[Skiboot] [PATCH] phb4/capp: Update DMA read engines set in APC_FSM_READ_MASK based on link-width

[Andrew Donnellan]

On 10/08/18 19:04, Vaibhav Jain wrote:
> Commit 47c09cdfe7a3("phb4/capp: Calculate STQ/DMA read engines based
> on link-width for PEC") update the CAPP init sequence by calculating
> the needed STQ/DMA-read engines based on link width and populating it
> in XPEC_NEST_CAPP_CNTL register. This however needs to be synchronized
> with the value set in CAPP APC FSM Read Machine Mask Register.
> 
> Hence this patch update phb4_init_capp_regs() to calculate the link
> width of the stack on PEC2 and populate the same values as previously
> populated in PEC CAPP_CNTL register.
> 
> Cc: stable # v5.7+
> Fixes: 47c09cdfe7a3("phb4/capp: Calculate STQ/DMA read engines based on link-width for PEC")
> Signed-off-by: Vaibhav Jain <vaibhav at linux.ibm.com>

Minor style comments below

Otherwise this looks okay.

Reviewed-by: Andrew Donnellan <andrew.donnellan at au1.ibm.com>

> ---
>   hw/phb4.c | 20 +++++++++++++++++---
>   1 file changed, 17 insertions(+), 3 deletions(-)
> 
> diff --git a/hw/phb4.c b/hw/phb4.c
> index 5e07e2bc..19e9a1ec 100644
> --- a/hw/phb4.c
> +++ b/hw/phb4.c
> @@ -3948,10 +3948,24 @@ static void phb4_init_capp_regs(struct phb4 *p, uint32_t capp_eng)
>   		xscom_write(p->chip_id, XPT_FSM_RMM + offset, reg);
>   	}
>   	if (p->index == CAPP1_PHB_INDEX) {
> -		/* Set 30 Read machines for CAPP Minus 20-27 for DMA */
> -		reg = 0xFFFFF00E00000000;
> -		if (capp_eng & CAPP_MAX_DMA_READ_ENGINES)
> +
> +		if (capp_eng & CAPP_MAX_DMA_READ_ENGINES) {
>   			reg = 0xF000000000000000;
> +		} else {
> +			/* Check if PEC is in x8 or x16 mode */
> +			xscom_read(p->chip_id, XPEC_PCI2_CPLT_CONF1, &reg);
> +			if ((reg & XPEC_PCI2_IOVALID_MASK) ==
> +			    XPEC_PCI2_IOVALID_X16)
> +				/* 0-47 (Read machines) are available for
> +				 * capp use
> +				 */
> +				reg = 0x0000FFFFFFFFFFFFULL;
> +			else
> +				/* Set 30 Read machines for CAPP Minus
> +				 * 20-27 for DMA
> +				 */
> +				reg = 0xFFFFF00E00000000;

It'd be more consistent to pad these numbers out to 16 digits, and to 
use the ULL suffix or not consistently as well

> +		}
>   		xscom_write(p->chip_id, APC_FSM_READ_MASK + offset, reg);
>   		xscom_write(p->chip_id, XPT_FSM_RMM + offset, reg);
>   	}
> 

-- 
Andrew Donnellan              OzLabs, ADL Canberra
andrew.donnellan at au1.ibm.com  IBM Australia Limited