[PATCH v3 1/2] platform/x86/amd/pmf: Add BIOS_INPUTS_MAX macro to replace hardcoded array size

[PATCH v3 1/2] platform/x86/amd/pmf: Add BIOS_INPUTS_MAX macro to replace hardcoded array size

[Shyam Sundar S K]

Define a new macro BIOS_INPUTS_MAX, to represent the maximum number of
BIOS input values. Replace hardcoded array sizes in relevant structures
with this macro to improve readability and maintainability.

Reviewed-by: Mario Limonciello (AMD) <superm1@kernel.org>
Tested-by: Yijun Shen <Yijun.Shen@Dell.com>
Co-developed-by: Patil Rajesh Reddy <Patil.Reddy@amd.com>
Signed-off-by: Patil Rajesh Reddy <Patil.Reddy@amd.com>
Signed-off-by: Shyam Sundar S K <Shyam-sundar.S-k@amd.com>
---
v3:
 - No change

v2:
 - New patch spinned from v1
 - Add new BIOS_INPUTS_MAX macro and replace hardcoded values

 drivers/platform/x86/amd/pmf/pmf.h | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/drivers/platform/x86/amd/pmf/pmf.h b/drivers/platform/x86/amd/pmf/pmf.h
index bd19f2a6bc78..2145df4128cd 100644
--- a/drivers/platform/x86/amd/pmf/pmf.h
+++ b/drivers/platform/x86/amd/pmf/pmf.h
@@ -119,6 +119,7 @@ struct cookie_header {
 
 #define APTS_MAX_STATES		16
 #define CUSTOM_BIOS_INPUT_BITS	GENMASK(16, 7)
+#define BIOS_INPUTS_MAX		10
 
 typedef void (*apmf_event_handler_t)(acpi_handle handle, u32 event, void *data);
 
@@ -204,7 +205,7 @@ struct apmf_sbios_req_v1 {
 	u8 skin_temp_apu;
 	u8 skin_temp_hs2;
 	u8 enable_cnqf;
-	u32 custom_policy[10];
+	u32 custom_policy[BIOS_INPUTS_MAX];
 } __packed;
 
 struct apmf_sbios_req_v2 {
@@ -216,7 +217,7 @@ struct apmf_sbios_req_v2 {
 	u32 stt_min_limit;
 	u8 skin_temp_apu;
 	u8 skin_temp_hs2;
-	u32 custom_policy[10];
+	u32 custom_policy[BIOS_INPUTS_MAX];
 } __packed;
 
 struct apmf_fan_idx {
@@ -355,7 +356,7 @@ enum power_modes_v2 {
 };
 
 struct pmf_bios_inputs_prev {
-	u32 custom_bios_inputs[10];
+	u32 custom_bios_inputs[BIOS_INPUTS_MAX];
 };
 
 struct amd_pmf_dev {
@@ -451,7 +452,7 @@ struct os_power_slider {
 struct amd_pmf_notify_smart_pc_update {
 	u16 size;
 	u32 pending_req;
-	u32 custom_bios[10];
+	u32 custom_bios[BIOS_INPUTS_MAX];
 } __packed;
 
 struct fan_table_control {
-- 
2.34.1

[PATCH v3 2/2] platform/x86/amd/pmf: Use ring buffer to store custom BIOS input values

[Shyam Sundar S K]

Custom BIOS input values can be updated by multiple sources, such as power
mode changes and sensor events, each triggering a custom BIOS input event.
When these events occur in rapid succession, new data may overwrite
previous values before they are processed, resulting in lost updates.

To address this, introduce a fixed-size, power-of-two ring buffer to
capture every custom BIOS input event, storing both the pending request
and its associated input values. Access to the ring buffer is synchronized
using a mutex.

The previous use of memset() to clear the pending request structure after
each event is removed, as each BIOS input value is now copied into the
buffer as a snapshot. Consumers now process entries directly from the ring
buffer, making explicit clearing of the pending request structure
unnecessary.

Reviewed-by: Mario Limonciello (AMD) <superm1@kernel.org>
Tested-by: Yijun Shen <Yijun.Shen@Dell.com>
Co-developed-by: Patil Rajesh Reddy <Patil.Reddy@amd.com>
Signed-off-by: Patil Rajesh Reddy <Patil.Reddy@amd.com>
Signed-off-by: Shyam Sundar S K <Shyam-sundar.S-k@amd.com>
---
v3:
 - include headers wherever missing
 - use dev_warn() instead of dev_WARN_ONCE()
 - remove generic struct names
 - enhance ringbuffer mechanism to handle common path
 - other cosmetic remarks

v2:
 - Add dev_WARN_ONCE()
 - Change variable name rb_mutex to cbi_mutex
 - Move tail increment logic above pending request check

 drivers/platform/x86/amd/pmf/acpi.c   | 42 +++++++++++++++++++++++++++
 drivers/platform/x86/amd/pmf/core.c   |  3 ++
 drivers/platform/x86/amd/pmf/pmf.h    | 21 ++++++++++++++
 drivers/platform/x86/amd/pmf/spc.c    | 36 +++++++++++++----------
 drivers/platform/x86/amd/pmf/tee-if.c |  2 ++
 5 files changed, 89 insertions(+), 15 deletions(-)

diff --git a/drivers/platform/x86/amd/pmf/acpi.c b/drivers/platform/x86/amd/pmf/acpi.c
index 13c4fec2c7ef..4750ae6d70b0 100644
--- a/drivers/platform/x86/amd/pmf/acpi.c
+++ b/drivers/platform/x86/amd/pmf/acpi.c
@@ -9,6 +9,9 @@
  */
 
 #include <linux/acpi.h>
+#include <linux/array_size.h>
+#include <linux/cleanup.h>
+#include <linux/dev_printk.h>
 #include "pmf.h"
 
 #define APMF_CQL_NOTIFICATION  2
@@ -331,6 +334,41 @@ int apmf_get_sbios_requests(struct amd_pmf_dev *pdev, struct apmf_sbios_req *req
 									 req, sizeof(*req));
 }
 
+/* Store custom BIOS inputs data in ring buffer */
+static void amd_pmf_custom_bios_inputs_rb(struct amd_pmf_dev *pmf_dev)
+{
+	struct pmf_cbi_ring_buffer *rb = &pmf_dev->cbi_buf;
+	struct pmf_bios_input_entry entry = { };
+	int i;
+
+	guard(mutex)(&pmf_dev->cbi_mutex);
+
+	switch (pmf_dev->cpu_id) {
+	case AMD_CPU_ID_PS:
+		for (i = 0; i < ARRAY_SIZE(custom_bios_inputs_v1); i++)
+			entry.val[i] = pmf_dev->req1.custom_policy[i];
+		entry.preq = pmf_dev->req1.pending_req;
+		break;
+	case PCI_DEVICE_ID_AMD_1AH_M20H_ROOT:
+	case PCI_DEVICE_ID_AMD_1AH_M60H_ROOT:
+		for (i = 0; i < ARRAY_SIZE(custom_bios_inputs); i++)
+			entry.val[i] = pmf_dev->req.custom_policy[i];
+		entry.preq = pmf_dev->req.pending_req;
+		break;
+	default:
+		return;
+	}
+
+	if (CIRC_SPACE(rb->head, rb->tail, CUSTOM_BIOS_INPUT_RING_ENTRIES) == 0) {
+		/* Rare case: ensures the newest BIOS input value is kept */
+		dev_warn(pmf_dev->dev, "Overwriting BIOS input value, data may be lost\n");
+		rb->tail = (rb->tail + 1) & (CUSTOM_BIOS_INPUT_RING_ENTRIES - 1);
+	}
+
+	rb->data[rb->head] = entry;
+	rb->head = (rb->head + 1) & (CUSTOM_BIOS_INPUT_RING_ENTRIES - 1);
+}
+
 static void amd_pmf_handle_early_preq(struct amd_pmf_dev *pdev)
 {
 	if (!pdev->cb_flag)
@@ -356,6 +394,8 @@ static void apmf_event_handler_v2(acpi_handle handle, u32 event, void *data)
 	dev_dbg(pmf_dev->dev, "Pending request (preq): 0x%x\n", pmf_dev->req.pending_req);
 
 	amd_pmf_handle_early_preq(pmf_dev);
+
+	amd_pmf_custom_bios_inputs_rb(pmf_dev);
 }
 
 static void apmf_event_handler_v1(acpi_handle handle, u32 event, void *data)
@@ -374,6 +414,8 @@ static void apmf_event_handler_v1(acpi_handle handle, u32 event, void *data)
 	dev_dbg(pmf_dev->dev, "Pending request (preq1): 0x%x\n", pmf_dev->req1.pending_req);
 
 	amd_pmf_handle_early_preq(pmf_dev);
+
+	amd_pmf_custom_bios_inputs_rb(pmf_dev);
 }
 
 static void apmf_event_handler(acpi_handle handle, u32 event, void *data)
diff --git a/drivers/platform/x86/amd/pmf/core.c b/drivers/platform/x86/amd/pmf/core.c
index bc544a4a5266..8d5ac84ae025 100644
--- a/drivers/platform/x86/amd/pmf/core.c
+++ b/drivers/platform/x86/amd/pmf/core.c
@@ -11,6 +11,7 @@
 #include <linux/debugfs.h>
 #include <linux/iopoll.h>
 #include <linux/module.h>
+#include <linux/mutex.h>
 #include <linux/pci.h>
 #include <linux/platform_device.h>
 #include <linux/power_supply.h>
@@ -468,6 +469,7 @@ static int amd_pmf_probe(struct platform_device *pdev)
 	mutex_init(&dev->lock);
 	mutex_init(&dev->update_mutex);
 	mutex_init(&dev->cb_mutex);
+	mutex_init(&dev->cbi_mutex);
 
 	apmf_acpi_init(dev);
 	platform_set_drvdata(pdev, dev);
@@ -494,6 +496,7 @@ static void amd_pmf_remove(struct platform_device *pdev)
 	mutex_destroy(&dev->lock);
 	mutex_destroy(&dev->update_mutex);
 	mutex_destroy(&dev->cb_mutex);
+	mutex_destroy(&dev->cbi_mutex);
 }
 
 static const struct attribute_group *amd_pmf_driver_groups[] = {
diff --git a/drivers/platform/x86/amd/pmf/pmf.h b/drivers/platform/x86/amd/pmf/pmf.h
index 2145df4128cd..5a18b3604b6e 100644
--- a/drivers/platform/x86/amd/pmf/pmf.h
+++ b/drivers/platform/x86/amd/pmf/pmf.h
@@ -12,7 +12,9 @@
 #define PMF_H
 
 #include <linux/acpi.h>
+#include <linux/circ_buf.h>
 #include <linux/input.h>
+#include <linux/mutex_types.h>
 #include <linux/platform_device.h>
 #include <linux/platform_profile.h>
 
@@ -120,6 +122,7 @@ struct cookie_header {
 #define APTS_MAX_STATES		16
 #define CUSTOM_BIOS_INPUT_BITS	GENMASK(16, 7)
 #define BIOS_INPUTS_MAX		10
+#define CUSTOM_BIOS_INPUT_RING_ENTRIES	64	/* Must be power of two for CIRC_* macros */
 
 typedef void (*apmf_event_handler_t)(acpi_handle handle, u32 event, void *data);
 
@@ -359,6 +362,22 @@ struct pmf_bios_inputs_prev {
 	u32 custom_bios_inputs[BIOS_INPUTS_MAX];
 };
 
+/**
+ * struct pmf_bios_input_entry - Snapshot of custom BIOS input event
+ * @val: Array of custom BIOS input values
+ * @preq: Pending request value associated with this event
+ */
+struct pmf_bios_input_entry {
+	u32 val[BIOS_INPUTS_MAX];
+	u32 preq;
+};
+
+struct pmf_cbi_ring_buffer {
+	struct pmf_bios_input_entry data[CUSTOM_BIOS_INPUT_RING_ENTRIES];
+	int head;
+	int tail;
+};
+
 struct amd_pmf_dev {
 	void __iomem *regbase;
 	void __iomem *smu_virt_addr;
@@ -407,6 +426,8 @@ struct amd_pmf_dev {
 	struct apmf_sbios_req_v1 req1;
 	struct pmf_bios_inputs_prev cb_prev; /* To preserve custom BIOS inputs */
 	bool cb_flag;			     /* To handle first custom BIOS input */
+	struct pmf_cbi_ring_buffer cbi_buf;
+	struct mutex cbi_mutex;		     /* Protects ring buffer access */
 };
 
 struct apmf_sps_prop_granular_v2 {
diff --git a/drivers/platform/x86/amd/pmf/spc.c b/drivers/platform/x86/amd/pmf/spc.c
index 85192c7536b8..7c6bbfaa785a 100644
--- a/drivers/platform/x86/amd/pmf/spc.c
+++ b/drivers/platform/x86/amd/pmf/spc.c
@@ -11,6 +11,7 @@
 
 #include <acpi/button.h>
 #include <linux/amd-pmf-io.h>
+#include <linux/cleanup.h>
 #include <linux/power_supply.h>
 #include <linux/units.h>
 #include "pmf.h"
@@ -132,30 +133,41 @@ static void amd_pmf_set_ta_custom_bios_input(struct ta_pmf_enact_table *in, int
 	}
 }
 
-static void amd_pmf_update_bios_inputs(struct amd_pmf_dev *pdev, u32 pending_req,
+static void amd_pmf_update_bios_inputs(struct amd_pmf_dev *pdev, struct pmf_bios_input_entry *data,
 				       const struct amd_pmf_pb_bitmap *inputs,
-				       const u32 *custom_policy, struct ta_pmf_enact_table *in)
+				       struct ta_pmf_enact_table *in)
 {
 	unsigned int i;
 
 	for (i = 0; i < ARRAY_SIZE(custom_bios_inputs); i++) {
-		if (!(pending_req & inputs[i].bit_mask))
+		if (!(data->preq & inputs[i].bit_mask))
 			continue;
-		amd_pmf_set_ta_custom_bios_input(in, i, custom_policy[i]);
-		pdev->cb_prev.custom_bios_inputs[i] = custom_policy[i];
-		dev_dbg(pdev->dev, "Custom BIOS Input[%d]: %u\n", i, custom_policy[i]);
+		amd_pmf_set_ta_custom_bios_input(in, i, data->val[i]);
+		pdev->cb_prev.custom_bios_inputs[i] = data->val[i];
+		dev_dbg(pdev->dev, "Custom BIOS Input[%d]: %u\n", i, data->val[i]);
 	}
 }
 
 static void amd_pmf_get_custom_bios_inputs(struct amd_pmf_dev *pdev,
 					   struct ta_pmf_enact_table *in)
 {
+	struct pmf_cbi_ring_buffer *rb = &pdev->cbi_buf;
+	struct pmf_bios_input_entry entry = { };
 	unsigned int i;
 
+	guard(mutex)(&pdev->cbi_mutex);
+
 	for (i = 0; i < ARRAY_SIZE(custom_bios_inputs); i++)
 		amd_pmf_set_ta_custom_bios_input(in, i, pdev->cb_prev.custom_bios_inputs[i]);
 
-	if (!(pdev->req.pending_req || pdev->req1.pending_req))
+	if (CIRC_CNT(rb->head, rb->tail, CUSTOM_BIOS_INPUT_RING_ENTRIES) == 0)
+		return;	/* return if ring buffer is empty */
+
+	entry = rb->data[rb->tail];
+	rb->tail = (rb->tail + 1) & (CUSTOM_BIOS_INPUT_RING_ENTRIES - 1);
+
+	/* If no active custom BIOS input pending request, do not consume further work */
+	if (!entry.preq)
 		return;
 
 	if (!pdev->smart_pc_enabled)
@@ -165,20 +177,14 @@ static void amd_pmf_get_custom_bios_inputs(struct amd_pmf_dev *pdev,
 	case PMF_IF_V1:
 		if (!is_apmf_bios_input_notifications_supported(pdev))
 			return;
-		amd_pmf_update_bios_inputs(pdev, pdev->req1.pending_req, custom_bios_inputs_v1,
-					   pdev->req1.custom_policy, in);
+		amd_pmf_update_bios_inputs(pdev, &entry, custom_bios_inputs_v1, in);
 		break;
 	case PMF_IF_V2:
-		amd_pmf_update_bios_inputs(pdev, pdev->req.pending_req, custom_bios_inputs,
-					   pdev->req.custom_policy, in);
+		amd_pmf_update_bios_inputs(pdev, &entry, custom_bios_inputs, in);
 		break;
 	default:
 		break;
 	}
-
-	/* Clear pending requests after handling */
-	memset(&pdev->req, 0, sizeof(pdev->req));
-	memset(&pdev->req1, 0, sizeof(pdev->req1));
 }
 
 static void amd_pmf_get_c0_residency(u16 *core_res, size_t size, struct ta_pmf_enact_table *in)
diff --git a/drivers/platform/x86/amd/pmf/tee-if.c b/drivers/platform/x86/amd/pmf/tee-if.c
index 6e8116bef4f6..add742e33e1e 100644
--- a/drivers/platform/x86/amd/pmf/tee-if.c
+++ b/drivers/platform/x86/amd/pmf/tee-if.c
@@ -579,6 +579,8 @@ int amd_pmf_init_smart_pc(struct amd_pmf_dev *dev)
 		status = ret == TA_PMF_TYPE_SUCCESS;
 		if (status) {
 			dev->cb_flag = true;
+			dev->cbi_buf.head = 0;
+			dev->cbi_buf.tail = 0;
 			break;
 		}
 		amd_pmf_tee_deinit(dev);
-- 
2.34.1

Re: [PATCH v3 2/2] platform/x86/amd/pmf: Use ring buffer to store custom BIOS input values

[Ilpo Järvinen]

On Fri, 7 Nov 2025, Shyam Sundar S K wrote:

> Custom BIOS input values can be updated by multiple sources, such as power
> mode changes and sensor events, each triggering a custom BIOS input event.
> When these events occur in rapid succession, new data may overwrite
> previous values before they are processed, resulting in lost updates.
>
> To address this, introduce a fixed-size, power-of-two ring buffer to
> capture every custom BIOS input event, storing both the pending request
> and its associated input values. Access to the ring buffer is synchronized
> using a mutex.
> 
> The previous use of memset() to clear the pending request structure after
> each event is removed, as each BIOS input value is now copied into the
> buffer as a snapshot. Consumers now process entries directly from the ring
> buffer, making explicit clearing of the pending request structure
> unnecessary.
> 
> Reviewed-by: Mario Limonciello (AMD) <superm1@kernel.org>
> Tested-by: Yijun Shen <Yijun.Shen@Dell.com>
> Co-developed-by: Patil Rajesh Reddy <Patil.Reddy@amd.com>
> Signed-off-by: Patil Rajesh Reddy <Patil.Reddy@amd.com>
> Signed-off-by: Shyam Sundar S K <Shyam-sundar.S-k@amd.com>
> ---
> v3:
>  - include headers wherever missing
>  - use dev_warn() instead of dev_WARN_ONCE()
>  - remove generic struct names
>  - enhance ringbuffer mechanism to handle common path
>  - other cosmetic remarks
> 
> v2:
>  - Add dev_WARN_ONCE()
>  - Change variable name rb_mutex to cbi_mutex
>  - Move tail increment logic above pending request check
> 
>  drivers/platform/x86/amd/pmf/acpi.c   | 42 +++++++++++++++++++++++++++
>  drivers/platform/x86/amd/pmf/core.c   |  3 ++
>  drivers/platform/x86/amd/pmf/pmf.h    | 21 ++++++++++++++
>  drivers/platform/x86/amd/pmf/spc.c    | 36 +++++++++++++----------
>  drivers/platform/x86/amd/pmf/tee-if.c |  2 ++
>  5 files changed, 89 insertions(+), 15 deletions(-)
> 
> diff --git a/drivers/platform/x86/amd/pmf/acpi.c b/drivers/platform/x86/amd/pmf/acpi.c
> index 13c4fec2c7ef..4750ae6d70b0 100644
> --- a/drivers/platform/x86/amd/pmf/acpi.c
> +++ b/drivers/platform/x86/amd/pmf/acpi.c
> @@ -9,6 +9,9 @@
>   */
>  
>  #include <linux/acpi.h>
> +#include <linux/array_size.h>
> +#include <linux/cleanup.h>
> +#include <linux/dev_printk.h>
>  #include "pmf.h"
>  
>  #define APMF_CQL_NOTIFICATION  2
> @@ -331,6 +334,41 @@ int apmf_get_sbios_requests(struct amd_pmf_dev *pdev, struct apmf_sbios_req *req
>  									 req, sizeof(*req));
>  }
>  
> +/* Store custom BIOS inputs data in ring buffer */
> +static void amd_pmf_custom_bios_inputs_rb(struct amd_pmf_dev *pmf_dev)
> +{
> +	struct pmf_cbi_ring_buffer *rb = &pmf_dev->cbi_buf;
> +	struct pmf_bios_input_entry entry = { };
> +	int i;
> +
> +	guard(mutex)(&pmf_dev->cbi_mutex);
> +
> +	switch (pmf_dev->cpu_id) {
> +	case AMD_CPU_ID_PS:
> +		for (i = 0; i < ARRAY_SIZE(custom_bios_inputs_v1); i++)
> +			entry.val[i] = pmf_dev->req1.custom_policy[i];
> +		entry.preq = pmf_dev->req1.pending_req;
> +		break;
> +	case PCI_DEVICE_ID_AMD_1AH_M20H_ROOT:
> +	case PCI_DEVICE_ID_AMD_1AH_M60H_ROOT:
> +		for (i = 0; i < ARRAY_SIZE(custom_bios_inputs); i++)
> +			entry.val[i] = pmf_dev->req.custom_policy[i];
> +		entry.preq = pmf_dev->req.pending_req;
> +		break;
> +	default:
> +		return;
> +	}
> +
> +	if (CIRC_SPACE(rb->head, rb->tail, CUSTOM_BIOS_INPUT_RING_ENTRIES) == 0) {
> +		/* Rare case: ensures the newest BIOS input value is kept */
> +		dev_warn(pmf_dev->dev, "Overwriting BIOS input value, data may be lost\n");
> +		rb->tail = (rb->tail + 1) & (CUSTOM_BIOS_INPUT_RING_ENTRIES - 1);
> +	}
> +
> +	rb->data[rb->head] = entry;

I'd prefer the entry is construct in place.

> +	rb->head = (rb->head + 1) & (CUSTOM_BIOS_INPUT_RING_ENTRIES - 1);
> +}
> +
>  static void amd_pmf_handle_early_preq(struct amd_pmf_dev *pdev)
>  {
>  	if (!pdev->cb_flag)
> @@ -356,6 +394,8 @@ static void apmf_event_handler_v2(acpi_handle handle, u32 event, void *data)
>  	dev_dbg(pmf_dev->dev, "Pending request (preq): 0x%x\n", pmf_dev->req.pending_req);
>  
>  	amd_pmf_handle_early_preq(pmf_dev);
> +
> +	amd_pmf_custom_bios_inputs_rb(pmf_dev);
>  }
>  
>  static void apmf_event_handler_v1(acpi_handle handle, u32 event, void *data)
> @@ -374,6 +414,8 @@ static void apmf_event_handler_v1(acpi_handle handle, u32 event, void *data)
>  	dev_dbg(pmf_dev->dev, "Pending request (preq1): 0x%x\n", pmf_dev->req1.pending_req);
>  
>  	amd_pmf_handle_early_preq(pmf_dev);
> +
> +	amd_pmf_custom_bios_inputs_rb(pmf_dev);
>  }
>  
>  static void apmf_event_handler(acpi_handle handle, u32 event, void *data)
> diff --git a/drivers/platform/x86/amd/pmf/core.c b/drivers/platform/x86/amd/pmf/core.c
> index bc544a4a5266..8d5ac84ae025 100644
> --- a/drivers/platform/x86/amd/pmf/core.c
> +++ b/drivers/platform/x86/amd/pmf/core.c
> @@ -11,6 +11,7 @@
>  #include <linux/debugfs.h>
>  #include <linux/iopoll.h>
>  #include <linux/module.h>
> +#include <linux/mutex.h>
>  #include <linux/pci.h>
>  #include <linux/platform_device.h>
>  #include <linux/power_supply.h>
> @@ -468,6 +469,7 @@ static int amd_pmf_probe(struct platform_device *pdev)
>  	mutex_init(&dev->lock);
>  	mutex_init(&dev->update_mutex);
>  	mutex_init(&dev->cb_mutex);
> +	mutex_init(&dev->cbi_mutex);

devm_mutex_init() + add a patch to convert the existing once to use it 
too. And don't forget the error handling as devm_*() can fail.

>  	apmf_acpi_init(dev);
>  	platform_set_drvdata(pdev, dev);
> @@ -494,6 +496,7 @@ static void amd_pmf_remove(struct platform_device *pdev)
>  	mutex_destroy(&dev->lock);
>  	mutex_destroy(&dev->update_mutex);
>  	mutex_destroy(&dev->cb_mutex);
> +	mutex_destroy(&dev->cbi_mutex);
>  }
>  
>  static const struct attribute_group *amd_pmf_driver_groups[] = {
> diff --git a/drivers/platform/x86/amd/pmf/pmf.h b/drivers/platform/x86/amd/pmf/pmf.h
> index 2145df4128cd..5a18b3604b6e 100644
> --- a/drivers/platform/x86/amd/pmf/pmf.h
> +++ b/drivers/platform/x86/amd/pmf/pmf.h
> @@ -12,7 +12,9 @@
>  #define PMF_H
>  
>  #include <linux/acpi.h>
> +#include <linux/circ_buf.h>
>  #include <linux/input.h>
> +#include <linux/mutex_types.h>
>  #include <linux/platform_device.h>
>  #include <linux/platform_profile.h>
>  
> @@ -120,6 +122,7 @@ struct cookie_header {
>  #define APTS_MAX_STATES		16
>  #define CUSTOM_BIOS_INPUT_BITS	GENMASK(16, 7)
>  #define BIOS_INPUTS_MAX		10
> +#define CUSTOM_BIOS_INPUT_RING_ENTRIES	64	/* Must be power of two for CIRC_* macros */
>  
>  typedef void (*apmf_event_handler_t)(acpi_handle handle, u32 event, void *data);
>  
> @@ -359,6 +362,22 @@ struct pmf_bios_inputs_prev {
>  	u32 custom_bios_inputs[BIOS_INPUTS_MAX];
>  };
>  
> +/**
> + * struct pmf_bios_input_entry - Snapshot of custom BIOS input event
> + * @val: Array of custom BIOS input values
> + * @preq: Pending request value associated with this event
> + */
> +struct pmf_bios_input_entry {
> +	u32 val[BIOS_INPUTS_MAX];
> +	u32 preq;
> +};
> +
> +struct pmf_cbi_ring_buffer {
> +	struct pmf_bios_input_entry data[CUSTOM_BIOS_INPUT_RING_ENTRIES];
> +	int head;
> +	int tail;
> +};
> +
>  struct amd_pmf_dev {
>  	void __iomem *regbase;
>  	void __iomem *smu_virt_addr;
> @@ -407,6 +426,8 @@ struct amd_pmf_dev {
>  	struct apmf_sbios_req_v1 req1;
>  	struct pmf_bios_inputs_prev cb_prev; /* To preserve custom BIOS inputs */
>  	bool cb_flag;			     /* To handle first custom BIOS input */
> +	struct pmf_cbi_ring_buffer cbi_buf;
> +	struct mutex cbi_mutex;		     /* Protects ring buffer access */
>  };
>  
>  struct apmf_sps_prop_granular_v2 {
> diff --git a/drivers/platform/x86/amd/pmf/spc.c b/drivers/platform/x86/amd/pmf/spc.c
> index 85192c7536b8..7c6bbfaa785a 100644
> --- a/drivers/platform/x86/amd/pmf/spc.c
> +++ b/drivers/platform/x86/amd/pmf/spc.c
> @@ -11,6 +11,7 @@
>  
>  #include <acpi/button.h>
>  #include <linux/amd-pmf-io.h>
> +#include <linux/cleanup.h>
>  #include <linux/power_supply.h>
>  #include <linux/units.h>
>  #include "pmf.h"
> @@ -132,30 +133,41 @@ static void amd_pmf_set_ta_custom_bios_input(struct ta_pmf_enact_table *in, int
>  	}
>  }
>  
> -static void amd_pmf_update_bios_inputs(struct amd_pmf_dev *pdev, u32 pending_req,
> +static void amd_pmf_update_bios_inputs(struct amd_pmf_dev *pdev, struct pmf_bios_input_entry *data,
>  				       const struct amd_pmf_pb_bitmap *inputs,
> -				       const u32 *custom_policy, struct ta_pmf_enact_table *in)
> +				       struct ta_pmf_enact_table *in)
>  {
>  	unsigned int i;
>  
>  	for (i = 0; i < ARRAY_SIZE(custom_bios_inputs); i++) {
> -		if (!(pending_req & inputs[i].bit_mask))
> +		if (!(data->preq & inputs[i].bit_mask))
>  			continue;
> -		amd_pmf_set_ta_custom_bios_input(in, i, custom_policy[i]);
> -		pdev->cb_prev.custom_bios_inputs[i] = custom_policy[i];
> -		dev_dbg(pdev->dev, "Custom BIOS Input[%d]: %u\n", i, custom_policy[i]);
> +		amd_pmf_set_ta_custom_bios_input(in, i, data->val[i]);
> +		pdev->cb_prev.custom_bios_inputs[i] = data->val[i];
> +		dev_dbg(pdev->dev, "Custom BIOS Input[%d]: %u\n", i, data->val[i]);
>  	}
>  }
>  
>  static void amd_pmf_get_custom_bios_inputs(struct amd_pmf_dev *pdev,
>  					   struct ta_pmf_enact_table *in)
>  {
> +	struct pmf_cbi_ring_buffer *rb = &pdev->cbi_buf;
> +	struct pmf_bios_input_entry entry = { };
>  	unsigned int i;
>  
> +	guard(mutex)(&pdev->cbi_mutex);
> +
>  	for (i = 0; i < ARRAY_SIZE(custom_bios_inputs); i++)
>  		amd_pmf_set_ta_custom_bios_input(in, i, pdev->cb_prev.custom_bios_inputs[i]);
>  
> -	if (!(pdev->req.pending_req || pdev->req1.pending_req))
> +	if (CIRC_CNT(rb->head, rb->tail, CUSTOM_BIOS_INPUT_RING_ENTRIES) == 0)
> +		return;	/* return if ring buffer is empty */
> +
> +	entry = rb->data[rb->tail];
> +	rb->tail = (rb->tail + 1) & (CUSTOM_BIOS_INPUT_RING_ENTRIES - 1);
> +
> +	/* If no active custom BIOS input pending request, do not consume further work */
> +	if (!entry.preq)
>  		return;

Should this function empty the whole ring, not just process one entry?

>  	if (!pdev->smart_pc_enabled)
> @@ -165,20 +177,14 @@ static void amd_pmf_get_custom_bios_inputs(struct amd_pmf_dev *pdev,
>  	case PMF_IF_V1:
>  		if (!is_apmf_bios_input_notifications_supported(pdev))
>  			return;
> -		amd_pmf_update_bios_inputs(pdev, pdev->req1.pending_req, custom_bios_inputs_v1,
> -					   pdev->req1.custom_policy, in);
> +		amd_pmf_update_bios_inputs(pdev, &entry, custom_bios_inputs_v1, in);
>  		break;
>  	case PMF_IF_V2:
> -		amd_pmf_update_bios_inputs(pdev, pdev->req.pending_req, custom_bios_inputs,
> -					   pdev->req.custom_policy, in);
> +		amd_pmf_update_bios_inputs(pdev, &entry, custom_bios_inputs, in);
>  		break;
>  	default:
>  		break;
>  	}
> -
> -	/* Clear pending requests after handling */
> -	memset(&pdev->req, 0, sizeof(pdev->req));
> -	memset(&pdev->req1, 0, sizeof(pdev->req1));
>  }
>  
>  static void amd_pmf_get_c0_residency(u16 *core_res, size_t size, struct ta_pmf_enact_table *in)
> diff --git a/drivers/platform/x86/amd/pmf/tee-if.c b/drivers/platform/x86/amd/pmf/tee-if.c
> index 6e8116bef4f6..add742e33e1e 100644
> --- a/drivers/platform/x86/amd/pmf/tee-if.c
> +++ b/drivers/platform/x86/amd/pmf/tee-if.c
> @@ -579,6 +579,8 @@ int amd_pmf_init_smart_pc(struct amd_pmf_dev *dev)
>  		status = ret == TA_PMF_TYPE_SUCCESS;
>  		if (status) {
>  			dev->cb_flag = true;
> +			dev->cbi_buf.head = 0;
> +			dev->cbi_buf.tail = 0;
>  			break;
>  		}
>  		amd_pmf_tee_deinit(dev);
> 

-- 
 i.

Re: [PATCH v3 1/2] platform/x86/amd/pmf: Add BIOS_INPUTS_MAX macro to replace hardcoded array size

[Ilpo Järvinen]

[-- Attachment #1: Type: text/plain, Size: 2354 bytes --]

On Fri, 7 Nov 2025, Shyam Sundar S K wrote:

> Define a new macro BIOS_INPUTS_MAX, to represent the maximum number of
> BIOS input values. Replace hardcoded array sizes in relevant structures
> with this macro to improve readability and maintainability.
> 
> Reviewed-by: Mario Limonciello (AMD) <superm1@kernel.org>
> Tested-by: Yijun Shen <Yijun.Shen@Dell.com>
> Co-developed-by: Patil Rajesh Reddy <Patil.Reddy@amd.com>
> Signed-off-by: Patil Rajesh Reddy <Patil.Reddy@amd.com>
> Signed-off-by: Shyam Sundar S K <Shyam-sundar.S-k@amd.com>
> ---
> v3:
>  - No change
> 
> v2:
>  - New patch spinned from v1
>  - Add new BIOS_INPUTS_MAX macro and replace hardcoded values
> 
>  drivers/platform/x86/amd/pmf/pmf.h | 9 +++++----
>  1 file changed, 5 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/platform/x86/amd/pmf/pmf.h b/drivers/platform/x86/amd/pmf/pmf.h
> index bd19f2a6bc78..2145df4128cd 100644
> --- a/drivers/platform/x86/amd/pmf/pmf.h
> +++ b/drivers/platform/x86/amd/pmf/pmf.h
> @@ -119,6 +119,7 @@ struct cookie_header {
>  
>  #define APTS_MAX_STATES		16
>  #define CUSTOM_BIOS_INPUT_BITS	GENMASK(16, 7)
> +#define BIOS_INPUTS_MAX		10
>  
>  typedef void (*apmf_event_handler_t)(acpi_handle handle, u32 event, void *data);
>  
> @@ -204,7 +205,7 @@ struct apmf_sbios_req_v1 {
>  	u8 skin_temp_apu;
>  	u8 skin_temp_hs2;
>  	u8 enable_cnqf;
> -	u32 custom_policy[10];
> +	u32 custom_policy[BIOS_INPUTS_MAX];
>  } __packed;
>  
>  struct apmf_sbios_req_v2 {
> @@ -216,7 +217,7 @@ struct apmf_sbios_req_v2 {
>  	u32 stt_min_limit;
>  	u8 skin_temp_apu;
>  	u8 skin_temp_hs2;
> -	u32 custom_policy[10];
> +	u32 custom_policy[BIOS_INPUTS_MAX];
>  } __packed;
>  
>  struct apmf_fan_idx {
> @@ -355,7 +356,7 @@ enum power_modes_v2 {
>  };
>  
>  struct pmf_bios_inputs_prev {
> -	u32 custom_bios_inputs[10];
> +	u32 custom_bios_inputs[BIOS_INPUTS_MAX];
>  };
>  
>  struct amd_pmf_dev {
> @@ -451,7 +452,7 @@ struct os_power_slider {
>  struct amd_pmf_notify_smart_pc_update {
>  	u16 size;
>  	u32 pending_req;
> -	u32 custom_bios[10];
> +	u32 custom_bios[BIOS_INPUTS_MAX];

Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>

Unrelated to the patch, I'm not entirely sure though why the naming 
differs for custom_bios_inputs vs custom_bios.


-- 
 i.

Re: [PATCH v3 2/2] platform/x86/amd/pmf: Use ring buffer to store custom BIOS input values

[Shyam Sundar S K]

On 11/18/2025 15:45, Ilpo Järvinen wrote:
> On Fri, 7 Nov 2025, Shyam Sundar S K wrote:
> 
>> Custom BIOS input values can be updated by multiple sources, such as power
>> mode changes and sensor events, each triggering a custom BIOS input event.
>> When these events occur in rapid succession, new data may overwrite
>> previous values before they are processed, resulting in lost updates.
>>
>> To address this, introduce a fixed-size, power-of-two ring buffer to
>> capture every custom BIOS input event, storing both the pending request
>> and its associated input values. Access to the ring buffer is synchronized
>> using a mutex.
>>
>> The previous use of memset() to clear the pending request structure after
>> each event is removed, as each BIOS input value is now copied into the
>> buffer as a snapshot. Consumers now process entries directly from the ring
>> buffer, making explicit clearing of the pending request structure
>> unnecessary.
>>
>> Reviewed-by: Mario Limonciello (AMD) <superm1@kernel.org>
>> Tested-by: Yijun Shen <Yijun.Shen@Dell.com>
>> Co-developed-by: Patil Rajesh Reddy <Patil.Reddy@amd.com>
>> Signed-off-by: Patil Rajesh Reddy <Patil.Reddy@amd.com>
>> Signed-off-by: Shyam Sundar S K <Shyam-sundar.S-k@amd.com>
>> ---
>> v3:
>>  - include headers wherever missing
>>  - use dev_warn() instead of dev_WARN_ONCE()
>>  - remove generic struct names
>>  - enhance ringbuffer mechanism to handle common path
>>  - other cosmetic remarks
>>
>> v2:
>>  - Add dev_WARN_ONCE()
>>  - Change variable name rb_mutex to cbi_mutex
>>  - Move tail increment logic above pending request check
>>
>>  drivers/platform/x86/amd/pmf/acpi.c   | 42 +++++++++++++++++++++++++++
>>  drivers/platform/x86/amd/pmf/core.c   |  3 ++
>>  drivers/platform/x86/amd/pmf/pmf.h    | 21 ++++++++++++++
>>  drivers/platform/x86/amd/pmf/spc.c    | 36 +++++++++++++----------
>>  drivers/platform/x86/amd/pmf/tee-if.c |  2 ++
>>  5 files changed, 89 insertions(+), 15 deletions(-)
>>
>> diff --git a/drivers/platform/x86/amd/pmf/acpi.c b/drivers/platform/x86/amd/pmf/acpi.c
>> index 13c4fec2c7ef..4750ae6d70b0 100644
>> --- a/drivers/platform/x86/amd/pmf/acpi.c
>> +++ b/drivers/platform/x86/amd/pmf/acpi.c
>> @@ -9,6 +9,9 @@
>>   */
>>  
>>  #include <linux/acpi.h>
>> +#include <linux/array_size.h>
>> +#include <linux/cleanup.h>
>> +#include <linux/dev_printk.h>
>>  #include "pmf.h"
>>  
>>  #define APMF_CQL_NOTIFICATION  2
>> @@ -331,6 +334,41 @@ int apmf_get_sbios_requests(struct amd_pmf_dev *pdev, struct apmf_sbios_req *req
>>  									 req, sizeof(*req));
>>  }
>>  
>> +/* Store custom BIOS inputs data in ring buffer */
>> +static void amd_pmf_custom_bios_inputs_rb(struct amd_pmf_dev *pmf_dev)
>> +{
>> +	struct pmf_cbi_ring_buffer *rb = &pmf_dev->cbi_buf;
>> +	struct pmf_bios_input_entry entry = { };
>> +	int i;
>> +
>> +	guard(mutex)(&pmf_dev->cbi_mutex);
>> +
>> +	switch (pmf_dev->cpu_id) {
>> +	case AMD_CPU_ID_PS:
>> +		for (i = 0; i < ARRAY_SIZE(custom_bios_inputs_v1); i++)
>> +			entry.val[i] = pmf_dev->req1.custom_policy[i];
>> +		entry.preq = pmf_dev->req1.pending_req;
>> +		break;
>> +	case PCI_DEVICE_ID_AMD_1AH_M20H_ROOT:
>> +	case PCI_DEVICE_ID_AMD_1AH_M60H_ROOT:
>> +		for (i = 0; i < ARRAY_SIZE(custom_bios_inputs); i++)
>> +			entry.val[i] = pmf_dev->req.custom_policy[i];
>> +		entry.preq = pmf_dev->req.pending_req;
>> +		break;
>> +	default:
>> +		return;
>> +	}
>> +
>> +	if (CIRC_SPACE(rb->head, rb->tail, CUSTOM_BIOS_INPUT_RING_ENTRIES) == 0) {
>> +		/* Rare case: ensures the newest BIOS input value is kept */
>> +		dev_warn(pmf_dev->dev, "Overwriting BIOS input value, data may be lost\n");
>> +		rb->tail = (rb->tail + 1) & (CUSTOM_BIOS_INPUT_RING_ENTRIES - 1);
>> +	}
>> +
>> +	rb->data[rb->head] = entry;
> 
> I'd prefer the entry is construct in place.
> 
>> +	rb->head = (rb->head + 1) & (CUSTOM_BIOS_INPUT_RING_ENTRIES - 1);
>> +}
>> +
>>  static void amd_pmf_handle_early_preq(struct amd_pmf_dev *pdev)
>>  {
>>  	if (!pdev->cb_flag)
>> @@ -356,6 +394,8 @@ static void apmf_event_handler_v2(acpi_handle handle, u32 event, void *data)
>>  	dev_dbg(pmf_dev->dev, "Pending request (preq): 0x%x\n", pmf_dev->req.pending_req);
>>  
>>  	amd_pmf_handle_early_preq(pmf_dev);
>> +
>> +	amd_pmf_custom_bios_inputs_rb(pmf_dev);
>>  }
>>  
>>  static void apmf_event_handler_v1(acpi_handle handle, u32 event, void *data)
>> @@ -374,6 +414,8 @@ static void apmf_event_handler_v1(acpi_handle handle, u32 event, void *data)
>>  	dev_dbg(pmf_dev->dev, "Pending request (preq1): 0x%x\n", pmf_dev->req1.pending_req);
>>  
>>  	amd_pmf_handle_early_preq(pmf_dev);
>> +
>> +	amd_pmf_custom_bios_inputs_rb(pmf_dev);
>>  }
>>  
>>  static void apmf_event_handler(acpi_handle handle, u32 event, void *data)
>> diff --git a/drivers/platform/x86/amd/pmf/core.c b/drivers/platform/x86/amd/pmf/core.c
>> index bc544a4a5266..8d5ac84ae025 100644
>> --- a/drivers/platform/x86/amd/pmf/core.c
>> +++ b/drivers/platform/x86/amd/pmf/core.c
>> @@ -11,6 +11,7 @@
>>  #include <linux/debugfs.h>
>>  #include <linux/iopoll.h>
>>  #include <linux/module.h>
>> +#include <linux/mutex.h>
>>  #include <linux/pci.h>
>>  #include <linux/platform_device.h>
>>  #include <linux/power_supply.h>
>> @@ -468,6 +469,7 @@ static int amd_pmf_probe(struct platform_device *pdev)
>>  	mutex_init(&dev->lock);
>>  	mutex_init(&dev->update_mutex);
>>  	mutex_init(&dev->cb_mutex);
>> +	mutex_init(&dev->cbi_mutex);
> 
> devm_mutex_init() + add a patch to convert the existing once to use it 
> too. And don't forget the error handling as devm_*() can fail.
> 
>>  	apmf_acpi_init(dev);
>>  	platform_set_drvdata(pdev, dev);
>> @@ -494,6 +496,7 @@ static void amd_pmf_remove(struct platform_device *pdev)
>>  	mutex_destroy(&dev->lock);
>>  	mutex_destroy(&dev->update_mutex);
>>  	mutex_destroy(&dev->cb_mutex);
>> +	mutex_destroy(&dev->cbi_mutex);
>>  }
>>  
>>  static const struct attribute_group *amd_pmf_driver_groups[] = {
>> diff --git a/drivers/platform/x86/amd/pmf/pmf.h b/drivers/platform/x86/amd/pmf/pmf.h
>> index 2145df4128cd..5a18b3604b6e 100644
>> --- a/drivers/platform/x86/amd/pmf/pmf.h
>> +++ b/drivers/platform/x86/amd/pmf/pmf.h
>> @@ -12,7 +12,9 @@
>>  #define PMF_H
>>  
>>  #include <linux/acpi.h>
>> +#include <linux/circ_buf.h>
>>  #include <linux/input.h>
>> +#include <linux/mutex_types.h>
>>  #include <linux/platform_device.h>
>>  #include <linux/platform_profile.h>
>>  
>> @@ -120,6 +122,7 @@ struct cookie_header {
>>  #define APTS_MAX_STATES		16
>>  #define CUSTOM_BIOS_INPUT_BITS	GENMASK(16, 7)
>>  #define BIOS_INPUTS_MAX		10
>> +#define CUSTOM_BIOS_INPUT_RING_ENTRIES	64	/* Must be power of two for CIRC_* macros */
>>  
>>  typedef void (*apmf_event_handler_t)(acpi_handle handle, u32 event, void *data);
>>  
>> @@ -359,6 +362,22 @@ struct pmf_bios_inputs_prev {
>>  	u32 custom_bios_inputs[BIOS_INPUTS_MAX];
>>  };
>>  
>> +/**
>> + * struct pmf_bios_input_entry - Snapshot of custom BIOS input event
>> + * @val: Array of custom BIOS input values
>> + * @preq: Pending request value associated with this event
>> + */
>> +struct pmf_bios_input_entry {
>> +	u32 val[BIOS_INPUTS_MAX];
>> +	u32 preq;
>> +};
>> +
>> +struct pmf_cbi_ring_buffer {
>> +	struct pmf_bios_input_entry data[CUSTOM_BIOS_INPUT_RING_ENTRIES];
>> +	int head;
>> +	int tail;
>> +};
>> +
>>  struct amd_pmf_dev {
>>  	void __iomem *regbase;
>>  	void __iomem *smu_virt_addr;
>> @@ -407,6 +426,8 @@ struct amd_pmf_dev {
>>  	struct apmf_sbios_req_v1 req1;
>>  	struct pmf_bios_inputs_prev cb_prev; /* To preserve custom BIOS inputs */
>>  	bool cb_flag;			     /* To handle first custom BIOS input */
>> +	struct pmf_cbi_ring_buffer cbi_buf;
>> +	struct mutex cbi_mutex;		     /* Protects ring buffer access */
>>  };
>>  
>>  struct apmf_sps_prop_granular_v2 {
>> diff --git a/drivers/platform/x86/amd/pmf/spc.c b/drivers/platform/x86/amd/pmf/spc.c
>> index 85192c7536b8..7c6bbfaa785a 100644
>> --- a/drivers/platform/x86/amd/pmf/spc.c
>> +++ b/drivers/platform/x86/amd/pmf/spc.c
>> @@ -11,6 +11,7 @@
>>  
>>  #include <acpi/button.h>
>>  #include <linux/amd-pmf-io.h>
>> +#include <linux/cleanup.h>
>>  #include <linux/power_supply.h>
>>  #include <linux/units.h>
>>  #include "pmf.h"
>> @@ -132,30 +133,41 @@ static void amd_pmf_set_ta_custom_bios_input(struct ta_pmf_enact_table *in, int
>>  	}
>>  }
>>  
>> -static void amd_pmf_update_bios_inputs(struct amd_pmf_dev *pdev, u32 pending_req,
>> +static void amd_pmf_update_bios_inputs(struct amd_pmf_dev *pdev, struct pmf_bios_input_entry *data,
>>  				       const struct amd_pmf_pb_bitmap *inputs,
>> -				       const u32 *custom_policy, struct ta_pmf_enact_table *in)
>> +				       struct ta_pmf_enact_table *in)
>>  {
>>  	unsigned int i;
>>  
>>  	for (i = 0; i < ARRAY_SIZE(custom_bios_inputs); i++) {
>> -		if (!(pending_req & inputs[i].bit_mask))
>> +		if (!(data->preq & inputs[i].bit_mask))
>>  			continue;
>> -		amd_pmf_set_ta_custom_bios_input(in, i, custom_policy[i]);
>> -		pdev->cb_prev.custom_bios_inputs[i] = custom_policy[i];
>> -		dev_dbg(pdev->dev, "Custom BIOS Input[%d]: %u\n", i, custom_policy[i]);
>> +		amd_pmf_set_ta_custom_bios_input(in, i, data->val[i]);
>> +		pdev->cb_prev.custom_bios_inputs[i] = data->val[i];
>> +		dev_dbg(pdev->dev, "Custom BIOS Input[%d]: %u\n", i, data->val[i]);
>>  	}
>>  }
>>  
>>  static void amd_pmf_get_custom_bios_inputs(struct amd_pmf_dev *pdev,
>>  					   struct ta_pmf_enact_table *in)
>>  {
>> +	struct pmf_cbi_ring_buffer *rb = &pdev->cbi_buf;
>> +	struct pmf_bios_input_entry entry = { };
>>  	unsigned int i;
>>  
>> +	guard(mutex)(&pdev->cbi_mutex);
>> +
>>  	for (i = 0; i < ARRAY_SIZE(custom_bios_inputs); i++)
>>  		amd_pmf_set_ta_custom_bios_input(in, i, pdev->cb_prev.custom_bios_inputs[i]);
>>  
>> -	if (!(pdev->req.pending_req || pdev->req1.pending_req))
>> +	if (CIRC_CNT(rb->head, rb->tail, CUSTOM_BIOS_INPUT_RING_ENTRIES) == 0)
>> +		return;	/* return if ring buffer is empty */
>> +
>> +	entry = rb->data[rb->tail];
>> +	rb->tail = (rb->tail + 1) & (CUSTOM_BIOS_INPUT_RING_ENTRIES - 1);
>> +
>> +	/* If no active custom BIOS input pending request, do not consume further work */
>> +	if (!entry.preq)
>>  		return;
> 
> Should this function empty the whole ring, not just process one entry?

Yes. This function should drain the entire ring buffer - but not all
at once (i.e. process one entry for each invocation)

Ack for other comments.

Thanks,
Shyam

> 
>>  	if (!pdev->smart_pc_enabled)
>> @@ -165,20 +177,14 @@ static void amd_pmf_get_custom_bios_inputs(struct amd_pmf_dev *pdev,
>>  	case PMF_IF_V1:
>>  		if (!is_apmf_bios_input_notifications_supported(pdev))
>>  			return;
>> -		amd_pmf_update_bios_inputs(pdev, pdev->req1.pending_req, custom_bios_inputs_v1,
>> -					   pdev->req1.custom_policy, in);
>> +		amd_pmf_update_bios_inputs(pdev, &entry, custom_bios_inputs_v1, in);
>>  		break;
>>  	case PMF_IF_V2:
>> -		amd_pmf_update_bios_inputs(pdev, pdev->req.pending_req, custom_bios_inputs,
>> -					   pdev->req.custom_policy, in);
>> +		amd_pmf_update_bios_inputs(pdev, &entry, custom_bios_inputs, in);
>>  		break;
>>  	default:
>>  		break;
>>  	}
>> -
>> -	/* Clear pending requests after handling */
>> -	memset(&pdev->req, 0, sizeof(pdev->req));
>> -	memset(&pdev->req1, 0, sizeof(pdev->req1));
>>  }
>>  
>>  static void amd_pmf_get_c0_residency(u16 *core_res, size_t size, struct ta_pmf_enact_table *in)
>> diff --git a/drivers/platform/x86/amd/pmf/tee-if.c b/drivers/platform/x86/amd/pmf/tee-if.c
>> index 6e8116bef4f6..add742e33e1e 100644
>> --- a/drivers/platform/x86/amd/pmf/tee-if.c
>> +++ b/drivers/platform/x86/amd/pmf/tee-if.c
>> @@ -579,6 +579,8 @@ int amd_pmf_init_smart_pc(struct amd_pmf_dev *dev)
>>  		status = ret == TA_PMF_TYPE_SUCCESS;
>>  		if (status) {
>>  			dev->cb_flag = true;
>> +			dev->cbi_buf.head = 0;
>> +			dev->cbi_buf.tail = 0;
>>  			break;
>>  		}
>>  		amd_pmf_tee_deinit(dev);
>>
>