Re: åå:[PATCH 4/6] MIPS: Loongson: Add DMA support for 7A1000

[Tiezhu Yang]

On 03/09/2020 04:44 PM, Jiaxun Yang wrote:
>   ---- å ææä, 2020-03-09 16:23:24 Tiezhu Yang <yangtiezhu@xxxxxxxxxxx> æå ----
>   > Implement __phys_to_dma() and __dma_to_phys() according to the
>   > node id offset in 7A1000 DMA route config register.
>
> That design shocked me a lot. And It is known that some firmware didn't configure
> HT Recieve window correctly to make it work. So probably for mainline kernel,
> just set DMA_MASK to limit LS7A DMA address to Node0 would be a better Option?

Hi Jiaxun,

Let me rethink it and find a proper way.

>   
>   > Signed-off-by: Tiezhu Yang <yangtiezhu@xxxxxxxxxxx>
>   > ---
>   >  arch/mips/include/asm/mach-loongson64/boot_param.h |  1 +
>   >  arch/mips/loongson64/dma.c                         | 49 +++++++++++++++++++++-
>   >  arch/mips/loongson64/init.c                        | 13 ++++++
>   >  3 files changed, 61 insertions(+), 2 deletions(-)
>   >
>   > diff --git a/arch/mips/include/asm/mach-loongson64/boot_param.h b/arch/mips/include/asm/mach-loongson64/boot_param.h
>   > index 225a563..60e7a7e 100644
>   > --- a/arch/mips/include/asm/mach-loongson64/boot_param.h
>   > +++ b/arch/mips/include/asm/mach-loongson64/boot_param.h
>   > @@ -218,5 +218,6 @@ struct loongson_system_configuration {
>   >  extern struct efi_memory_map_loongson *loongson_memmap;
>   >  extern struct loongson_system_configuration loongson_sysconf;
>   >  extern struct board_devices *eboard;
>   > +extern u32 node_id_offset;
>   >
>   >  #endif
>   > diff --git a/arch/mips/loongson64/dma.c b/arch/mips/loongson64/dma.c
>   > index 5e86635..997c257 100644
>   > --- a/arch/mips/loongson64/dma.c
>   > +++ b/arch/mips/loongson64/dma.c
>   > @@ -2,24 +2,69 @@
>   >  #include <linux/dma-direct.h>
>   >  #include <linux/init.h>
>   >  #include <linux/swiotlb.h>
>   > +#include <boot_param.h>
>   >
>   > -dma_addr_t __phys_to_dma(struct device *dev, phys_addr_t paddr)
>   > +struct loongson_dma_ops {
>   > +    dma_addr_t (*phys_to_dma)(struct device *dev, phys_addr_t paddr);
>   > +    phys_addr_t (*dma_to_phys)(struct device *dev, dma_addr_t daddr);
>   > +};
>   > +
>   > +struct loongson_dma_ops loongson_dma;
>   > +
>   > +dma_addr_t __rs780e_phys_to_dma(struct device *dev, phys_addr_t paddr)
>   >  {
>   >      /* We extract 2bit node id (bit 44~47, only bit 44~45 used now) from
>   >       * Loongson-3's 48bit address space and embed it into 40bit */
>   >      long nid = (paddr >> 44) & 0x3;
>   > +
>   >      return ((nid << 44) ^ paddr) | (nid << 37);
>   >  }
>   >
>   > -phys_addr_t __dma_to_phys(struct device *dev, dma_addr_t daddr)
>   > +dma_addr_t __ls7a_phys_to_dma(struct device *dev, phys_addr_t paddr)
>   > +{
>   > +    long nid = (paddr >> 44) & 0x3;
>   > +
>   > +    return ((nid << 44) ^ paddr) | (nid << (36 + node_id_offset));
>   > +}
>   > +
>   > +
>   > +dma_addr_t __phys_to_dma(struct device *dev, phys_addr_t paddr)
>   > +{
>   > +    return loongson_dma.phys_to_dma(dev, paddr);
>   > +}
>   > +
>   > +phys_addr_t __rs780e_dma_to_phys(struct device *dev, dma_addr_t daddr)
>   >  {
>   >      /* We extract 2bit node id (bit 44~47, only bit 44~45 used now) from
>   >       * Loongson-3's 48bit address space and embed it into 40bit */
>   >      long nid = (daddr >> 37) & 0x3;
>   > +
>   >      return ((nid << 37) ^ daddr) | (nid << 44);
>   >  }
>   >
>   > +phys_addr_t __ls7a_dma_to_phys(struct device *dev, dma_addr_t daddr)
>   > +{
>   > +    long nid = (daddr >> (36 + node_id_offset)) & 0x3;
>   > +
>   > +    return ((nid << (36 + node_id_offset)) ^ daddr) | (nid << 44);
>   > +}
>   > +
>   > +phys_addr_t __dma_to_phys(struct device *dev, dma_addr_t daddr)
>   > +{
>   > +    return loongson_dma.dma_to_phys(dev, daddr);
>   > +}
>   > +
>   >  void __init plat_swiotlb_setup(void)
>   >  {
>   >      swiotlb_init(1);
>   > +
>   > +    if (strstr(eboard->name, "780E")) {
>   > +        loongson_dma.phys_to_dma = __rs780e_phys_to_dma;
>   > +        loongson_dma.dma_to_phys = __rs780e_dma_to_phys;
>   > +    }
>   > +
>   > +    if (strstr(eboard->name, "7A1000")) {
>   > +        loongson_dma.phys_to_dma = __ls7a_phys_to_dma;
>   > +        loongson_dma.dma_to_phys = __ls7a_dma_to_phys;
>   > +    }
>   >  }
>   > diff --git a/arch/mips/loongson64/init.c b/arch/mips/loongson64/init.c
>   > index 5ac1a0f..dd8463d 100644
>   > --- a/arch/mips/loongson64/init.c
>   > +++ b/arch/mips/loongson64/init.c
>   > @@ -12,6 +12,11 @@
>   >  #include <asm/fw/fw.h>
>   >
>   >  #include <loongson.h>
>   > +#include <boot_param.h>
>   > +
>   > +#define NODE_ID_OFFSET_ADDR     0x90000E001001041CULL
>   > +
>   > +u32 node_id_offset;
>   >
>   >  static void __init mips_nmi_setup(void)
>   >  {
>   > @@ -23,6 +28,11 @@ static void __init mips_nmi_setup(void)
>   >      flush_icache_range((unsigned long)base, (unsigned long)base + 0x80);
>   >  }
>   >
>   > +static void ls7a_early_config(void)
>   > +{
>   > +    node_id_offset = (*(u32 *)NODE_ID_OFFSET_ADDR >> 8) & 0x1F;
>
> Please avoid raw pointer. Use readl/writel instead.

OK, I will do it.

Thanks,

Tiezhu Yang

>   > +}
>   > +
>   >  void __init prom_init(void)
>   >  {
>   >      fw_init_cmdline();
>   > @@ -32,6 +42,9 @@ void __init prom_init(void)
>   >      set_io_port_base((unsigned long)
>   >          ioremap(LOONGSON_PCIIO_BASE, LOONGSON_PCIIO_SIZE));
>   >
>   > +    if (strstr(eboard->name, "7A1000"))
>   > +        ls7a_early_config();
>   > +
>   >      prom_init_numa_memory();
>   >
>   >      /* Hardcode to CPU UART 0 */
>   > --
>   > 2.1.0
>   >
>   >