On Mon, Mar 3, 2014 at 4:01 PM, Jason Gunthorpe <jgunthorpe@xxxxxxxxxxxxxxxxxxxx> wrote: > On Mon, Mar 03, 2014 at 03:40:43PM -0800, Tim Harvey wrote: > >> of_irq_parse_and_map_pci(). The GIC function that translates the >> interrupt per domain is given irq_data: 0x123 0x04 0x00 > > This has been shifted by 1 byte.. > >> IRQ 123, which should get 32 added to it for irq155). Instead, the >> implementation of gic_irq_domain_xlate() >> (http://lxr.missinglinkelectronics.com/linux/drivers/irqchip/irq-gic.c#L832) >> adds 32 to the 0x04 returning 20: >> [ 1.841781] of_irq_parse_raw: /soc/pcie@0x01000000:00000001 >> [ 1.841813] of_irq_parse_raw: ipar=/soc/pcie@0x01000000, size=1 >> [ 1.841838] -> addrsize=3 >> [ 1.841870] -> match=1 (imaplen=28) > ^^^^^^^^^^^^^ > > That looks odd, it should be the number of dwords in the > interrupt-map, you have 4 lines of 8 dwords each, so it should be > 32. (+cc Grant Likely) imaplen does indeed get initialized to 32 (size of interrupt-map / sizeof(u32)) but its printed above after its been decremented in the loop which is misleading (http://lxr.missinglinkelectronics.com/linux/drivers/of/irq.c#L201) The issue appears to me to be a bug in of_irq_parse_raw() which has been around since Graht's original commit: http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/drivers/of/irq.c?id=7dc2e1134a22dc242175d5321c0c9e97d16eb87b diff --git a/drivers/of/irq.c b/drivers/of/irq.c index 9bcf2cf..8829197 100644 --- a/drivers/of/irq.c +++ b/drivers/of/irq.c @@ -237,11 +237,11 @@ int of_irq_parse_raw(const __be32 *addr, struct of_phandle /* Check for malformed properties */ if (WARN_ON(newaddrsize + newintsize > MAX_PHANDLE_ARGS) goto fail; - if (imaplen < (newaddrsize + newintsize)) + if (imaplen < newintsize) goto fail; - imap += newaddrsize + newintsize; - imaplen -= newaddrsize + newintsize; + imap += newintsize; + imaplen -= newintsize; pr_debug(" -> imaplen=%d\n", imaplen); } The issue is that the interrupt-map table point (imap) needs to be incremented over the parent unit interrupt specifier which is newintsize cells, not newaddrsize + newintsize cells. The invalid calculation would cause the pointer to get mis-aligned and thus only the first interrupt entry would ever get properly checked for a match. It looks like of_irq_parse_raw() is only called from of_irq_parse_pci() which prior to Lucas' patch was only called from pci_read_irq_line() called from pcibios_setup_device() used in arch/arm/powerpc, so perhaps this function isn't widely used explaining why the bug was never caught. I'll post a patch shortly with the above fix. <snip> >> [ 1.841972] irq_create_of_mapping: calling xlate for 123/4/0 3 > > And it is the wrong data.. 123/4/0 is right - this is shifted because of the issue above. With the above patch Lucas' original patch now operates correctly to resolve the 4 legacy PCI interrupts required when using a P2P bridge on the IMX6. Tim -- To unsubscribe from this list: send the line "unsubscribe linux-tegra" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
