Re: [PATCH v2 4/4] drm/xe/remapper: Reprogram remapper index on PM resume events

["Nilawar, Badal" <badal.nilawar@intel.com>]

On 18-11-2025 02:23, Umesh Nerlige Ramappa wrote:
> Device enters the D3 cold state during both runtime and system suspend,
> which requires reprogramming the SoC re-mapper index
>
> Signed-off-by: Umesh Nerlige Ramappa <umesh.nerlige.ramappa@intel.com>
> ---
>   drivers/gpu/drm/xe/xe_device_types.h |  6 ++++++
>   drivers/gpu/drm/xe/xe_pm.c           |  5 +++++
>   drivers/gpu/drm/xe/xe_soc_remapper.c | 17 ++++++++++++++++-
>   drivers/gpu/drm/xe/xe_soc_remapper.h |  1 +
>   4 files changed, 28 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/xe/xe_device_types.h b/drivers/gpu/drm/xe/xe_device_types.h
> index de23fff3262c..9875e3db4a1f 100644
> --- a/drivers/gpu/drm/xe/xe_device_types.h
> +++ b/drivers/gpu/drm/xe/xe_device_types.h
> @@ -551,6 +551,12 @@ struct xe_device {
>   	struct {
>   		/* Serialize access to SoC Remapper's index registers */
>   		spinlock_t lock;
> +
> +		/* Last value of INDEX1 register */

Use prescribed kernel doc format, here and other places in the file.
/** @soc_remapper.state: Last value of INDEX1 register */

> +		u32 state;
> +
> +		/* A flag indicating state is initialized */
> +		bool state_initialized;

We can eliminate this flag by initializing state to an invalid value 
such as UINT_MAX, and then check this value before restoring the SoC 
remapper register in the resume function.

Thanks,
Badal

>   	} soc_remapper;
>   
>   	/**
> diff --git a/drivers/gpu/drm/xe/xe_pm.c b/drivers/gpu/drm/xe/xe_pm.c
> index 44924512830f..8a1b440df4ce 100644
> --- a/drivers/gpu/drm/xe/xe_pm.c
> +++ b/drivers/gpu/drm/xe/xe_pm.c
> @@ -24,6 +24,7 @@
>   #include "xe_late_bind_fw.h"
>   #include "xe_pcode.h"
>   #include "xe_pxp.h"
> +#include "xe_soc_remapper.h"
>   #include "xe_sriov_vf_ccs.h"
>   #include "xe_trace.h"
>   #include "xe_vm.h"
> @@ -236,6 +237,8 @@ int xe_pm_resume(struct xe_device *xe)
>   	drm_dbg(&xe->drm, "Resuming device\n");
>   	trace_xe_pm_resume(xe, __builtin_return_address(0));
>   
> +	xe_soc_remapper_resume(xe);
> +
>   	for_each_gt(gt, xe, id)
>   		xe_gt_idle_disable_c6(gt);
>   
> @@ -633,6 +636,8 @@ int xe_pm_runtime_resume(struct xe_device *xe)
>   
>   	xe_rpm_lockmap_acquire(xe);
>   
> +	xe_soc_remapper_resume(xe);
> +
>   	for_each_gt(gt, xe, id)
>   		xe_gt_idle_disable_c6(gt);
>   
> diff --git a/drivers/gpu/drm/xe/xe_soc_remapper.c b/drivers/gpu/drm/xe/xe_soc_remapper.c
> index ed6b6c594e51..c425195f7152 100644
> --- a/drivers/gpu/drm/xe/xe_soc_remapper.c
> +++ b/drivers/gpu/drm/xe/xe_soc_remapper.c
> @@ -13,9 +13,12 @@ static void xe_soc_remapper_set_region(struct xe_device *xe, struct xe_reg reg,
>   				       u32 mask, u32 val)
>   {
>   	unsigned long flags;
> +	u32 old;
>   
>   	spin_lock_irqsave(&xe->soc_remapper.lock, flags);
> -	xe_mmio_rmw32(xe_root_tile_mmio(xe), reg, mask, val);
> +	old = xe_mmio_rmw32(xe_root_tile_mmio(xe), reg, mask, val);
> +	xe->soc_remapper.state = (old & ~mask) | val;
> +	xe->soc_remapper.state_initialized = true;
>   	spin_unlock_irqrestore(&xe->soc_remapper.lock, flags);
>   }
>   
> @@ -31,6 +34,18 @@ void xe_soc_remapper_set_sysctrl_region(struct xe_device *xe, u32 index)
>   				   REG_FIELD_PREP(SG_REMAP_SYSCTRL_MASK, index));
>   }
>   
> +void xe_soc_remapper_resume(struct xe_device *xe)
> +{
> +	unsigned long flags;
> +
> +	if (!xe->soc_remapper.state_initialized)
> +		return;
> +
> +	spin_lock_irqsave(&xe->soc_remapper.lock, flags);
> +	xe_mmio_write32(xe_root_tile_mmio(xe), SG_REMAP_INDEX1, xe->soc_remapper.state);
> +	spin_unlock_irqrestore(&xe->soc_remapper.lock, flags);
> +}
> +
>   int xe_soc_remapper_init(struct xe_device *xe)
>   {
>   	spin_lock_init(&xe->soc_remapper.lock);
> diff --git a/drivers/gpu/drm/xe/xe_soc_remapper.h b/drivers/gpu/drm/xe/xe_soc_remapper.h
> index 289aa41c3408..507701c74f6f 100644
> --- a/drivers/gpu/drm/xe/xe_soc_remapper.h
> +++ b/drivers/gpu/drm/xe/xe_soc_remapper.h
> @@ -13,5 +13,6 @@
>   int xe_soc_remapper_init(struct xe_device *xe);
>   void xe_soc_remapper_set_telem_region(struct xe_device *xe, u32 index);
>   void xe_soc_remapper_set_sysctrl_region(struct xe_device *xe, u32 index);
> +void xe_soc_remapper_resume(struct xe_device *xe);
>   
>   #endif