From: Anup Patel <anup@brainfault.org>
To: Atish Patra <atish.patra@wdc.com>
Cc: Albert Ou <aou@eecs.berkeley.edu>,
Jason Cooper <jason@lakedaemon.net>,
Nick Hu <nickhu@andestech.com>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Daniel Lezcano <daniel.lezcano@linaro.org>,
Heiko Carstens <heiko.carstens@de.ibm.com>,
"linux-kernel@vger.kernel.org List"
<linux-kernel@vger.kernel.org>,
Mike Rapoport <rppt@linux.ibm.com>,
"Rafael J. Wysocki" <rafael.j.wysocki@intel.com>,
Vincent Chen <vincent.chen@sifive.com>,
Geert Uytterhoeven <geert@linux-m68k.org>,
"Eric W. Biederman" <ebiederm@xmission.com>,
Paul Walmsley <paul.walmsley@sifive.com>,
Marc Zyngier <maz@kernel.org>,
Palmer Dabbelt <palmer@dabbelt.com>,
linux-riscv <linux-riscv@lists.infradead.org>,
Borislav Petkov <bp@suse.de>,
Thomas Gleixner <tglx@linutronix.de>, Mao Han <han_mao@c-sky.com>,
Kees Cook <keescook@chromium.org>
Subject: Re: [PATCH v9 12/12] irqchip/sifive-plic: Initialize the plic handler when cpu comes online
Date: Fri, 21 Feb 2020 11:44:06 +0530 [thread overview]
Message-ID: <CAAhSdy2nY1LStqDJPU10CN2d=p5XQzkE2RjXdkXoAoumhyO5-A@mail.gmail.com> (raw)
In-Reply-To: <20200221004413.12869-13-atish.patra@wdc.com>
On Fri, Feb 21, 2020 at 6:14 AM Atish Patra <atish.patra@wdc.com> wrote:
>
> Currently, plic threshold and priority are only initialized once in the
> beginning. However, threshold can be set to disabled if cpu is marked
> offline with cpu hotplug feature. This will not allow to change the
> irq affinity to a cpu that just came online.
>
> Add plic specific cpu hotplug callback and initialize the per cpu handler
> when cpu comes online.
>
> Signed-off-by: Atish Patra <atish.patra@wdc.com>
> ---
> arch/riscv/kernel/traps.c | 2 +-
> drivers/irqchip/irq-sifive-plic.c | 38 +++++++++++++++++++++++++++----
> include/linux/cpuhotplug.h | 1 +
> 3 files changed, 36 insertions(+), 5 deletions(-)
>
> diff --git a/arch/riscv/kernel/traps.c b/arch/riscv/kernel/traps.c
> index 8e13ad45ccaa..16c59807da6a 100644
> --- a/arch/riscv/kernel/traps.c
> +++ b/arch/riscv/kernel/traps.c
> @@ -157,5 +157,5 @@ void trap_init(void)
> /* Set the exception vector address */
> csr_write(CSR_TVEC, &handle_exception);
> /* Enable interrupts */
> - csr_write(CSR_IE, IE_SIE | IE_EIE);
> + csr_write(CSR_IE, IE_SIE);
> }
> diff --git a/drivers/irqchip/irq-sifive-plic.c b/drivers/irqchip/irq-sifive-plic.c
> index aa4af886e43a..7c7f37393f99 100644
> --- a/drivers/irqchip/irq-sifive-plic.c
> +++ b/drivers/irqchip/irq-sifive-plic.c
> @@ -4,6 +4,7 @@
> * Copyright (C) 2018 Christoph Hellwig
> */
> #define pr_fmt(fmt) "plic: " fmt
> +#include <linux/cpu.h>
> #include <linux/interrupt.h>
> #include <linux/io.h>
> #include <linux/irq.h>
> @@ -55,6 +56,9 @@
> #define CONTEXT_THRESHOLD 0x00
> #define CONTEXT_CLAIM 0x04
>
> +#define PLIC_DISABLE_THRESHOLD 0xf
> +#define PLIC_ENABLE_THRESHOLD 0
> +
> static void __iomem *plic_regs;
>
> struct plic_handler {
> @@ -230,6 +234,32 @@ static int plic_find_hart_id(struct device_node *node)
> return -1;
> }
>
> +static void plic_set_threshold(struct plic_handler *handler, u32 threshold)
> +{
> + /* priority must be > threshold to trigger an interrupt */
> + writel(threshold, handler->hart_base + CONTEXT_THRESHOLD);
> +}
> +
> +static int plic_dying_cpu(unsigned int cpu)
> +{
> + struct plic_handler *handler = this_cpu_ptr(&plic_handlers);
> +
> + csr_clear(CSR_IE, IE_EIE);
> + plic_set_threshold(handler, PLIC_DISABLE_THRESHOLD);
> +
> + return 0;
> +}
> +
> +static int plic_starting_cpu(unsigned int cpu)
> +{
> + struct plic_handler *handler = this_cpu_ptr(&plic_handlers);
> +
> + csr_set(CSR_IE, IE_EIE);
> + plic_set_threshold(handler, PLIC_ENABLE_THRESHOLD);
> +
> + return 0;
> +}
> +
> static int __init plic_init(struct device_node *node,
> struct device_node *parent)
> {
> @@ -267,7 +297,6 @@ static int __init plic_init(struct device_node *node,
> struct plic_handler *handler;
> irq_hw_number_t hwirq;
> int cpu, hartid;
> - u32 threshold = 0;
>
> if (of_irq_parse_one(node, i, &parent)) {
> pr_err("failed to parse parent for context %d.\n", i);
> @@ -301,7 +330,7 @@ static int __init plic_init(struct device_node *node,
> handler = per_cpu_ptr(&plic_handlers, cpu);
> if (handler->present) {
> pr_warn("handler already present for context %d.\n", i);
> - threshold = 0xffffffff;
> + plic_set_threshold(handler, PLIC_DISABLE_THRESHOLD);
> goto done;
> }
>
> @@ -313,13 +342,14 @@ static int __init plic_init(struct device_node *node,
> plic_regs + ENABLE_BASE + i * ENABLE_PER_HART;
>
> done:
> - /* priority must be > threshold to trigger an interrupt */
> - writel(threshold, handler->hart_base + CONTEXT_THRESHOLD);
> for (hwirq = 1; hwirq <= nr_irqs; hwirq++)
> plic_toggle(handler, hwirq, 0);
> nr_handlers++;
> }
>
> + cpuhp_setup_state(CPUHP_AP_IRQ_SIFIVE_PLIC_STARTING,
> + "irqchip/sifive/plic:starting",
> + plic_starting_cpu, plic_dying_cpu);
> pr_info("mapped %d interrupts with %d handlers for %d contexts.\n",
> nr_irqs, nr_handlers, nr_contexts);
> set_handle_irq(plic_handle_irq);
> diff --git a/include/linux/cpuhotplug.h b/include/linux/cpuhotplug.h
> index d37c17e68268..77d70b633531 100644
> --- a/include/linux/cpuhotplug.h
> +++ b/include/linux/cpuhotplug.h
> @@ -102,6 +102,7 @@ enum cpuhp_state {
> CPUHP_AP_IRQ_ARMADA_XP_STARTING,
> CPUHP_AP_IRQ_BCM2836_STARTING,
> CPUHP_AP_IRQ_MIPS_GIC_STARTING,
> + CPUHP_AP_IRQ_SIFIVE_PLIC_STARTING,
> CPUHP_AP_ARM_MVEBU_COHERENCY,
> CPUHP_AP_MICROCODE_LOADER,
> CPUHP_AP_PERF_X86_AMD_UNCORE_STARTING,
> --
> 2.25.0
>
Looks good to me.
Reviewed-by: Anup Patel <anup@brainfault.org>
I will rebase my RISC-V local interrupt controller driver patches
upon this patch series.
Regards,
Anup
prev parent reply other threads:[~2020-02-21 6:14 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-02-21 0:44 [PATCH v9 00/12] Add support for SBI v0.2 and CPU hotplug Atish Patra
2020-02-21 0:44 ` [PATCH v9 01/12] RISC-V: Mark existing SBI as 0.1 SBI Atish Patra
2020-02-21 0:44 ` [PATCH v9 02/12] RISC-V: Add basic support for SBI v0.2 Atish Patra
2020-03-09 10:33 ` Bin Meng
2020-03-10 6:21 ` Atish Patra
2020-02-21 0:44 ` [PATCH v9 03/12] RISC-V: Add SBI v0.2 extension definitions Atish Patra
2020-02-21 0:44 ` [PATCH v9 04/12] RISC-V: Introduce a new config for SBI v0.1 Atish Patra
2020-02-21 0:44 ` [PATCH v9 05/12] RISC-V: Implement new SBI v0.2 extensions Atish Patra
2020-02-21 0:44 ` [PATCH v9 06/12] RISC-V: Move relocate and few other functions out of __init Atish Patra
2020-02-21 0:44 ` [PATCH v9 07/12] RISC-V: Add cpu_ops and modify default booting method Atish Patra
2020-02-21 0:44 ` [PATCH v9 08/12] RISC-V: Export SBI error to linux error mapping function Atish Patra
2020-02-21 6:01 ` Anup Patel
2020-02-21 0:44 ` [PATCH v9 09/12] RISC-V: Add SBI HSM extension definitions Atish Patra
2020-02-21 6:03 ` Anup Patel
2020-02-21 0:44 ` [PATCH v9 10/12] RISC-V: Add supported for ordered booting method using HSM Atish Patra
2020-02-21 6:08 ` Anup Patel
2020-02-21 0:44 ` [PATCH v9 11/12] RISC-V: Support cpu hotplug Atish Patra
2020-02-21 6:12 ` Anup Patel
2020-02-21 0:44 ` [PATCH v9 12/12] irqchip/sifive-plic: Initialize the plic handler when cpu comes online Atish Patra
2020-02-21 6:14 ` Anup Patel [this message]
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