LoongArch: Retrieve CPU package ID from PPTT when available
Currently, the LoongArch CPU topology initialization code calculates
each core's package ID by dividing its physical ID by loongson_sysconf.
cores_per_package. This relies on the assumption that cores_per_package
counts in the same domain as physical IDs.
On Loongson-3B6000 (XB612B0V_1.2), cores_per_package matches the visible
core count -- 24 in this case. However, the physical IDs range from 0 to
31 in a noncontinuous fashion:
$ cat /proc/cpuinfo | grep -i -F 'global_id'
global_id : 0
global_id : 1
global_id : 4
global_id : 5
global_id : 6
global_id : 7
global_id : 8
global_id : 9
global_id : 10
global_id : 11
global_id : 14
global_id : 15
global_id : 16
global_id : 17
global_id : 20
global_id : 21
global_id : 22
global_id : 23
global_id : 26
global_id : 27
global_id : 28
global_id : 29
global_id : 30
global_id : 31
Retrieve the exact package ID from ACPI PPTT when available, in the same
style as retrieving the core ID and thread ID in parse_acpi_topology().
Use this information in loongson_init_secondary() when the PPTT readout
is successful. The original division logic is kept as a fallback.
Meanwhile, since some existing code paths like loongson3_cpufreq expect
a continuous integer sequence of package IDs in [0, MAX_PACKAGES) when
retrieving from cpu_data[], here we also canonicalize the package ID to
be filled in parse_acpi_topology() to meet such an expectation.
Cc: stable@vger.kernel.org
Tested-by: Mingcong Bai <jeffbai@aosc.io>
Co-developed-by: Xi Ruoyao <xry111@xry111.site>
Signed-off-by: Xi Ruoyao <xry111@xry111.site>
Signed-off-by: Rong Bao <rong.bao@csmantle.top>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>