[PATCH 1/2] drm/xe/guc: Add helpers for GuC KLVs

Michal Wajdeczko michal.wajdeczko at intel.com
Tue Apr 9 09:42:52 UTC 2024



On 09.04.2024 00:00, John Harrison wrote:
> On 4/8/2024 11:14, Michal Wajdeczko wrote:
>> Many of the GuC actions use KLVs to pass additional parameters or
>> configuration data. Add few helper functions for better reporting
>> any information related to KLVs.
>>
>> Signed-off-by: Michal Wajdeczko <michal.wajdeczko at intel.com>
>> ---
>>   drivers/gpu/drm/xe/Makefile             |   1 +
>>   drivers/gpu/drm/xe/xe_guc_klv_helpers.c | 133 ++++++++++++++++++++++++
>>   drivers/gpu/drm/xe/xe_guc_klv_helpers.h |  51 +++++++++
>>   3 files changed, 185 insertions(+)
>>   create mode 100644 drivers/gpu/drm/xe/xe_guc_klv_helpers.c
>>   create mode 100644 drivers/gpu/drm/xe/xe_guc_klv_helpers.h
>>
>> diff --git a/drivers/gpu/drm/xe/Makefile b/drivers/gpu/drm/xe/Makefile
>> index e5b1715f721e..ec0d1fb49b1e 100644
>> --- a/drivers/gpu/drm/xe/Makefile
>> +++ b/drivers/gpu/drm/xe/Makefile
>> @@ -98,6 +98,7 @@ xe-y += xe_bb.o \
>>       xe_guc_debugfs.o \
>>       xe_guc_hwconfig.o \
>>       xe_guc_id_mgr.o \
>> +    xe_guc_klv_helpers.o \
>>       xe_guc_log.o \
>>       xe_guc_pc.o \
>>       xe_guc_submit.o \
>> diff --git a/drivers/gpu/drm/xe/xe_guc_klv_helpers.c
>> b/drivers/gpu/drm/xe/xe_guc_klv_helpers.c
>> new file mode 100644
>> index 000000000000..c39fda08afcb
>> --- /dev/null
>> +++ b/drivers/gpu/drm/xe/xe_guc_klv_helpers.c
>> @@ -0,0 +1,133 @@
>> +// SPDX-License-Identifier: MIT
>> +/*
>> + * Copyright © 2024 Intel Corporation
>> + */
>> +
>> +#include <linux/bitfield.h>
>> +#include <drm/drm_print.h>
>> +
>> +#include "abi/guc_klvs_abi.h"
>> +#include "xe_guc_klv_helpers.h"
>> +
>> +#define make_u64(hi, lo) ((u64)((u64)(u32)(hi) << 32 | (u32)(lo)))
>> +
>> +/**
>> + * xe_guc_klv_key_to_string - Convert KLV key into friendly name.
>> + * @key: the `GuC KLV`_ key
>> + *
>> + * Return: name of the KLV key.
>> + */
>> +const char *xe_guc_klv_key_to_string(u16 key)
>> +{
>> +    switch (key) {
>> +    /* VGT POLICY keys */
>> +    case GUC_KLV_VGT_POLICY_SCHED_IF_IDLE_KEY:
>> +        return "sched_if_idle";
>> +    case GUC_KLV_VGT_POLICY_ADVERSE_SAMPLE_PERIOD_KEY:
>> +        return "sample_period";
>> +    case GUC_KLV_VGT_POLICY_RESET_AFTER_VF_SWITCH_KEY:
>> +        return "reset_engine";
>> +    /* VF CFG keys */
>> +    case GUC_KLV_VF_CFG_GGTT_START_KEY:
>> +        return "ggtt_start";
>> +    case GUC_KLV_VF_CFG_GGTT_SIZE_KEY:
>> +        return "ggtt_size";
>> +    case GUC_KLV_VF_CFG_LMEM_SIZE_KEY:
>> +        return "lmem_size";
>> +    case GUC_KLV_VF_CFG_NUM_CONTEXTS_KEY:
>> +        return "num_contexts";
>> +    case GUC_KLV_VF_CFG_TILE_MASK_KEY:
>> +        return "tile_mask";
>> +    case GUC_KLV_VF_CFG_NUM_DOORBELLS_KEY:
>> +        return "num_doorbells";
>> +    case GUC_KLV_VF_CFG_EXEC_QUANTUM_KEY:
>> +        return "exec_quantum";
>> +    case GUC_KLV_VF_CFG_PREEMPT_TIMEOUT_KEY:
>> +        return "preempt_timeout";
>> +    case GUC_KLV_VF_CFG_BEGIN_DOORBELL_ID_KEY:
>> +        return "begin_db_id";
>> +    case GUC_KLV_VF_CFG_BEGIN_CONTEXT_ID_KEY:
>> +        return "begin_ctx_id";
>> +    }
>> +    return "(unknown)";
>> +}
>> +
>> +/**
>> + * xe_guc_klv_print - Print content of the buffer with `GuC KLV`_.
>> + * @klvs: the buffer with KLVs
>> + * @num_dwords: number of dwords (u32) available in the buffer
>> + * @p: the &drm_printer
>> + *
>> + * The buffer may contain more than one KLV.
>> + */
>> +void xe_guc_klv_print(const u32 *klvs, u32 num_dwords, struct
>> drm_printer *p)
>> +{
>> +    while (num_dwords >= GUC_KLV_LEN_MIN) {
>> +        u32 key = FIELD_GET(GUC_KLV_0_KEY, klvs[0]);
>> +        u32 len = FIELD_GET(GUC_KLV_0_LEN, klvs[0]);
>> +
>> +        klvs += GUC_KLV_LEN_MIN;
>> +        num_dwords -= GUC_KLV_LEN_MIN;
>> +
>> +        if (num_dwords < len) {
>> +            drm_printf(p, "{ key %#06x : truncated %zu of %zu bytes
>> %*ph } # %s\n",
>> +                   key, num_dwords * sizeof(u32), len * sizeof(u32),
>> +                   (int)(num_dwords * sizeof(u32)), klvs,
>> +                   xe_guc_klv_key_to_string(key));
>> +            return;
>> +        }
>> +
>> +        switch (len) {
>> +        case 0:
>> +            drm_printf(p, "{ key %#06x : no value } # %s\n",
>> +                   key, xe_guc_klv_key_to_string(key));
>> +            break;
>> +        case 1:
>> +            drm_printf(p, "{ key %#06x : 32b value %u } # %s\n",
>> +                   key, klvs[0], xe_guc_klv_key_to_string(key));
>> +            break;
>> +        case 2:
>> +            drm_printf(p, "{ key %#06x : 64b value %#llx } # %s\n",
>> +                   key, make_u64(klvs[1], klvs[0]),
> Or maybe it is actually two separate 32bit words? Why bother forcing it
> to a u64 with a brand new custom helper? Seems simpler to just print it
> as a pair of 32s, the reader can trivially combine it to a single 64 in
> their head if printing as hex anyway.

but majority (if not all) of KLVs with len=2 hold the 64b value and for
remaining KLVs the reader can trivially split 64b hex value into two 32b

> 
> Also, there is no code to actually use any of these helpers yet? I
> thought adding unused code was not allowed. You have to have a purpose,
> at least in the same series if not the same patch.

actual use is coming as part of the larger series with SR-IOV PF
support, but sent helper separately to minimize this upcoming series and
not distract reviewers with secondary helpers outside of SR-IOV scope

> 
> John.
> 
>> +                   xe_guc_klv_key_to_string(key));
>> +            break;
>> +        default:
>> +            drm_printf(p, "{ key %#06x : %zu bytes %*ph } # %s\n",
>> +                   key, len * sizeof(u32), (int)(len * sizeof(u32)),
>> +                   klvs, xe_guc_klv_key_to_string(key));
>> +            break;
>> +        }
>> +
>> +        klvs += len;
>> +        num_dwords -= len;
>> +    }
>> +
>> +    /* we don't expect any leftovers, fix if KLV header is ever
>> changed */
>> +    BUILD_BUG_ON(GUC_KLV_LEN_MIN > 1);
>> +}
>> +
>> +/**
>> + * xe_guc_klv_count - Count KLVs present in the buffer.
>> + * @klvs: the buffer with KLVs
>> + * @num_dwords: number of dwords (u32) in the buffer
>> + *
>> + * Return: number of recognized KLVs or
>> + *          a negative error code if KLV buffer is truncated.
>> + */
>> +int xe_guc_klv_count(const u32 *klvs, u32 num_dwords)
>> +{
>> +    int num_klvs = 0;
>> +
>> +    while (num_dwords >= GUC_KLV_LEN_MIN) {
>> +        u32 len = FIELD_GET(GUC_KLV_0_LEN, klvs[0]);
>> +
>> +        if (num_dwords < len + GUC_KLV_LEN_MIN)
>> +            return -ENODATA;
>> +
>> +        klvs += GUC_KLV_LEN_MIN + len;
>> +        num_dwords -= GUC_KLV_LEN_MIN + len;
>> +        num_klvs++;
>> +    }
>> +
>> +    return num_dwords ? -ENODATA : num_klvs;
>> +}
>> diff --git a/drivers/gpu/drm/xe/xe_guc_klv_helpers.h
>> b/drivers/gpu/drm/xe/xe_guc_klv_helpers.h
>> new file mode 100644
>> index 000000000000..b835e0ebe6db
>> --- /dev/null
>> +++ b/drivers/gpu/drm/xe/xe_guc_klv_helpers.h
>> @@ -0,0 +1,51 @@
>> +/* SPDX-License-Identifier: MIT */
>> +/*
>> + * Copyright © 2024 Intel Corporation
>> + */
>> +
>> +#ifndef _XE_GUC_KLV_HELPERS_H_
>> +#define _XE_GUC_KLV_HELPERS_H_
>> +
>> +#include <linux/types.h>
>> +
>> +struct drm_printer;
>> +
>> +const char *xe_guc_klv_key_to_string(u16 key);
>> +
>> +void xe_guc_klv_print(const u32 *klvs, u32 num_dwords, struct
>> drm_printer *p);
>> +int xe_guc_klv_count(const u32 *klvs, u32 num_dwords);
>> +
>> +/**
>> + * PREP_GUC_KLV - Prepare KLV header value based on provided key and
>> len.
>> + * @key: KLV key
>> + * @len: KLV length
>> + *
>> + * Return: value of the KLV header (u32).
>> + */
>> +#define PREP_GUC_KLV(key, len) \
>> +    (FIELD_PREP(GUC_KLV_0_KEY, (key)) | \
>> +     FIELD_PREP(GUC_KLV_0_LEN, (len)))
>> +
>> +/**
>> + * PREP_GUC_KLV_CONST - Prepare KLV header value based on const key
>> and len.
>> + * @key: const KLV key
>> + * @len: const KLV length
>> + *
>> + * Return: value of the KLV header (u32).
>> + */
>> +#define PREP_GUC_KLV_CONST(key, len) \
>> +    (FIELD_PREP_CONST(GUC_KLV_0_KEY, (key)) | \
>> +     FIELD_PREP_CONST(GUC_KLV_0_LEN, (len)))
>> +
>> +/**
>> + * PREP_GUC_KLV_TAG - Prepare KLV header value based on unique KLV
>> definition tag.
>> + * @TAG: unique tag of the KLV definition
>> + *
>> + * Combine separate KEY and LEN definitions of the KLV identified by
>> the TAG.
>> + *
>> + * Return: value of the KLV header (u32).
>> + */
>> +#define PREP_GUC_KLV_TAG(TAG) \
>> +    PREP_GUC_KLV_CONST(GUC_KLV_##TAG##_KEY, GUC_KLV_##TAG##_LEN)
>> +
>> +#endif
> 


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