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Subject[PATCH v6 2/3] ARM: bcm2835: Add the Raspberry Pi firmware driver
Date
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.

v2: Drop power-domains stuff for now since we don't have the driver
core support to make it useful. Move to drivers/firmware/.
Capitalize the enums. De-global the firmware variable. Use the
firmware device to allocate our DMA buffer, so that the dma-ranges
DT property gets respected. Simplify the property tag transaction
interface even more, leaving a multi-tag interface still
available. For conciseness, rename "raspberrypi" to "rpi" on all
functions/enums/structs, and the "firmware" variable to "fw".
Print when the driver is probed successfully, since debugging
-EPROBE_DEFER handling is such a big part of bcm2835 development.
Drop -EBUSY mailbox handling since the mailbox core has been fixed
to return -EPROBE_DEFER in -next.

v3: Use kernel-doc style for big comments (from Noralf), drop stale
comment, use "dev" when freeing DMA as well.

v4: Move description comment into copyright comment, drop a dead
initialization of "ret", and print the firmware revision at probe
time.

v5: Rename the compatible to "raspberrypi,bcm2835-firmware", move
include to not say "property", add functions to get struct
rpi_firmware from the device_node and put when done, make property
functions take the rpi_firmware instead and never return
-EPROBE_DEFER, put the driver under its own RASPBERRYPI_FIRMWARE
Kconfig.

v6: Drop the try_module_get/module_put stuff, since all clients will
be referencing our symbols in order to call those functions,
anyway. Fix the kerneldoc comments for the changes in v5.

Signed-off-by: Eric Anholt <eric@anholt.net>
---
drivers/firmware/Kconfig | 7 +
drivers/firmware/Makefile | 1 +
drivers/firmware/raspberrypi.c | 260 +++++++++++++++++++++++++++++
include/soc/bcm2835/raspberrypi-firmware.h | 115 +++++++++++++
4 files changed, 383 insertions(+)
create mode 100644 drivers/firmware/raspberrypi.c
create mode 100644 include/soc/bcm2835/raspberrypi-firmware.h

diff --git a/drivers/firmware/Kconfig b/drivers/firmware/Kconfig
index 6517132..564aa5b 100644
--- a/drivers/firmware/Kconfig
+++ b/drivers/firmware/Kconfig
@@ -136,6 +136,13 @@ config QCOM_SCM
bool
depends on ARM || ARM64

+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.
+
source "drivers/firmware/google/Kconfig"
source "drivers/firmware/efi/Kconfig"

diff --git a/drivers/firmware/Makefile b/drivers/firmware/Makefile
index 3fdd391..ee101a2 100644
--- a/drivers/firmware/Makefile
+++ b/drivers/firmware/Makefile
@@ -13,6 +13,7 @@ obj-$(CONFIG_ISCSI_IBFT) += iscsi_ibft.o
obj-$(CONFIG_FIRMWARE_MEMMAP) += memmap.o
obj-$(CONFIG_QCOM_SCM) += qcom_scm.o
CFLAGS_qcom_scm.o :=$(call as-instr,.arch_extension sec,-DREQUIRES_SEC=1)
+obj-$(CONFIG_RASPBERRYPI_FIRMWARE) += raspberrypi.o

obj-$(CONFIG_GOOGLE_FIRMWARE) += google/
obj-$(CONFIG_EFI) += efi/
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");
diff --git a/include/soc/bcm2835/raspberrypi-firmware.h b/include/soc/bcm2835/raspberrypi-firmware.h
new file mode 100644
index 0000000..9d9efb7
--- /dev/null
+++ b/include/soc/bcm2835/raspberrypi-firmware.h
@@ -0,0 +1,115 @@
+/*
+ * 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/types.h>
+#include <linux/of_device.h>
+
+struct rpi_firmware;
+
+enum rpi_firmware_property_status {
+ RPI_FIRMWARE_STATUS_REQUEST = 0,
+ RPI_FIRMWARE_STATUS_SUCCESS = 0x80000000,
+ RPI_FIRMWARE_STATUS_ERROR = 0x80000001,
+};
+
+/**
+ * struct rpi_firmware_property_tag_header - Firmware property tag header
+ * @tag: One of enum_mbox_property_tag.
+ * @buf_size: The number of bytes in the value buffer following this
+ * struct.
+ * @req_resp_size: On submit, the length of the request (though it doesn't
+ * appear to be currently used by the firmware). On return,
+ * the length of the response (always 4 byte aligned), with
+ * the low bit set.
+ */
+struct rpi_firmware_property_tag_header {
+ u32 tag;
+ u32 buf_size;
+ u32 req_resp_size;
+};
+
+enum rpi_firmware_property_tag {
+ RPI_FIRMWARE_PROPERTY_END = 0,
+ RPI_FIRMWARE_GET_FIRMWARE_REVISION = 0x00000001,
+
+ RPI_FIRMWARE_SET_CURSOR_INFO = 0x00008010,
+ RPI_FIRMWARE_SET_CURSOR_STATE = 0x00008011,
+
+ RPI_FIRMWARE_GET_BOARD_MODEL = 0x00010001,
+ RPI_FIRMWARE_GET_BOARD_REVISION = 0x00010002,
+ RPI_FIRMWARE_GET_BOARD_MAC_ADDRESS = 0x00010003,
+ RPI_FIRMWARE_GET_BOARD_SERIAL = 0x00010004,
+ RPI_FIRMWARE_GET_ARM_MEMORY = 0x00010005,
+ RPI_FIRMWARE_GET_VC_MEMORY = 0x00010006,
+ RPI_FIRMWARE_GET_CLOCKS = 0x00010007,
+ RPI_FIRMWARE_GET_POWER_STATE = 0x00020001,
+ RPI_FIRMWARE_GET_TIMING = 0x00020002,
+ RPI_FIRMWARE_SET_POWER_STATE = 0x00028001,
+ RPI_FIRMWARE_GET_CLOCK_STATE = 0x00030001,
+ RPI_FIRMWARE_GET_CLOCK_RATE = 0x00030002,
+ RPI_FIRMWARE_GET_VOLTAGE = 0x00030003,
+ RPI_FIRMWARE_GET_MAX_CLOCK_RATE = 0x00030004,
+ RPI_FIRMWARE_GET_MAX_VOLTAGE = 0x00030005,
+ RPI_FIRMWARE_GET_TEMPERATURE = 0x00030006,
+ RPI_FIRMWARE_GET_MIN_CLOCK_RATE = 0x00030007,
+ RPI_FIRMWARE_GET_MIN_VOLTAGE = 0x00030008,
+ RPI_FIRMWARE_GET_TURBO = 0x00030009,
+ RPI_FIRMWARE_GET_MAX_TEMPERATURE = 0x0003000a,
+ RPI_FIRMWARE_ALLOCATE_MEMORY = 0x0003000c,
+ RPI_FIRMWARE_LOCK_MEMORY = 0x0003000d,
+ RPI_FIRMWARE_UNLOCK_MEMORY = 0x0003000e,
+ RPI_FIRMWARE_RELEASE_MEMORY = 0x0003000f,
+ RPI_FIRMWARE_EXECUTE_CODE = 0x00030010,
+ RPI_FIRMWARE_EXECUTE_QPU = 0x00030011,
+ RPI_FIRMWARE_SET_ENABLE_QPU = 0x00030012,
+ RPI_FIRMWARE_GET_DISPMANX_RESOURCE_MEM_HANDLE = 0x00030014,
+ RPI_FIRMWARE_GET_EDID_BLOCK = 0x00030020,
+ RPI_FIRMWARE_SET_CLOCK_STATE = 0x00038001,
+ RPI_FIRMWARE_SET_CLOCK_RATE = 0x00038002,
+ RPI_FIRMWARE_SET_VOLTAGE = 0x00038003,
+ RPI_FIRMWARE_SET_TURBO = 0x00038009,
+
+ /* Dispmanx TAGS */
+ RPI_FIRMWARE_FRAMEBUFFER_ALLOCATE = 0x00040001,
+ RPI_FIRMWARE_FRAMEBUFFER_BLANK = 0x00040002,
+ RPI_FIRMWARE_FRAMEBUFFER_GET_PHYSICAL_WIDTH_HEIGHT = 0x00040003,
+ RPI_FIRMWARE_FRAMEBUFFER_GET_VIRTUAL_WIDTH_HEIGHT = 0x00040004,
+ RPI_FIRMWARE_FRAMEBUFFER_GET_DEPTH = 0x00040005,
+ RPI_FIRMWARE_FRAMEBUFFER_GET_PIXEL_ORDER = 0x00040006,
+ RPI_FIRMWARE_FRAMEBUFFER_GET_ALPHA_MODE = 0x00040007,
+ RPI_FIRMWARE_FRAMEBUFFER_GET_PITCH = 0x00040008,
+ RPI_FIRMWARE_FRAMEBUFFER_GET_VIRTUAL_OFFSET = 0x00040009,
+ RPI_FIRMWARE_FRAMEBUFFER_GET_OVERSCAN = 0x0004000a,
+ RPI_FIRMWARE_FRAMEBUFFER_GET_PALETTE = 0x0004000b,
+ RPI_FIRMWARE_FRAMEBUFFER_RELEASE = 0x00048001,
+ RPI_FIRMWARE_FRAMEBUFFER_TEST_PHYSICAL_WIDTH_HEIGHT = 0x00044003,
+ RPI_FIRMWARE_FRAMEBUFFER_TEST_VIRTUAL_WIDTH_HEIGHT = 0x00044004,
+ RPI_FIRMWARE_FRAMEBUFFER_TEST_DEPTH = 0x00044005,
+ RPI_FIRMWARE_FRAMEBUFFER_TEST_PIXEL_ORDER = 0x00044006,
+ RPI_FIRMWARE_FRAMEBUFFER_TEST_ALPHA_MODE = 0x00044007,
+ RPI_FIRMWARE_FRAMEBUFFER_TEST_VIRTUAL_OFFSET = 0x00044009,
+ RPI_FIRMWARE_FRAMEBUFFER_TEST_OVERSCAN = 0x0004400a,
+ RPI_FIRMWARE_FRAMEBUFFER_TEST_PALETTE = 0x0004400b,
+ RPI_FIRMWARE_FRAMEBUFFER_SET_PHYSICAL_WIDTH_HEIGHT = 0x00048003,
+ RPI_FIRMWARE_FRAMEBUFFER_SET_VIRTUAL_WIDTH_HEIGHT = 0x00048004,
+ RPI_FIRMWARE_FRAMEBUFFER_SET_DEPTH = 0x00048005,
+ RPI_FIRMWARE_FRAMEBUFFER_SET_PIXEL_ORDER = 0x00048006,
+ RPI_FIRMWARE_FRAMEBUFFER_SET_ALPHA_MODE = 0x00048007,
+ RPI_FIRMWARE_FRAMEBUFFER_SET_VIRTUAL_OFFSET = 0x00048009,
+ RPI_FIRMWARE_FRAMEBUFFER_SET_OVERSCAN = 0x0004800a,
+ RPI_FIRMWARE_FRAMEBUFFER_SET_PALETTE = 0x0004800b,
+
+ RPI_FIRMWARE_GET_COMMAND_LINE = 0x00050001,
+ RPI_FIRMWARE_GET_DMA_CHANNELS = 0x00060001,
+};
+
+int rpi_firmware_property(struct rpi_firmware *fw,
+ u32 tag, void *data, size_t len);
+int rpi_firmware_property_list(struct rpi_firmware *fw,
+ void *data, size_t tag_size);
+struct rpi_firmware *rpi_firmware_get(struct device_node *firmware_node);
--
2.1.4


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