linux-kernel - Re: [PATCH] irqchip/bcm-6345-l1: show MMIO address

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Message-ID: <CAKR-sGdkQeyvSNouVTZPXsSKP8Dzh+DM8YxXf-93K4orqKrifA@mail.gmail.com>
Date:   Thu, 16 Mar 2023 20:34:07 +0100
From:   Álvaro Fernández Rojas <noltari@...il.com>
To:     Florian Fainelli <f.fainelli@...il.com>
Cc:     jonas.gorski@...il.com, bcm-kernel-feedback-list@...adcom.com,
        tglx@...utronix.de, maz@...nel.org, linux-mips@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH] irqchip/bcm-6345-l1: show MMIO address

El jue, 16 mar 2023 a las 20:10, Florian Fainelli
(<f.fainelli@...il.com>) escribió:
>
> On 3/16/23 12:04, Álvaro Fernández Rojas wrote:
> > El jue, 16 mar 2023 a las 19:13, Florian Fainelli
> > (<f.fainelli@...il.com>) escribió:
> >>
> >> On 3/16/23 11:07, Álvaro Fernández Rojas wrote:
> >>> It's safe to show MMIO address.
> >>>
> >>> Signed-off-by: Álvaro Fernández Rojas <noltari@...il.com>
> >>
> >> This is going to be the kernel virtual address, and while on MIPS it is
> >> easy to resolve to the physical address because these platforms map
> >> registers through KSEG0/1, on other platforms like ARM/ARM64 the kernel
> >> virtual addresses are pretty meaningless unless what you want to debug
> >> is how ioremap() mapped the address.
> >>
> >> I would rather do the following change:
> >>
> >> diff --git a/drivers/irqchip/irq-bcm6345-l1.c
> >> b/drivers/irqchip/irq-bcm6345-l1.c
> >> index 1bd0621c4ce2..832957d363a4 100644
> >> --- a/drivers/irqchip/irq-bcm6345-l1.c
> >> +++ b/drivers/irqchip/irq-bcm6345-l1.c
> >> @@ -261,6 +261,8 @@ static int __init bcm6345_l1_init_one(struct
> >> device_node *dn,
> >>           if (!cpu->map_base)
> >>                   return -ENOMEM;
> >>
> >> +       request_mem_region(res.start, sz, res.name);
> >> +
> >>           for (i = 0; i < n_words; i++) {
> >>                   cpu->enable_cache[i] = 0;
> >>                   __raw_writel(0, cpu->map_base + reg_enable(intc, i));
> >>
> >> such that this shows up in /proc/iomem. WDYT?
> >
> > I tried doing it that way, but it still shows (ptrval):
> > [    0.000000] irq_bcm6345_l1: registered BCM6345 L1 intc (IRQs: 32)
> > [    0.000000] irq_bcm6345_l1:   CPU0 at MMIO 0x(ptrval) (irq = 2)
>
> Well yes, if you don't remove the pr_info() you are still going to be
> printing it, and because map_base is the return of ioremap() which is a
> kernel virtual address, it is still hashed, also see Marc's message that
> came in. I guess I should have been way more explicit and also provide a
> tentative patch that also took out the pr_info().

Ah, sorry for that, I didn't get your point...
However, I'd rather keep the pr_info, so I just removed the MMIO address in v2.

>
> >
> > I checked /proc/iomem and it's shown:
> > root@...nWrt:/# cat /proc/iomem
> > 00000000-03ffffff : System RAM
> >    00010000-0068e96f : Kernel code
> >    0068e970-008834ff : Kernel data
> >    01610000-016458e7 : Kernel bss
> > 08000000-0800ffff : BCM6348 PCI IO space
> > 1e000000-1fffffff : 1e000000.nor nor@...00000
> > 30000000-37ffffff : pci@...e1000
> >    30000000-3000ffff : 0000:00:01.0
> >      30000000-3000ffff : ath9k
> > fffe0004-fffe0007 : fffe0004.clock-controller clock-controller@...e0004
> > fffe000c-fffe0013 : interrupt-controller@...e000c
> > fffe0034-fffe0037 : fffe0034.reset-controller reset-controller@...e0034
> > fffe005c-fffe0067 : fffe005c.watchdog watchdog@...e005c
> > fffe0100-fffe0117 : fffe0100.serial serial@...e0100
> > fffe1000-fffe11ff : fffe1000.pci pci
> > fffe1300-fffe13ff : fffe1300.usb usb@...e1300
> > fffe1400-fffe14ff : fffe1400.usb usb@...e1400
> > fffe1500-fffe1537 : fffe1500.usb-phy usb-phy@...e1500
> >
> > Any idea why this could be hapenning?
>
> We now have the desired resource listed using its physical address:
>
> fffe000c-fffe0013 : interrupt-controller@...e000c
>
> There could be a variety of improvements to how request_mem_region() is
> called if you want to provide a break down of each resource on a per-CPU
> basis.
> --
> Florian
>

Álvaro