[Skiboot] [PATCH 3/3] npu2: hw-procedures: Refactor reset_ntl procedure

[alistair at popple.id.au]

Ideally we shouldn't loop in skiboot but rather return INPROGRESS. However
in practice I've never seen HW loop on these more than once or twice so it
should be ok for now, especially as these procedures only ever run once
per boot.

Reviewed-by: Alistair Popple <alistair at popple.id.au>

> Change the implementation of reset_ntl to match the latest programming
> guide documentation.
>
> Signed-off-by: Reza Arbab <arbab at linux.vnet.ibm.com>
> ---
>  hw/npu2-hw-procedures.c | 73
> +++++++++++++++++++++++++++++++++++++++----------
>  1 file changed, 58 insertions(+), 15 deletions(-)
>
> diff --git a/hw/npu2-hw-procedures.c b/hw/npu2-hw-procedures.c
> index c24489f..1db171a 100644
> --- a/hw/npu2-hw-procedures.c
> +++ b/hw/npu2-hw-procedures.c
> @@ -191,17 +191,27 @@ static uint32_t nop(struct npu2_dev *npu_dev
> __unused)
>  }
>  DEFINE_PROCEDURE(nop);
>
> -/* Procedure 1.2.1 (RESET_NPU_DL) from opt_programmerguide.odt. Also
> - * incorporates AT reset. */
> -static uint32_t reset_ntl(struct npu2_dev *ndev __unused)
> +static bool poll_fence_status(struct npu2_dev *ndev, uint64_t val)
>  {
> -	return PROCEDURE_NEXT;
> +	uint64_t fs;
> +	int i;
> +
> +	for (i = 0; i < 4096; i++) {
> +		fs = npu2_read(ndev->npu, NPU2_NTL_CQ_FENCE_STATUS(ndev));
> +		if ((fs & 0xc000000000000000) == val)
> +			return true;
> +	}
> +
> +	NPU2DEVERR(ndev, "NPU2_NTL_CQ_FENCE_STATUS timeout (0x%llx)\n", val);
> +	return false;
>  }
>
> -static uint32_t reset_ndl(struct npu2_dev *ndev)
> +/* Procedure 1.2.1 - Reset NPU/NDL */
> +static uint32_t reset_ntl(struct npu2_dev *ndev)
>  {
>  	uint64_t val;
>
> +	/* Write PRI */
>  	if ((ndev->pl_xscom_base & 0xFFFFFFFF) == 0x9010C3F)
>  		val = SETFIELD(PPC_BITMASK(0,1), 0ull, ndev->index % 3);
>  	else {
> @@ -220,24 +230,57 @@ static uint32_t reset_ndl(struct npu2_dev *ndev)
>
>  	npu2_write_mask(ndev->npu, NPU2_NTL_PRI_CFG(ndev), val, -1ULL);
>
> -	val = PPC_BIT32(0) | PPC_BIT32(1);
> +	/* NTL Reset */
> +	val = npu2_read(ndev->npu, NPU2_NTL_MISC_CFG1(ndev));
> +	val |= PPC_BIT(8) | PPC_BIT(9);
> +	npu2_write(ndev->npu, NPU2_NTL_MISC_CFG1(ndev), val);
> +
> +	if (!poll_fence_status(ndev, 0xc000000000000000))
> +		return PROCEDURE_COMPLETE | PROCEDURE_FAILED;
>
> +	return PROCEDURE_NEXT;
> +}
> +
> +static uint32_t reset_ndl(struct npu2_dev *ndev)
> +{
> +	uint64_t val;
> +
> +	val = npu2_read_4b(ndev->npu, NPU2_NTL_DL_CONTROL(ndev));
> +	val |= PPC_BIT32(0) | PPC_BIT32(1);
>  	npu2_write_4b(ndev->npu, NPU2_NTL_DL_CONTROL(ndev), val);
> -	npu2_write_4b(ndev->npu, NPU2_NTL_DL_CONTROL(ndev), 0);
> -	npu2_write_4b(ndev->npu, NPU2_NTL_DL_CONFIG(ndev), PPC_BIT32(0));
>
> -	/* NTL Reset */
> -	val = PPC_BIT(8) | PPC_BIT(9);
> -	npu2_write(ndev->npu, NPU2_NTL_MISC_CFG1(ndev), val);
> -	val = PPC_BIT(8);
> +	val = npu2_read_4b(ndev->npu, NPU2_NTL_DL_CONTROL(ndev));
> +	val &= ~(PPC_BIT32(0) | PPC_BIT32(1));
> +	npu2_write_4b(ndev->npu, NPU2_NTL_DL_CONTROL(ndev), val);
> +
> +	val = PPC_BIT32(0);
> +	npu2_write_4b(ndev->npu, NPU2_NTL_DL_CONFIG(ndev), val);
> +
> +	return PROCEDURE_NEXT;
> +}
> +
> +static uint32_t reset_ntl_release(struct npu2_dev *ndev)
> +{
> +	uint64_t val;
> +
> +	val = npu2_read(ndev->npu, NPU2_NTL_MISC_CFG1(ndev));
> +	val &= 0xFFBFFFFFFFFFFFFF;
>  	npu2_write(ndev->npu, NPU2_NTL_MISC_CFG1(ndev), val);
> -	val = 0;
> +
> +	if (!poll_fence_status(ndev, 0x8000000000000000))
> +		return PROCEDURE_COMPLETE | PROCEDURE_FAILED;
> +
> +	val = npu2_read(ndev->npu, NPU2_NTL_MISC_CFG1(ndev));
> +	val &= 0xFF3FFFFFFFFFFFFF;
>  	npu2_write(ndev->npu, NPU2_NTL_MISC_CFG1(ndev), val);
>
> +	if (!poll_fence_status(ndev, 0x0))
> +		return PROCEDURE_COMPLETE | PROCEDURE_FAILED;
> +
>  	return PROCEDURE_NEXT;
>  }
>
> -static uint32_t reset_ntl_release(struct npu2_dev *ndev)
> +static uint32_t reset_ntl_finish(struct npu2_dev *ndev)
>  {
>  	/* Credit Setup */
>  	npu2_write(ndev->npu, NPU2_NTL_CRED_HDR_CREDIT_TX(ndev),
> 0x0200000000000000);
> @@ -257,7 +300,7 @@ static uint32_t reset_ntl_release(struct npu2_dev
> *ndev)
>
>  	return PROCEDURE_COMPLETE;
>  }
> -DEFINE_PROCEDURE(reset_ntl, reset_ndl, reset_ntl_release);
> +DEFINE_PROCEDURE(reset_ntl, reset_ndl, reset_ntl_release,
> reset_ntl_finish);
>
>  /* Procedure 1.2.2 - Reset I/O PHY Lanes */
>  static uint32_t phy_reset(struct npu2_dev *ndev)
> --
> 1.8.3.1
>
>