomem *base;
+
+ if (!sti_mbox_tx_is_ready(chan))
+ return -EBUSY;
+
+ base = mdev->base + (instance * sizeof(u32));
+
+ /* Send event to co-processor */
+ writel_relaxed(BIT(channel), base + pdata->irq_set);
+
+ dev_dbg(mdev->dev,
+ "Sent via Mailbox %s: instance: %d channel: %d\n",
+ mdev->name, instance, channel);
+
+ return 0;
+}
+
+static int sti_mbox_startup_chan(struct mbox_chan *chan)
+{
+ sti_mbox_clear_irq(chan);
+ sti_mbox_enable_channel(chan);
+
+ return 0;
+}
+
+static void sti_mbox_shutdown_chan(struct mbox_chan *chan)
+{
+ struct sti_channel *chan_info = chan->con_priv;
+ struct mbox_controller *mbox = chan_info->mdev->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;
+ }
+
+ sti_mbox_disable_channel(chan);
+ sti_mbox_clear_irq(chan);
+
+ /* Reset channel */
+ memset(chan, 0, sizeof(*chan));
+ chan->mbox = mbox;
+ chan->txdone_method = TXDONE_BY_POLL;
+ spin_lock_init(&chan->lock);
+}
+
+static struct mbox_chan *sti_mbox_xlate(struct mbox_controller *mbox,
+ const struct of_phandle_args *spec)
+{
+ struct sti_mbox_device *mdev = dev_get_drvdata(mbox->dev);
+ struct sti_mbox_pdata *pdata = dev_get_platdata(mdev->dev);
+ struct sti_channel *chan_info;
+ struct mbox_chan *chan = NULL;
+ unsigned int instance = spec->args[0];
+ unsigned int channel = spec->args[1];
+ unsigned int direction = spec->args[2];
+ int i;
+
+ /* Bounds checking */
+ if (instance >= pdata->num_inst || channel >= pdata->num_chan) {
+ dev_err(mbox->dev,
+ "Invalid channel requested instance: %d channel: %d\n",
+ instance, channel);
+ return NULL;
+ }
+
+ for (i = 0; i < mbox->num_chans; i++) {
+ chan_info = mbox->chans[i].con_priv;
+
+ /* Is requested channel free? */
+ if (direction != MBOX_LOOPBACK &&
+ chan_info &&
+ mbox->dev == chan_info->mdev->dev &&
+ instance == chan_info->instance &&
+ channel == chan_info->channel) {
+ dev_err(mbox->dev, "Channel in use\n");
+ return NULL;
+ }
+
+ /* Find the first free slot */
+ if (!chan && !chan_info)
+ chan = &mbox->chans[i];
+ }
+
+ if (!chan) {
+ dev_err(mbox->dev, "No free channels left\n");
+ return NULL;
+ }
+
+ chan_info = devm_kzalloc(mbox->dev, sizeof(*chan_info), GFP_KERNEL);
+ if (!chan_info)
+ return NULL;
+
+ chan_info->mdev = mdev;
+ chan_info->instance = instance;
+ chan_info->channel = channel;
+ chan_info->direction = direction;
+
+ chan->con_priv = chan_info;
+
+ dev_info(mbox->dev,
+ "Mbox: %s: Created channel:\n"
+ " instance: %d channel: %d direction: %s\n",
+ mdev->name, instance, channel,
+ direction == MBOX_LOOPBACK ? "Loopback" :
+ direction == MBOX_TX ? "Tx" : "Rx");
+
+ return chan;
+}
+
+static struct mbox_chan_ops sti_mbox_ops = {
+ .startup = sti_mbox_startup_chan,
+ .shutdown = sti_mbox_shutdown_chan,
+ .send_data = sti_mbox_send_data,
+ .last_tx_done = sti_mbox_tx_is_ready,
+};
+
+static const struct sti_mbox_pdata mbox_stih407_pdata = {
+ .num_inst = 4,
+ .num_chan = 32,
+ .irq_val = 0x04,
+ .irq_set = 0x24,
+ .irq_clr = 0x44,
+ .ena_val = 0x64,
+ .ena_set = 0x84,
+ .ena_clr = 0xa4,
+};
+
+static const struct of_device_id sti_mailbox_match[] = {
+ {
+ .compatible = "st,stih407-mailbox",
+ .data = (void *)&mbox_stih407_pdata
+ },
+ { }
+};
+
+static int sti_mbox_probe(struct platform_device *pdev)
+{
+ const struct of_device_id *match;
+ struct mbox_controller *mbox;
+ struct sti_mbox_device *mdev;
+ struct device_node *np = pdev->dev.of_node;
+ struct mbox_chan *chans;
+ struct resource *res;
+ int irq;
+ int ret;
+
+ match = of_match_device(sti_mailbox_match, &pdev->dev);
+ if (!match) {
+ dev_err(&pdev->dev, "No configuration found\n");
+ return -ENODEV;
+ }
+ pdev->dev.platform_data = (struct sti_mbox_pdata *) match->data;
+
+ mdev = devm_kzalloc(&pdev->dev, sizeof(*mdev), GFP_KERNEL);
+ if (!mdev)
+ return -ENOMEM;
+
+ platform_set_drvdata(pdev, mdev);
+
+ res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ mdev->base = devm_ioremap_resource(&pdev->dev, res);
+ if (!mdev->base)
+ return -ENOMEM;
+
+ ret = of_property_read_string(np, "mbox-name", &mdev->name);
+ if (ret)
+ mdev->name = np->full_name;
+
+ mbox = devm_kzalloc(&pdev->dev, sizeof(*mbox), GFP_KERNEL);
+ if (!mbox)
+ return -ENOMEM;
+
+ chans = devm_kzalloc(&pdev->dev,
+ sizeof(*chans) * STI_MBOX_CHAN_MAX, GFP_KERNEL);
+ if (!chans)
+ return -ENOMEM;
+
+ mdev->dev = &pdev->dev;
+ mdev->mbox = mbox;
+
+ /* STi Mailbox does not have a Tx-Done or Tx-Ready IRQ */
+ mbox->txdone_irq = false;
+ mbox->txdone_poll = true;
+ mbox->txpoll_period = 100;
+ mbox->ops = &sti_mbox_ops;
+ mbox->dev = mdev->dev;
+ mbox->of_xlate = sti_mbox_xlate;
+ mbox->chans = chans;
+ mbox->num_chans = STI_MBOX_CHAN_MAX;
+
+ ret = mbox_controller_register(mbox);
+ if (ret)
+ return ret;
+
+ /* It's okay for Tx Mailboxes to not supply IRQs */
+ irq = platform_get_irq(pdev, 0);
+ if (irq < 0) {
+ dev_info(&pdev->dev,
+ "%s: Registered Tx only Mailbox\n", mdev->name);
+ return 0;
+ }
+
+ ret = devm_request_threaded_irq(&pdev->dev, irq,
+ sti_mbox_irq_handler,
+ sti_mbox_thread_handler,
+ IRQF_ONESHOT, mdev->name, mdev);
+ if (ret) {
+ dev_err(&pdev->dev, "Can't claim IRQ %d\n", irq);
+ mbox_controller_unregister(mbox);
+ return -EINVAL;
+ }
+
+ dev_info(&pdev->dev, "%s: Registered Tx/Rx Mailbox\n", mdev->name);
+
+ return 0;
+}
+
+static int sti_mbox_remove(struct platform_device *pdev)
+{
+ struct sti_mbox_device *mdev = platform_get_drvdata(pdev);
+
+ mbox_controller_unregister(mdev->mbox);
+
+ return 0;
+}
+
+static struct platform_driver sti_mbox_driver = {
+ .probe = sti_mbox_probe,
+ .remove = sti_mbox_remove,
+ .driver = {
+ .name = "sti-mailbox",
+ .of_match_table = sti_mailbox_match,
+ },
+};
+
+static int __init sti_mbox_init(void)
+{
+ return platform_driver_register(&sti_mbox_driver);
+}
+
+static void __exit sti_mbox_exit(void)
+{
+ platform_driver_unregister(&sti_mbox_driver);
+}
+
+postcore_initcall(sti_mbox_init);
+module_exit(sti_mbox_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("STMicroelectronics Mailbox Controller");
+MODULE_AUTHOR("Lee Jones <lee.jones@linaro.org");
+MODULE_ALIAS("platform:mailbox-sti");
--
1.9.1