[RFC PATCH 3/3] Enable BCM2835 mailbox support
Craig McGeachie
slapdau at yahoo.com.au
Fri Sep 13 07:32:40 EDT 2013
Implement BCM2835 CPU thermal sensor support.
Signed-off-by: Craig McGeachie <slapdau at yahoo.com.au>
---
Beyond the usual reviews of rubbish code, there are two points
here that I'm looking for feedback on.
First is the placement of the mailbox directory make target in
drivers/Makefile. I placed it as early as I did in anticipation of
implemented a frame buffer driver, which needs mailbox support at
probe time. Another option would be to initialise the driver at
architecture initialisation time, but I'm unfamiliar with good
practice about when to initialise different bits and pieces.
Especially with generic mailbox support looking kinda new.
Second is the propmsg_ fuctions and related structures. They don't
belong here. And the fact that they are is something that would
count against this being an acceptable patch. But I don't know
where to put them. It's the header file I have trouble with. I
don't really know where I can put it. Multi-architecture support
rules out arch/arm/mach-bcm2835, and I don't want to place a header
file that only supports one very specific system into include.
---
diff --git a/arch/arm/boot/dts/bcm2835.dtsi b/arch/arm/boot/dts/bcm2835.dtsi
index 88855c0..b91cd44 100644
--- a/arch/arm/boot/dts/bcm2835.dtsi
+++ b/arch/arm/boot/dts/bcm2835.dtsi
@@ -37,6 +37,10 @@
brcm,channel-nums = <0 1 3 8>;
};
+ thermal {
+ compatible = "brcm,bcm2835-thermal";
+ };
+
watchdog {
compatible = "brcm,bcm2835-pm-wdt";
reg = <0x7e100000 0x28>;
diff --git a/arch/arm/configs/bcm2835_defconfig b/arch/arm/configs/bcm2835_defconfig
index cc067bc..8bd210c 100644
--- a/arch/arm/configs/bcm2835_defconfig
+++ b/arch/arm/configs/bcm2835_defconfig
@@ -67,6 +67,8 @@ CONFIG_SPI=y
CONFIG_SPI_BCM2835=y
CONFIG_GPIO_SYSFS=y
# CONFIG_HWMON is not set
+CONFIG_THERMAL=y
+CONFIG_BCM2835_THERMAL=y
CONFIG_FB=y
CONFIG_FB_SIMPLE=y
CONFIG_FRAMEBUFFER_CONSOLE=y
diff --git a/drivers/Makefile b/drivers/Makefile
index ab93de8..035114d 100644
--- a/drivers/Makefile
+++ b/drivers/Makefile
@@ -15,6 +15,9 @@ obj-y += pwm/
obj-$(CONFIG_PCI) += pci/
obj-$(CONFIG_PARISC) += parisc/
obj-$(CONFIG_RAPIDIO) += rapidio/
+
+# Mailbox must come before drivers that rely on it
+obj-$(CONFIG_MAILBOX) += mailbox/
obj-y += video/
obj-y += idle/
@@ -133,7 +136,6 @@ obj-y += platform/
#common clk code
obj-y += clk/
-obj-$(CONFIG_MAILBOX) += mailbox/
obj-$(CONFIG_HWSPINLOCK) += hwspinlock/
obj-$(CONFIG_NFC) += nfc/
obj-$(CONFIG_IOMMU_SUPPORT) += iommu/
diff --git a/drivers/thermal/Kconfig b/drivers/thermal/Kconfig
index e988c81..2cc29a5 100644
--- a/drivers/thermal/Kconfig
+++ b/drivers/thermal/Kconfig
@@ -130,6 +130,15 @@ config DOVE_THERMAL
Support for the Dove thermal sensor driver in the Linux thermal
framework.
+config BCM2835_THERMAL
+ tristate "Temperature sensor on Broadcom BCM2835 SoC"
+ depends on ARCH_BCM2835
+ depends on BCM2835_MBOX
+ help
+ Support for the Broadcom BCM2835 thermal sensor driver in the Linux
+ thermal framework. The BCM2835 has one sensor on chip, with one trip
+ point and no cooling devices.
+
config DB8500_THERMAL
bool "DB8500 thermal management"
depends on ARCH_U8500
diff --git a/drivers/thermal/Makefile b/drivers/thermal/Makefile
index 67184a2..bd9e42c 100644
--- a/drivers/thermal/Makefile
+++ b/drivers/thermal/Makefile
@@ -25,3 +25,4 @@ obj-$(CONFIG_DB8500_CPUFREQ_COOLING) += db8500_cpufreq_cooling.o
obj-$(CONFIG_INTEL_POWERCLAMP) += intel_powerclamp.o
obj-$(CONFIG_X86_PKG_TEMP_THERMAL) += x86_pkg_temp_thermal.o
obj-$(CONFIG_TI_SOC_THERMAL) += ti-soc-thermal/
+obj-$(CONFIG_BCM2835_THERMAL) += bcm2835-thermal.o
diff --git a/drivers/thermal/bcm2835-thermal.c b/drivers/thermal/bcm2835-thermal.c
new file mode 100644
index 0000000..33d9539
--- /dev/null
+++ b/drivers/thermal/bcm2835-thermal.c
@@ -0,0 +1,274 @@
+/*
+ * Copyright (C) 2013 Craig McGeachie
+ *
+ * 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.
+ *
+ * This device presents the BCM2835 SoC temperature sensor as a thermal
+ * device.
+ */
+
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/platform_device.h>
+#include <linux/device.h>
+#include <linux/slab.h>
+#include <linux/thermal.h>
+#include <linux/dma-mapping.h>
+#include <linux/mailbox_client.h>
+#include <linux/mutex.h>
+
+#define VC_TAG_GET_TEMP 0x00030006
+#define VC_TAG_GET_MAX_TEMP 0x0003000A
+#define VC_SUCCESS 0x80000000
+
+struct prop_msg {
+ u32 msg_size;
+ u32 code;
+};
+
+struct prop_tag_hdr {
+ u32 tag_id;
+ u32 buf_size;
+ u32 indicator;
+};
+
+struct prop_tmp_tag {
+ struct prop_tag_hdr hdr;
+ u32 id;
+ u32 val;
+};
+
+static void *propmsg_init(void *buf, size_t size)
+{
+ u32 num_cells = size >> 2;
+ if (num_cells < 3)
+ return 0;
+ memset(buf, 0, size);
+ ((u32 *)buf)[0] = num_cells - 1;
+ ((u32 *)buf)[num_cells - 1] = 2;
+ return buf;
+}
+
+static void *propmsg_addtag(void *buf, size_t size, u32 tag_id)
+{
+ u32 num_cells = ((size + 3) & -4) >> 2;
+ u32 last_cell = ((u32 *)buf)[0];
+ u32 nxt_cell = ((u32 *)buf)[last_cell];
+ u32 free_cells = last_cell - nxt_cell;
+ if (free_cells < num_cells || num_cells <= 3) {
+ return 0;
+ } else {
+ void *ret = &((u32 *)buf)[nxt_cell];
+ ((struct prop_tag_hdr *) ret)->tag_id = tag_id;
+ ((struct prop_tag_hdr *) ret)->buf_size = (num_cells - 3) << 2;
+ ((struct prop_tag_hdr *) ret)->indicator = (num_cells - 3) << 2;
+ ((u32 *)buf)[last_cell] = nxt_cell + num_cells;
+ return ret;
+ }
+}
+
+static void propmsg_finish(void *buf)
+{
+ u32 last_cell = ((u32 *)buf)[0];
+ u32 nxt_cell = ((u32 *)buf)[last_cell];
+ ((u32 *)buf)[nxt_cell] = 0;
+ ((u32 *)buf)[0] = (nxt_cell + 1) << 2;
+ ((u32 *)buf)[1] = 0;
+}
+
+#if 0
+
+static void *propmsg_firsttag(void *msg)
+{
+ return ((struct prop_msg *) msg) + 1;
+}
+
+static void *propmsg_nexttag(void *curr)
+{
+ u32 tag_size = ((struct prop_tag_hdr *)curr)->buf_size;
+ void *next_tag = (char *)curr + sizeof(struct prop_tag_hdr) + tag_size;
+ return ((struct prop_tag_hdr *) next_tag)->tag_id == 0 ? 0 : next_tag;
+}
+
+#endif
+
+struct bcm2835_therm {
+ struct device *dev;
+ struct thermal_zone_device *thermal_dev;
+ struct completion comp;
+ struct mutex lock;
+};
+
+static void bcm2835_rxcb(void *cl_id, void *mssg)
+{
+ struct bcm2835_therm *therm = cl_id;
+ complete(&therm->comp);
+}
+
+static int do_message(struct bcm2835_therm *therm, dma_addr_t msg_handle)
+{
+ struct device *dev = therm->dev;
+ struct ipc_client therm_mbox;
+ void *channel;
+ int ret = 0;
+
+ memset(&therm_mbox, 0, sizeof(therm_mbox));
+ therm_mbox.chan_name = "bcm2835:property";
+ therm_mbox.rxcb = bcm2835_rxcb;
+ therm_mbox.cl_id = therm;
+ mutex_lock(&therm->lock);
+ INIT_COMPLETION(therm->comp);
+ channel = ipc_request_channel(&therm_mbox);
+ if (!channel) {
+ dev_err(dev, "No ipc channel\n");
+ ret = -EAGAIN;
+ goto exit;
+ }
+ ipc_send_message(channel, (void *) msg_handle);
+ wait_for_completion(&therm->comp);
+ ipc_free_channel(channel);
+exit:
+ mutex_unlock(&therm->lock);
+ return ret;
+}
+
+static int bcm2835_get_temp_common(struct thermal_zone_device *thermal_dev,
+ unsigned long *temp, u32 temp_type)
+{
+ struct bcm2835_therm *therm = thermal_dev->devdata;
+ struct device *dev = therm->dev;
+ void *buf = 0, *msg;
+ int msgsize = sizeof(struct prop_msg) + sizeof(struct prop_tmp_tag)
+ + sizeof(u32);
+ dma_addr_t dma_handle;
+ int alignment = max(16, dma_get_cache_alignment());
+ struct prop_tmp_tag *tmp_tag;
+ int ret = 0;
+
+ buf = kzalloc(msgsize + alignment, GFP_KERNEL | GFP_DMA);
+ if (!buf) {
+ dev_err(dev, "kzalloc failed\n");
+ ret = -ENOMEM;
+ goto exit;
+ }
+ msg = PTR_ALIGN(buf, alignment);
+ propmsg_init(msg, msgsize);
+ tmp_tag = propmsg_addtag(msg, sizeof(struct prop_tmp_tag), temp_type);
+ BUG_ON(!tmp_tag); /* msgsize should be large enough to ensure success */
+ propmsg_finish(msg);
+ dma_handle = dma_map_single(dev, msg, msgsize, DMA_BIDIRECTIONAL);
+ if (dma_mapping_error(dev, dma_handle)) {
+ dev_err(dev, "No DMA address\n");
+ ret = -ENOMEM;
+ goto exit;
+ }
+ print_hex_dump(KERN_DEBUG, "req - ", DUMP_PREFIX_ADDRESS, 16, 4, msg,
+ msgsize, false);
+ ret = do_message(therm, dma_handle);
+ print_hex_dump(KERN_DEBUG, "rep - ", DUMP_PREFIX_ADDRESS, 16, 4, msg,
+ msgsize, false);
+ dma_unmap_single(dev, dma_handle, msgsize, DMA_BIDIRECTIONAL);
+ if (ret)
+ goto exit;
+ if (!(tmp_tag->hdr.indicator & VC_SUCCESS)) {
+ dev_err(dev, "VC request failed 0x%08X\n",
+ tmp_tag->hdr.indicator);
+ ret = -EAGAIN;
+ } else {
+ *temp = tmp_tag->val;
+ }
+exit:
+ kfree(buf);
+ return ret;
+}
+
+static int bcm2835_get_temp(struct thermal_zone_device *thermal_dev,
+ unsigned long *temp)
+{
+ return bcm2835_get_temp_common(thermal_dev, temp, VC_TAG_GET_TEMP);
+}
+
+static int bcm2835_get_max_temp(struct thermal_zone_device *thermal_dev,
+ int trip_num, unsigned long *temp)
+{
+ return bcm2835_get_temp_common(thermal_dev, temp, VC_TAG_GET_MAX_TEMP);
+}
+
+static int bcm2835_get_trip_type(struct thermal_zone_device *thermal_dev,
+ int trip_num, enum thermal_trip_type *trip_type)
+{
+ *trip_type = THERMAL_TRIP_HOT;
+ return 0;
+}
+
+
+static int bcm2835_get_mode(struct thermal_zone_device *thermal_dev,
+ enum thermal_device_mode *dev_mode)
+{
+ *dev_mode = THERMAL_DEVICE_ENABLED;
+ return 0;
+}
+
+static struct thermal_zone_device_ops ops = {
+ .get_temp = bcm2835_get_temp,
+ .get_trip_temp = bcm2835_get_max_temp,
+ .get_trip_type = bcm2835_get_trip_type,
+ .get_mode = bcm2835_get_mode,
+};
+
+static int bcm2835_thermal_probe(struct platform_device *pdev)
+{
+ struct device *dev = &pdev->dev;
+ struct bcm2835_therm *therm = devm_kzalloc(dev, sizeof(*therm),
+ GFP_KERNEL);
+ if (!therm) {
+ dev_err(dev, "Failed to allocate memory\n");
+ return -ENOMEM;
+ }
+ therm->dev = dev;
+ mutex_init(&therm->lock);
+ init_completion(&therm->comp);
+ therm->thermal_dev = thermal_zone_device_register("bcm2835_thermal", 1,
+ 0, therm, &ops, NULL, 0, 0);
+ if (IS_ERR(therm->thermal_dev)) {
+ dev_err(dev, "Unable to register the thermal device");
+ return PTR_ERR(therm->thermal_dev);
+ }
+ platform_set_drvdata(pdev, therm);
+ dev_info(dev, "%s enabled\n", pdev->name);
+ return 0;
+}
+
+
+static int bcm2835_thermal_remove(struct platform_device *pdev)
+{
+ struct bcm2835_therm *therm = platform_get_drvdata(pdev);
+ thermal_zone_device_unregister(therm->thermal_dev);
+ return 0;
+}
+
+static const struct of_device_id bcm2835_thermal_of_match[] = {
+ { .compatible = "brcm,bcm2835-thermal", },
+ {},
+};
+MODULE_DEVICE_TABLE(of, bcm2835_thermal_of_match);
+
+static struct platform_driver bcm2835_thermal_driver = {
+ .driver = {
+ .name = "bcm2835_thermal",
+ .owner = THIS_MODULE,
+ .of_match_table = bcm2835_thermal_of_match,
+ },
+ .probe = bcm2835_thermal_probe,
+ .remove = bcm2835_thermal_remove,
+};
+
+module_platform_driver(bcm2835_thermal_driver);
+
+MODULE_AUTHOR("Craig McGeachie");
+MODULE_DESCRIPTION("BCM2835 thermal driver");
+MODULE_LICENSE("GPL v2");
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