mailbox: Add support for ST's Mailbox IP
authorLee Jones <lee.jones@linaro.org>
Fri, 16 Oct 2015 07:21:28 +0000 (08:21 +0100)
committerJassi Brar <jaswinder.singh@linaro.org>
Sat, 17 Oct 2015 05:06:56 +0000 (10:36 +0530)
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>
Signed-off-by: Jassi Brar <jaswinder.singh@linaro.org>
drivers/mailbox/Kconfig
drivers/mailbox/Makefile
drivers/mailbox/mailbox-sti.c [new file with mode: 0644]

index bbec5009cdc2b8bd7d82612a17c07805d845575b..7b53386f94151b5fb4fd6753c9374d14c98a7b26 100644 (file)
@@ -71,4 +71,11 @@ 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
index 8e6d82218a09422d7849e5e83dbd19324e593763..7cb476643833c578fc69d779edf5de2ccfd98ecb 100644 (file)
@@ -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 (file)
index 0000000..f11d4e8
--- /dev/null
@@ -0,0 +1,513 @@
+/*
+ * 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 specfic 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_is_ready(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);
+
+       if (!(readl_relaxed(base + STI_ENA_VAL_OFFSET) & BIT(channel))) {
+               dev_dbg(mdev->dev, "Mbox: %s: inst: %d, chan: %d disabled\n",
+                       mdev->name, instance, channel);
+               return false;
+       }
+
+       if (readl_relaxed(base + STI_IRQ_VAL_OFFSET) & 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;
+       unsigned int instance = chan_info->instance;
+       unsigned int channel = chan_info->channel;
+       void __iomem *base = MBOX_BASE(mdev, instance);
+
+       /* Send event to co-processor */
+       writel_relaxed(BIT(channel), base + STI_IRQ_SET_OFFSET);
+
+       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;
+       }
+
+       /* Reset channel */
+       sti_mbox_disable_channel(chan);
+       sti_mbox_clear_irq(chan);
+       chan->con_priv = NULL;
+}
+
+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];
+       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 ERR_PTR(-EINVAL);
+       }
+
+       for (i = 0; i < mbox->num_chans; i++) {
+               chan_info = mbox->chans[i].con_priv;
+
+               /* Is requested channel free? */
+               if (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 ERR_PTR(-EBUSY);
+               }
+
+               /*
+                * Find the first free slot, then continue checking
+                * to see if requested channel is in use
+                */
+               if (!chan && !chan_info)
+                       chan = &mbox->chans[i];
+       }
+
+       if (!chan) {
+               dev_err(mbox->dev, "No free channels left\n");
+               return ERR_PTR(-EBUSY);
+       }
+
+       chan_info = devm_kzalloc(mbox->dev, sizeof(*chan_info), GFP_KERNEL);
+       if (!chan_info)
+               return ERR_PTR(-ENOMEM);
+
+       chan_info->mdev         = mdev;
+       chan_info->instance     = instance;
+       chan_info->channel      = channel;
+
+       chan->con_priv = chan_info;
+
+       dev_info(mbox->dev,
+                "Mbox: %s: Created channel: instance: %d channel: %d\n",
+                mdev->name, instance, channel);
+
+       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,
+};
+
+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;
+
+       spin_lock_init(&mdev->lock);
+
+       /* 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,
+       },
+};
+module_platform_driver(sti_mbox_driver);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("STMicroelectronics Mailbox Controller");
+MODULE_AUTHOR("Lee Jones <lee.jones@linaro.org");
+MODULE_ALIAS("platform:mailbox-sti");