ARM: bcm2835: Add the Raspberry Pi firmware driver
This gives us a function for making mailbox property channel requests
of the firmware, which is most notable in that it will let us get and
set clock rates.
Signed-off-by: Eric Anholt <eric@anholt.net>
Acked-by: Stephen Warren <swarren@wwwdotorg.org>
diff --git a/drivers/firmware/raspberrypi.c b/drivers/firmware/raspberrypi.c
new file mode 100644
index 0000000..dd506cd
--- /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");