Module Name: src
Committed By: jmcneill
Date: Thu Sep 2 20:57:57 UTC 2021
Modified Files:
src/sys/arch/arm/apple: apple_platform.c
Log Message:
apple: derive CPU speed from mpidr_el1
According to https://github.com/AsahiLinux/docs/wiki/HW%3AARM-System-Registers,
MPIDR_EL1 Aff2 determines whether a core is an efficiency or performance
core. Replace the compat data table with code that uses the aff2 value
for fake DMIPS/MHz value, to hopefully maintain compatibility with future
cores.
To generate a diff of this commit:
cvs rdiff -u -r1.2 -r1.3 src/sys/arch/arm/apple/apple_platform.c
Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.
Modified files:
Index: src/sys/arch/arm/apple/apple_platform.c
diff -u src/sys/arch/arm/apple/apple_platform.c:1.2 src/sys/arch/arm/apple/apple_platform.c:1.3
--- src/sys/arch/arm/apple/apple_platform.c:1.2 Wed Sep 1 23:05:03 2021
+++ src/sys/arch/arm/apple/apple_platform.c Thu Sep 2 20:57:57 2021
@@ -1,4 +1,4 @@
-/* $NetBSD: apple_platform.c,v 1.2 2021/09/01 23:05:03 jmcneill Exp $ */
+/* $NetBSD: apple_platform.c,v 1.3 2021/09/02 20:57:57 jmcneill Exp $ */
/*-
* Copyright (c) 2021 Jared McNeill <jmcne...@invisible.ca>
@@ -27,7 +27,7 @@
*/
#include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: apple_platform.c,v 1.2 2021/09/01 23:05:03 jmcneill Exp $");
+__KERNEL_RCSID(0, "$NetBSD: apple_platform.c,v 1.3 2021/09/02 20:57:57 jmcneill Exp $");
#include <sys/param.h>
#include <sys/bus.h>
@@ -58,18 +58,6 @@ __KERNEL_RCSID(0, "$NetBSD: apple_platfo
#include <arch/evbarm/fdt/platform.h>
-/*
- * Faux DMIPS/MHz values for known CPU types. The values themselves are
- * unimportant except as relative comparisons between different CPUs on
- * the same system.
- */
-static const struct device_compatible_entry cpu_capacity_compat_data[] = {
- /* Apple M1 */
- { .compat = "apple,icestorm", .value = 0 }, /* efficiency core */
- { .compat = "apple,firestorm", .value = 1 }, /* performance core */
- DEVICE_COMPAT_EOL
-};
-
extern struct bus_space arm_generic_bs_tag;
struct arm32_bus_dma_tag apple_coherent_dma_tag;
@@ -198,14 +186,21 @@ apple_platform_device_register(device_t
if (device_is_a(self, "cpu")) {
struct fdt_attach_args * const faa = aux;
- const int phandle = faa->faa_phandle;
- const struct device_compatible_entry *dce;
+ bus_addr_t cpuid;
- dce = of_compatible_lookup(phandle, cpu_capacity_compat_data);
- if (dce != NULL) {
- prop_dictionary_set_uint32(prop, "capacity_dmips_mhz",
- dce->value);
+ if (fdtbus_get_reg(faa->faa_phandle, 0, &cpuid, NULL) != 0) {
+ cpuid = 0;
}
+
+ /*
+ * On Apple M1 (and hopefully later models), AFF2 is 0 for
+ * efficiency and 1 for performance cores. Use this value
+ * to provide a fake DMIPS/MHz value -- the actual number
+ * only matters in relation to the value presented by other
+ * cores.
+ */
+ const u_int aff2 = __SHIFTOUT(cpuid, MPIDR_AFF2);
+ prop_dictionary_set_uint32(prop, "capacity_dmips_mhz", aff2);
return;
}
