[openib-general] [PATCH 5/6] Use pci_find_ht_capability() in drivers/pci/quirks.c

[Brice Goglin]

You don't have any TTL in the while loop below, neither in the while
loop in pci_find_next_ht_capability(). It's paranoid, but I'd rather
keep a TTL in both loops (a brain-damaged capability chain in the PCI
config space could lead to an infinite loop without any clue of what's
going on, not easy to find out...).

Apart from that, I like the idea.

Brice



Michael Ellerman wrote:
> Use pci_find_ht_capability() in drivers/pci/quirks.c.
>
> I'm pretty sure the logic is unchanged here, but someone please eye-ball it
> for me. I've changed the message to be a little shorter, it's now:
>
> PCI: Found (enabled|disabled) HT MSI mapping on xxxx:xx:xx.x
>
> Signed-off-by: Michael Ellerman <michael at ellerman.id.au>
> ---
>
>  drivers/pci/quirks.c |   27 +++++++++++++++------------
>  1 file changed, 15 insertions(+), 12 deletions(-)
>
> Index: msi/drivers/pci/quirks.c
> ===================================================================
> --- msi.orig/drivers/pci/quirks.c
> +++ msi/drivers/pci/quirks.c
> @@ -1724,19 +1724,22 @@ DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_AM
>   * return 1 if a HT MSI capability is found and enabled */
>  static int __devinit msi_ht_cap_enabled(struct pci_dev *dev)
>  {
> -	u8 pos;
> -	int ttl;
> -	for (pos = pci_find_capability(dev, PCI_CAP_ID_HT), ttl = 48;
> -	     pos && ttl;
> -	     pos = pci_find_next_capability(dev, pos, PCI_CAP_ID_HT), ttl--) {
> -		u32 cap_hdr;
> -		/* MSI mapping section according to Hypertransport spec */
> -		if (pci_read_config_dword(dev, pos, &cap_hdr) == 0
> -		    && (cap_hdr & 0xf8000000) == 0xa8000000 /* MSI mapping */) {
> -			printk(KERN_INFO "PCI: Found HT MSI mapping on %s with capability %s\n",
> -			       pci_name(dev), cap_hdr & 0x10000 ? "enabled" : "disabled");
> -			return (cap_hdr & 0x10000) != 0; /* MSI mapping cap enabled */
> +	int pos;
> +
> +	pos = pci_find_ht_capability(dev, HT_CAPTYPE_MSI_MAPPING);
> +	while (pos) {
> +		u8 flags;
> +
> +		if (pci_read_config_byte(dev,
> +				pos + HT_MSI_FLAGS, &flags) == 0) {
> +			printk(KERN_INFO "PCI: Found %s HT MSI Mapping on %s\n",
> +				flags & HT_MSI_FLAGS_ENABLE ?
> +				"enabled" : "disabled", pci_name(dev));
> +			return (flags & HT_MSI_FLAGS_ENABLE) != 0;
>  		}
> +
> +		pos = pci_find_next_ht_capability(dev, pos,
> +				HT_CAPTYPE_MSI_MAPPING);
>  	}
>  	return 0;
>  }
>