[Skiboot] [PATCH] SCOM restore for DARN and XIVE

[Stewart Smith]

Akshay Adiga <akshay.adiga at linux.vnet.ibm.com> writes:
> While waking up from stop11, we want NCU_DARN_BAR to have enable bit set.
> Without this stop_api call, the value restored is without enable bit set.
> We loose NCU_SPEC_BAR when the quad goes into stop11, stop_api will
> restore while waking up from stop11.
>
> Signed-off-by: Akshay Adiga <akshay.adiga at linux.vnet.ibm.com>
> ---
>  hw/nx.c   | 12 +++++++++++-
>  hw/xive.c |  8 ++++++++
>  2 files changed, 19 insertions(+), 1 deletion(-)
>
> diff --git a/hw/nx.c b/hw/nx.c
> index 64ac793..8431c3c 100644
> --- a/hw/nx.c
> +++ b/hw/nx.c
> @@ -24,6 +24,7 @@
>  #include <chip.h>
>  #include <xscom-p9-regs.h>
>  #include <phys-map.h>
> +#include <p9_stop_api.H>
>
>  extern void nx_p9_rng_init(void);
>
> @@ -31,7 +32,7 @@ void nx_p9_rng_init(void)
>  {
>  	struct proc_chip *chip;
>  	struct cpu_thread *c;
> -	uint64_t bar, tmp;
> +	uint64_t bar, tmp, rc;
>
>  	if (proc_gen != proc_gen_p9)
>  		return;
> @@ -65,6 +66,15 @@ void nx_p9_rng_init(void)
>  						P9X_EX_NCU_DARN_BAR);
>  			xscom_write(chip->id, addr,
>  				    bar | P9X_EX_NCU_DARN_BAR_EN);
> +			rc = p9_stop_save_scom(( void *)chip->homer_base,
> +				       	addr, bar | P9X_EX_NCU_DARN_BAR_EN,
> +					P9_STOP_SCOM_REPLACE,
> +					P9_STOP_SECTION_CORE_SCOM);
> +			if (rc) {
> +				prlog(PR_ERR,
> +					" stopapi for DARN_BAR failed %lld",
> +					rc);
> +			}

Don't need {} for single line ifs

Also, this (and below) I think should just say p9_stop_api rather than
'stopapi' here and 'STOP_API' below.

I also think the error handling here is incorrect.

IF we can't get stop to save and restore the DARN_BAR then we either
need to disable deep stop states or DARN.
> @@ -3111,6 +3112,7 @@ static void xive_configure_ex_special_bar(struct xive *x, struct cpu_thread *c)
>  {
>  	uint64_t xa, val;
>  	int64_t rc;
> +	struct proc_chip *chip = get_chip(c->chip_id);
>
>  	xive_cpu_dbg(c, "Setting up special BAR\n");
>  	xa = XSCOM_ADDR_P9_EX(pir_to_core_id(c->pir), P9X_EX_NCU_SPEC_BAR);
> @@ -3123,6 +3125,12 @@ static void xive_configure_ex_special_bar(struct xive *x, struct cpu_thread *c)
>  		xive_cpu_err(c, "Failed to setup NCU_SPEC_BAR\n");
>  		/* XXXX  what do do now ? */
>  	}
> +	rc = p9_stop_save_scom(( void *)chip->homer_base, xa, val,
> +				P9_STOP_SCOM_REPLACE, P9_STOP_SECTION_EQ_SCOM);
> +	if (rc) {
> +		xive_cpu_err(c, "STOP_API failed for NCU_SPEC_BAR rc=%lld\n",rc);
> +
> +	}
>  }

I think we need to handle the error case here too, although I'm not sure
what options we have in this case...

-- 
Stewart Smith
OPAL Architect, IBM.