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MIPS: CPS: Detect CPUs in secondary clusters 

As a first step towards supporting multi-cluster systems, detect cores &
VPs in secondary clusters & record their cluster information in the
cpu_data array. The "VP topology" line printed during boot is extended
to display multiple clusters. On a single cluster it shows output like
the following:

  VP topology: {4,4}

This would indicate a system with 2 cores which each contain 4 VPs. We
extend this to cover multiple clusters in a natural way:

  VP topology: {4,4},{2,2}

This would indicate a system with 2 clusters. The first cluster contains
2 cores which each contain 4 VPs. The second cluster contains 2 cores
which each contain 2 VPs.

Actually booting these cores & VPs is left to further patches once other
pieces are in place.

Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/17017/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
This commit is contained in:
Paul Burton 2017-08-12 19:49:43 -07:00 committed by Ralf Baechle
parent 3c9b416621
commit 1ec9dd80be
1 changed files with 50 additions and 28 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

68
arch/mips/kernel/smp-cps.c
View File

@ -40,44 +40,58 @@ static int __init setup_nothreads(char *s)
}
early_param("nothreads", setup_nothreads);
static unsigned core_vpe_count(unsigned core)
static unsigned core_vpe_count(unsigned int cluster, unsigned core)
{
if (threads_disabled)
return 1;
return mips_cps_numvps(0, core);
return mips_cps_numvps(cluster, core);
}
static void __init cps_smp_setup(void)
{
unsigned int ncores, nvpes, core_vpes;
unsigned int nclusters, ncores, nvpes, core_vpes;
unsigned long core_entry;
int c, v;
int cl, c, v;
/* Detect & record VPE topology */
ncores = mips_cps_numcores(0);
nvpes = 0;
nclusters = mips_cps_numclusters();
pr_info("%s topology ", cpu_has_mips_r6 ? "VP" : "VPE");
for (c = nvpes = 0; c < ncores; c++) {
core_vpes = core_vpe_count(c);
pr_cont("%c%u", c ? ',' : '{', core_vpes);
for (cl = 0; cl < nclusters; cl++) {
if (cl > 0)
pr_cont(",");
pr_cont("{");
/* Use the number of VPEs in core 0 for smp_num_siblings */
if (!c)
ncores = mips_cps_numcores(cl);
for (c = 0; c < ncores; c++) {
core_vpes = core_vpe_count(cl, c);
if (c > 0)
pr_cont(",");
pr_cont("%u", core_vpes);
/* Use the number of VPEs in cluster 0 core 0 for smp_num_siblings */
if (!cl && !c)
smp_num_siblings = core_vpes;
for (v = 0; v < min_t(int, core_vpes, NR_CPUS - nvpes); v++) {
cpu_set_cluster(&cpu_data[nvpes + v], cl);
cpu_set_core(&cpu_data[nvpes + v], c);
cpu_set_vpe_id(&cpu_data[nvpes + v], v);
}
nvpes += core_vpes;
}
pr_cont("} total %u\n", nvpes);
pr_cont("}");
}
pr_cont(" total %u\n", nvpes);
/* Indicate present CPUs (CPU being synonymous with VPE) */
for (v = 0; v < min_t(unsigned, nvpes, NR_CPUS); v++) {
set_cpu_possible(v, true);
set_cpu_present(v, true);
set_cpu_possible(v, cpu_cluster(&cpu_data[v]) == 0);
set_cpu_present(v, cpu_cluster(&cpu_data[v]) == 0);
__cpu_number_map[v] = v;
__cpu_logical_map[v] = v;
}
@ -109,7 +123,7 @@ static void __init cps_smp_setup(void)
static void __init cps_prepare_cpus(unsigned int max_cpus)
{
unsigned ncores, core_vpes, c, cca;
bool cca_unsuitable;
bool cca_unsuitable, cores_limited;
u32 *entry_code;
mips_mt_set_cpuoptions();
@ -129,19 +143,22 @@ static void __init cps_prepare_cpus(unsigned int max_cpus)
}
/* Warn the user if the CCA prevents multi-core */
ncores = mips_cps_numcores(0);
if ((cca_unsuitable || cpu_has_dc_aliases) && ncores > 1) {
cores_limited = false;
if (cca_unsuitable || cpu_has_dc_aliases) {
for_each_present_cpu(c) {
if (cpus_are_siblings(smp_processor_id(), c))
continue;
set_cpu_present(c, false);
cores_limited = true;
}
}
if (cores_limited)
pr_warn("Using only one core due to %s%s%s\n",
cca_unsuitable ? "unsuitable CCA" : "",
(cca_unsuitable && cpu_has_dc_aliases) ? " & " : "",
cpu_has_dc_aliases ? "dcache aliasing" : "");
for_each_present_cpu(c) {
if (!cpus_are_siblings(smp_processor_id(), c))
set_cpu_present(c, false);
}
}
/*
* Patch the start of mips_cps_core_entry to provide:
*
@ -156,6 +173,7 @@ static void __init cps_prepare_cpus(unsigned int max_cpus)
__sync();
/* Allocate core boot configuration structs */
ncores = mips_cps_numcores(0);
mips_cps_core_bootcfg = kcalloc(ncores, sizeof(*mips_cps_core_bootcfg),
GFP_KERNEL);
if (!mips_cps_core_bootcfg) {
@ -165,7 +183,7 @@ static void __init cps_prepare_cpus(unsigned int max_cpus)
/* Allocate VPE boot configuration structs */
for (c = 0; c < ncores; c++) {
core_vpes = core_vpe_count(c);
core_vpes = core_vpe_count(0, c);
mips_cps_core_bootcfg[c].vpe_config = kcalloc(core_vpes,
sizeof(*mips_cps_core_bootcfg[c].vpe_config),
GFP_KERNEL);
@ -288,6 +306,10 @@ static int cps_boot_secondary(int cpu, struct task_struct *idle)
unsigned int remote;
int err;
/* We don't yet support booting CPUs in other clusters */
if (cpu_cluster(&cpu_data[cpu]) != cpu_cluster(&current_cpu_data))
return -ENOSYS;
vpe_cfg->pc = (unsigned long)&smp_bootstrap;
vpe_cfg->sp = __KSTK_TOS(idle);
vpe_cfg->gp = (unsigned long)task_thread_info(idle);