[PATCH v2] lib: utils/irqchip: Automatically delegate T-HEAD PLIC access

[Anup Patel]

On Mon, Oct 18, 2021 at 11:04 AM Samuel Holland <samuel at sholland.org> wrote:
>
> The T-HEAD PLIC implementation requires setting a delegation bit
> to allow access from S-mode. Now that the T-HEAD PLIC has its own
> compatible string, set this bit automatically from the PLIC driver,
> instead of reaching into the PLIC's MMIO space from another driver.
>
> Signed-off-by: Samuel Holland <samuel at sholland.org>
>
> ---
>
> Changes in v2:
>  - Use the thead,c900-plic compatible instead of the D1 compatible.
>  - Also apply this change to other T-HEAD device tree examples.
>  - Remove the plic-delegate code from the thead,reset-sample driver.
>  - Drop the return value from thead_plic_plat_init().

Looks good to me.

Reviewed-by: Anup Patel <anup.patel at wdc.com>

Applied this patch to the riscv/opensbi repo.

Thanks,
Anup

>
> The compatible string is added in the patch series here:
> https://lore.kernel.org/linux-riscv/20211016032200.2869998-1-guoren@kernel.org/T/
> ---
>  docs/platform/thead-c9xx.md          | 12 +++---------
>  lib/utils/irqchip/fdt_irqchip_plic.c | 15 +++++++++++++++
>  lib/utils/reset/fdt_reset_thead.c    |  8 --------
>  3 files changed, 18 insertions(+), 17 deletions(-)
>
> diff --git a/docs/platform/thead-c9xx.md b/docs/platform/thead-c9xx.md
> index c0daeb7..3490ed5 100644
> --- a/docs/platform/thead-c9xx.md
> +++ b/docs/platform/thead-c9xx.md
> @@ -51,11 +51,6 @@ DTS Example1: (Single core, eg: Allwinner D1 - c906)
>                 compatible = "simple-bus";
>                 ranges;
>
> -               reset: reset-sample {
> -                       compatible = "thead,reset-sample";
> -                       plic-delegate = <0x0 0x101ffffc>;
> -               };
> -
>                 clint0: clint at 14000000 {
>                         compatible = "riscv,clint0";
>                         interrupts-extended = <
> @@ -67,7 +62,8 @@ DTS Example1: (Single core, eg: Allwinner D1 - c906)
>
>                 intc: interrupt-controller at 10000000 {
>                         #interrupt-cells = <1>;
> -                       compatible = "riscv,plic0";
> +                       compatible = "allwinner,sun20i-d1-plic",
> +                                    "thead,c900-plic";
>                         interrupt-controller;
>                         interrupts-extended = <
>                                 &cpu0_intc  0xffffffff &cpu0_intc  9
> @@ -150,7 +146,6 @@ DTS Example2: (Multi cores with soc reset-regs)
>
>                 reset: reset-sample {
>                         compatible = "thead,reset-sample";
> -                       plic-delegate = <0xff 0xd81ffffc>;
>                         entry-reg = <0xff 0xff019050>;
>                         entry-cnt = <4>;
>                         control-reg = <0xff 0xff015004>;
> @@ -173,7 +168,7 @@ DTS Example2: (Multi cores with soc reset-regs)
>
>                 intc: interrupt-controller at ffd8000000 {
>                         #interrupt-cells = <1>;
> -                       compatible = "riscv,plic0";
> +                       compatible = "thead,c900-plic";
>                         interrupt-controller;
>                         interrupts-extended = <
>                                 &cpu0_intc  0xffffffff &cpu0_intc  9
> @@ -194,7 +189,6 @@ DTS Example2: (Multi cores with old reset csrs)
>  ```
>         reset: reset-sample {
>                 compatible = "thead,reset-sample";
> -               plic-delegate = <0xff 0xd81ffffc>;
>                 using-csr-reset;
>                 csr-copy = <0x7c0 0x7c1 0x7c2 0x7c3 0x7c5 0x7cc
>                             0x3b0 0x3b1 0x3b2 0x3b3
> diff --git a/lib/utils/irqchip/fdt_irqchip_plic.c b/lib/utils/irqchip/fdt_irqchip_plic.c
> index 18d2797..8d375be 100644
> --- a/lib/utils/irqchip/fdt_irqchip_plic.c
> +++ b/lib/utils/irqchip/fdt_irqchip_plic.c
> @@ -9,6 +9,7 @@
>
>  #include <libfdt.h>
>  #include <sbi/riscv_asm.h>
> +#include <sbi/riscv_io.h>
>  #include <sbi/sbi_error.h>
>  #include <sbi/sbi_hartmask.h>
>  #include <sbi_utils/fdt/fdt_helper.h>
> @@ -91,6 +92,11 @@ static int irqchip_plic_cold_init(void *fdt, int nodeoff,
>         if (rc)
>                 return rc;
>
> +       if (match->data) {
> +               void (*plic_plat_init)(struct plic_data *) = match->data;
> +               plic_plat_init(pd);
> +       }
> +
>         rc = plic_cold_irqchip_init(pd);
>         if (rc)
>                 return rc;
> @@ -106,9 +112,18 @@ static int irqchip_plic_cold_init(void *fdt, int nodeoff,
>         return irqchip_plic_update_hartid_table(fdt, nodeoff, pd);
>  }
>
> +#define THEAD_PLIC_CTRL_REG 0x1ffffc
> +
> +static void thead_plic_plat_init(struct plic_data *pd)
> +{
> +       writel_relaxed(BIT(0), (void *)pd->addr + THEAD_PLIC_CTRL_REG);
> +}
> +
>  static const struct fdt_match irqchip_plic_match[] = {
>         { .compatible = "riscv,plic0" },
>         { .compatible = "sifive,plic-1.0.0" },
> +       { .compatible = "thead,c900-plic",
> +         .data = thead_plic_plat_init },
>         { },
>  };
>
> diff --git a/lib/utils/reset/fdt_reset_thead.c b/lib/utils/reset/fdt_reset_thead.c
> index 750b7aa..d491687 100644
> --- a/lib/utils/reset/fdt_reset_thead.c
> +++ b/lib/utils/reset/fdt_reset_thead.c
> @@ -82,14 +82,6 @@ static int thead_reset_init(void *fdt, int nodeoff,
>                         clone_csrs(cnt);
>         }
>
> -
> -       /* Delegate plic enable regs for S-mode */
> -       val = fdt_getprop(fdt, nodeoff, "plic-delegate", &len);
> -       if (len > 0 && val) {
> -               p = (void *)(ulong)fdt64_to_cpu(*val);
> -               writel(BIT(0), p);
> -       }
> -
>         /* Old reset method for secondary harts */
>         if (fdt_getprop(fdt, nodeoff, "using-csr-reset", &len)) {
>                 csr_write(0x7c7, (ulong)&__thead_pre_start_warm);
> --
> 2.32.0
>
>
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