Re: [PATCH] riscv-platform-spec: PLIC and CLINT for Linux-2022 platform


Alistair Francis
 

On Wed, 2021-05-05 at 12:30 +0800, Abner Chang wrote:
From: Abner Chang <renba.chang@...>

Initial description of PLIC + CLINT section of Linux-2022 platform.

In this commit,
- Not sure where to put the [DEPRECATED].
- Change the reference of PLIC in section 2.2.2. Interrupt Controller
to
  1.1.3.2 PLIC + CLINT section.

Signed-off-by: Abner Chang <renba.chang@...>
Cc: Alistair Francis <alistair.francis@...>
Cc: Sunil V L <sunilvl@...>
---
 riscv-platform-spec.adoc | 19 ++++++++++++++-----
 1 file changed, 14 insertions(+), 5 deletions(-)

diff --git a/riscv-platform-spec.adoc b/riscv-platform-spec.adoc
index 160c74a..f9179fb 100644
--- a/riscv-platform-spec.adoc
+++ b/riscv-platform-spec.adoc
@@ -49,9 +49,19 @@ include::profiles.adoc[]
 * Start Address
 
 ==== Interrupt Controller
-* AIA
-* PLIC + CLINT
-* Interrupt Assignments
+===== AIA
+===== PLIC + CLINT [DEPRECATED][[PLICCLINT]]
Is the CLINT also deprecated?

From what I can tell in the AIA spec it doesn't include a replacement
for the CLINT. What should be used for mtime/mtimecmp instead?

Alistair

+The Platform Level Interrupt Controller (PLIC) provides facilities
to route
+the non-local global interrupts to the external interrupt of a hart
context
+with a given privilege mode in a given hart. The number of non-local
interrupt
+sources supported by PLIC and how does each of them connect to the
hart context
+is PLIC core implementation-specific. Refer to
https://github.com/riscv/riscv-plic-spec/blob/master/riscv-plic.adoc[RISC-V
 PLIC Specification]
+for the PLIC operation parameters details. On the contrast, the Core
Local
+Interrupt (CLINT) provides the local interrupt mechanism for timer
and software
+interrupt to the Machine mode of hart. The operation parameters of
local interrupt
+is CLINT implementation-specific.
+
+===== Interrupt Assignments
 
 ==== System Peripherals
 * UART/Serial Console
@@ -289,8 +299,7 @@ Any RISC-V system that uses at least RV32/64G can
meet the Embedded-2022
 specification.
 
 ==== Interrupt Controller
-Embedded systems are recommended to use a spec compliant
-https://github.com/riscv/riscv-plic-spec[PLIC], a spec compliant
+Embedded systems are recommended to use a spec compliant
<<PLICCLINT,PLIC>>, a spec compliant
 
https://github.com/riscv/riscv-fast-interrupt/blob/master/clic.adoc[CLIC]
 or both a CLIC and and PLIC.

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