Merge tag 'arm/soc/for-4.4/rpi-drivers' of https://github.com/Broadcom/stblinux into next/drivers

This pull request contains the Raspberry Pi firmware driver, for communicating
with the VPU which has exclusive control of some of the peripherals.

Eric adds the actual firmware driver and Alexander fixes the header file which
was missing include guards.

* tag 'arm/soc/for-4.4/rpi-drivers' of https://github.com/Broadcom/stblinux:
  ARM: bcm2835: add mutual inclusion protection
  ARM: bcm2835: Add the Raspberry Pi firmware driver

Signed-off-by: Olof Johansson <olof@lixom.net>

3 files changed, 268 insertions, 0 deletions

diff --git a/drivers/firmware/Kconfig b/drivers/firmware/Kconfig
index d00c6d338cc3..cf478fe6b335 100644
--- a/drivers/firmware/Kconfig
+++ b/drivers/firmware/Kconfig
@@ -154,6 +154,13 @@ config ISCSI_IBFT
 	  detect iSCSI boot parameters dynamically during system boot, say Y.
 	  Otherwise, say N.
 
+config RASPBERRYPI_FIRMWARE
+	tristate "Raspberry Pi Firmware Driver"
+	depends on BCM2835_MBOX
+	help
+	  This option enables support for communicating with the firmware on the
+	  Raspberry Pi.
+
 config QCOM_SCM
 	bool
 	depends on ARM || ARM64
diff --git a/drivers/firmware/Makefile b/drivers/firmware/Makefile
index b984dd7d9ccb..48dd4175297e 100644
--- a/drivers/firmware/Makefile
+++ b/drivers/firmware/Makefile
@@ -13,6 +13,7 @@ obj-$(CONFIG_DMIID)		+= dmi-id.o
 obj-$(CONFIG_ISCSI_IBFT_FIND)	+= iscsi_ibft_find.o
 obj-$(CONFIG_ISCSI_IBFT)	+= iscsi_ibft.o
 obj-$(CONFIG_FIRMWARE_MEMMAP)	+= memmap.o
+obj-$(CONFIG_RASPBERRYPI_FIRMWARE) += raspberrypi.o
 obj-$(CONFIG_QCOM_SCM)		+= qcom_scm.o
 obj-$(CONFIG_QCOM_SCM_64)	+= qcom_scm-64.o
 obj-$(CONFIG_QCOM_SCM_32)	+= qcom_scm-32.o
diff --git a/drivers/firmware/raspberrypi.c b/drivers/firmware/raspberrypi.c
new file mode 100644
index 000000000000..dd506cd3a5b8
--- /dev/null
+++ b/drivers/firmware/raspberrypi.c
@@ -0,0 +1,260 @@
+/*
+ * Defines interfaces for interacting wtih the Raspberry Pi firmware's
+ * property channel.
+ *
+ * Copyright © 2015 Broadcom
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/dma-mapping.h>
+#include <linux/mailbox_client.h>
+#include <linux/module.h>
+#include <linux/of_platform.h>
+#include <linux/platform_device.h>
+#include <soc/bcm2835/raspberrypi-firmware.h>
+
+#define MBOX_MSG(chan, data28)		(((data28) & ~0xf) | ((chan) & 0xf))
+#define MBOX_CHAN(msg)			((msg) & 0xf)
+#define MBOX_DATA28(msg)		((msg) & ~0xf)
+#define MBOX_CHAN_PROPERTY		8
+
+struct rpi_firmware {
+	struct mbox_client cl;
+	struct mbox_chan *chan; /* The property channel. */
+	struct completion c;
+	u32 enabled;
+};
+
+static DEFINE_MUTEX(transaction_lock);
+
+static void response_callback(struct mbox_client *cl, void *msg)
+{
+	struct rpi_firmware *fw = container_of(cl, struct rpi_firmware, cl);
+	complete(&fw->c);
+}
+
+/*
+ * Sends a request to the firmware through the BCM2835 mailbox driver,
+ * and synchronously waits for the reply.
+ */
+static int
+rpi_firmware_transaction(struct rpi_firmware *fw, u32 chan, u32 data)
+{
+	u32 message = MBOX_MSG(chan, data);
+	int ret;
+
+	WARN_ON(data & 0xf);
+
+	mutex_lock(&transaction_lock);
+	reinit_completion(&fw->c);
+	ret = mbox_send_message(fw->chan, &message);
+	if (ret >= 0) {
+		wait_for_completion(&fw->c);
+		ret = 0;
+	} else {
+		dev_err(fw->cl.dev, "mbox_send_message returned %d\n", ret);
+	}
+	mutex_unlock(&transaction_lock);
+
+	return ret;
+}
+
+/**
+ * rpi_firmware_property_list - Submit firmware property list
+ * @fw:		Pointer to firmware structure from rpi_firmware_get().
+ * @data:	Buffer holding tags.
+ * @tag_size:	Size of tags buffer.
+ *
+ * Submits a set of concatenated tags to the VPU firmware through the
+ * mailbox property interface.
+ *
+ * The buffer header and the ending tag are added by this function and
+ * don't need to be supplied, just the actual tags for your operation.
+ * See struct rpi_firmware_property_tag_header for the per-tag
+ * structure.
+ */
+int rpi_firmware_property_list(struct rpi_firmware *fw,
+			       void *data, size_t tag_size)
+{
+	size_t size = tag_size + 12;
+	u32 *buf;
+	dma_addr_t bus_addr;
+	int ret;
+
+	/* Packets are processed a dword at a time. */
+	if (size & 3)
+		return -EINVAL;
+
+	buf = dma_alloc_coherent(fw->cl.dev, PAGE_ALIGN(size), &bus_addr,
+				 GFP_ATOMIC);
+	if (!buf)
+		return -ENOMEM;
+
+	/* The firmware will error out without parsing in this case. */
+	WARN_ON(size >= 1024 * 1024);
+
+	buf[0] = size;
+	buf[1] = RPI_FIRMWARE_STATUS_REQUEST;
+	memcpy(&buf[2], data, tag_size);
+	buf[size / 4 - 1] = RPI_FIRMWARE_PROPERTY_END;
+	wmb();
+
+	ret = rpi_firmware_transaction(fw, MBOX_CHAN_PROPERTY, bus_addr);
+
+	rmb();
+	memcpy(data, &buf[2], tag_size);
+	if (ret == 0 && buf[1] != RPI_FIRMWARE_STATUS_SUCCESS) {
+		/*
+		 * The tag name here might not be the one causing the
+		 * error, if there were multiple tags in the request.
+		 * But single-tag is the most common, so go with it.
+		 */
+		dev_err(fw->cl.dev, "Request 0x%08x returned status 0x%08x\n",
+			buf[2], buf[1]);
+		ret = -EINVAL;
+	}
+
+	dma_free_coherent(fw->cl.dev, PAGE_ALIGN(size), buf, bus_addr);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(rpi_firmware_property_list);
+
+/**
+ * rpi_firmware_property - Submit single firmware property
+ * @fw:		Pointer to firmware structure from rpi_firmware_get().
+ * @tag:	One of enum_mbox_property_tag.
+ * @tag_data:	Tag data buffer.
+ * @buf_size:	Buffer size.
+ *
+ * Submits a single tag to the VPU firmware through the mailbox
+ * property interface.
+ *
+ * This is a convenience wrapper around
+ * rpi_firmware_property_list() to avoid some of the
+ * boilerplate in property calls.
+ */
+int rpi_firmware_property(struct rpi_firmware *fw,
+			  u32 tag, void *tag_data, size_t buf_size)
+{
+	/* Single tags are very small (generally 8 bytes), so the
+	 * stack should be safe.
+	 */
+	u8 data[buf_size + sizeof(struct rpi_firmware_property_tag_header)];
+	struct rpi_firmware_property_tag_header *header =
+		(struct rpi_firmware_property_tag_header *)data;
+	int ret;
+
+	header->tag = tag;
+	header->buf_size = buf_size;
+	header->req_resp_size = 0;
+	memcpy(data + sizeof(struct rpi_firmware_property_tag_header),
+	       tag_data, buf_size);
+
+	ret = rpi_firmware_property_list(fw, &data, sizeof(data));
+	memcpy(tag_data,
+	       data + sizeof(struct rpi_firmware_property_tag_header),
+	       buf_size);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(rpi_firmware_property);
+
+static void
+rpi_firmware_print_firmware_revision(struct rpi_firmware *fw)
+{
+	u32 packet;
+	int ret = rpi_firmware_property(fw,
+					RPI_FIRMWARE_GET_FIRMWARE_REVISION,
+					&packet, sizeof(packet));
+
+	if (ret == 0) {
+		struct tm tm;
+
+		time_to_tm(packet, 0, &tm);
+
+		dev_info(fw->cl.dev,
+			 "Attached to firmware from %04ld-%02d-%02d %02d:%02d\n",
+			 tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday,
+			 tm.tm_hour, tm.tm_min);
+	}
+}
+
+static int rpi_firmware_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct rpi_firmware *fw;
+
+	fw = devm_kzalloc(dev, sizeof(*fw), GFP_KERNEL);
+	if (!fw)
+		return -ENOMEM;
+
+	fw->cl.dev = dev;
+	fw->cl.rx_callback = response_callback;
+	fw->cl.tx_block = true;
+
+	fw->chan = mbox_request_channel(&fw->cl, 0);
+	if (IS_ERR(fw->chan)) {
+		int ret = PTR_ERR(fw->chan);
+		if (ret != -EPROBE_DEFER)
+			dev_err(dev, "Failed to get mbox channel: %d\n", ret);
+		return ret;
+	}
+
+	init_completion(&fw->c);
+
+	platform_set_drvdata(pdev, fw);
+
+	rpi_firmware_print_firmware_revision(fw);
+
+	return 0;
+}
+
+static int rpi_firmware_remove(struct platform_device *pdev)
+{
+	struct rpi_firmware *fw = platform_get_drvdata(pdev);
+
+	mbox_free_channel(fw->chan);
+
+	return 0;
+}
+
+/**
+ * rpi_firmware_get - Get pointer to rpi_firmware structure.
+ * @firmware_node:    Pointer to the firmware Device Tree node.
+ *
+ * Returns NULL is the firmware device is not ready.
+ */
+struct rpi_firmware *rpi_firmware_get(struct device_node *firmware_node)
+{
+	struct platform_device *pdev = of_find_device_by_node(firmware_node);
+
+	if (!pdev)
+		return NULL;
+
+	return platform_get_drvdata(pdev);
+}
+EXPORT_SYMBOL_GPL(rpi_firmware_get);
+
+static const struct of_device_id rpi_firmware_of_match[] = {
+	{ .compatible = "raspberrypi,bcm2835-firmware", },
+	{},
+};
+MODULE_DEVICE_TABLE(of, rpi_firmware_of_match);
+
+static struct platform_driver rpi_firmware_driver = {
+	.driver = {
+		.name = "raspberrypi-firmware",
+		.of_match_table = rpi_firmware_of_match,
+	},
+	.probe		= rpi_firmware_probe,
+	.remove		= rpi_firmware_remove,
+};
+module_platform_driver(rpi_firmware_driver);
+
+MODULE_AUTHOR("Eric Anholt <eric@anholt.net>");
+MODULE_DESCRIPTION("Raspberry Pi firmware driver");
+MODULE_LICENSE("GPL v2");