[PATCH v4] drivers/coresight: Add Ultrasoc System Memory Buffer driver
liuqi (BA)
liuqi115 at huawei.com
Mon Mar 14 03:04:14 PDT 2022
On 2022/3/10 6:49, Suzuki K Poulose wrote:
> Hi
>
> On 28/01/2022 06:17, Qi Liu wrote:
>> This patch adds driver for Ultrasoc SMB(System Memory Buffer)
>> device. SMB provides a way to buffer messages from ETM, and
>> store these CPU instructions in system memory.
>>
>> SMB is developed by Ultrasoc technology, which is acquired by
>> Siemens, and we still use "Ultrasoc" to name driver.
>>
>> Signed-off-by: Qi Liu <liuqi115 at huawei.com>
>> Tested-by: JunHao He <hejunhao2 at hisilicon.com>
>
> Please find my comments below. In general :
>
> 1) Please run checkpatch and fix the warnings
> 2) Add documentation for :
> - A brief description of the device and the firmware bindings (see
> comments below )
> - Sysfs attributes
> 3) Other minor comments on the code
>
Hi Suzuki,
thanks a lot for your review! and some replies inline.
>> ---
[...]
>> --- a/drivers/hwtracing/coresight/Kconfig
>> +++ b/drivers/hwtracing/coresight/Kconfig
>> @@ -201,4 +201,14 @@ config CORESIGHT_TRBE
>> To compile this driver as a module, choose M here: the module
>> will be
>> called coresight-trbe.
>> +config ULTRASOC_SMB
>> + tristate "Ultrasoc system memory buffer drivers"
>> + depends on ARM64 && CORESIGHT_LINKS_AND_SINKS
>
> Given that this driver absolutely only works with ACPI, please could
> you add that dependency here ?
yes, I'll add this, thanks.
>
>> + help
>> + This driver provides support for the Ultrasoc system memory
>> buffer (SMB).
>> + SMB is responsible for receiving the trace data from Coresight
>> ETM devices
>> + and storing them to a system buffer.
>> +
>> + To compile this driver as a module, choose M here: the module
>> will be
>> + called ultrasoc-smb.
>> endif
>> diff --git a/drivers/hwtracing/coresight/Makefile
>> b/drivers/hwtracing/coresight/Makefile
>> index b6c4a48140ec..344dba8d6ff8 100644
>> --- a/drivers/hwtracing/coresight/Makefile
>> +++ b/drivers/hwtracing/coresight/Makefile
>> @@ -27,3 +27,4 @@ obj-$(CONFIG_CORESIGHT_CTI) += coresight-cti.o
>> obj-$(CONFIG_CORESIGHT_TRBE) += coresight-trbe.o
>> coresight-cti-y := coresight-cti-core.o coresight-cti-platform.o \
>> coresight-cti-sysfs.o
>> +obj-$(CONFIG_ULTRASOC_SMB) += ultrasoc-smb.o
>> diff --git a/drivers/hwtracing/coresight/ultrasoc-smb.c
>> b/drivers/hwtracing/coresight/ultrasoc-smb.c
>> new file mode 100644
>> index 000000000000..a18d061aab61
>> --- /dev/null
>> +++ b/drivers/hwtracing/coresight/ultrasoc-smb.c
>> @@ -0,0 +1,602 @@
>> +// SPDX-License-Identifier: MIT/GPL
>> +/*
>> + * Siemens System Memory Buffer driver.
>> + * Copyright(c) 2022, HiSilicon Limited.
>> + */
>> +
>> +#include <linux/acpi.h>
>> +#include <linux/circ_buf.h>
>> +#include <linux/err.h>
>> +#include <linux/module.h>
>> +#include <linux/mod_devicetable.h>
>> +#include <linux/platform_device.h>
>> +
>> +#include "ultrasoc-smb.h"
>> +
>> +DEFINE_CORESIGHT_DEVLIST(sink_devs, "smb");
>
> minor nit: This name could be confused with SMB (samba) under linux
> especially when it appears under /dev/smbN as a misc device.
>
got it, I'll rename this device. How about /dev/ultra_smbN?
>> +
>> +static bool smb_buffer_is_empty(struct smb_drv_data *drvdata)
>> +{
>> + u32 buf_status = readl(drvdata->base + SMB_LB_INT_STS);
>> +
>> + return buf_status & BIT(0) ? false : true;
>> +}
>> +
[...]
>> +
>> +static ssize_t smb_read(struct file *file, char __user *data, size_t
>> len, loff_t *ppos)
>> +{
>> + struct smb_drv_data *drvdata = container_of(file->private_data,
>> + struct smb_drv_data, miscdev);
>> + struct smb_data_buffer *sdb = &drvdata->sdb;
>> + struct device *dev = &drvdata->csdev->dev;
>> + unsigned long flags;
>> + int to_copy = 0;
>> +
>> + spin_lock_irqsave(&drvdata->spinlock, flags);
>> +
>> + if (!sdb->data_size) {
>> + smb_update_data_size(drvdata);
>> + if (!sdb->data_size)
>> + goto out;
>> + }
>> +
>> + if (atomic_read(drvdata->csdev->refcnt)) {
>> + to_copy = -EBUSY;
>> + goto out;
>> + }
>> +
>
> Shouldn't this be performed *before* updating the data_size above ?
> Looking at the smb_update_data_size() it "purges" the data. Is that
> acceptable ?
ah, yes, we should get this before updating the data_size. I'll fix
this, thanks.
>
>> + to_copy = min(sdb->data_size, len);
>> +
>> + /* Copy parts of trace data when the read pointer will wrap
>> around SMB buffer. */
>> + if (sdb->rd_offset + to_copy > sdb->buf_size)
[...]
>> +static struct attribute *smb_sink_attrs[] = {
>> + &dev_attr_read_pos.attr,
>> + &dev_attr_write_pos.attr,
>> + &dev_attr_buf_status.attr,
>> + &dev_attr_buf_size.attr,
>> + NULL,
>> +};
>
> Please could you also update the sysfs ABI files with a brief
> description of the above attributes ?
>
> e.g., Documentation/ABI/testing/sysfs-bus-coresight-devices-tmc
>
yes, sure. I'll do this.
>> +
>> +static const struct attribute_group smb_sink_group = {
>> + .attrs = smb_sink_attrs,
>> + .name = "status",
>> +};
>> +
[...]
>> +
>> +static int smb_enable_perf(struct smb_drv_data *drvdata, void *data)
>> +{
>> + struct device *dev = &drvdata->csdev->dev;
>> + struct perf_output_handle *handle = data;
>> + pid_t pid;
>> +
>> + if (drvdata->mode == CS_MODE_SYSFS) {
>> + dev_err(dev, "Device is already in used by sysfs\n");
>
> Please could you convert this to dev_dbg() ? An -EBUSY should
> be sufficient to indicate that the resource is busy.
>
got it, thanks, will fix this.
>> + return -EBUSY;
>> + }
>> +
>> + /* Get a handle on the pid of the target process*/
>> + pid = task_pid_nr(handle->event->owner);
>> + if (drvdata->pid != -1 && drvdata->pid != pid) {
>> + dev_err(dev, "Device is already in used by other session\n");
>
> Same here.
>
ok.
>> + return -EBUSY;
>> + }
>> + /* The sink is already enabled by this session. */
>> + if (drvdata->pid == pid)
>> + return 0;
>
> If the sink is shared by multiple events of the same group, don't
> we need a refcount to make sure we don't disable the buffer when
> an event goes away ?
>
we increase this refcount in smb_enable(), if smb_enable_sysfs() or
smb_enable_perf() is enabled successfully, we increase the refcount.
So, when the sink is shared by multiple events of the same group,
refcount will be increased too. thanks.
>> +
>> + if (smb_set_perf_buffer(handle))
>> + return -EINVAL;
>> +
>> + smb_enable_hw(drvdata);
>> + drvdata->pid = pid;
>> + drvdata->mode = CS_MODE_PERF;
>> +
>> + return 0;
>> +}
>> +
>> +static int smb_enable(struct coresight_device *csdev, u32 mode, void
>> *data)
>> +{
>> + struct smb_drv_data *drvdata = dev_get_drvdata(csdev->dev.parent);
>> + unsigned long flags;
>> + int ret = -EINVAL;
>> +
>> + /* Do nothing if trace data is reading by other interface now. */
>> + if (local_read(&drvdata->reading))
>> + return -EBUSY;
>> +
>> + spin_lock_irqsave(&drvdata->spinlock, flags);
>> +
>> + if (mode == CS_MODE_SYSFS)
>> + ret = smb_enable_sysfs(drvdata);
>> +
>> + if (mode == CS_MODE_PERF)
>> + ret = smb_enable_perf(drvdata, data);
>> +
>> + spin_unlock_irqrestore(&drvdata->spinlock, flags);
>> +
>> + if (ret)
>> + return ret;
>> +
>> + atomic_inc(csdev->refcnt);
>> + dev_dbg(&csdev->dev, "Ultrasoc SMB enabled\n");
>> +
>> + return 0;
>> +}
>> +
>> +static int smb_disable(struct coresight_device *csdev)
>> +{
>> + struct smb_drv_data *drvdata = dev_get_drvdata(csdev->dev.parent);
>> + unsigned long flags;
>> +
>> + spin_lock_irqsave(&drvdata->spinlock, flags);
>> +
>> + if (atomic_dec_return(csdev->refcnt)) {
>
> We need to increment the refcnt for every event that shares the
> sink for perf mode. Please see my comments above.
>
>> + spin_unlock_irqrestore(&drvdata->spinlock, flags);
>> + return -EBUSY;
>> + }
>> +
>> + WARN_ON_ONCE(drvdata->mode == CS_MODE_DISABLED);
>> + smb_disable_hw(drvdata);
>> +
>> + /*
>> + * Data remaining in hardware path will be sent to SMB after
>> purge, so needs to
>> + * synchronize the read pointer to write pointer in perf mode.
>
> Please run checkpatch on your submission ^^^
>
>
this comment is more than 80 word but less than 120 word, so there's no
checkpatch warning~ I'll modify it to 80 words per line next version :)
>> + */
>> + smb_purge_data(drvdata);
>> + if (drvdata->mode == CS_MODE_PERF)
>> + writel(readl(drvdata->base + SMB_LB_WR_ADDR), drvdata->base +
>> SMB_LB_RD_ADDR);
>
> Same here. Why don't we do this for CS_MODE_SYSFS ?
>
when SMB is disabled, we need to do purge, in case data remaining in
hardware path influence next trace.
when we use sysfs interface, smb_disable() is called before smb_read(),
so the purged data will be dumped to userspace together.
But when using perf interface, smb_disable() is called after
smb_update_buffer(), so we need to synchronize the read pointer to write
pointer, to make sure these data won't influence next trace. Thanks.
>> +
>> + /* Dissociate from the target process. */
>> + drvdata->pid = -1;
>> + drvdata->mode = CS_MODE_DISABLED;
>> + spin_unlock_irqrestore(&drvdata->spinlock, flags);
>> +
>> + dev_dbg(&csdev->dev, "Ultrasoc SMB disabled\n");
>> + return 0;
>> +}
>> +
[...]
>> +
>> +static void smb_sync_perf_buffer(struct smb_drv_data *drvdata,
>> + struct cs_buffers *buf, unsigned long data_size)
>> +{
>> + struct smb_data_buffer *sdb = &drvdata->sdb;
>> + char **dst_pages = (char **)buf->data_pages;
>> + unsigned long buf_offset = buf->offset;
>
> Please could you rename this to page_offset ?
>
yes, sure.
>> + unsigned int cur = buf->cur;
>> + unsigned long to_copy;
>> +
>
>> + while (data_size) {
>> + /* Copy parts of trace data when the read pointer will wrap
>> around SMB buffer. */
>
> Wrap the lines please.
>
> Please could you do :
>
> unsigned long page_space = (PAGE_SIZE - page_offset);
>
>
>> + if (sdb->rd_offset + PAGE_SIZE - buf_offset > sdb->buf_size)
>
> ^^ if (sdb->rd_offset + page_space > sdb->buf_size)
>
>> + to_copy = sdb->buf_size - sdb->rd_offset;
>> + else
>> + to_copy = min(data_size, PAGE_SIZE - buf_offset);
>
> to_copy = min(data_size, page_space);
>
>> +
>> + memcpy_fromio(dst_pages[cur] + buf_offset, sdb->buf_base +
>> sdb->rd_offset, to_copy);
>
> memcpy_fromio(dst_pages[cur] + page_offset, ...
>
>> +
>> + buf_offset += to_copy;
>> + if (buf_offset >= PAGE_SIZE) {
>
> That becomes much simpler to follow with the rename to page_offset.
>
sure, I'll do this next time. thanks.
>> + buf_offset = 0;
>> + cur++;
>> + cur %= buf->nr_pages;
>> + }
>> + data_size -= to_copy;
>> + /* ensure memcpy finished before update the read pointer */
>
> Why and how ?
>
this comment is used to express we do memcpy first, then update read
pointer. Seems it's misleading, I'll delete it next time, thanks.
>> + sdb->rd_offset += to_copy;
>> + sdb->rd_offset %= sdb->buf_size;
>> + }
>> +
>> + sdb->data_size = 0;
>> + writel(sdb->start_addr + sdb->rd_offset, drvdata->base +
>> SMB_LB_RD_ADDR);
>> + smb_reset_buffer_status(drvdata);
>> +}
>> +
>> +static unsigned long smb_update_buffer(struct coresight_device *csdev,
>> + struct perf_output_handle *handle,
>> + void *sink_config)
>> +{
>> + struct smb_drv_data *drvdata = dev_get_drvdata(csdev->dev.parent);
>> + struct smb_data_buffer *sdb = &drvdata->sdb;
>> + struct cs_buffers *buf = sink_config;
>> + unsigned long data_size = 0;
>> + unsigned long flags;
>> + bool lost = false;
>> +
>> + if (!buf)
>> + return 0;
>> +
>> + spin_lock_irqsave(&drvdata->spinlock, flags);
>> +
>> + /* Don't do anything if another tracer is using this sink. */
>> + if (atomic_read(csdev->refcnt) != 1)
>> + goto out;
>> +
>> + smb_update_data_size(drvdata);
>> + data_size = sdb->data_size;
>
> Please could you add in a comment on what we do here below ?
got it, will add this, thanks.
>
>> + if (data_size > handle->size) > + sdb->rd_offset +=
>> data_size - handle->size;
>> + sdb->rd_offset %= sdb->buf_size;
>> + data_size = handle->size;
>> + lost = true;
>> + }
>> +
>> + smb_sync_perf_buffer(drvdata, buf, data_size);
>> + if (!buf->snapshot && lost)
>> + perf_aux_output_flag(handle, PERF_AUX_FLAG_TRUNCATED);
>> +
>> +out:
>> + spin_unlock_irqrestore(&drvdata->spinlock, flags);
>> + return data_size;
>> +}
>> +
>> +static const struct coresight_ops_sink smb_cs_ops = {
>> + .enable = smb_enable,
>> + .disable = smb_disable,
>> + .alloc_buffer = smb_alloc_buffer,
>> + .free_buffer = smb_free_buffer,
>> + .update_buffer = smb_update_buffer,
>> +};
>> +
>> +static const struct coresight_ops cs_ops = {
>> + .sink_ops = &smb_cs_ops,
>> +};
>> +
>> +static int smb_init_data_buffer(struct platform_device *pdev, struct
>> smb_data_buffer *sdb)
>> +{
>> + struct resource *res;
>> + void __iomem *base;
>> +
>> + res = platform_get_resource(pdev, IORESOURCE_MEM, 1);
>
> What are these IO bases ? What does 0 stand for ? What is 1 for ?
>
> Please could you add a documentation under
>
> Documentation/trace/coresight/.
>
> Doesn't need to be too detailed. But a basic description would be helpful.
>
yes, I'll add this, thanks.
>
>> + if (IS_ERR(res)) {
>> + dev_err(&pdev->dev, "SMB device failed to get resource\n");
>> + return -EINVAL;
>> + }
>> +
>> + sdb->start_addr = res->start & SMB_BASE_LOW_MASK;
>> + sdb->buf_size = resource_size(res);
>> + if (sdb->buf_size == 0)
>> + return -EINVAL;
>> +
>> + base = devm_ioremap_resource(&pdev->dev, res);
>> + if (IS_ERR(base))
>> + return PTR_ERR(base);
>> +
>> + sdb->buf_base = base;
>> +
>> + return 0;
>> +}
>> +
>> +static void smb_init_hw(struct smb_drv_data *drvdata)
>> +{
>> + u32 value;
>> +
>> + /* First disable smb and clear the status of SMB buffer */
>> + smb_reset_buffer_status(drvdata);
>> + smb_disable_hw(drvdata);
>> + smb_purge_data(drvdata);
>> +
>> + /* Using smb in single-end mode, and set other configures default */
>> + value = SMB_BUF_CFG_STREAMING | SMB_BUF_SINGLE_END | SMB_BUF_EN;
>> + writel(value, drvdata->base + SMB_LB_CFG_LO);
>> + value = SMB_MSG_FILTER(0x0, 0xff);
>
> Could we not simply say :
>
>
>> + writel(value, drvdata->base + SMB_LB_CFG_HI);
>> +
>
> #define SMB_CFG_MSG_FILTER 0xff00
>
> writel(SMB_CFG_MSG_FILTER, drvdata->base + SMB_LB_CFG_HI) ?
>
>
> Just like you do below for the other registers ? Anyways, none of these
> values make any sense to the reader without the Reference Manual. The
> best you could do is stick a sensible name for the value like you do
> below.
>
yes, I'll do this, thanks.
>> + writel(SMB_GLOBAL_CFG, drvdata->base + SMB_CFG_REG);
>> + writel(SMB_GLB_INT_CFG, drvdata->base + SMB_GLOBAL_INT);
>> + writel(SMB_BUF_INT_CFG, drvdata->base + SMB_LB_INT_CTRL);
>> +}
[...]
>> +
>> +static void smb_unregister_sink(struct smb_drv_data *drvdata)
>> +{
>> + misc_deregister(&drvdata->miscdev);
>> + coresight_unregister(drvdata->csdev);
>> +}
>> +
>> +/*
>> + * Send ultrasoc messge to control hardwares on the tracing path,
>> + * using DSM calls to avoid exposing ultrasoc message format.
>> + */
>> +static int smb_config_inport(struct device *dev, bool enable)
>> +{
>> + u32 flag = enable ? 1 : 0;
>> + union acpi_object *obj;
>> + guid_t guid;
>> +
>> + if (guid_parse("82ae1283-7f6a-4cbe-aa06-53e8fb24db18", &guid)) {
>
> Please could you add symbolic name for this UUID string and a comment on
> what this will do ?
>
sure, I'll fix this, thanks.
>> + dev_err(dev, "Get GUID failed\n");
>> + return -EINVAL;
>> + }
>> +
>> + obj = acpi_evaluate_dsm(ACPI_HANDLE(dev), &guid, 0, flag, NULL);
>
> What are the parameters ? What do they mean ?
>
We need to initialize the register before tracing, but the vendor does
not want us to expose these initialize information, so we add these set
function in ACPI and use a ACPI handler to call this function. Thanks.
>> + if (!obj)
>> + dev_err(dev, "ACPI handle failed\n");
>> + else
>> + ACPI_FREE(obj);
>> +
>> + return 0;
>> +}
>> +
[...]
>> +#ifdef CONFIG_ACPI
>> +static const struct acpi_device_id ultrasoc_smb_acpi_match[] = {
>> + {"HISI03A1", 0},
>> + {},
>> +};
>> +MODULE_DEVICE_TABLE(acpi, ultrasoc_smb_acpi_match);
>> +#endif
>
> As mentioned above this driver must depend on the ACPI and thus
> you may remove the #ifdef
got it, thanks
>
>> +
>> +static struct platform_driver smb_driver = {
>> + .driver = {
>> + .name = "ultrasoc-smb",
>> + .acpi_match_table = ACPI_PTR(ultrasoc_smb_acpi_match),
>> + .suppress_bind_attrs = true,
>> + },
>> + .probe = smb_probe,
>> + .remove = smb_remove,
>> +};
>> +module_platform_driver(smb_driver);
>> +
>> +MODULE_DESCRIPTION("Ultrasoc smb driver");
>> +MODULE_LICENSE("Dual MIT/GPL");
>> +MODULE_AUTHOR("Jonathan Zhou <jonathan.zhouwen at huawei.com>");
>> +MODULE_AUTHOR("Qi Liu <liuqi115 at huawei.com>");
>> diff --git a/drivers/hwtracing/coresight/ultrasoc-smb.h
>> b/drivers/hwtracing/coresight/ultrasoc-smb.h
>> new file mode 100644
>> index 000000000000..a7c76140ee46
>> --- /dev/null
>> +++ b/drivers/hwtracing/coresight/ultrasoc-smb.h
>> @@ -0,0 +1,100 @@
>> +/* SPDX-License-Identifier: MIT */
>> +/*
>> + * Siemens System Memory Buffer driver.
>> + * Copyright(c) 2022, HiSilicon Limited.
>> + */
>> +
>> +#ifndef _ULTRASOC_SMB_H
>> +#define _ULTRASOC_SMB_H
>> +
>> +#include <linux/coresight.h>
>> +#include <linux/list.h>
>> +#include <linux/miscdevice.h>
>> +
>> +#include "coresight-etm-perf.h"
>> +#include "coresight-priv.h"
>> +
>> +/* Offset of SMB logical buffer registers */
>> +#define SMB_CFG_REG 0X0
>> +#define SMB_GLOBAL_EN 0X4
>> +#define SMB_GLOBAL_INT 0X8
>> +#define SMB_LB_CFG_LO 0X40
>> +#define SMB_LB_CFG_HI 0X44
>> +#define SMB_LB_INT_CTRL 0X48
>> +#define SMB_LB_INT_STS 0X4C
>> +#define SMB_LB_LIMIT 0X58
>> +#define SMB_LB_RD_ADDR 0X5C
>> +#define SMB_LB_WR_ADDR 0X60
>> +#define SMB_LB_PURGE 0X64
>> +
>> +/* Set SMB_CFG_REG register */
>> +#define SMB_IDLE_PRD(period) ((((period) - 216) & 0xf) << 12)
>> +#define SMB_MEM_WR(credit, rate) (((credit) << 16) | ((rate) << 18))
>> +#define SMB_MEM_RD(credit, rate) (((credit) << 22) | ((rate) << 24))
>> +#define SMB_BURST_LEN(len) (((len) - 1) << 4)
>> +#define SMB_GLOBAL_CFG (SMB_IDLE_PRD(231) |
>> SMB_MEM_WR(0x3, 0x0) | \
>> + SMB_MEM_RD(0x3, 0x6) | SMB_BURST_LEN(16))
>> +
>> +/* Set SMB_GLOBAL_INT register */
>> +#define SMB_INT_EN BIT(0)
>> +#define SMB_INT_TYPE_PULSE BIT(1)
>> +#define SMB_INT_POLARITY_HIGH BIT(2)
>> +#define SMB_GLB_INT_CFG (SMB_INT_EN | SMB_INT_TYPE_PULSE |
>> SMB_INT_POLARITY_HIGH)
>> +
>> +/* Set SMB_LB_CFG_LO register */
>> +#define SMB_BUF_EN BIT(0)
>> +#define SMB_BUF_SINGLE_END BIT(1)
>> +#define SMB_BUF_INIT BIT(8)
>> +#define SMB_BUF_CONTINUOUS BIT(11)
>> +#define SMB_FLOW_MASK GENMASK(19, 16)
>> +#define SMB_BUF_CFG_STREAMING (SMB_BUF_INIT |
>> SMB_BUF_CONTINUOUS | SMB_FLOW_MASK)
>> +#define SMB_BASE_LOW_MASK GENMASK(31, 0)
>> +
>> +/* Set SMB_LB_CFG_HI register */
>> +#define SMB_MSG_FILTER(lower, upper) (((lower) & 0xff) | (((upper)
>> & 0xff) << 8))
>
> There is only one place where this is used and it is unnecessarily
> confusing. Why not simply define:
>
> #define SMB_CFG_MSG_FILTER 0xff00
>
>
got it, I'll do this.
thanks a lot.
Qi
>> +#define SMB_BUF_INT_EN BIT(0)
>> +#define SMB_BUF_NOTE_MASK GENMASK(11, 8)
>> +#define SMB_BUF_INT_CFG (SMB_BUF_INT_EN | SMB_BUF_NOTE_MASK)
>> +
>> +/**
>> + * struct smb_data_buffer - Details of the buffer used by SMB
>> + * @buf_base : Memory mapped base address of SMB.
>> + * @start_addr : SMB buffer start Physical address.
>> + * @buf_size : Size of the buffer.
>> + * @data_size : Size of Trace data copy to userspace.
>> + * @rd_offset : Offset of the read pointer in the buffer.
>> + */
>> +struct smb_data_buffer {
>> + void __iomem *buf_base;
>> + u32 start_addr;
>> + unsigned long buf_size;
>> + unsigned long data_size;
>> + unsigned long rd_offset;
>> +};
>> +
>> +/**
>> + * struct smb_drv_data - specifics associated to an SMB component
>> + * @base : Memory mapped base address for SMB component.
>> + * @csdev : Component vitals needed by the framework.
>> + * @sdb : Data buffer for SMB.
>> + * @miscdev : Specifics to handle "/dev/smb" entry.
>> + * @spinlock : Only one at a time pls.
>> + * @reading : Synchronise user space access to SMB buffer.
>> + * @pid : Process ID of the process being monitored by the
>> session
>> + * that is using this component.
>> + * @mode : how this SMB is being used, perf mode or sysfs mode.
>> + */
>> +struct smb_drv_data {
>> + void __iomem *base;
>> + struct coresight_device *csdev;
>> + struct smb_data_buffer sdb;
>> + struct miscdevice miscdev;
>> + spinlock_t spinlock;
>> + local_t reading;
>> + pid_t pid;
>> + u32 mode;
>> +};
>> +
>> +#define smb_reg(name, offset) coresight_simple_reg32(struct
>> smb_drv_data, name, offset)
>> +
>> +#endif
>
> Suzuki
> .
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