Re: [RFC 07/16] drm/nouveau/bar/nvc0: support chips without BAR3

[Alexandre Courbot <acourbot@nvidia.com>]

On 02/04/2014 12:54 PM, Ben Skeggs wrote:
> On Sat, Feb 1, 2014 at 1:16 PM, Alexandre Courbot <acourbot@nvidia.com> wrote:
>> Adapt the NVC0 BAR driver to make it able to support chips that do not
>> expose a BAR3. When this happens, BAR1 is then used for USERD mapping
>> and the BAR alloc() functions is disabled, making GPU objects unable
>> to rely on BAR for data access and falling back to PRAMIN.
>>
>> Signed-off-by: Alexandre Courbot <acourbot@nvidia.com>
>> ---
>>   drivers/gpu/drm/nouveau/core/subdev/bar/nvc0.c | 115 +++++++++++++------------
>>   1 file changed, 61 insertions(+), 54 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/nouveau/core/subdev/bar/nvc0.c b/drivers/gpu/drm/nouveau/core/subdev/bar/nvc0.c
>> index 3f30db6..c2bb0e5 100644
>> --- a/drivers/gpu/drm/nouveau/core/subdev/bar/nvc0.c
>> +++ b/drivers/gpu/drm/nouveau/core/subdev/bar/nvc0.c
>> @@ -79,87 +79,88 @@ nvc0_bar_unmap(struct nouveau_bar *bar, struct nouveau_vma *vma)
>>   }
>>
>>   static int
>> -nvc0_bar_ctor(struct nouveau_object *parent, struct nouveau_object *engine,
>> -             struct nouveau_oclass *oclass, void *data, u32 size,
>> -             struct nouveau_object **pobject)
>> +nvc0_bar_init_vm(struct nvc0_bar_priv *priv, int nr, int bar)
>>   {
>> -       struct nouveau_device *device = nv_device(parent);
>> -       struct nvc0_bar_priv *priv;
>> +       struct nouveau_device *device = nv_device(&priv->base);
>>          struct nouveau_gpuobj *mem;
>>          struct nouveau_vm *vm;
>> +       resource_size_t bar_len;
>>          int ret;
>>
>> -       ret = nouveau_bar_create(parent, engine, oclass, &priv);
>> -       *pobject = nv_object(priv);
>> -       if (ret)
>> -               return ret;
>> -
>> -       /* BAR3 */
>>          ret = nouveau_gpuobj_new(nv_object(priv), NULL, 0x1000, 0, 0,
>> -                               &priv->bar[0].mem);
>> -       mem = priv->bar[0].mem;
>> +                               &priv->bar[nr].mem);
>> +       mem = priv->bar[nr].mem;
>>          if (ret)
>>                  return ret;
>>
>>          ret = nouveau_gpuobj_new(nv_object(priv), NULL, 0x8000, 0, 0,
>> -                               &priv->bar[0].pgd);
>> +                               &priv->bar[nr].pgd);
>>          if (ret)
>>                  return ret;
>>
>> -       ret = nouveau_vm_new(device, 0, nv_device_resource_len(device, 3), 0, &vm);
>> +       bar_len = nv_device_resource_len(device, bar);
>> +
>> +       ret = nouveau_vm_new(device, 0, bar_len, 0, &vm);
>>          if (ret)
>>                  return ret;
>>
>>          atomic_inc(&vm->engref[NVDEV_SUBDEV_BAR]);
>>
>> -       ret = nouveau_gpuobj_new(nv_object(priv), NULL,
>> -                                (nv_device_resource_len(device, 3) >> 12) * 8,
>> -                                0x1000, NVOBJ_FLAG_ZERO_ALLOC,
>> -                                &vm->pgt[0].obj[0]);
>> -       vm->pgt[0].refcount[0] = 1;
>> -       if (ret)
>> -               return ret;
>> +       /*
>> +        * Bootstrap page table lookup.
>> +        */
>> +       if (bar == 3) {
>> +               ret = nouveau_gpuobj_new(nv_object(priv), NULL,
>> +                                        (bar_len >> 12) * 8, 0x1000,
>> +                                        NVOBJ_FLAG_ZERO_ALLOC,
>> +                                       &vm->pgt[0].obj[0]);
>> +               vm->pgt[0].refcount[0] = 1;
>> +               if (ret)
>> +                       return ret;
>> +       }
>>
>> -       ret = nouveau_vm_ref(vm, &priv->bar[0].vm, priv->bar[0].pgd);
>> +       ret = nouveau_vm_ref(vm, &priv->bar[nr].vm, priv->bar[nr].pgd);
>>          nouveau_vm_ref(NULL, &vm, NULL);
>>          if (ret)
>>                  return ret;
>>
>> -       nv_wo32(mem, 0x0200, lower_32_bits(priv->bar[0].pgd->addr));
>> -       nv_wo32(mem, 0x0204, upper_32_bits(priv->bar[0].pgd->addr));
>> -       nv_wo32(mem, 0x0208, lower_32_bits(nv_device_resource_len(device, 3) - 1));
>> -       nv_wo32(mem, 0x020c, upper_32_bits(nv_device_resource_len(device, 3) - 1));
>> +       nv_wo32(mem, 0x0200, lower_32_bits(priv->bar[nr].pgd->addr));
>> +       nv_wo32(mem, 0x0204, upper_32_bits(priv->bar[nr].pgd->addr));
>> +       nv_wo32(mem, 0x0208, lower_32_bits(bar_len - 1));
>> +       nv_wo32(mem, 0x020c, upper_32_bits(bar_len - 1));
>>
>> -       /* BAR1 */
>> -       ret = nouveau_gpuobj_new(nv_object(priv), NULL, 0x1000, 0, 0,
>> -                               &priv->bar[1].mem);
>> -       mem = priv->bar[1].mem;
>> -       if (ret)
>> -               return ret;
>> +       return 0;
>> +}
>>
>> -       ret = nouveau_gpuobj_new(nv_object(priv), NULL, 0x8000, 0, 0,
>> -                               &priv->bar[1].pgd);
>> -       if (ret)
>> -               return ret;
>> +static int
>> +nvc0_bar_ctor(struct nouveau_object *parent, struct nouveau_object *engine,
>> +             struct nouveau_oclass *oclass, void *data, u32 size,
>> +             struct nouveau_object **pobject)
>> +{
>> +       struct nouveau_device *device = nv_device(parent);
>> +       struct nvc0_bar_priv *priv;
>> +       bool has_bar3 = nv_device_resource_len(device, 3) != 0;
>> +       int ret;
>>
>> -       ret = nouveau_vm_new(device, 0, nv_device_resource_len(device, 1), 0, &vm);
>> +       ret = nouveau_bar_create(parent, engine, oclass, &priv);
>> +       *pobject = nv_object(priv);
>>          if (ret)
>>                  return ret;
>>
>> -       atomic_inc(&vm->engref[NVDEV_SUBDEV_BAR]);
>> +       /* BAR3 */
>> +       if (has_bar3) {
>> +               ret = nvc0_bar_init_vm(priv, 0, 3);
>> +               if (ret)
>> +                       return ret;
>> +               priv->base.alloc = nouveau_bar_alloc;
>> +               priv->base.kmap = nvc0_bar_kmap;
>> +       }
>>
>> -       ret = nouveau_vm_ref(vm, &priv->bar[1].vm, priv->bar[1].pgd);
>> -       nouveau_vm_ref(NULL, &vm, NULL);
>> +       /* BAR1 */
>> +       ret = nvc0_bar_init_vm(priv, 1, 1);
>>          if (ret)
>>                  return ret;
>>
>> -       nv_wo32(mem, 0x0200, lower_32_bits(priv->bar[1].pgd->addr));
>> -       nv_wo32(mem, 0x0204, upper_32_bits(priv->bar[1].pgd->addr));
>> -       nv_wo32(mem, 0x0208, lower_32_bits(nv_device_resource_len(device, 1) - 1));
>> -       nv_wo32(mem, 0x020c, upper_32_bits(nv_device_resource_len(device, 1) - 1));
>> -
>> -       priv->base.alloc = nouveau_bar_alloc;
>> -       priv->base.kmap = nvc0_bar_kmap;
>>          priv->base.umap = nvc0_bar_umap;
>>          priv->base.unmap = nvc0_bar_unmap;
>>          priv->base.flush = nv84_bar_flush;
>> @@ -176,12 +177,16 @@ nvc0_bar_dtor(struct nouveau_object *object)
>>          nouveau_gpuobj_ref(NULL, &priv->bar[1].pgd);
>>          nouveau_gpuobj_ref(NULL, &priv->bar[1].mem);
>>
>> -       if (priv->bar[0].vm) {
>> -               nouveau_gpuobj_ref(NULL, &priv->bar[0].vm->pgt[0].obj[0]);
>> -               nouveau_vm_ref(NULL, &priv->bar[0].vm, priv->bar[0].pgd);
>> +       if (priv->bar[0].mem) {
>> +               if (priv->bar[0].vm) {
>> +                       nouveau_gpuobj_ref(NULL,
>> +                                          &priv->bar[0].vm->pgt[0].obj[0]);
>> +                       nouveau_vm_ref(NULL, &priv->bar[0].vm,
>> +                                      priv->bar[0].pgd);
>> +               }
>> +               nouveau_gpuobj_ref(NULL, &priv->bar[0].pgd);
>> +               nouveau_gpuobj_ref(NULL, &priv->bar[0].mem);
>>          }
>> -       nouveau_gpuobj_ref(NULL, &priv->bar[0].pgd);
>> -       nouveau_gpuobj_ref(NULL, &priv->bar[0].mem);
> Did the conditional on priv->bar[0].mem fix anything here?  The ref()
> functions called are designed to handle the NULL pointers already.

You're right, this test is not needed at all. Thanks.