Re: [PATCH v3 5/6] MIPS: implement architecture-specific 'pci_remap_iospace()'

From: "Jiaxun Yang" <jiaxun.yang@flygoat.com>
To: "Xi Ruoyao" <xry111@mengyan1223.wang>,
	"Sergio Paracuellos" <sergio.paracuellos@gmail.com>,
	"Thomas Bogendoerfer" <tsbogend@alpha.franken.de>
Cc: robh@kernel.org, "Arnd Bergmann" <arnd@arndb.de>,
	catalin.marinas@arm.com, Liviu.Dudau@arm.com,
	"Bjorn Helgaas" <bhelgaas@google.com>,
	matthias.bgg@gmail.com,
	"Greg Kroah-Hartman" <gregkh@linuxfoundation.org>,
	"linux-mips@vger.kernel.org" <linux-mips@vger.kernel.org>,
	linux-pci <linux-pci@vger.kernel.org>,
	linux-staging@lists.linux.dev, neil@brown.name,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH v3 5/6] MIPS: implement architecture-specific 'pci_remap_iospace()'
Date: Thu, 16 Dec 2021 13:07:43 +0000	[thread overview]
Message-ID: <6ee31420-ef67-471e-a924-a0158b4a9428@www.fastmail.com> (raw)
In-Reply-To: <67687e579e633d42dc501cfb6746c1cb9f600112.camel@mengyan1223.wang>

在2021年12月16日十二月 上午11:44，Xi Ruoyao写道：
> On Sat, 2021-09-25 at 22:32 +0200, Sergio Paracuellos wrote:
>> To make PCI IO work we need to properly virtually map IO cpu physical address
>> and set this virtual address as the address of the first PCI IO port which
>> is set using function 'set_io_port_base()'.
>> 
>> Acked-by: Arnd Bergmann <arnd@arndb.de>
>> Signed-off-by: Sergio Paracuellos <sergio.paracuellos@gmail.com>
>
> Hi,
>
> the change is causing a WARNING on loongson64g-4core-ls7a:
>
> [    0.105781] loongson-pci 1a000000.pci:       IO 
> 0x0018020000..0x001803ffff ->
>  0x0000020000
> [    0.105792] loongson-pci 1a000000.pci:      MEM 
> 0x0040000000..0x007fffffff ->
>  0x0040000000
> [    0.105801] ------------[ cut here ]------------
> [    0.105804] WARNING: CPU: 0 PID: 1 at arch/mips/pci/pci-generic.c:55 
> pci_remap_iospace+0x80/0x88
> [    0.105815] resource start address is not zero
>
> I'm not sure how to fix this one.
>
>> ---
>>  arch/mips/include/asm/pci.h |  2 ++
>>  arch/mips/pci/pci-generic.c | 14 ++++++++++++++
>>  2 files changed, 16 insertions(+)
>> 
>> diff --git a/arch/mips/include/asm/pci.h b/arch/mips/include/asm/pci.h
>> index 9ffc8192adae..35270984a5f0 100644
>> --- a/arch/mips/include/asm/pci.h
>> +++ b/arch/mips/include/asm/pci.h
>> @@ -20,6 +20,8 @@
>>  #include <linux/list.h>
>>  #include <linux/of.h>
>>  
>> +#define pci_remap_iospace pci_remap_iospace
>> +
>>  #ifdef CONFIG_PCI_DRIVERS_LEGACY
>>  
>>  /*
>> diff --git a/arch/mips/pci/pci-generic.c b/arch/mips/pci/pci-generic.c
>> index 95b00017886c..18eb8a453a86 100644
>> --- a/arch/mips/pci/pci-generic.c
>> +++ b/arch/mips/pci/pci-generic.c
>> @@ -46,3 +46,17 @@ void pcibios_fixup_bus(struct pci_bus *bus)
>>  {
>>         pci_read_bridge_bases(bus);
>>  }
>> +
>> +int pci_remap_iospace(const struct resource *res, phys_addr_t phys_addr)
>> +{
>> +       unsigned long vaddr;
>> +
>> +       if (res->start != 0) {
>> +               WARN_ONCE(1, "resource start address is not zero\n");
>> +               return -ENODEV;
>> +       }
>> +
>> +       vaddr = (unsigned long)ioremap(phys_addr, resource_size(res));
>> +       set_io_port_base(vaddr);
>> +       return 0;
>> +}

Hi all,

Another way could be keeping a linked list about PIO->PHYS mapping instead of using the single io_port_base variable.

Thanks.

>
> -- 
> Xi Ruoyao <xry111@mengyan1223.wang>
> School of Aerospace Science and Technology, Xidian University

-- 
- Jiaxun