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authorPaul Burton <paul.burton@imgtec.com>2014-01-15 14:31:53 +0400
committerRalf Baechle <ralf@linux-mips.org>2014-03-27 02:00:12 +0400
commit0ee958e102b62b418c2fb46c3439d4262067a5fc (patch)
treee69192dc3112657cdde015ea8a43594a41a24d89 /arch/mips/kernel
parentb86c2247a20f5d8b6f2b3bd0dfd2c9c8c6908b5e (diff)
downloadlinux-0ee958e102b62b418c2fb46c3439d4262067a5fc.tar.xz
MIPS: Coherent Processing System SMP implementation
This patch introduces a new SMP implementation for systems implementing the MIPS Coherent Processing System architecture. The kernel will make use of the Coherence Manager, Cluster Power Controller & Global Interrupt Controller in order to detect, bring up & make use of other cores in the system. SMTC is not supported, so only a single TC per VPE in the system is used. That is, this option enables an SMVP style setup but across multiple cores. Signed-off-by: Paul Burton <paul.burton@imgtec.com> Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/6362/ Patchwork: https://patchwork.linux-mips.org/patch/6611/ Patchwork: https://patchwork.linux-mips.org/patch/6651/ Patchwork: https://patchwork.linux-mips.org/patch/6652/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Diffstat (limited to 'arch/mips/kernel')
-rw-r--r--arch/mips/kernel/Makefile1
-rw-r--r--arch/mips/kernel/asm-offsets.c13
-rw-r--r--arch/mips/kernel/cps-vec.S191
-rw-r--r--arch/mips/kernel/cpu-probe.c2
-rw-r--r--arch/mips/kernel/smp-cps.c335
5 files changed, 542 insertions, 0 deletions
diff --git a/arch/mips/kernel/Makefile b/arch/mips/kernel/Makefile
index a6a87173e17a..277dab301cea 100644
--- a/arch/mips/kernel/Makefile
+++ b/arch/mips/kernel/Makefile
@@ -53,6 +53,7 @@ obj-$(CONFIG_MIPS_MT_FPAFF) += mips-mt-fpaff.o
obj-$(CONFIG_MIPS_MT_SMTC) += smtc.o smtc-asm.o smtc-proc.o
obj-$(CONFIG_MIPS_MT_SMP) += smp-mt.o
obj-$(CONFIG_MIPS_CMP) += smp-cmp.o
+obj-$(CONFIG_MIPS_CPS) += smp-cps.o cps-vec.o
obj-$(CONFIG_MIPS_GIC_IPI) += smp-gic.o
obj-$(CONFIG_CPU_MIPSR2) += spram.o
diff --git a/arch/mips/kernel/asm-offsets.c b/arch/mips/kernel/asm-offsets.c
index 0c2e853c3db4..8a2a45d4b147 100644
--- a/arch/mips/kernel/asm-offsets.c
+++ b/arch/mips/kernel/asm-offsets.c
@@ -16,6 +16,7 @@
#include <linux/suspend.h>
#include <asm/ptrace.h>
#include <asm/processor.h>
+#include <asm/smp-cps.h>
#include <linux/kvm_host.h>
@@ -397,3 +398,15 @@ void output_kvm_defines(void)
OFFSET(COP0_STATUS, mips_coproc, reg[MIPS_CP0_STATUS][0]);
BLANK();
}
+
+#ifdef CONFIG_MIPS_CPS
+void output_cps_defines(void)
+{
+ COMMENT(" MIPS CPS offsets. ");
+ OFFSET(BOOTCFG_CORE, boot_config, core);
+ OFFSET(BOOTCFG_VPE, boot_config, vpe);
+ OFFSET(BOOTCFG_PC, boot_config, pc);
+ OFFSET(BOOTCFG_SP, boot_config, sp);
+ OFFSET(BOOTCFG_GP, boot_config, gp);
+}
+#endif
diff --git a/arch/mips/kernel/cps-vec.S b/arch/mips/kernel/cps-vec.S
new file mode 100644
index 000000000000..f7a46db4b161
--- /dev/null
+++ b/arch/mips/kernel/cps-vec.S
@@ -0,0 +1,191 @@
+/*
+ * Copyright (C) 2013 Imagination Technologies
+ * Author: Paul Burton <paul.burton@imgtec.com>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation; either version 2 of the License, or (at your
+ * option) any later version.
+ */
+
+#include <asm/addrspace.h>
+#include <asm/asm.h>
+#include <asm/asm-offsets.h>
+#include <asm/asmmacro.h>
+#include <asm/cacheops.h>
+#include <asm/mipsregs.h>
+
+#define GCR_CL_COHERENCE_OFS 0x2008
+
+.section .text.cps-vec
+.balign 0x1000
+.set noreorder
+
+LEAF(mips_cps_core_entry)
+ /*
+ * These first 8 bytes will be patched by cps_smp_setup to load the
+ * base address of the CM GCRs into register v1.
+ */
+ .quad 0
+
+ /* Check whether we're here due to an NMI */
+ mfc0 k0, CP0_STATUS
+ and k0, k0, ST0_NMI
+ beqz k0, not_nmi
+ nop
+
+ /* This is an NMI */
+ la k0, nmi_handler
+ jr k0
+ nop
+
+not_nmi:
+ /* Setup Cause */
+ li t0, CAUSEF_IV
+ mtc0 t0, CP0_CAUSE
+
+ /* Setup Status */
+ li t0, ST0_CU1 | ST0_CU0
+ mtc0 t0, CP0_STATUS
+
+ /*
+ * Clear the bits used to index the caches. Note that the architecture
+ * dictates that writing to any of TagLo or TagHi selects 0 or 2 should
+ * be valid for all MIPS32 CPUs, even those for which said writes are
+ * unnecessary.
+ */
+ mtc0 zero, CP0_TAGLO, 0
+ mtc0 zero, CP0_TAGHI, 0
+ mtc0 zero, CP0_TAGLO, 2
+ mtc0 zero, CP0_TAGHI, 2
+ ehb
+
+ /* Primary cache configuration is indicated by Config1 */
+ mfc0 v0, CP0_CONFIG, 1
+
+ /* Detect I-cache line size */
+ _EXT t0, v0, MIPS_CONF1_IL_SHF, MIPS_CONF1_IL_SZ
+ beqz t0, icache_done
+ li t1, 2
+ sllv t0, t1, t0
+
+ /* Detect I-cache size */
+ _EXT t1, v0, MIPS_CONF1_IS_SHF, MIPS_CONF1_IS_SZ
+ xori t2, t1, 0x7
+ beqz t2, 1f
+ li t3, 32
+ addi t1, t1, 1
+ sllv t1, t3, t1
+1: /* At this point t1 == I-cache sets per way */
+ _EXT t2, v0, MIPS_CONF1_IA_SHF, MIPS_CONF1_IA_SZ
+ addi t2, t2, 1
+ mul t1, t1, t0
+ mul t1, t1, t2
+
+ li a0, KSEG0
+ add a1, a0, t1
+1: cache Index_Store_Tag_I, 0(a0)
+ add a0, a0, t0
+ bne a0, a1, 1b
+ nop
+icache_done:
+
+ /* Detect D-cache line size */
+ _EXT t0, v0, MIPS_CONF1_DL_SHF, MIPS_CONF1_DL_SZ
+ beqz t0, dcache_done
+ li t1, 2
+ sllv t0, t1, t0
+
+ /* Detect D-cache size */
+ _EXT t1, v0, MIPS_CONF1_DS_SHF, MIPS_CONF1_DS_SZ
+ xori t2, t1, 0x7
+ beqz t2, 1f
+ li t3, 32
+ addi t1, t1, 1
+ sllv t1, t3, t1
+1: /* At this point t1 == D-cache sets per way */
+ _EXT t2, v0, MIPS_CONF1_DA_SHF, MIPS_CONF1_DA_SZ
+ addi t2, t2, 1
+ mul t1, t1, t0
+ mul t1, t1, t2
+
+ li a0, KSEG0
+ addu a1, a0, t1
+ subu a1, a1, t0
+1: cache Index_Store_Tag_D, 0(a0)
+ bne a0, a1, 1b
+ add a0, a0, t0
+dcache_done:
+
+ /* Set Kseg0 cacheable, coherent, write-back, write-allocate */
+ mfc0 t0, CP0_CONFIG
+ ori t0, 0x7
+ xori t0, 0x2
+ mtc0 t0, CP0_CONFIG
+ ehb
+
+ /* Enter the coherent domain */
+ li t0, 0xff
+ sw t0, GCR_CL_COHERENCE_OFS(v1)
+ ehb
+
+ /* Jump to kseg0 */
+ la t0, 1f
+ jr t0
+ nop
+
+1: /* We're up, cached & coherent */
+
+ /*
+ * TODO: We should check the VPE number we intended to boot here, and
+ * if non-zero we should start that VPE and stop this one. For
+ * the moment this doesn't matter since CPUs are brought up
+ * sequentially and in order, but once hotplug is implemented
+ * this will need revisiting.
+ */
+
+ /* Off we go! */
+ la t0, mips_cps_bootcfg
+ lw t1, BOOTCFG_PC(t0)
+ lw gp, BOOTCFG_GP(t0)
+ lw sp, BOOTCFG_SP(t0)
+ jr t1
+ nop
+ END(mips_cps_core_entry)
+
+.org 0x200
+LEAF(excep_tlbfill)
+ b .
+ nop
+ END(excep_tlbfill)
+
+.org 0x280
+LEAF(excep_xtlbfill)
+ b .
+ nop
+ END(excep_xtlbfill)
+
+.org 0x300
+LEAF(excep_cache)
+ b .
+ nop
+ END(excep_cache)
+
+.org 0x380
+LEAF(excep_genex)
+ b .
+ nop
+ END(excep_genex)
+
+.org 0x400
+LEAF(excep_intex)
+ b .
+ nop
+ END(excep_intex)
+
+.org 0x480
+LEAF(excep_ejtag)
+ la k0, ejtag_debug_handler
+ jr k0
+ nop
+ END(excep_ejtag)
diff --git a/arch/mips/kernel/cpu-probe.c b/arch/mips/kernel/cpu-probe.c
index ac09248b7468..c1ee8b4d2144 100644
--- a/arch/mips/kernel/cpu-probe.c
+++ b/arch/mips/kernel/cpu-probe.c
@@ -398,8 +398,10 @@ static void decode_configs(struct cpuinfo_mips *c)
mips_probe_watch_registers(c);
+#ifndef CONFIG_MIPS_CPS
if (cpu_has_mips_r2)
c->core = read_c0_ebase() & 0x3ff;
+#endif
}
#define R4K_OPTS (MIPS_CPU_TLB | MIPS_CPU_4KEX | MIPS_CPU_4K_CACHE \
diff --git a/arch/mips/kernel/smp-cps.c b/arch/mips/kernel/smp-cps.c
new file mode 100644
index 000000000000..536eec0d21b6
--- /dev/null
+++ b/arch/mips/kernel/smp-cps.c
@@ -0,0 +1,335 @@
+/*
+ * Copyright (C) 2013 Imagination Technologies
+ * Author: Paul Burton <paul.burton@imgtec.com>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation; either version 2 of the License, or (at your
+ * option) any later version.
+ */
+
+#include <linux/io.h>
+#include <linux/sched.h>
+#include <linux/slab.h>
+#include <linux/smp.h>
+#include <linux/types.h>
+
+#include <asm/cacheflush.h>
+#include <asm/gic.h>
+#include <asm/mips-cm.h>
+#include <asm/mips-cpc.h>
+#include <asm/mips_mt.h>
+#include <asm/mipsregs.h>
+#include <asm/smp-cps.h>
+#include <asm/time.h>
+#include <asm/uasm.h>
+
+static DECLARE_BITMAP(core_power, NR_CPUS);
+
+struct boot_config mips_cps_bootcfg;
+
+static void init_core(void)
+{
+ unsigned int nvpes, t;
+ u32 mvpconf0, vpeconf0, vpecontrol, tcstatus, tcbind, status;
+
+ if (!cpu_has_mipsmt)
+ return;
+
+ /* Enter VPE configuration state */
+ dvpe();
+ set_c0_mvpcontrol(MVPCONTROL_VPC);
+
+ /* Retrieve the count of VPEs in this core */
+ mvpconf0 = read_c0_mvpconf0();
+ nvpes = ((mvpconf0 & MVPCONF0_PVPE) >> MVPCONF0_PVPE_SHIFT) + 1;
+ smp_num_siblings = nvpes;
+
+ for (t = 1; t < nvpes; t++) {
+ /* Use a 1:1 mapping of TC index to VPE index */
+ settc(t);
+
+ /* Bind 1 TC to this VPE */
+ tcbind = read_tc_c0_tcbind();
+ tcbind &= ~TCBIND_CURVPE;
+ tcbind |= t << TCBIND_CURVPE_SHIFT;
+ write_tc_c0_tcbind(tcbind);
+
+ /* Set exclusive TC, non-active, master */
+ vpeconf0 = read_vpe_c0_vpeconf0();
+ vpeconf0 &= ~(VPECONF0_XTC | VPECONF0_VPA);
+ vpeconf0 |= t << VPECONF0_XTC_SHIFT;
+ vpeconf0 |= VPECONF0_MVP;
+ write_vpe_c0_vpeconf0(vpeconf0);
+
+ /* Declare TC non-active, non-allocatable & interrupt exempt */
+ tcstatus = read_tc_c0_tcstatus();
+ tcstatus &= ~(TCSTATUS_A | TCSTATUS_DA);
+ tcstatus |= TCSTATUS_IXMT;
+ write_tc_c0_tcstatus(tcstatus);
+
+ /* Halt the TC */
+ write_tc_c0_tchalt(TCHALT_H);
+
+ /* Allow only 1 TC to execute */
+ vpecontrol = read_vpe_c0_vpecontrol();
+ vpecontrol &= ~VPECONTROL_TE;
+ write_vpe_c0_vpecontrol(vpecontrol);
+
+ /* Copy (most of) Status from VPE 0 */
+ status = read_c0_status();
+ status &= ~(ST0_IM | ST0_IE | ST0_KSU);
+ status |= ST0_CU0;
+ write_vpe_c0_status(status);
+
+ /* Copy Config from VPE 0 */
+ write_vpe_c0_config(read_c0_config());
+ write_vpe_c0_config7(read_c0_config7());
+
+ /* Ensure no software interrupts are pending */
+ write_vpe_c0_cause(0);
+
+ /* Sync Count */
+ write_vpe_c0_count(read_c0_count());
+ }
+
+ /* Leave VPE configuration state */
+ clear_c0_mvpcontrol(MVPCONTROL_VPC);
+}
+
+static void __init cps_smp_setup(void)
+{
+ unsigned int ncores, nvpes, core_vpes;
+ int c, v;
+ u32 core_cfg, *entry_code;
+
+ /* Detect & record VPE topology */
+ ncores = mips_cm_numcores();
+ pr_info("VPE topology ");
+ for (c = nvpes = 0; c < ncores; c++) {
+ if (cpu_has_mipsmt && config_enabled(CONFIG_MIPS_MT_SMP)) {
+ write_gcr_cl_other(c << CM_GCR_Cx_OTHER_CORENUM_SHF);
+ core_cfg = read_gcr_co_config();
+ core_vpes = ((core_cfg & CM_GCR_Cx_CONFIG_PVPE_MSK) >>
+ CM_GCR_Cx_CONFIG_PVPE_SHF) + 1;
+ } else {
+ core_vpes = 1;
+ }
+
+ pr_cont("%c%u", c ? ',' : '{', core_vpes);
+
+ for (v = 0; v < min_t(int, core_vpes, NR_CPUS - nvpes); v++) {
+ cpu_data[nvpes + v].core = c;
+#ifdef CONFIG_MIPS_MT_SMP
+ cpu_data[nvpes + v].vpe_id = v;
+#endif
+ }
+
+ nvpes += core_vpes;
+ }
+ 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);
+ __cpu_number_map[v] = v;
+ __cpu_logical_map[v] = v;
+ }
+
+ /* Core 0 is powered up (we're running on it) */
+ bitmap_set(core_power, 0, 1);
+
+ /* Disable MT - we only want to run 1 TC per VPE */
+ if (cpu_has_mipsmt)
+ dmt();
+
+ /* Initialise core 0 */
+ init_core();
+
+ /* Patch the start of mips_cps_core_entry to provide the CM base */
+ entry_code = (u32 *)&mips_cps_core_entry;
+ UASM_i_LA(&entry_code, 3, (long)mips_cm_base);
+
+ /* Make core 0 coherent with everything */
+ write_gcr_cl_coherence(0xff);
+}
+
+static void __init cps_prepare_cpus(unsigned int max_cpus)
+{
+ mips_mt_set_cpuoptions();
+}
+
+static void boot_core(struct boot_config *cfg)
+{
+ u32 access;
+
+ /* Select the appropriate core */
+ write_gcr_cl_other(cfg->core << CM_GCR_Cx_OTHER_CORENUM_SHF);
+
+ /* Set its reset vector */
+ write_gcr_co_reset_base(CKSEG1ADDR((unsigned long)mips_cps_core_entry));
+
+ /* Ensure its coherency is disabled */
+ write_gcr_co_coherence(0);
+
+ /* Ensure the core can access the GCRs */
+ access = read_gcr_access();
+ access |= 1 << (CM_GCR_ACCESS_ACCESSEN_SHF + cfg->core);
+ write_gcr_access(access);
+
+ /* Copy cfg */
+ mips_cps_bootcfg = *cfg;
+
+ if (mips_cpc_present()) {
+ /* Select the appropriate core */
+ write_cpc_cl_other(cfg->core << CPC_Cx_OTHER_CORENUM_SHF);
+
+ /* Reset the core */
+ write_cpc_co_cmd(CPC_Cx_CMD_RESET);
+ } else {
+ /* Take the core out of reset */
+ write_gcr_co_reset_release(0);
+ }
+
+ /* The core is now powered up */
+ bitmap_set(core_power, cfg->core, 1);
+}
+
+static void boot_vpe(void *info)
+{
+ struct boot_config *cfg = info;
+ u32 tcstatus, vpeconf0;
+
+ /* Enter VPE configuration state */
+ dvpe();
+ set_c0_mvpcontrol(MVPCONTROL_VPC);
+
+ settc(cfg->vpe);
+
+ /* Set the TC restart PC */
+ write_tc_c0_tcrestart((unsigned long)&smp_bootstrap);
+
+ /* Activate the TC, allow interrupts */
+ tcstatus = read_tc_c0_tcstatus();
+ tcstatus &= ~TCSTATUS_IXMT;
+ tcstatus |= TCSTATUS_A;
+ write_tc_c0_tcstatus(tcstatus);
+
+ /* Clear the TC halt bit */
+ write_tc_c0_tchalt(0);
+
+ /* Activate the VPE */
+ vpeconf0 = read_vpe_c0_vpeconf0();
+ vpeconf0 |= VPECONF0_VPA;
+ write_vpe_c0_vpeconf0(vpeconf0);
+
+ /* Set the stack & global pointer registers */
+ write_tc_gpr_sp(cfg->sp);
+ write_tc_gpr_gp(cfg->gp);
+
+ /* Leave VPE configuration state */
+ clear_c0_mvpcontrol(MVPCONTROL_VPC);
+
+ /* Enable other VPEs to execute */
+ evpe(EVPE_ENABLE);
+}
+
+static void cps_boot_secondary(int cpu, struct task_struct *idle)
+{
+ struct boot_config cfg;
+ unsigned int remote;
+ int err;
+
+ cfg.core = cpu_data[cpu].core;
+ cfg.vpe = cpu_vpe_id(&cpu_data[cpu]);
+ cfg.pc = (unsigned long)&smp_bootstrap;
+ cfg.sp = __KSTK_TOS(idle);
+ cfg.gp = (unsigned long)task_thread_info(idle);
+
+ if (!test_bit(cfg.core, core_power)) {
+ /* Boot a VPE on a powered down core */
+ boot_core(&cfg);
+ return;
+ }
+
+ if (cfg.core != current_cpu_data.core) {
+ /* Boot a VPE on another powered up core */
+ for (remote = 0; remote < NR_CPUS; remote++) {
+ if (cpu_data[remote].core != cfg.core)
+ continue;
+ if (cpu_online(remote))
+ break;
+ }
+ BUG_ON(remote >= NR_CPUS);
+
+ err = smp_call_function_single(remote, boot_vpe, &cfg, 1);
+ if (err)
+ panic("Failed to call remote CPU\n");
+ return;
+ }
+
+ BUG_ON(!cpu_has_mipsmt);
+
+ /* Boot a VPE on this core */
+ boot_vpe(&cfg);
+}
+
+static void cps_init_secondary(void)
+{
+ /* Disable MT - we only want to run 1 TC per VPE */
+ if (cpu_has_mipsmt)
+ dmt();
+
+ /* TODO: revisit this assumption once hotplug is implemented */
+ if (cpu_vpe_id(&current_cpu_data) == 0)
+ init_core();
+
+ change_c0_status(ST0_IM, STATUSF_IP3 | STATUSF_IP4 |
+ STATUSF_IP6 | STATUSF_IP7);
+}
+
+static void cps_smp_finish(void)
+{
+ write_c0_compare(read_c0_count() + (8 * mips_hpt_frequency / HZ));
+
+#ifdef CONFIG_MIPS_MT_FPAFF
+ /* If we have an FPU, enroll ourselves in the FPU-full mask */
+ if (cpu_has_fpu)
+ cpu_set(smp_processor_id(), mt_fpu_cpumask);
+#endif /* CONFIG_MIPS_MT_FPAFF */
+
+ local_irq_enable();
+}
+
+static void cps_cpus_done(void)
+{
+}
+
+static struct plat_smp_ops cps_smp_ops = {
+ .smp_setup = cps_smp_setup,
+ .prepare_cpus = cps_prepare_cpus,
+ .boot_secondary = cps_boot_secondary,
+ .init_secondary = cps_init_secondary,
+ .smp_finish = cps_smp_finish,
+ .send_ipi_single = gic_send_ipi_single,
+ .send_ipi_mask = gic_send_ipi_mask,
+ .cpus_done = cps_cpus_done,
+};
+
+int register_cps_smp_ops(void)
+{
+ if (!mips_cm_present()) {
+ pr_warn("MIPS CPS SMP unable to proceed without a CM\n");
+ return -ENODEV;
+ }
+
+ /* check we have a GIC - we need one for IPIs */
+ if (!(read_gcr_gic_status() & CM_GCR_GIC_STATUS_EX_MSK)) {
+ pr_warn("MIPS CPS SMP unable to proceed without a GIC\n");
+ return -ENODEV;
+ }
+
+ register_smp_ops(&cps_smp_ops);
+ return 0;
+}