On Wed, Jan 6, 2021 at 2:42 PM Jim Quinlan <james.quinlan@xxxxxxxxxxxx> wrote: > > ---------- Forwarded message --------- > From: Bjorn Helgaas <helgaas@xxxxxxxxxx> > Date: Wed, Jan 6, 2021 at 2:19 PM > Subject: Re: [PATCH v2 5/6] PCI: brcmstb: Add panic/die handler to RC driver > To: Jim Quinlan <james.quinlan@xxxxxxxxxxxx> > Cc: <linux-pci@xxxxxxxxxxxxxxx>, Nicolas Saenz Julienne > <nsaenzjulienne@xxxxxxx>, <broonie@xxxxxxxxxx>, > <bcm-kernel-feedback-list@xxxxxxxxxxxx>, Lorenzo Pieralisi > <lorenzo.pieralisi@xxxxxxx>, Rob Herring <robh@xxxxxxxxxx>, Bjorn > Helgaas <bhelgaas@xxxxxxxxxx>, Florian Fainelli > <f.fainelli@xxxxxxxxx>, moderated list:BROADCOM BCM2711/BCM2835 ARM > ARCHITECTURE <linux-rpi-kernel@xxxxxxxxxxxxxxxxxxx>, moderated > list:BROADCOM BCM2711/BCM2835 ARM ARCHITECTURE > <linux-arm-kernel@xxxxxxxxxxxxxxxxxxx>, open list > <linux-kernel@xxxxxxxxxxxxxxx> > > > On Mon, Nov 30, 2020 at 04:11:42PM -0500, Jim Quinlan wrote: > > Whereas most PCIe HW returns 0xffffffff on illegal accesses and the like, > > by default Broadcom's STB PCIe controller effects an abort. This simple > > handler determines if the PCIe controller was the cause of the abort and if > > so, prints out diagnostic info. > > > > Example output: > > brcm-pcie 8b20000.pcie: Error: Mem Acc: 32bit, Read, @0x38000000 > > brcm-pcie 8b20000.pcie: Type: TO=0 Abt=0 UnspReq=1 AccDsble=0 BadAddr=0 > > What does this mean for all the other PCI core code that expects > 0xffffffff data returns? Does it work? Does it break differently on > STB than on other platforms? Hi Bjorn, Our PCIe HW causes a CPU abort when this happens. Occasionally a customer will have a fault handler try to fix up the abort and continue on, but we recommend solving the root problem. This commit just gives us a chance to glean info about the problem. Our newer SOCs have a mode that doesn't abort and instead returns 0xffffffff. BTW, can you point me to example files where "PCI core code that expects 0xffffffff data returns" [on bad accesses]? Regards, Jim Quinlan Broadcom STB > > > +/* > > + * Dump out pcie errors on die or panic. > > s/pcie/PCIe/ > This could be a single-line comment. > > > + */ >
