linux-kernel - Re: [PATCH 2/5] MIPS: Loongson64: Process ISA Node in DeviceTree

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Date:   Mon, 20 Jul 2020 18:01:07 +0800
From:   Huacai Chen <chenhc@...ote.com>
To:     Jiaxun Yang <jiaxun.yang@...goat.com>
Cc:     "open list:MIPS" <linux-mips@...r.kernel.org>,
        Rob Herring <robh+dt@...nel.org>,
        Thomas Bogendoerfer <tsbogend@...ha.franken.de>,
        Frank Rowand <frowand.list@...il.com>,
        Paul Burton <paulburton@...nel.org>,
        Nathan Chancellor <natechancellor@...il.com>,
        Nick Desaulniers <ndesaulniers@...gle.com>,
        devicetree@...r.kernel.org, LKML <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 2/5] MIPS: Loongson64: Process ISA Node in DeviceTree

Hi, Jiaxun,

On Mon, Jul 20, 2020 at 3:44 PM Jiaxun Yang <jiaxun.yang@...goat.com> wrote:
>
> Previously, we're hardcoding resserved ISA I/O Space in code, now
> we're processing reverved I/O via DeviceTree directly. Using the ranges
> property to determine the size and address of reserved I/O space.
Maybe it is better to reserve a default legacy io range if there is no
"isa" node in the .dts file?

Huacai
>
> Signed-off-by: Jiaxun Yang <jiaxun.yang@...goat.com>
> ---
>  arch/mips/loongson64/init.c | 85 ++++++++++++++++++++++++++-----------
>  1 file changed, 60 insertions(+), 25 deletions(-)
>
> diff --git a/arch/mips/loongson64/init.c b/arch/mips/loongson64/init.c
> index 59ddadace83f..028d7b324ec2 100644
> --- a/arch/mips/loongson64/init.c
> +++ b/arch/mips/loongson64/init.c
> @@ -7,6 +7,8 @@
>  #include <linux/irqchip.h>
>  #include <linux/logic_pio.h>
>  #include <linux/memblock.h>
> +#include <linux/of.h>
> +#include <linux/of_address.h>
>  #include <asm/bootinfo.h>
>  #include <asm/traps.h>
>  #include <asm/smp-ops.h>
> @@ -63,41 +65,74 @@ void __init prom_free_prom_memory(void)
>  {
>  }
>
> -static __init void reserve_pio_range(void)
> +static int __init add_legacy_isa_io(struct fwnode_handle *fwnode, phys_addr_t addr,
> +                            resource_size_t    size)
>  {
> +       int ret = 0;
>         struct logic_pio_hwaddr *range;
> +       unsigned long vaddr;
>
>         range = kzalloc(sizeof(*range), GFP_ATOMIC);
>         if (!range)
> -               return;
> +               return -ENOMEM;
>
> -       range->fwnode = &of_root->fwnode;
> -       range->size = MMIO_LOWER_RESERVED;
> -       range->hw_start = LOONGSON_PCIIO_BASE;
> +       range->fwnode = fwnode;
> +       range->size = size;
> +       range->hw_start = addr;
>         range->flags = LOGIC_PIO_CPU_MMIO;
>
> -       if (logic_pio_register_range(range)) {
> -               pr_err("Failed to reserve PIO range for legacy ISA\n");
> -               goto free_range;
> +       ret = logic_pio_register_range(range);
> +       if (ret) {
> +               kfree(range);
> +               return ret;
> +       }
> +
> +       /* Legacy ISA must placed at the start of PCI_IOBASE */
> +       if (range->io_start != 0) {
> +               logic_pio_unregister_range(range);
> +               kfree(range);
> +               return -EINVAL;
>         }
>
> -       if (WARN(range->io_start != 0,
> -                       "Reserved PIO range does not start from 0\n"))
> -               goto unregister;
> -
> -       /*
> -        * i8259 would access I/O space, so mapping must be done here.
> -        * Please remove it when all drivers can be managed by logic_pio.
> -        */
> -       ioremap_page_range(PCI_IOBASE, PCI_IOBASE + MMIO_LOWER_RESERVED,
> -                               LOONGSON_PCIIO_BASE,
> -                               pgprot_device(PAGE_KERNEL));
> -
> -       return;
> -unregister:
> -       logic_pio_unregister_range(range);
> -free_range:
> -       kfree(range);
> +       vaddr = PCI_IOBASE + range->io_start;
> +
> +       ioremap_page_range(vaddr, vaddr + size, addr, pgprot_device(PAGE_KERNEL));
> +
> +       return 0;
> +}
> +
> +static __init void reserve_pio_range(void)
> +{
> +       struct device_node *np;
> +
> +       for_each_node_by_name(np, "isa") {
> +               struct of_pci_range range;
> +               struct of_pci_range_parser parser;
> +
> +               pr_info("ISA Bridge: %pOF\n", np);
> +
> +               if (of_pci_range_parser_init(&parser, np)) {
> +                       pr_info("Failed to parse resources.\n");
> +                       break;
> +               }
> +
> +               for_each_of_pci_range(&parser, &range) {
> +                       switch (range.flags & IORESOURCE_TYPE_BITS) {
> +                       case IORESOURCE_IO:
> +                               pr_info(" IO 0x%016llx..0x%016llx\n",
> +                                       range.cpu_addr,
> +                                       range.cpu_addr + range.size - 1);
> +                               if (add_legacy_isa_io(&np->fwnode, range.cpu_addr, range.size))
> +                                       pr_warn("Failed to reserve legacy IO in Logic PIO\n");
> +                               break;
> +                       case IORESOURCE_MEM:
> +                               pr_info(" MEM 0x%016llx..0x%016llx\n",
> +                                       range.cpu_addr,
> +                                       range.cpu_addr + range.size - 1);
> +                               break;
> +                       }
> +               }
> +       }
>  }
>
>  void __init arch_init_irq(void)
> --
> 2.28.0.rc1
>