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SubjectRe: [PATCH v3] x86/PCI: Add support for the Intel 82378ZB/82379AB (SIO/SIO.A) PIRQ router
On Sun, Jan 02, 2022 at 11:24:52PM +0000, Maciej W. Rozycki wrote:
> The Intel 82378ZB System I/O (SIO) and 82379AB System I/O APIC (SIO.A)
> ISA bridges implement PCI interrupt steering with a PIRQ router[1][2]
> that is exactly the same as that of the PIIX and ICH southbridges (or
> actually the other way round, given that the SIO ASIC was there first).
>
> An earlier version of the SIO, the 82378IB[3][4], does not implement PCI
> interrupt steering however, so we need to exclude it by checking the low
> nibble of the PCI Revision Identification Register[5][6] for being at
> least 3.
>
> There is a note in the 82379AB specification update[7] saying that the
> device ID for that chip is 0x7, rather than 0x484 as stated in the
> datasheet[8]. It looks like a red herring however, for no report has
> been ever seen with that value quoted and it matches the documented
> default value of the PCI Command Register, which comes next after the
> PCI Device Identification Register, so it looks like a copy-&-paste
> editorial mistake.
>
> NB the 82378ZB has been commonly used with smaller DEC Alpha systems
> with the contents of the Revision Identification Register reported as
> one of 0x3, 0x43, or 0x84, so the masking of the high nibble seems
> indeed right by empirical observation. The value in the high nibble
> might be either random, or depend on the batch, or correspond to some
> other state such as reset straps.
>
> References:
>
> [1] "82378 System I/O (SIO)", Intel Corporation, Order Number:
> 290473-004, December 1994, Section 4.1.26 "PIRQ[3:0]#--PIRQ Route
> Control Registers"
>
> [2] "82378ZB System I/O (SIO) and 82379AB System I/O APIC (SIO.A)",
> Intel Corporation, Order Number: 290571-001, March 1996, Section
> 3.1.25. "PIRQ[3:0]#--PIRQ Route Control Registers", p. 48
>
> [3] "82378IB System I/O (SIO)", Intel Corporation, Order Number:
> 290473-002, April 1993, Section 5.8.7.7 "Edge and Level Triggered
> Modes"
>
> [4] "82378IB to 82378ZB Errata Fix and Feature Enhancement Conversion
> FOL933002-01",
> <https://web.archive.org/web/19990421045433/http://support.intel.com/support/chipsets/420/8511.htm>
>
> [5] "82378 System I/O (SIO)", Intel Corporation, Order Number:
> 290473-004, December 1994, Section 4.1.5. "RID--Revision
> Identification Register"
>
> [6] "82378ZB System I/O (SIO) and 82379AB System I/O APIC (SIO.A)",
> Intel Corporation, Order Number: 290571-001, March 1996, Section
> 3.1.5. "RID--Revision Identification Register", p. 34
>
> [7] "Intel 82379AB (SIO.A) System I/O Component Specification Update",
> Intel Corporation, Order Number: 297734-001, May, 1996, "Component
> Identification via Programming Interface", p. 5
>
> [8] "82378ZB System I/O (SIO) and 82379AB System I/O APIC (SIO.A)",
> Intel Corporation, Order Number: 290571-001, March 1996, Section
> 3.1.2. "DID--Device Identification Register", p. 33
>
> Signed-off-by: Maciej W. Rozycki <macro@orcam.me.uk>
> ---
> Hi,
>
> Reposting as it seems to have been missed and now needs to be regenerated
> to resolve a merge conflict with a later change that did make it.
>
> Please apply.

No objection from me, but I know zero about this code, so I'll let the
x86/IRQ guys deal with this.

> Changes from v2:
>
> - Regenerate for a merge conflict.
>
> Changes from v1:
>
> - Add [PATCH] annotation (umm...).
>
> - Fix RID values listed to include 0x84 rather than 0x83 (braino).
> ---
> arch/x86/pci/irq.c | 11 +++++++++--
> 1 file changed, 9 insertions(+), 2 deletions(-)
>
> linux-x86-pirq-router-sio.diff
> Index: linux-macro/arch/x86/pci/irq.c
> ===================================================================
> --- linux-macro.orig/arch/x86/pci/irq.c
> +++ linux-macro/arch/x86/pci/irq.c
> @@ -801,11 +801,18 @@ static __init int intel_router_probe(str
> return 0;
>
> switch (device) {
> + u8 rid;
> case PCI_DEVICE_ID_INTEL_82375:
> r->name = "PCEB/ESC";
> r->get = pirq_esc_get;
> r->set = pirq_esc_set;
> return 1;
> + case PCI_DEVICE_ID_INTEL_82378:
> + pci_read_config_byte(router, PCI_REVISION_ID, &rid);
> + /* Tell 82378IB (rev < 3) and 82378ZB/82379AB apart. */
> + if ((rid & 0xfu) < 3)
> + break;
> + fallthrough;
> case PCI_DEVICE_ID_INTEL_82371FB_0:
> case PCI_DEVICE_ID_INTEL_82371SB_0:
> case PCI_DEVICE_ID_INTEL_82371AB_0:
> @@ -847,7 +854,7 @@ static __init int intel_router_probe(str
> case PCI_DEVICE_ID_INTEL_ICH10_3:
> case PCI_DEVICE_ID_INTEL_PATSBURG_LPC_0:
> case PCI_DEVICE_ID_INTEL_PATSBURG_LPC_1:
> - r->name = "PIIX/ICH";
> + r->name = "SIO/PIIX/ICH";
> r->get = pirq_piix_get;
> r->set = pirq_piix_set;
> return 1;
> @@ -866,7 +873,7 @@ static __init int intel_router_probe(str
> device <= PCI_DEVICE_ID_INTEL_DH89XXCC_LPC_MAX)
> || (device >= PCI_DEVICE_ID_INTEL_PANTHERPOINT_LPC_MIN &&
> device <= PCI_DEVICE_ID_INTEL_PANTHERPOINT_LPC_MAX)) {
> - r->name = "PIIX/ICH";
> + r->name = "SIO/PIIX/ICH";
> r->get = pirq_piix_get;
> r->set = pirq_piix_set;
> return 1;

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