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drm/imagination: Add gpuid module parameter

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The "gpuid" module parameter is used to override the gpuid read from a
hardware register and is useful for testing the loading of different
firmware (including processing of the firmware header) without having
the hardware to hand.

Signed-off-by: Alexandru Dadu <alexandru.dadu@imgtec.com>
Reviewed-by: Alessio Belle <alessio.belle@imgtec.com>
Link: https://patch.msgid.link/20260113-device-support-info-v1-4-91e5db7f7294@imgtec.com
Signed-off-by: Matt Coster <matt.coster@imgtec.com>
This commit is contained in:
Alexandru Dadu
2026-01-13 10:16:42 +00:00
committed by Matt Coster
parent ee184ab0ff
commit 3bf7413734
2 changed files with 114 additions and 10 deletions
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117
drivers/gpu/drm/imagination/pvr_device.c
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@@ -421,23 +421,21 @@ err_free_filename:
}
/**
* pvr_load_gpu_id() - Load a PowerVR device's GPU ID (BVNC) from control registers.
* pvr_gpuid_decode_reg() - Decode the GPU ID from GPU register
*
* Sets struct pvr_dev.gpu_id.
* Sets the b, v, n, c fields of struct pvr_dev.gpu_id.
*
* @pvr_dev: Target PowerVR device.
* @gpu_id: Output to be updated with the GPU ID.
*/
static void
pvr_load_gpu_id(struct pvr_device *pvr_dev)
pvr_gpuid_decode_reg(const struct pvr_device *pvr_dev, struct pvr_gpu_id *gpu_id)
{
struct pvr_gpu_id *gpu_id = &pvr_dev->gpu_id;
u64 bvnc;
/*
* Try reading the BVNC using the newer (cleaner) method first. If the
* B value is zero, fall back to the older method.
*/
bvnc = pvr_cr_read64(pvr_dev, ROGUE_CR_CORE_ID__PBVNC);
u64 bvnc = pvr_cr_read64(pvr_dev, ROGUE_CR_CORE_ID__PBVNC);
gpu_id->b = PVR_CR_FIELD_GET(bvnc, CORE_ID__PBVNC__BRANCH_ID);
if (gpu_id->b != 0) {
@@ -456,6 +454,107 @@ pvr_load_gpu_id(struct pvr_device *pvr_dev)
}
}
/**
* pvr_gpuid_decode_string() - Decode the GPU ID from a module input string
*
* Sets the b, v, n, c fields of struct pvr_dev.gpu_id.
*
* @pvr_dev: Target PowerVR device.
* @param_bvnc: GPU ID (BVNC) module parameter.
* @gpu_id: Output to be updated with the GPU ID.
*/
static int
pvr_gpuid_decode_string(const struct pvr_device *pvr_dev,
const char *param_bvnc, struct pvr_gpu_id *gpu_id)
{
const struct drm_device *drm_dev = &pvr_dev->base;
char str_cpy[PVR_GPUID_STRING_MAX_LENGTH];
char *pos, *tkn;
int ret, idx = 0;
u16 user_bvnc_u16[4];
u8 dot_cnt = 0;
ret = strscpy(str_cpy, param_bvnc);
/*
* strscpy() should return at least a size 7 for the input to be valid.
* Returns -E2BIG for the case when the string is empty or too long.
*/
if (ret < PVR_GPUID_STRING_MIN_LENGTH) {
drm_info(drm_dev,
"Invalid size of the input GPU ID (BVNC): %s",
str_cpy);
return -EINVAL;
}
while (*param_bvnc) {
if (*param_bvnc == '.')
dot_cnt++;
param_bvnc++;
}
if (dot_cnt != 3) {
drm_info(drm_dev,
"Invalid format of the input GPU ID (BVNC): %s",
str_cpy);
return -EINVAL;
}
pos = str_cpy;
while ((tkn = strsep(&pos, ".")) != NULL && idx < 4) {
/* kstrtou16() will also handle the case of consecutive dots */
ret = kstrtou16(tkn, 10, &user_bvnc_u16[idx]);
if (ret) {
drm_info(drm_dev,
"Invalid format of the input GPU ID (BVNC): %s",
str_cpy);
return -EINVAL;
}
idx++;
}
gpu_id->b = user_bvnc_u16[0];
gpu_id->v = user_bvnc_u16[1];
gpu_id->n = user_bvnc_u16[2];
gpu_id->c = user_bvnc_u16[3];
return 0;
}
static char *pvr_gpuid_override;
module_param_named(gpuid, pvr_gpuid_override, charp, 0400);
MODULE_PARM_DESC(gpuid, "GPU ID (BVNC) to be used instead of the value read from hardware.");
/**
* pvr_load_gpu_id() - Load a PowerVR device's GPU ID (BVNC) from control
* registers or input parameter. The input parameter is processed instead
* of the GPU register if provided.
*
* Sets the arch field of struct pvr_dev.gpu_id.
*
* @pvr_dev: Target PowerVR device.
*/
static int
pvr_load_gpu_id(struct pvr_device *pvr_dev)
{
struct pvr_gpu_id *gpu_id = &pvr_dev->gpu_id;
if (!pvr_gpuid_override || !pvr_gpuid_override[0]) {
pvr_gpuid_decode_reg(pvr_dev, gpu_id);
} else {
drm_warn(from_pvr_device(pvr_dev),
"Using custom GPU ID (BVNC) provided by the user!");
int err = pvr_gpuid_decode_string(pvr_dev, pvr_gpuid_override,
gpu_id);
if (err)
return err;
}
return 0;
}
/**
* pvr_set_dma_info() - Set PowerVR device DMA information
* @pvr_dev: Target PowerVR device.
@@ -516,7 +615,9 @@ pvr_device_gpu_init(struct pvr_device *pvr_dev)
{
int err;
pvr_load_gpu_id(pvr_dev);
err = pvr_load_gpu_id(pvr_dev);
if (err)
return err;
err = pvr_request_firmware(pvr_dev);
if (err)