Re: [PATCH 2/4] riscv: add functions for reading the IPI status

Hi Lukas

From: Lukas Auer [mailto:lukas.auer@aisec.fraunhofer.de] Sent: Wednesday, December 04, 2019 5:40 AM To: u-boot@lists.denx.de Cc: Rick Jian-Zhi Chen(陳建志); Anup Patel; Bin Meng; Lukas Auer; Anup Patel; Atish Patra Subject: [PATCH 2/4] riscv: add functions for reading the IPI status

Add the function riscv_get_ipi() for reading the pending status of IPIs. The supported controllers are Andes' Platform Level Interrupt Controller (PLIC), the Supervisor Binary Interface (SBI), and SiFive's Core Local Interruptor (CLINT).

Signed-off-by: Lukas Auer lukas.auer@aisec.fraunhofer.de

I do not have access to the datasheet of the Andes PLIC. The riscv_clear_ipi() implementation seems to read the IPI status from the claim register before writing back the results to clear them. Based on this, I also used the claim register. Rick, please let me know if that is ok or if I should use the pending register instead.

Yes.

Please use pending register instead of claim register.

Thanks Rick

arch/riscv/lib/andes_plic.c | 9 +++++++++ arch/riscv/lib/sbi_ipi.c | 11 +++++++++++ arch/riscv/lib/sifive_clint.c | 9 +++++++++ arch/riscv/lib/smp.c | 12 ++++++++++++ 4 files changed, 41 insertions(+)

diff --git a/arch/riscv/lib/andes_plic.c b/arch/riscv/lib/andes_plic.c index 28568e4e2b..731ac3a148 100644 --- a/arch/riscv/lib/andes_plic.c +++ b/arch/riscv/lib/andes_plic.c @@ -114,6 +114,15 @@ int riscv_clear_ipi(int hart) return 0; }

+int riscv_get_ipi(int hart, int *pending) {

•   PLIC_BASE_GET();
  

•   *pending = !!readl((void __iomem *)CLAIM_REG(gd->arch.plic, hart));
  

•   return 0;
  

+}

static const struct udevice_id andes_plic_ids[] = { { .compatible = "riscv,plic1", .data = RISCV_SYSCON_PLIC }, { } diff --git a/arch/riscv/lib/sbi_ipi.c b/arch/riscv/lib/sbi_ipi.c index 170346da68..9a698ce74e 100644 --- a/arch/riscv/lib/sbi_ipi.c +++ b/arch/riscv/lib/sbi_ipi.c @@ -23,3 +23,14 @@ int riscv_clear_ipi(int hart)

    return 0;

}

+int riscv_get_ipi(int hart, int *pending) {

•   /*
  

•    * The SBI does not support reading the IPI status. We always return 0
  

•    * to indicate that no IPI is pending.
  

•    */
  

•   *pending = 0;
  

•   return 0;
  

+} diff --git a/arch/riscv/lib/sifive_clint.c b/arch/riscv/lib/sifive_clint.c index d24e0d585b..d7899d16d7 100644 --- a/arch/riscv/lib/sifive_clint.c +++ b/arch/riscv/lib/sifive_clint.c @@ -71,6 +71,15 @@ int riscv_clear_ipi(int hart) return 0; }

+int riscv_get_ipi(int hart, int *pending) {

•   CLINT_BASE_GET();
  

•   *pending = readl((void __iomem *)MSIP_REG(gd->arch.clint, hart));
  

•   return 0;
  

+}

static const struct udevice_id sifive_clint_ids[] = { { .compatible = "riscv,clint0", .data = RISCV_SYSCON_CLINT }, { } diff --git a/arch/riscv/lib/smp.c b/arch/riscv/lib/smp.c index cc66f15567..6ff0de4b74 100644 --- a/arch/riscv/lib/smp.c +++ b/arch/riscv/lib/smp.c @@ -31,6 +31,18 @@ extern int riscv_send_ipi(int hart); */ extern int riscv_clear_ipi(int hart);

+/**

• • riscv_get_ipi() - Get status of inter-processor interrupt (IPI)
• • Platform code must provide this function.
• • @hart: Hart ID of hart to be checked
• • @pending: Pointer to variable with result of the check,

• •       1 if IPI is pending, 0 otherwise
    

• • @return 0 if OK, -ve on error
• */

+extern int riscv_get_ipi(int hart, int *pending);

static int send_ipi_many(struct ipi_data *ipi) { ofnode node, cpus; -- 2.21.0