Re: [PATCH v4 2/2] cxl: read PHB indications from the device tree

[Frederic Barrat <fbarrat@linux.vnet.ibm.com>]

Le 15/12/2017 à 14:48, Philippe Bergheaud a écrit :
> Configure the P9 XSL_DSNCTL register with PHB indications found
> in the device tree, or else use legacy hard-coded values.
> 
> Signed-off-by: Philippe Bergheaud <felix@linux.vnet.ibm.com>
> ---
> Changelog:
> 
> v2: New patch. Use the new device tree property "ibm,phb-indications".
> 
> v3: No change.
> 
> v4: No functional change.
>      Drop cosmetic fix in comment.
> 
> This patch depends on the following skiboot prerequisite:
> 
> https://patchwork.ozlabs.org/patch/849162/
> ---
>   drivers/misc/cxl/cxl.h    |  2 +-
>   drivers/misc/cxl/cxllib.c |  2 +-
>   drivers/misc/cxl/pci.c    | 40 +++++++++++++++++++++++++++++++++++-----
>   3 files changed, 37 insertions(+), 7 deletions(-)
> 
> diff --git a/drivers/misc/cxl/cxl.h b/drivers/misc/cxl/cxl.h
> index e46a4062904a..5a6e9a921c2b 100644
> --- a/drivers/misc/cxl/cxl.h
> +++ b/drivers/misc/cxl/cxl.h
> @@ -1062,7 +1062,7 @@ int cxl_psl_purge(struct cxl_afu *afu);
>   int cxl_calc_capp_routing(struct pci_dev *dev, u64 *chipid,
>   			  u32 *phb_index, u64 *capp_unit_id);
>   int cxl_slot_is_switched(struct pci_dev *dev);
> -int cxl_get_xsl9_dsnctl(u64 capp_unit_id, u64 *reg);
> +int cxl_get_xsl9_dsnctl(struct pci_dev *dev, u64 capp_unit_id, u64 *reg);
>   u64 cxl_calculate_sr(bool master, bool kernel, bool real_mode, bool p9);
> 
>   void cxl_native_irq_dump_regs_psl9(struct cxl_context *ctx);
> diff --git a/drivers/misc/cxl/cxllib.c b/drivers/misc/cxl/cxllib.c
> index dc9bc1807fdf..61f80d586279 100644
> --- a/drivers/misc/cxl/cxllib.c
> +++ b/drivers/misc/cxl/cxllib.c
> @@ -99,7 +99,7 @@ int cxllib_get_xsl_config(struct pci_dev *dev, struct cxllib_xsl_config *cfg)
>   	if (rc)
>   		return rc;
> 
> -	rc = cxl_get_xsl9_dsnctl(capp_unit_id, &cfg->dsnctl);
> +	rc = cxl_get_xsl9_dsnctl(dev, capp_unit_id, &cfg->dsnctl);
>   	if (rc)
>   		return rc;
>   	if (cpu_has_feature(CPU_FTR_POWER9_DD1)) {
> diff --git a/drivers/misc/cxl/pci.c b/drivers/misc/cxl/pci.c
> index 19969ee86d6f..c58fb28685af 100644
> --- a/drivers/misc/cxl/pci.c
> +++ b/drivers/misc/cxl/pci.c
> @@ -409,7 +409,36 @@ int cxl_calc_capp_routing(struct pci_dev *dev, u64 *chipid,
>   	return 0;
>   }
> 
> -int cxl_get_xsl9_dsnctl(u64 capp_unit_id, u64 *reg)
> +static u64 nbwind = 0;
> +static u64 asnind = 0;
> +static u64 capiind = 0;

Could we avoid the globals and keep the static within 
get_phb_indications() and have the function return them as out 
parameters? It would seem cleaner to me.

   Fred

> +static int get_phb_indications(struct pci_dev *dev)
> +{
> +	struct device_node *np;
> +	const __be32 *prop;
> +
> +	if (capiind)
> +		return 0;
> +
> +	if (!(np = pnv_pci_get_phb_node(dev)))
> +		return -1;
> +
> +	prop = of_get_property(np, "ibm,phb-indications", NULL);
> +	if (!prop) {
> +		nbwind = 0x0300UL; /* legacy values */
> +		asnind = 0x0400UL;
> +		capiind = 0x0200UL;
> +	} else {
> +		nbwind = (u64)be32_to_cpu(prop[2]);
> +		asnind = (u64)be32_to_cpu(prop[1]);
> +		capiind = (u64)be32_to_cpu(prop[0]);
> +	}
> +	of_node_put(np);
> +	return 0;
> +}
> +
> +int cxl_get_xsl9_dsnctl(struct pci_dev *dev, u64 capp_unit_id, u64 *reg)
>   {
>   	u64 xsl_dsnctl;
> 
> @@ -423,7 +452,8 @@ int cxl_get_xsl9_dsnctl(u64 capp_unit_id, u64 *reg)
>   	 * Tell XSL where to route data to.
>   	 * The field chipid should match the PHB CAPI_CMPM register
>   	 */
> -	xsl_dsnctl = ((u64)0x2 << (63-7)); /* Bit 57 */
> +	get_phb_indications(dev);


> +	xsl_dsnctl = (capiind << (63-15)); /* Bit 57 */
>   	xsl_dsnctl |= (capp_unit_id << (63-15));
> 
>   	/* nMMU_ID Defaults to: b’000001001’*/
> @@ -437,14 +467,14 @@ int cxl_get_xsl9_dsnctl(u64 capp_unit_id, u64 *reg)
>   		 * nbwind=0x03, bits [57:58], must include capi indicator.
>   		 * Not supported on P9 DD1.
>   		 */
> -		xsl_dsnctl |= ((u64)0x03 << (63-47));
> +		xsl_dsnctl |= (nbwind << (63-55));
> 
>   		/*
>   		 * Upper 16b address bits of ASB_Notify messages sent to the
>   		 * system. Need to match the PHB’s ASN Compare/Mask Register.
>   		 * Not supported on P9 DD1.
>   		 */
> -		xsl_dsnctl |= ((u64)0x04 << (63-55));
> +		xsl_dsnctl |= asnind;
>   	}
> 
>   	*reg = xsl_dsnctl;
> @@ -464,7 +494,7 @@ static int init_implementation_adapter_regs_psl9(struct cxl *adapter,
>   	if (rc)
>   		return rc;
> 
> -	rc = cxl_get_xsl9_dsnctl(capp_unit_id, &xsl_dsnctl);
> +	rc = cxl_get_xsl9_dsnctl(dev, capp_unit_id, &xsl_dsnctl);
>   	if (rc)
>   		return rc;
>