From 2beae018fbbebbf7fd3cde7fed9035d4d4826842 Mon Sep 17 00:00:00 2001
From: Andrew Penner <andrew.penner@protonmail.com>
Date: Fri, 1 Apr 2022 21:27:22 +0100
Subject: [PATCH] rpi-cmdline: Add ability to specify CPUs to add to the
 isolcpus list

Signed-off-by: Andrew Penner <andrew.penner@protonmail.com>
---
 recipes-bsp/bootfiles/rpi-cmdline.bb | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/recipes-bsp/bootfiles/rpi-cmdline.bb b/recipes-bsp/bootfiles/rpi-cmdline.bb
index 50c2b53..413ca4d 100644
--- a/recipes-bsp/bootfiles/rpi-cmdline.bb
+++ b/recipes-bsp/bootfiles/rpi-cmdline.bb
@@ -29,6 +29,18 @@ CMDLINE_LOGO ?= '${@oe.utils.conditional("DISABLE_RPI_BOOT_LOGO", "1", "logo.nol
 # to enable kernel debugging.
 CMDLINE_DEBUG ?= ""
 
+# Add a request to isolate processors from the Linux scheduler. ISOLATED_CPUS
+# may have the form of a comma separated list of processor numbers "0,1,3", a
+# range "0-2", a combination of the two "0-1,3", or a single processor you may
+# not specify ALL processors simultaneously
+def setup_isolcpus(d):
+    string = ""
+    if d.getVar('ISOLATED_CPUS'):
+        string = 'isolcpus=' + d.getVar('ISOLATED_CPUS')
+    return string
+
+CMDLINE_ISOL_CPUS ?= "${@setup_isolcpus(d)}"
+
 # Add RNDIS capabilities (must be after rootwait)
 # example: 
 # CMDLINE_RNDIS = "modules-load=dwc2,g_ether g_ether.host_addr=<some MAC 
@@ -37,6 +49,7 @@ CMDLINE_DEBUG ?= ""
 CMDLINE_RNDIS ?= ""
 
 CMDLINE = " \
+    ${CMDLINE_ISOL_CPUS} \
     ${CMDLINE_DWC_OTG} \
     ${CMDLINE_SERIAL} \
     ${CMDLINE_ROOTFS} \