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SubjectRe: [PATCH v6 1/2] drivers/coresight: Add UltraSoc System Memory Buffer driver
From
Hi Qi

On 06/06/2022 14:02, 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.

nit: "CPU instruction trace" 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@huawei.com>
> Tested-by: JunHao He <hejunhao2@hisilicon.com>
> ---
> drivers/hwtracing/coresight/Kconfig | 10 +
> drivers/hwtracing/coresight/Makefile | 1 +
> drivers/hwtracing/coresight/ultrasoc-smb.c | 663 +++++++++++++++++++++
> drivers/hwtracing/coresight/ultrasoc-smb.h | 110 ++++
> 4 files changed, 784 insertions(+)
> create mode 100644 drivers/hwtracing/coresight/ultrasoc-smb.c
> create mode 100644 drivers/hwtracing/coresight/ultrasoc-smb.h
>
> diff --git a/drivers/hwtracing/coresight/Kconfig b/drivers/hwtracing/coresight/Kconfig
> index 514a9b8086e3..4380eb1a0a73 100644
> --- a/drivers/hwtracing/coresight/Kconfig
> +++ b/drivers/hwtracing/coresight/Kconfig

...

> 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..44b4bceb6f28
> --- /dev/null
> +++ b/drivers/hwtracing/coresight/ultrasoc-smb.c

...

> +static int smb_open(struct inode *inode, struct file *file)
> +{
> + struct smb_drv_data *drvdata = container_of(file->private_data,
> + struct smb_drv_data, miscdev);
> + unsigned long flags;
> + int ret = 0;
> +
> + spin_lock_irqsave(&drvdata->spinlock, flags);
> +
> + if (local_read(&drvdata->reading)) {
> + ret = -EBUSY;
> + goto out;
> + }
> +
> + if (drvdata->mode == CS_MODE_PERF) {
> + ret = -EINVAL;
> + goto out;
> + }
> +
> +out:
> + spin_unlock_irqrestore(&drvdata->spinlock, flags);
> + return ret;
> +}
> +
> +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 (atomic_read(drvdata->csdev->refcnt)) {
> + spin_unlock_irqrestore(&drvdata->spinlock, flags);
> + return -EBUSY;
> + }
> +
> + if (local_cmpxchg(&drvdata->reading, 0, 1)) {
> + spin_unlock_irqrestore(&drvdata->spinlock, flags);
> + return -EBUSY;
> + }
> +

Shouldn't this be done in smb_open() ? Otherwise, a subsequent read
will fail with EBUSY ?
i.e,
fd = open(/dev/ultra_smb0, ..);

# size of the SMB buffer = 1M,
size = read(fd, buf, SZ_4K);
/* Do something the buf */
if (size >= 0)
size = read(fd, buf, SZ_4K);

^^ This would fail, isn't it ?

> + if (!sdb->data_size) {
> + smb_update_data_size(drvdata);
> + if (!sdb->data_size)
> + goto out;
> + }
> +
> + to_copy = min(sdb->data_size, len);
> +
> + /* Copy parts of trace data when read pointer wrap around SMB buffer */
> + if (sdb->rd_offset + to_copy > sdb->buf_size)
> + to_copy = sdb->buf_size - sdb->rd_offset;
> +
> + if (copy_to_user(data, (void *)sdb->buf_base + sdb->rd_offset,
> + to_copy)) {
> + dev_dbg(dev, "Failed to copy data to user.\n");
> + to_copy = -EFAULT;
> + goto out;
> + }
> +
> + *ppos += to_copy;
> + sdb->data_size -= to_copy;
> + sdb->rd_offset += to_copy;
> + sdb->rd_offset %= sdb->buf_size;
> + writel(sdb->start_addr + sdb->rd_offset,
> + drvdata->base + SMB_LB_RD_ADDR);
> + dev_dbg(dev, "%d bytes copied.\n", to_copy);
> +out:
> + if (!sdb->data_size)
> + smb_reset_buffer_status(drvdata);
> + spin_unlock_irqrestore(&drvdata->spinlock, flags);
> + return to_copy;
> +}
> +
> +static int smb_release(struct inode *inode, struct file *file)
> +{
> + struct smb_drv_data *drvdata = container_of(file->private_data,
> + struct smb_drv_data, miscdev);
> + local_set(&drvdata->reading, 0);
> + return 0;
> +}
> +
> +static const struct file_operations smb_fops = {
> + .owner = THIS_MODULE,
> + .open = smb_open,
> + .read = smb_read,
> + .release = smb_release,
> + .llseek = no_llseek,
> +};
> +
> +smb_reg(read_pos, SMB_LB_RD_ADDR);
> +smb_reg(write_pos, SMB_LB_WR_ADDR);
> +smb_reg(buf_status, SMB_LB_INT_STS);
> +
> +static ssize_t buf_size_show(struct device *dev, struct device_attribute *attr,
> + char *buf)
> +{
> + struct smb_drv_data *drvdata = dev_get_drvdata(dev->parent);
> +
> + return sysfs_emit(buf, "0x%lx\n", drvdata->sdb.buf_size);
> +}
> +static DEVICE_ATTR_RO(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,
> +};
> +
> +static const struct attribute_group smb_sink_group = {
> + .attrs = smb_sink_attrs,
> + .name = "mgmt",
> +};
> +
> +static const struct attribute_group *smb_sink_groups[] = {
> + &smb_sink_group,
> + NULL,
> +};
> +
> +static int smb_set_perf_buffer(struct perf_output_handle *handle)
> +{
> + struct cs_buffers *buf = etm_perf_sink_config(handle);
> + u32 head;
> +
> + if (!buf)
> + return -EINVAL;
> +
> + /* Wrap head around to the amount of space we have */
> + head = handle->head & ((buf->nr_pages << PAGE_SHIFT) - 1);
> +
> + /* Find the page to write to and offset within that page */
> + buf->cur = head / PAGE_SIZE;
> + buf->offset = head % PAGE_SIZE;
> +

I believe these fields should be dropped and instead use the
handle->head, to determine the page number and offset. See the
TMC-ETR driver for e.g.

> + local_set(&buf->data_size, 0);
> +
> + return 0;
> +}
> +
> +static void smb_enable_hw(struct smb_drv_data *drvdata)
> +{
> + writel(0x1, drvdata->base + SMB_GLOBAL_EN);
> +}
> +
> +static void smb_disable_hw(struct smb_drv_data *drvdata)
> +{
> + writel(0x0, drvdata->base + SMB_GLOBAL_EN);
> +}
> +
> +static int smb_enable_sysfs(struct coresight_device *csdev)
> +{
> + struct smb_drv_data *drvdata = dev_get_drvdata(csdev->dev.parent);
> + unsigned long flags;
> + int ret = 0;
> +
> + spin_lock_irqsave(&drvdata->spinlock, flags);
> + if (drvdata->mode == CS_MODE_PERF) {
> + ret = -EBUSY;
> + goto out;
> + }
> +
> + if (drvdata->mode == CS_MODE_DISABLED) {
> + smb_enable_hw(drvdata);
> + drvdata->mode = CS_MODE_SYSFS;
> + }
> +
> + atomic_inc(csdev->refcnt);
> +out:
> + spin_unlock_irqrestore(&drvdata->spinlock, flags);
> + return ret;
> +}
> +
> +static int smb_enable_perf(struct coresight_device *csdev, void *data)
> +{
> + struct smb_drv_data *drvdata = dev_get_drvdata(csdev->dev.parent);
> + struct device *dev = &drvdata->csdev->dev;
> + struct perf_output_handle *handle = data;
> + struct cs_buffers *buf = etm_perf_sink_config(handle);
> + unsigned long flags;
> + int ret = 0;
> + pid_t pid;
> +
> + spin_lock_irqsave(&drvdata->spinlock, flags);
> + if (drvdata->mode == CS_MODE_SYSFS) {
> + dev_dbg(dev, "Device is already in used by sysfs.\n");
> + ret = -EBUSY;
> + goto out;
> + }
> +
> + /* Get a handle on the pid of the target process */
> + pid = buf->pid;
> + if (drvdata->pid != -1 && drvdata->pid != pid) {
> + dev_dbg(dev, "Device is already in used by other session.\n");
> + ret = -EBUSY;
> + goto out;
> + }
> +
> + /* The sink is already enabled by this session */
> + if (drvdata->pid == pid) {
> + atomic_inc(csdev->refcnt);
> + goto out;
> + }
> +
> + ret = smb_set_perf_buffer(handle);
> + if (ret)
> + goto out;
> +
> + smb_enable_hw(drvdata);
> + drvdata->pid = pid;
> + drvdata->mode = CS_MODE_PERF;
> + atomic_inc(csdev->refcnt);
> +out:
> + spin_unlock_irqrestore(&drvdata->spinlock, flags);
> + return ret;
> +}
> +
> +static int smb_enable(struct coresight_device *csdev, u32 mode, void *data)
> +{
> + struct smb_drv_data *drvdata = dev_get_drvdata(csdev->dev.parent);
> + int ret;
> +
> + /* Do nothing if trace data is reading by other interface now */
> + if (local_read(&drvdata->reading))
> + return -EBUSY;
> +

Is there global switch for all the inports ? Or is there a control for
individual inports to the SMB ? Do we need additional information here
to enable the corresponding port ?

> + switch (mode) {
> + case CS_MODE_SYSFS:
> + ret = smb_enable_sysfs(csdev);
> + break;
> + case CS_MODE_PERF:
> + ret = smb_enable_perf(csdev, data);
> + break;
> + default:
> + ret = -EINVAL;
> + break;
> + }
> +
> + if (ret)
> + return ret;
> + 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 (local_read(&drvdata->reading)) {
> + spin_unlock_irqrestore(&drvdata->spinlock, flags);
> + return -EBUSY;
> + }
> +
> + if (atomic_dec_return(csdev->refcnt)) {
> + spin_unlock_irqrestore(&drvdata->spinlock, flags);
> + return -EBUSY;
> + }
> +
> + WARN_ON_ONCE(drvdata->mode == CS_MODE_DISABLED);
> + smb_disable_hw(drvdata);
> + smb_purge_data(drvdata);
> +
> + /* 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_alloc_buffer(struct coresight_device *csdev,
> + struct perf_event *event, void **pages,
> + int nr_pages, bool overwrite)
> +{
> + struct cs_buffers *buf;
> + int node;
> +
> + node = (event->cpu == -1) ? NUMA_NO_NODE : cpu_to_node(event->cpu);
> + buf = kzalloc_node(sizeof(struct cs_buffers), GFP_KERNEL, node);
> + if (!buf)
> + return NULL;
> +
> + buf->snapshot = overwrite;
> + buf->nr_pages = nr_pages;
> + buf->data_pages = pages;
> + buf->pid = task_pid_nr(event->owner);
> +
> + return buf;
> +}
> +
> +static void smb_free_buffer(void *config)
> +{
> + struct cs_buffers *buf = config;
> +
> + kfree(buf);
> +}
> +
> +static void smb_sync_perf_buffer(struct smb_drv_data *drvdata,
> + struct cs_buffers *buf,
> + unsigned long data_size)

You may need to pass the aux_handle here, to determine the handle->head
and the size. See my comments above.

> +{
> + struct smb_data_buffer *sdb = &drvdata->sdb;
> + char **dst_pages = (char **)buf->data_pages;
> + unsigned long page_offset = buf->offset;
> + unsigned int cur = buf->cur;
> + unsigned long to_copy;
> +
> + while (data_size) {
> + unsigned long page_space = PAGE_SIZE - page_offset;
> +
> + /* Copy parts of trace data when read pointer wrap around */
> + if (sdb->rd_offset + page_space > sdb->buf_size)
> + to_copy = sdb->buf_size - sdb->rd_offset;
> + else
> + to_copy = min(data_size, page_space);
> +
> + memcpy_fromio(dst_pages[cur] + page_offset,
> + sdb->buf_base + sdb->rd_offset, to_copy);
> +
> + page_offset += to_copy;
> + if (page_offset >= PAGE_SIZE) {
> + page_offset = 0;
> + cur++;
> + cur %= buf->nr_pages;
> + }
> + data_size -= to_copy;
> + 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);
> +
> + /*
> + * Data remained in link cannot be purged when SMB is full, so
> + * synchronize the read pointer to write pointer, to make sure
> + * these remained data won't influence next trace.
> + */
> + if (sdb->full) {
> + smb_purge_data(drvdata);
> + writel(readl(drvdata->base + SMB_LB_WR_ADDR),
> + 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_disable_hw(drvdata);
> + smb_update_data_size(drvdata);
> + data_size = sdb->data_size;
> +
> + /*
> + * The SMB buffer may be bigger than the space available in the
> + * perf ring buffer (handle->size). If so advance the offset so
> + * that we get the latest trace data.
> + */
> + 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);
> +
> + smb_enable_hw(drvdata);
> +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);
> + 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)
> +{
> + /* First disable smb and clear the status of SMB buffer */
> + smb_reset_buffer_status(drvdata);
> + smb_disable_hw(drvdata);
> + smb_purge_data(drvdata);
> +
> + writel(SMB_BUF_CFG_STREAMING, drvdata->base + SMB_LB_CFG_LO);
> + writel(SMB_MSG_FILTER, drvdata->base + SMB_LB_CFG_HI);
> + 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 int smb_register_sink(struct platform_device *pdev,
> + struct smb_drv_data *drvdata)
> +{
> + struct coresight_platform_data *pdata = NULL;
> + struct coresight_desc desc = { 0 };
> + int ret;
> +
> + pdata = coresight_get_platform_data(&pdev->dev);
> + if (IS_ERR(pdata))
> + return PTR_ERR(pdata);
> +
> + desc.type = CORESIGHT_DEV_TYPE_SINK;
> + desc.subtype.sink_subtype = CORESIGHT_DEV_SUBTYPE_SINK_BUFFER;
> + desc.ops = &cs_ops;
> + desc.pdata = pdata;
> + desc.dev = &pdev->dev;
> + desc.groups = smb_sink_groups;
> + desc.name = coresight_alloc_device_name(&sink_devs, &pdev->dev);

Please fill in the csdev_access method for the device.
desc.access = CSDEV_ACCESS_IOMEM(drvdata->base);

> + if (!desc.name) {
> + dev_err(&pdev->dev, "Failed to alloc coresight device name.");
> + return -ENOMEM;
> + }
> +
> + drvdata->csdev = coresight_register(&desc);
> + if (IS_ERR(drvdata->csdev))
> + return PTR_ERR(drvdata->csdev);
> +
> + drvdata->miscdev.name = desc.name;
> + drvdata->miscdev.minor = MISC_DYNAMIC_MINOR;
> + drvdata->miscdev.fops = &smb_fops;
> + ret = misc_register(&drvdata->miscdev);
> + if (ret) {
> + coresight_unregister(drvdata->csdev);
> + dev_err(&pdev->dev, "Failed to register misc, ret=%d.\n", ret);
> + }
> +
> + return ret;
> +}
> +
> +static void smb_unregister_sink(struct smb_drv_data *drvdata)
> +{
> + misc_deregister(&drvdata->miscdev);
> + coresight_unregister(drvdata->csdev);
> +}
> +
> +static int smb_config_inport(struct device *dev, bool enable)
> +{
> + u64 func = enable ? 1 : 0;
> + union acpi_object *obj;
> + guid_t guid;
> + u64 rev = 0;
> +
> + /*
> + * Using DSM calls to enable/disable ultrasoc hardwares on
> + * tracing path, to prevent ultrasoc packet format being exposed.
> + */
> + if (guid_parse(ULTRASOC_SMB_DSM_UUID, &guid)) {
> + dev_err(dev, "Get GUID failed.\n");
> + return -EINVAL;
> + }
> +
> + obj = acpi_evaluate_dsm(ACPI_HANDLE(dev), &guid, rev, func, NULL);
> + if (!obj)
> + dev_err(dev, "ACPI handle failed!\n");
> + else
> + ACPI_FREE(obj);
> +
> + return 0;
> +}
> +
> +static int smb_probe(struct platform_device *pdev)
> +{
> + struct smb_drv_data *drvdata;
> + int ret;
> +
> + drvdata = devm_kzalloc(&pdev->dev, sizeof(*drvdata), GFP_KERNEL);
> + if (!drvdata)
> + return -ENOMEM;
> +
> + drvdata->base = devm_platform_ioremap_resource(pdev, 0);
> + if (IS_ERR(drvdata->base)) {
> + dev_err(&pdev->dev, "Failed to ioremap resource.\n");
> + return PTR_ERR(drvdata->base);
> + }
> +
> + ret = smb_init_data_buffer(pdev, &drvdata->sdb);
> + if (ret) {
> + dev_err(&pdev->dev, "Failed to init buffer, ret = %d.\n", ret);
> + return ret;
> + }
> +
> + smb_init_hw(drvdata);
> + spin_lock_init(&drvdata->spinlock);
> + drvdata->pid = -1;
> +
> + ret = smb_register_sink(pdev, drvdata);
> + if (ret) {
> + dev_err(&pdev->dev, "Failed to register smb sink.\n");
> + return ret;
> + }
> +
> + ret = smb_config_inport(&pdev->dev, true);
> + if (ret) {
> + smb_unregister_sink(drvdata);
> + return ret;
> + }
> +
> + platform_set_drvdata(pdev, drvdata);
> + return 0;
> +}
> +
> +static int smb_remove(struct platform_device *pdev)
> +{
> + struct smb_drv_data *drvdata = platform_get_drvdata(pdev);
> + int ret;
> +
> + ret = smb_config_inport(&pdev->dev, false);
> + if (ret)
> + return ret;
> +
> + smb_unregister_sink(drvdata);
> + return 0;
> +}
> +
> +static const struct acpi_device_id ultrasoc_smb_acpi_match[] = {
> + {"HISI03A1", 0},
> + {},
> +};
> +MODULE_DEVICE_TABLE(acpi, ultrasoc_smb_acpi_match);
> +
> +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");

"UltraSoc SMB CoreSight driver"

> +MODULE_LICENSE("Dual MIT/GPL");
> +MODULE_AUTHOR("Jonathan Zhou <jonathan.zhouwen@huawei.com>");
> +MODULE_AUTHOR("Qi Liu <liuqi115@huawei.com>");

> diff --git a/drivers/hwtracing/coresight/ultrasoc-smb.h b/drivers/hwtracing/coresight/ultrasoc-smb.h
> new file mode 100644
> index 000000000000..a01f869fe122
> --- /dev/null
> +++ b/drivers/hwtracing/coresight/ultrasoc-smb.h
> @@ -0,0 +1,110 @@
> +/* SPDX-License-Identifier: (GPL-2.0 OR MIT) */
> +/*
> + * Siemens System Memory Buffer driver.
> + * Copyright(c) 2021, 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 0x00
> +#define SMB_GLOBAL_EN 0x04
> +#define SMB_GLOBAL_INT 0x08
> +#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_BURST_LEN GENMASK(7, 4)
> +#define SMB_IDLE_PRD GENMASK(15, 12)
> +#define SMB_MEM_WR GENMASK(17, 16)
> +#define SMB_MEM_RD (GENMASK(26, 25) | GENMASK(23, 22))
> +#define SMB_GLOBAL_CFG (SMB_IDLE_PRD | SMB_MEM_WR | SMB_MEM_RD | \
> + SMB_BURST_LEN)
> +
> +/* 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)
What does the value GENMASK(19, 16) indicate for SMB_FLOW ? That is the
value being passed down. Please add a descriptive name.
.e.g,

#define SMB_FLOW_MODE_X GENMASK(19, 16)

Similarly for SMB_BUF_NOTE_MASK, unless there is an explanation.

> +#define SMB_BUF_CFG_STREAMING (SMB_BUF_INIT | SMB_BUF_CONTINUOUS | \
> + SMB_FLOW_MASK | SMB_BUF_SINGLE_END | \
> + SMB_BUF_EN)
> +
> +#define SMB_BASE_LOW_MASK GENMASK(31, 0)
> +
> +/* Set SMB_LB_CFG_HI register */
> +#define SMB_MSG_FILTER GENMASK(15, 8)
> +
> +/* Set SMB_LB_INT_CTRL */
> +#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.

Please align the field definitions.

> + * @data_size : Size of Trace data copy to userspace.
> + * @rd_offset : Offset of the read pointer in the buffer.
> + * @wr_offset : Offset of the write pointer in the buffer.
> + * @status : Status of SMB buffer.
> + */
> +struct smb_data_buffer {
> + void __iomem *buf_base;
> + u32 start_addr;
> + unsigned long buf_size;
> + unsigned long data_size;
> + unsigned long rd_offset;
> + unsigned long wr_offset;
> + bool full;
> +};
> +
> +/**
> + * 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/xyz.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.

Same as above.

> + * @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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