Re: [RFC 14/16] drm/nouveau/fb: add GK20A support

From: Ilia Mirkin
Date: Sat Feb 01 2014 - 18:29:18 EST

On Sat, Feb 1, 2014 at 8:40 AM, Lucas Stach <dev@xxxxxxxxxx> wrote:
> Am Samstag, den 01.02.2014, 12:16 +0900 schrieb Alexandre Courbot:
>> Add a clumsy-but-working FB support for GK20A. This chip only uses system
>> memory, so we allocate a big chunk using CMA and let the existing memory
>> managers work on it.
>>
>> A better future design would be to allocate objects directly from system
>> memory without having to suffer from the limitations of a large,
>> contiguous pool.
>>
> I don't know if Tegra124 is similar to 114 in this regard [hint: get the
> TRM out :)], but if you go for a dedicated VRAM allocator, wouldn't it
> make sense to take a chunk of the MMIO overlaid memory for this when
> possible, rather than carving this out of CPU accessible mem?

This is probably a stupid question... what do you need VRAM for
anyways? In _theory_ it's an abstraction to talk about memory that's
not accessible by the CPU. This is obviously not the case here, and
presumably the GPU can access all the memory in the system, so it can
be all treated as "GART" memory... AFAIK all accesses are behind the
in-GPU MMU, so contiguous physical memory isn't an issue either. In
practice, I suspect nouveau automatically sticks certain things into
vram (gpuobj's), but it should be feasible to make them optionally use
GART memory when VRAM is not available. I haven't really looked at the
details though, perhaps that's a major undertaking.

-ilia

>
>> Signed-off-by: Alexandre Courbot <acourbot@xxxxxxxxxx>
>> ---
>> drivers/gpu/drm/nouveau/Makefile | 2 +
>> drivers/gpu/drm/nouveau/core/include/subdev/fb.h | 1 +
>> drivers/gpu/drm/nouveau/core/subdev/fb/nvea.c | 28 ++++++++++
>> drivers/gpu/drm/nouveau/core/subdev/fb/priv.h | 1 +
>> drivers/gpu/drm/nouveau/core/subdev/fb/ramnvea.c | 67 ++++++++++++++++++++++++
>> 5 files changed, 99 insertions(+)
>> create mode 100644 drivers/gpu/drm/nouveau/core/subdev/fb/nvea.c
>> create mode 100644 drivers/gpu/drm/nouveau/core/subdev/fb/ramnvea.c
>>
>> diff --git a/drivers/gpu/drm/nouveau/Makefile b/drivers/gpu/drm/nouveau/Makefile
>> index 3548fcd..d9fe3e6 100644
>> --- a/drivers/gpu/drm/nouveau/Makefile
>> +++ b/drivers/gpu/drm/nouveau/Makefile
>> @@ -100,6 +100,7 @@ nouveau-y += core/subdev/fb/nvaa.o
>> nouveau-y += core/subdev/fb/nvaf.o
>> nouveau-y += core/subdev/fb/nvc0.o
>> nouveau-y += core/subdev/fb/nve0.o
>> +nouveau-y += core/subdev/fb/nvea.o
>> nouveau-y += core/subdev/fb/ramnv04.o
>> nouveau-y += core/subdev/fb/ramnv10.o
>> nouveau-y += core/subdev/fb/ramnv1a.o
>> @@ -114,6 +115,7 @@ nouveau-y += core/subdev/fb/ramnva3.o
>> nouveau-y += core/subdev/fb/ramnvaa.o
>> nouveau-y += core/subdev/fb/ramnvc0.o
>> nouveau-y += core/subdev/fb/ramnve0.o
>> +nouveau-y += core/subdev/fb/ramnvea.o
>> nouveau-y += core/subdev/fb/sddr3.o
>> nouveau-y += core/subdev/fb/gddr5.o
>> nouveau-y += core/subdev/gpio/base.o
>> diff --git a/drivers/gpu/drm/nouveau/core/include/subdev/fb.h b/drivers/gpu/drm/nouveau/core/include/subdev/fb.h
>> index d7ecafb..3905816 100644
>> --- a/drivers/gpu/drm/nouveau/core/include/subdev/fb.h
>> +++ b/drivers/gpu/drm/nouveau/core/include/subdev/fb.h
>> @@ -105,6 +105,7 @@ extern struct nouveau_oclass *nvaa_fb_oclass;
>> extern struct nouveau_oclass *nvaf_fb_oclass;
>> extern struct nouveau_oclass *nvc0_fb_oclass;
>> extern struct nouveau_oclass *nve0_fb_oclass;
>> +extern struct nouveau_oclass *nvea_fb_oclass;
>>
>> #include <subdev/bios/ramcfg.h>
>>
>> diff --git a/drivers/gpu/drm/nouveau/core/subdev/fb/nvea.c b/drivers/gpu/drm/nouveau/core/subdev/fb/nvea.c
>> new file mode 100644
>> index 0000000..5ff6029
>> --- /dev/null
>> +++ b/drivers/gpu/drm/nouveau/core/subdev/fb/nvea.c
>> @@ -0,0 +1,28 @@
>> +/*
>> + * Copyright (c) 2014, NVIDIA Corporation. All rights reserved.
>> + *
>> + * This program is free software; you can redistribute it and/or modify it
>> + * under the terms and conditions of the GNU General Public License,
>> + * version 2, as published by the Free Software Foundation.
>> + *
>> + * This program is distributed in the hope it will be useful, but WITHOUT
>> + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
>> + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
>> + * more details.
>> + *
>> + */
>> +
>> +#include "nvc0.h"
>> +
>> +struct nouveau_oclass *
>> +nvea_fb_oclass = &(struct nouveau_fb_impl) {
>> + .base.handle = NV_SUBDEV(FB, 0xea),
>> + .base.ofuncs = &(struct nouveau_ofuncs) {
>> + .ctor = nvc0_fb_ctor,
>> + .dtor = nvc0_fb_dtor,
>> + .init = nvc0_fb_init,
>> + .fini = _nouveau_fb_fini,
>> + },
>> + .memtype = nvc0_fb_memtype_valid,
>> + .ram = &nvea_ram_oclass,
>> +}.base;
>> diff --git a/drivers/gpu/drm/nouveau/core/subdev/fb/priv.h b/drivers/gpu/drm/nouveau/core/subdev/fb/priv.h
>> index edaf95d..0b95a25 100644
>> --- a/drivers/gpu/drm/nouveau/core/subdev/fb/priv.h
>> +++ b/drivers/gpu/drm/nouveau/core/subdev/fb/priv.h
>> @@ -32,6 +32,7 @@ extern struct nouveau_oclass nva3_ram_oclass;
>> extern struct nouveau_oclass nvaa_ram_oclass;
>> extern struct nouveau_oclass nvc0_ram_oclass;
>> extern struct nouveau_oclass nve0_ram_oclass;
>> +extern struct nouveau_oclass nvea_ram_oclass;
>>
>> int nouveau_sddr3_calc(struct nouveau_ram *ram);
>> int nouveau_gddr5_calc(struct nouveau_ram *ram, bool nuts);
>> diff --git a/drivers/gpu/drm/nouveau/core/subdev/fb/ramnvea.c b/drivers/gpu/drm/nouveau/core/subdev/fb/ramnvea.c
>> new file mode 100644
>> index 0000000..3038e08
>> --- /dev/null
>> +++ b/drivers/gpu/drm/nouveau/core/subdev/fb/ramnvea.c
>> @@ -0,0 +1,67 @@
>> +/*
>> + * Copyright (c) 2014, NVIDIA Corporation. All rights reserved.
>> + *
>> + * This program is free software; you can redistribute it and/or modify it
>> + * under the terms and conditions of the GNU General Public License,
>> + * version 2, as published by the Free Software Foundation.
>> + *
>> + * This program is distributed in the hope it will be useful, but WITHOUT
>> + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
>> + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
>> + * more details.
>> + *
>> + */
>> +
>> +/*
>> + * TODO replace this CMA-requiring horror with a proper allocator for GPU
>> + * objects in main memory. But for the moment it does the job and can reuse some
>> + * of the nvc0 functions.
>> + */
>> +
>> +#include "nvc0.h"
>> +
>> +#include <linux/dma-mapping.h>
>> +
>> +static int
>> +nvea_ram_ctor(struct nouveau_object *parent, struct nouveau_object *engine,
>> + struct nouveau_oclass *oclass, void *data, u32 datasize,
>> + struct nouveau_object **pobject)
>> +{
>> + struct nouveau_fb *pfb = nouveau_fb(parent);
>> + struct nouveau_ram *ram;
>> + void *vram;
>> + dma_addr_t dma_handle;
>> + int ret;
>> +
>> + ret = nouveau_ram_create(parent, engine, oclass, &ram);
>> + *pobject = nv_object(ram);
>> + if (ret)
>> + return ret;
>> +
>> + ram->type = NV_MEM_TYPE_STOLEN;
>> + /* Use a fixed size of 64MB for now */
>> + ram->size = 0x4000000;
>> + ram->stolen = (u64)0x00000000;
>> + vram = dma_alloc_coherent(nv_device_base(nv_device(parent)), ram->size,
>> + &dma_handle, GFP_KERNEL);
>> + if (!vram)
>> + return -ENOMEM;
>> +
>> + ret = nouveau_mm_init(&pfb->vram, dma_handle >> 12, ram->size >> 12, 1);
>> + if (ret)
>> + return ret;
>> +
>> + ram->get = nvc0_ram_get;
>> + ram->put = nvc0_ram_put;
>> + return 0;
>> +}
>> +
>> +struct nouveau_oclass
>> +nvea_ram_oclass = {
>> + .ofuncs = &(struct nouveau_ofuncs) {
>> + .ctor = nvea_ram_ctor,
>> + .dtor = _nouveau_ram_dtor,
>> + .init = _nouveau_ram_init,
>> + .fini = _nouveau_ram_fini,
>> + },
>> +};
>
>
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