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MIPS: CPS: Boot CPUs in secondary clusters
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Probe for & boot CPUs (cores & VPs) in secondary clusters (ie. not the
cluster that began booting Linux) when they are present in systems with
CM 3.5 or higher.

Signed-off-by: Paul Burton <paulburton@kernel.org>
Signed-off-by: Chao-ying Fu <cfu@wavecomp.com>
Signed-off-by: Dragan Mladjenovic <dragan.mladjenovic@syrmia.com>
Signed-off-by: Aleksandar Rikalo <arikalo@gmail.com>
Tested-by: Serge Semin <fancer.lancer@gmail.com>
Tested-by: Gregory CLEMENT <gregory.clement@bootlin.com>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
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Paul Burton authored and Thomas Bogendoerfer committed Feb 21, 2025
1 parent 75fa6a5 commit 0856c14
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Showing 4 changed files with 207 additions and 21 deletions.
18 changes: 18 additions & 0 deletions arch/mips/include/asm/mips-cm.h
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Original file line number Diff line number Diff line change
Expand Up @@ -255,6 +255,12 @@ GCR_ACCESSOR_RW(32, 0x130, l2_config)
GCR_ACCESSOR_RO(32, 0x150, sys_config2)
#define CM_GCR_SYS_CONFIG2_MAXVPW GENMASK(3, 0)

/* GCR_L2-RAM_CONFIG - Configuration & status of L2 cache RAMs */
GCR_ACCESSOR_RW(64, 0x240, l2_ram_config)
#define CM_GCR_L2_RAM_CONFIG_PRESENT BIT(31)
#define CM_GCR_L2_RAM_CONFIG_HCI_DONE BIT(30)
#define CM_GCR_L2_RAM_CONFIG_HCI_SUPPORTED BIT(29)

/* GCR_L2_PFT_CONTROL - Controls hardware L2 prefetching */
GCR_ACCESSOR_RW(32, 0x300, l2_pft_control)
#define CM_GCR_L2_PFT_CONTROL_PAGEMASK GENMASK(31, 12)
Expand All @@ -266,6 +272,18 @@ GCR_ACCESSOR_RW(32, 0x308, l2_pft_control_b)
#define CM_GCR_L2_PFT_CONTROL_B_CEN BIT(8)
#define CM_GCR_L2_PFT_CONTROL_B_PORTID GENMASK(7, 0)

/* GCR_L2_TAG_ADDR - Access addresses in L2 cache tags */
GCR_ACCESSOR_RW(64, 0x600, l2_tag_addr)

/* GCR_L2_TAG_STATE - Access L2 cache tag state */
GCR_ACCESSOR_RW(64, 0x608, l2_tag_state)

/* GCR_L2_DATA - Access data in L2 cache lines */
GCR_ACCESSOR_RW(64, 0x610, l2_data)

/* GCR_L2_ECC - Access ECC information from L2 cache lines */
GCR_ACCESSOR_RW(64, 0x618, l2_ecc)

/* GCR_L2SM_COP - L2 cache op state machine control */
GCR_ACCESSOR_RW(32, 0x620, l2sm_cop)
#define CM_GCR_L2SM_COP_PRESENT BIT(31)
Expand Down
1 change: 1 addition & 0 deletions arch/mips/include/asm/smp-cps.h
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Original file line number Diff line number Diff line change
Expand Up @@ -23,6 +23,7 @@ struct core_boot_config {
};

struct cluster_boot_config {
unsigned long *core_power;
struct core_boot_config *core_config;
};

Expand Down
4 changes: 3 additions & 1 deletion arch/mips/kernel/mips-cm.c
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Original file line number Diff line number Diff line change
Expand Up @@ -308,7 +308,9 @@ void mips_cm_lock_other(unsigned int cluster, unsigned int core,
FIELD_PREP(CM3_GCR_Cx_OTHER_VP, vp);

if (cm_rev >= CM_REV_CM3_5) {
val |= CM_GCR_Cx_OTHER_CLUSTER_EN;
if (cluster != cpu_cluster(&current_cpu_data))
val |= CM_GCR_Cx_OTHER_CLUSTER_EN;
val |= CM_GCR_Cx_OTHER_GIC_EN;
val |= FIELD_PREP(CM_GCR_Cx_OTHER_CLUSTER, cluster);
val |= FIELD_PREP(CM_GCR_Cx_OTHER_BLOCK, block);
} else {
Expand Down
205 changes: 185 additions & 20 deletions arch/mips/kernel/smp-cps.c
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Original file line number Diff line number Diff line change
Expand Up @@ -36,12 +36,56 @@ enum label_id {

UASM_L_LA(_not_nmi)

static DECLARE_BITMAP(core_power, NR_CPUS);
static u64 core_entry_reg;
static phys_addr_t cps_vec_pa;

struct cluster_boot_config *mips_cps_cluster_bootcfg;

static void power_up_other_cluster(unsigned int cluster)
{
u32 stat, seq_state;
unsigned int timeout;

mips_cm_lock_other(cluster, CM_GCR_Cx_OTHER_CORE_CM, 0,
CM_GCR_Cx_OTHER_BLOCK_LOCAL);
stat = read_cpc_co_stat_conf();
mips_cm_unlock_other();

seq_state = stat & CPC_Cx_STAT_CONF_SEQSTATE;
seq_state >>= __ffs(CPC_Cx_STAT_CONF_SEQSTATE);
if (seq_state == CPC_Cx_STAT_CONF_SEQSTATE_U5)
return;

/* Set endianness & power up the CM */
mips_cm_lock_other(cluster, 0, 0, CM_GCR_Cx_OTHER_BLOCK_GLOBAL);
write_cpc_redir_sys_config(IS_ENABLED(CONFIG_CPU_BIG_ENDIAN));
write_cpc_redir_pwrup_ctl(1);
mips_cm_unlock_other();

/* Wait for the CM to start up */
timeout = 1000;
mips_cm_lock_other(cluster, CM_GCR_Cx_OTHER_CORE_CM, 0,
CM_GCR_Cx_OTHER_BLOCK_LOCAL);
while (1) {
stat = read_cpc_co_stat_conf();
seq_state = stat & CPC_Cx_STAT_CONF_SEQSTATE;
seq_state >>= __ffs(CPC_Cx_STAT_CONF_SEQSTATE);
if (seq_state == CPC_Cx_STAT_CONF_SEQSTATE_U5)
break;

if (timeout) {
mdelay(1);
timeout--;
} else {
pr_warn("Waiting for cluster %u CM to power up... STAT_CONF=0x%x\n",
cluster, stat);
mdelay(1000);
}
}

mips_cm_unlock_other();
}

static unsigned __init core_vpe_count(unsigned int cluster, unsigned core)
{
return min(smp_max_threads, mips_cps_numvps(cluster, core));
Expand Down Expand Up @@ -178,6 +222,9 @@ static void __init cps_smp_setup(void)
pr_cont(",");
pr_cont("{");

if (mips_cm_revision() >= CM_REV_CM3_5)
power_up_other_cluster(cl);

ncores = mips_cps_numcores(cl);
for (c = 0; c < ncores; c++) {
core_vpes = core_vpe_count(cl, c);
Expand Down Expand Up @@ -205,18 +252,15 @@ static void __init cps_smp_setup(void)

/* Indicate present CPUs (CPU being synonymous with VPE) */
for (v = 0; v < min_t(unsigned, nvpes, NR_CPUS); v++) {
set_cpu_possible(v, cpu_cluster(&cpu_data[v]) == 0);
set_cpu_present(v, cpu_cluster(&cpu_data[v]) == 0);
set_cpu_possible(v, true);
set_cpu_present(v, true);
__cpu_number_map[v] = v;
__cpu_logical_map[v] = v;
}

/* Set a coherent default CCA (CWB) */
change_c0_config(CONF_CM_CMASK, 0x5);

/* Core 0 is powered up (we're running on it) */
bitmap_set(core_power, 0, 1);

/* Initialise core 0 */
mips_cps_core_init();

Expand Down Expand Up @@ -298,6 +342,10 @@ static void __init cps_prepare_cpus(unsigned int max_cpus)
goto err_out;
mips_cps_cluster_bootcfg[cl].core_config = core_bootcfg;

mips_cps_cluster_bootcfg[cl].core_power =
kcalloc(BITS_TO_LONGS(ncores), sizeof(unsigned long),
GFP_KERNEL);

/* Allocate VPE boot configuration structs */
for (c = 0; c < ncores; c++) {
core_vpes = core_vpe_count(cl, c);
Expand All @@ -309,11 +357,12 @@ static void __init cps_prepare_cpus(unsigned int max_cpus)
}
}

/* Mark this CPU as booted */
/* Mark this CPU as powered up & booted */
cl = cpu_cluster(&current_cpu_data);
c = cpu_core(&current_cpu_data);
cluster_bootcfg = &mips_cps_cluster_bootcfg[cl];
core_bootcfg = &cluster_bootcfg->core_config[c];
bitmap_set(cluster_bootcfg->core_power, cpu_core(&current_cpu_data), 1);
atomic_set(&core_bootcfg->vpe_mask, 1 << cpu_vpe_id(&current_cpu_data));

return;
Expand Down Expand Up @@ -341,13 +390,118 @@ static void __init cps_prepare_cpus(unsigned int max_cpus)
}
}

static void boot_core(unsigned int core, unsigned int vpe_id)
static void init_cluster_l2(void)
{
u32 stat, seq_state;
unsigned timeout;
u32 l2_cfg, l2sm_cop, result;

while (1) {
l2_cfg = read_gcr_redir_l2_ram_config();

/* If HCI is not supported, use the state machine below */
if (!(l2_cfg & CM_GCR_L2_RAM_CONFIG_PRESENT))
break;
if (!(l2_cfg & CM_GCR_L2_RAM_CONFIG_HCI_SUPPORTED))
break;

/* If the HCI_DONE bit is set, we're finished */
if (l2_cfg & CM_GCR_L2_RAM_CONFIG_HCI_DONE)
return;
}

l2sm_cop = read_gcr_redir_l2sm_cop();
if (WARN(!(l2sm_cop & CM_GCR_L2SM_COP_PRESENT),
"L2 init not supported on this system yet"))
return;

/* Clear L2 tag registers */
write_gcr_redir_l2_tag_state(0);
write_gcr_redir_l2_ecc(0);

/* Ensure the L2 tag writes complete before the state machine starts */
mb();

/* Wait for the L2 state machine to be idle */
do {
l2sm_cop = read_gcr_redir_l2sm_cop();
} while (l2sm_cop & CM_GCR_L2SM_COP_RUNNING);

/* Start a store tag operation */
l2sm_cop = CM_GCR_L2SM_COP_TYPE_IDX_STORETAG;
l2sm_cop <<= __ffs(CM_GCR_L2SM_COP_TYPE);
l2sm_cop |= CM_GCR_L2SM_COP_CMD_START;
write_gcr_redir_l2sm_cop(l2sm_cop);

/* Ensure the state machine starts before we poll for completion */
mb();

/* Wait for the operation to be complete */
do {
l2sm_cop = read_gcr_redir_l2sm_cop();
result = l2sm_cop & CM_GCR_L2SM_COP_RESULT;
result >>= __ffs(CM_GCR_L2SM_COP_RESULT);
} while (!result);

WARN(result != CM_GCR_L2SM_COP_RESULT_DONE_OK,
"L2 state machine failed cache init with error %u\n", result);
}

static void boot_core(unsigned int cluster, unsigned int core,
unsigned int vpe_id)
{
struct cluster_boot_config *cluster_cfg;
u32 access, stat, seq_state;
unsigned int timeout, ncores;

cluster_cfg = &mips_cps_cluster_bootcfg[cluster];
ncores = mips_cps_numcores(cluster);

if ((cluster != cpu_cluster(&current_cpu_data)) &&
bitmap_empty(cluster_cfg->core_power, ncores)) {
power_up_other_cluster(cluster);

mips_cm_lock_other(cluster, core, 0,
CM_GCR_Cx_OTHER_BLOCK_GLOBAL);

/* Ensure cluster GCRs are where we expect */
write_gcr_redir_base(read_gcr_base());
write_gcr_redir_cpc_base(read_gcr_cpc_base());
write_gcr_redir_gic_base(read_gcr_gic_base());

init_cluster_l2();

/* Mirror L2 configuration */
write_gcr_redir_l2_only_sync_base(read_gcr_l2_only_sync_base());
write_gcr_redir_l2_pft_control(read_gcr_l2_pft_control());
write_gcr_redir_l2_pft_control_b(read_gcr_l2_pft_control_b());

/* Mirror ECC/parity setup */
write_gcr_redir_err_control(read_gcr_err_control());

/* Set BEV base */
write_gcr_redir_bev_base(core_entry_reg);

mips_cm_unlock_other();
}

if (cluster != cpu_cluster(&current_cpu_data)) {
mips_cm_lock_other(cluster, core, 0,
CM_GCR_Cx_OTHER_BLOCK_GLOBAL);

/* Ensure the core can access the GCRs */
access = read_gcr_redir_access();
access |= BIT(core);
write_gcr_redir_access(access);

mips_cm_unlock_other();
} else {
/* Ensure the core can access the GCRs */
access = read_gcr_access();
access |= BIT(core);
write_gcr_access(access);
}

/* Select the appropriate core */
mips_cm_lock_other(0, core, 0, CM_GCR_Cx_OTHER_BLOCK_LOCAL);
mips_cm_lock_other(cluster, core, 0, CM_GCR_Cx_OTHER_BLOCK_LOCAL);

/* Set its reset vector */
if (mips_cm_is64)
Expand Down Expand Up @@ -416,7 +570,17 @@ static void boot_core(unsigned int core, unsigned int vpe_id)
mips_cm_unlock_other();

/* The core is now powered up */
bitmap_set(core_power, core, 1);
bitmap_set(cluster_cfg->core_power, core, 1);

/*
* Restore CM_PWRUP=0 so that the CM can power down if all the cores in
* the cluster do (eg. if they're all removed via hotplug.
*/
if (mips_cm_revision() >= CM_REV_CM3_5) {
mips_cm_lock_other(cluster, 0, 0, CM_GCR_Cx_OTHER_BLOCK_GLOBAL);
write_cpc_redir_pwrup_ctl(0);
mips_cm_unlock_other();
}
}

static void remote_vpe_boot(void *dummy)
Expand All @@ -442,10 +606,6 @@ 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(&raw_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);
Expand All @@ -454,14 +614,15 @@ static int cps_boot_secondary(int cpu, struct task_struct *idle)

preempt_disable();

if (!test_bit(core, core_power)) {
if (!test_bit(core, cluster_cfg->core_power)) {
/* Boot a VPE on a powered down core */
boot_core(core, vpe_id);
boot_core(cluster, core, vpe_id);
goto out;
}

if (cpu_has_vp) {
mips_cm_lock_other(0, core, vpe_id, CM_GCR_Cx_OTHER_BLOCK_LOCAL);
mips_cm_lock_other(cluster, core, vpe_id,
CM_GCR_Cx_OTHER_BLOCK_LOCAL);
if (mips_cm_is64)
write_gcr_co_reset64_base(core_entry_reg);
else
Expand Down Expand Up @@ -671,11 +832,15 @@ static void cps_cpu_die(unsigned int cpu) { }

static void cps_cleanup_dead_cpu(unsigned cpu)
{
unsigned int cluster = cpu_cluster(&cpu_data[cpu]);
unsigned core = cpu_core(&cpu_data[cpu]);
unsigned int vpe_id = cpu_vpe_id(&cpu_data[cpu]);
ktime_t fail_time;
unsigned stat;
int err;
struct cluster_boot_config *cluster_cfg;

cluster_cfg = &mips_cps_cluster_bootcfg[cluster];

/*
* Now wait for the CPU to actually offline. Without doing this that
Expand Down Expand Up @@ -727,7 +892,7 @@ static void cps_cleanup_dead_cpu(unsigned cpu)
} while (1);

/* Indicate the core is powered off */
bitmap_clear(core_power, core, 1);
bitmap_clear(cluster_cfg->core_power, core, 1);
} else if (cpu_has_mipsmt) {
/*
* Have a CPU with access to the offlined CPUs registers wait
Expand Down

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