Re: [RFC 3/3] checks: Add unit-address checks for PCI buses

[David Gibson <david-xT8FGy+AXnRB3Ne2BGzF6laj5H9X9Tb+@public.gmane.org>]

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On Wed, Mar 23, 2016 at 07:40:21PM -0500, Rob Herring wrote:
> PCI device unit addresses are in the form DD or DD,F where DD is the
> device 0-0x1f and F is the function 0-7. Add checks that the unit
> address matches this form.

Hmm.. we ought to be able to do a bit better than this, again by
constructing the expected unit address from reg.  While we're at it,
it probably makes sense to have that dependent on a check which makes
sure the first entry in a pci device's 'reg' is the config address.

Hmm.. I wonder if what might make sense is to have two whole
(possible) sublists of tests within the bus_type structure - one, a
list of checks to apply to bridge nodes and the other a list of checks
to apply to bus device nodes.

> Signed-off-by: Rob Herring <robh-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
> ---
>  checks.c | 20 ++++++++++++++++++++
>  1 file changed, 20 insertions(+)
> 
> diff --git a/checks.c b/checks.c
> index 82a7f38..1d0fcfb 100644
> --- a/checks.c
> +++ b/checks.c
> @@ -549,10 +549,30 @@ static bool is_pci_bridge(struct node *node)
>  	return false;
>  }
>  
> +static void pci_unit_addr(struct check *c, struct node *dt, struct node *node)
> +{
> +	const char *unitname = get_unitname(node);
> +	unsigned int dev, func;
> +	int ret;
> +
> +	ret = sscanf(unitname, "%2x,%1x", &dev, &func);
> +	if (ret >= 1) {
> +		if (dev > 0x1f)
> +			FAIL(c, "Node %s PCI device number out of range",
> +			     node->fullpath);
> +	}
> +	if (ret == 2) {
> +		if (func > 7)
> +			FAIL(c, "Node %s PCI function number out of range",
> +			     node->fullpath);
> +	}
> +}
> +
>  struct bus_type pci_bus_type = {
>          .expected_addr_cells = 3,
>          .expected_size_cells = 2,
>          .is_type = is_pci_bridge,
> +        .check_unit_addr = pci_unit_addr,
>  };
>  
>  static bool is_simple_bridge(struct node *node)

-- 
David Gibson			| I'll have my music baroque, and my code
david AT gibson.dropbear.id.au	| minimalist, thank you.  NOT _the_ _other_
				| _way_ _around_!
http://www.ozlabs.org/~dgibson

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