Re: [PATCH 4/4] drm/v3d: Fix and extend MMU error handling.

[Paul Kocialkowski <paul.kocialkowski@bootlin.com>]

Hi,

On Thu, 2019-04-18 at 17:10 -0700, Eric Anholt wrote:
> We were setting the wrong flags to enable PTI errors, so we were
> seeing reads to invalid PTEs show up as write errors.  Also, we
> weren't turning on the interrupts.  The AXI IDs we were dumping
> included the outstanding write number and so they looked basically
> random.  And the VIO_ADDR decoding was based on the MMU VA_WIDTH for
> the first platform I worked on and was wrong on others.  In short,
> this was a thorough mess from early HW enabling.
> 
> Tested on V3D 4.1 and 4.2 with intentional L2T, CLE, PTB, and TLB
> faults.

Didn't check the docs but looks sane too!

Reviewed-by: Paul Kocialkowski <paul.kocialkowski@bootlin.com>

Cheers,

Paul

> Signed-off-by: Eric Anholt <eric@anholt.net>
> ---
>  drivers/gpu/drm/v3d/v3d_drv.c  |  1 +
>  drivers/gpu/drm/v3d/v3d_drv.h  |  2 ++
>  drivers/gpu/drm/v3d/v3d_irq.c  | 31 +++++++++++++++++++++++++++----
>  drivers/gpu/drm/v3d/v3d_mmu.c  |  7 +++++--
>  drivers/gpu/drm/v3d/v3d_regs.h |  3 ++-
>  5 files changed, 37 insertions(+), 7 deletions(-)
> 
> diff --git a/drivers/gpu/drm/v3d/v3d_drv.c b/drivers/gpu/drm/v3d/v3d_drv.c
> index 7ab36192e6bc..9ce2e4ef6c2a 100644
> --- a/drivers/gpu/drm/v3d/v3d_drv.c
> +++ b/drivers/gpu/drm/v3d/v3d_drv.c
> @@ -494,6 +494,7 @@ static int v3d_platform_drm_probe(struct platform_device *pdev)
>  	mmu_debug = V3D_READ(V3D_MMU_DEBUG_INFO);
>  	dev->coherent_dma_mask =
>  		DMA_BIT_MASK(30 + V3D_GET_FIELD(mmu_debug, V3D_MMU_PA_WIDTH));
> +	v3d->va_width = 30 + V3D_GET_FIELD(mmu_debug, V3D_MMU_VA_WIDTH);
>  
>  	ident1 = V3D_READ(V3D_HUB_IDENT1);
>  	v3d->ver = (V3D_GET_FIELD(ident1, V3D_HUB_IDENT1_TVER) * 10 +
> diff --git a/drivers/gpu/drm/v3d/v3d_drv.h b/drivers/gpu/drm/v3d/v3d_drv.h
> index 6d31a6a5a08e..64682923018d 100644
> --- a/drivers/gpu/drm/v3d/v3d_drv.h
> +++ b/drivers/gpu/drm/v3d/v3d_drv.h
> @@ -63,6 +63,8 @@ struct v3d_dev {
>  	 */
>  	void *mmu_scratch;
>  	dma_addr_t mmu_scratch_paddr;
> +	/* virtual address bits from V3D to the MMU. */
> +	int va_width;
>  
>  	/* Number of V3D cores. */
>  	u32 cores;
> diff --git a/drivers/gpu/drm/v3d/v3d_irq.c b/drivers/gpu/drm/v3d/v3d_irq.c
> index fac3c542860b..268d8a889ac5 100644
> --- a/drivers/gpu/drm/v3d/v3d_irq.c
> +++ b/drivers/gpu/drm/v3d/v3d_irq.c
> @@ -162,10 +162,33 @@ v3d_hub_irq(int irq, void *arg)
>  		      V3D_HUB_INT_MMU_PTI |
>  		      V3D_HUB_INT_MMU_CAP)) {
>  		u32 axi_id = V3D_READ(V3D_MMU_VIO_ID);
> -		u64 vio_addr = (u64)V3D_READ(V3D_MMU_VIO_ADDR) << 8;
> -
> -		dev_err(v3d->dev, "MMU error from client %d at 0x%08llx%s%s%s\n",
> -			axi_id, (long long)vio_addr,
> +		u64 vio_addr = ((u64)V3D_READ(V3D_MMU_VIO_ADDR) <<
> +				(v3d->va_width - 32));
> +		static const char *const v3d41_axi_ids[] = {
> +			"L2T",
> +			"PTB",
> +			"PSE",
> +			"TLB",
> +			"CLE",
> +			"TFU",
> +			"MMU",
> +			"GMP",
> +		};
> +		const char *client = "?";
> +
> +		V3D_WRITE(V3D_MMU_CTL,
> +			  V3D_READ(V3D_MMU_CTL) & (V3D_MMU_CTL_CAP_EXCEEDED |
> +						   V3D_MMU_CTL_PT_INVALID |
> +						   V3D_MMU_CTL_WRITE_VIOLATION));
> +
> +		if (v3d->ver >= 41) {
> +			axi_id = axi_id >> 5;
> +			if (axi_id < ARRAY_SIZE(v3d41_axi_ids))
> +				client = v3d41_axi_ids[axi_id];
> +		}
> +
> +		dev_err(v3d->dev, "MMU error from client %s (%d) at 0x%llx%s%s%s\n",
> +			client, axi_id, (long long)vio_addr,
>  			((intsts & V3D_HUB_INT_MMU_WRV) ?
>  			 ", write violation" : ""),
>  			((intsts & V3D_HUB_INT_MMU_PTI) ?
> diff --git a/drivers/gpu/drm/v3d/v3d_mmu.c b/drivers/gpu/drm/v3d/v3d_mmu.c
> index 7a21f1787ab1..395e81d97163 100644
> --- a/drivers/gpu/drm/v3d/v3d_mmu.c
> +++ b/drivers/gpu/drm/v3d/v3d_mmu.c
> @@ -69,10 +69,13 @@ int v3d_mmu_set_page_table(struct v3d_dev *v3d)
>  	V3D_WRITE(V3D_MMU_PT_PA_BASE, v3d->pt_paddr >> V3D_MMU_PAGE_SHIFT);
>  	V3D_WRITE(V3D_MMU_CTL,
>  		  V3D_MMU_CTL_ENABLE |
> -		  V3D_MMU_CTL_PT_INVALID |
> +		  V3D_MMU_CTL_PT_INVALID_ENABLE |
>  		  V3D_MMU_CTL_PT_INVALID_ABORT |
> +		  V3D_MMU_CTL_PT_INVALID_INT |
>  		  V3D_MMU_CTL_WRITE_VIOLATION_ABORT |
> -		  V3D_MMU_CTL_CAP_EXCEEDED_ABORT);
> +		  V3D_MMU_CTL_WRITE_VIOLATION_INT |
> +		  V3D_MMU_CTL_CAP_EXCEEDED_ABORT |
> +		  V3D_MMU_CTL_CAP_EXCEEDED_INT);
>  	V3D_WRITE(V3D_MMU_ILLEGAL_ADDR,
>  		  (v3d->mmu_scratch_paddr >> V3D_MMU_PAGE_SHIFT) |
>  		  V3D_MMU_ILLEGAL_ADDR_ENABLE);
> diff --git a/drivers/gpu/drm/v3d/v3d_regs.h b/drivers/gpu/drm/v3d/v3d_regs.h
> index eda1e289976f..9bcb57781d31 100644
> --- a/drivers/gpu/drm/v3d/v3d_regs.h
> +++ b/drivers/gpu/drm/v3d/v3d_regs.h
> @@ -152,7 +152,8 @@
>  # define V3D_MMU_CTL_PT_INVALID_ABORT                  BIT(19)
>  # define V3D_MMU_CTL_PT_INVALID_INT                    BIT(18)
>  # define V3D_MMU_CTL_PT_INVALID_EXCEPTION              BIT(17)
> -# define V3D_MMU_CTL_WRITE_VIOLATION                   BIT(16)
> +# define V3D_MMU_CTL_PT_INVALID_ENABLE                 BIT(16)
> +# define V3D_MMU_CTL_WRITE_VIOLATION                   BIT(12)
>  # define V3D_MMU_CTL_WRITE_VIOLATION_ABORT             BIT(11)
>  # define V3D_MMU_CTL_WRITE_VIOLATION_INT               BIT(10)
>  # define V3D_MMU_CTL_WRITE_VIOLATION_EXCEPTION         BIT(9)
-- 
Paul Kocialkowski, Bootlin
Embedded Linux and kernel engineering
https://bootlin.com