diff options
Diffstat (limited to 'drivers/mailbox/mailbox-sti.c')
| -rw-r--r-- | drivers/mailbox/mailbox-sti.c | 514 |
1 files changed, 514 insertions, 0 deletions
diff --git a/drivers/mailbox/mailbox-sti.c b/drivers/mailbox/mailbox-sti.c new file mode 100644 index 000000000..779d41262 --- /dev/null +++ b/drivers/mailbox/mailbox-sti.c @@ -0,0 +1,514 @@ +/* + * 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_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 const 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 + }, + { } +}; +MODULE_DEVICE_TABLE(of, sti_mailbox_match); + +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 (IS_ERR(mdev->base)) + return PTR_ERR(mdev->base); + + 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_kcalloc(&pdev->dev, + STI_MBOX_CHAN_MAX, sizeof(*chans), 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"); |