[PATCH 03/11] habanalabs: support clock gating enable/disable
From: Oded Gabbay
Date: Mon May 11 2020 - 07:32:48 EST
In Gaudi there is a feature of clock gating certain engines.
Therefore, add this property to the device structure.
In addition, due to a limitation of this feature, the driver needs to
dynamically enable or disable this feature during run-time. Therefore, add
ASIC interface functions to enable/disable this function from the common
code.
Moreover, this feature must be turned off when the user wishes to debug the
ASIC by reading/writing registers and/or memory through the driver's
debugfs. Therefore, add an option to enable/disable clock gating via the
debugfs interface.
Signed-off-by: Oded Gabbay <oded.gabbay@xxxxxxxxx>
---
.../ABI/testing/debugfs-driver-habanalabs | 10 +++
drivers/misc/habanalabs/debugfs.c | 61 +++++++++++++++++++
drivers/misc/habanalabs/device.c | 4 ++
drivers/misc/habanalabs/goya/goya.c | 12 ++++
drivers/misc/habanalabs/habanalabs.h | 6 ++
drivers/misc/habanalabs/habanalabs_drv.c | 1 +
6 files changed, 94 insertions(+)
diff --git a/Documentation/ABI/testing/debugfs-driver-habanalabs b/Documentation/ABI/testing/debugfs-driver-habanalabs
index 67e04f2d7e1d..f6d9c2a8d528 100644
--- a/Documentation/ABI/testing/debugfs-driver-habanalabs
+++ b/Documentation/ABI/testing/debugfs-driver-habanalabs
@@ -8,6 +8,16 @@ Description: Sets the device address to be used for read or write through
only when the IOMMU is disabled.
The acceptable value is a string that starts with "0x"
+What: /sys/kernel/debug/habanalabs/hl<n>/clk_gate
+Date: May 2020
+KernelVersion: 5.8
+Contact: oded.gabbay@xxxxxxxxx
+Description: Allow the root user to disable/enable in runtime the clock
+ gating mechanism in Gaudi. Due to how Gaudi is built, the
+ clock gating needs to be disabled in order to access the
+ registers of the TPC and MME engines. This is sometimes needed
+ during debug by the user and hence the user needs this option
+
What: /sys/kernel/debug/habanalabs/hl<n>/command_buffers
Date: Jan 2019
KernelVersion: 5.1
diff --git a/drivers/misc/habanalabs/debugfs.c b/drivers/misc/habanalabs/debugfs.c
index 37beff3096f8..3c8dcdfba20c 100644
--- a/drivers/misc/habanalabs/debugfs.c
+++ b/drivers/misc/habanalabs/debugfs.c
@@ -970,6 +970,55 @@ static ssize_t hl_device_write(struct file *f, const char __user *buf,
return count;
}
+static ssize_t hl_clk_gate_read(struct file *f, char __user *buf,
+ size_t count, loff_t *ppos)
+{
+ struct hl_dbg_device_entry *entry = file_inode(f)->i_private;
+ struct hl_device *hdev = entry->hdev;
+ char tmp_buf[200];
+ ssize_t rc;
+
+ if (*ppos)
+ return 0;
+
+ sprintf(tmp_buf, "%d\n", hdev->clock_gating);
+ rc = simple_read_from_buffer(buf, strlen(tmp_buf) + 1, ppos, tmp_buf,
+ strlen(tmp_buf) + 1);
+
+ return rc;
+}
+
+static ssize_t hl_clk_gate_write(struct file *f, const char __user *buf,
+ size_t count, loff_t *ppos)
+{
+ struct hl_dbg_device_entry *entry = file_inode(f)->i_private;
+ struct hl_device *hdev = entry->hdev;
+ u32 value;
+ ssize_t rc;
+
+ if (atomic_read(&hdev->in_reset)) {
+ dev_warn_ratelimited(hdev->dev,
+ "Can't change clock gating during reset\n");
+ return 0;
+ }
+
+ rc = kstrtouint_from_user(buf, count, 10, &value);
+ if (rc)
+ return rc;
+
+ if (value) {
+ hdev->clock_gating = 1;
+ if (hdev->asic_funcs->enable_clock_gating)
+ hdev->asic_funcs->enable_clock_gating(hdev);
+ } else {
+ if (hdev->asic_funcs->disable_clock_gating)
+ hdev->asic_funcs->disable_clock_gating(hdev);
+ hdev->clock_gating = 0;
+ }
+
+ return count;
+}
+
static ssize_t hl_stop_on_err_read(struct file *f, char __user *buf,
size_t count, loff_t *ppos)
{
@@ -1058,6 +1107,12 @@ static const struct file_operations hl_device_fops = {
.write = hl_device_write
};
+static const struct file_operations hl_clk_gate_fops = {
+ .owner = THIS_MODULE,
+ .read = hl_clk_gate_read,
+ .write = hl_clk_gate_write
+};
+
static const struct file_operations hl_stop_on_err_fops = {
.owner = THIS_MODULE,
.read = hl_stop_on_err_read,
@@ -1201,6 +1256,12 @@ void hl_debugfs_add_device(struct hl_device *hdev)
dev_entry,
&hl_device_fops);
+ debugfs_create_file("clk_gate",
+ 0200,
+ dev_entry->root,
+ dev_entry,
+ &hl_clk_gate_fops);
+
debugfs_create_file("stop_on_err",
0644,
dev_entry->root,
diff --git a/drivers/misc/habanalabs/device.c b/drivers/misc/habanalabs/device.c
index f618cff9a167..7ce4540648cf 100644
--- a/drivers/misc/habanalabs/device.c
+++ b/drivers/misc/habanalabs/device.c
@@ -603,6 +603,9 @@ int hl_device_set_debug_mode(struct hl_device *hdev, bool enable)
hdev->in_debug = 0;
+ if (!hdev->hard_reset_pending)
+ hdev->asic_funcs->enable_clock_gating(hdev);
+
goto out;
}
@@ -613,6 +616,7 @@ int hl_device_set_debug_mode(struct hl_device *hdev, bool enable)
goto out;
}
+ hdev->asic_funcs->disable_clock_gating(hdev);
hdev->in_debug = 1;
out:
diff --git a/drivers/misc/habanalabs/goya/goya.c b/drivers/misc/habanalabs/goya/goya.c
index fb2ff82e0db5..56f415f9120a 100644
--- a/drivers/misc/habanalabs/goya/goya.c
+++ b/drivers/misc/habanalabs/goya/goya.c
@@ -5018,6 +5018,16 @@ int goya_armcp_info_get(struct hl_device *hdev)
return 0;
}
+static void goya_enable_clock_gating(struct hl_device *hdev)
+{
+
+}
+
+static void goya_disable_clock_gating(struct hl_device *hdev)
+{
+
+}
+
static bool goya_is_device_idle(struct hl_device *hdev, u32 *mask,
struct seq_file *s)
{
@@ -5239,6 +5249,8 @@ static const struct hl_asic_funcs goya_funcs = {
.mmu_invalidate_cache = goya_mmu_invalidate_cache,
.mmu_invalidate_cache_range = goya_mmu_invalidate_cache_range,
.send_heartbeat = goya_send_heartbeat,
+ .enable_clock_gating = goya_enable_clock_gating,
+ .disable_clock_gating = goya_disable_clock_gating,
.debug_coresight = goya_debug_coresight,
.is_device_idle = goya_is_device_idle,
.soft_reset_late_init = goya_soft_reset_late_init,
diff --git a/drivers/misc/habanalabs/habanalabs.h b/drivers/misc/habanalabs/habanalabs.h
index d77410886a67..b1c3a89c7f38 100644
--- a/drivers/misc/habanalabs/habanalabs.h
+++ b/drivers/misc/habanalabs/habanalabs.h
@@ -578,6 +578,8 @@ enum hl_pll_frequency {
* @mmu_invalidate_cache_range: flush specific MMU STLB cache lines with
* ASID-VA-size mask.
* @send_heartbeat: send is-alive packet to ArmCP and verify response.
+ * @enable_clock_gating: enable clock gating for reducing power consumption.
+ * @disable_clock_gating: disable clock for accessing registers on HBW.
* @debug_coresight: perform certain actions on Coresight for debugging.
* @is_device_idle: return true if device is idle, false otherwise.
* @soft_reset_late_init: perform certain actions needed after soft reset.
@@ -678,6 +680,8 @@ struct hl_asic_funcs {
void (*mmu_invalidate_cache_range)(struct hl_device *hdev, bool is_hard,
u32 asid, u64 va, u64 size);
int (*send_heartbeat)(struct hl_device *hdev);
+ void (*enable_clock_gating)(struct hl_device *hdev);
+ void (*disable_clock_gating)(struct hl_device *hdev);
int (*debug_coresight)(struct hl_device *hdev, void *data);
bool (*is_device_idle)(struct hl_device *hdev, u32 *mask,
struct seq_file *s);
@@ -1408,6 +1412,7 @@ struct hl_device_idle_busy_ts {
* huge pages.
* @init_done: is the initialization of the device done.
* @mmu_enable: is MMU enabled.
+ * @clock_gating: is clock gating enabled.
* @device_cpu_disabled: is the device CPU disabled (due to timeouts)
* @dma_mask: the dma mask that was set for this device
* @in_debug: is device under debug. This, together with fpriv_list, enforces
@@ -1494,6 +1499,7 @@ struct hl_device {
u8 dram_default_page_mapping;
u8 pmmu_huge_range;
u8 init_done;
+ u8 clock_gating;
u8 device_cpu_disabled;
u8 dma_mask;
u8 in_debug;
diff --git a/drivers/misc/habanalabs/habanalabs_drv.c b/drivers/misc/habanalabs/habanalabs_drv.c
index 5e73b456facd..822acb5a00bb 100644
--- a/drivers/misc/habanalabs/habanalabs_drv.c
+++ b/drivers/misc/habanalabs/habanalabs_drv.c
@@ -231,6 +231,7 @@ static void set_driver_behavior_per_device(struct hl_device *hdev)
hdev->fw_loading = 1;
hdev->cpu_queues_enable = 1;
hdev->heartbeat = 1;
+ hdev->clock_gating = 1;
hdev->reset_pcilink = 0;
}
--
2.17.1