Re: [PATCH V15 10/12] MIPS: Loongson 3: Add Loongson-3 SMP support

[Aurelien Jarno <aurelien@aurel32.net>]

On Sun, Jan 05, 2014 at 07:14:49PM +0800, Huacai Chen wrote:
> Thank you, all your suggestions will be taken.

Thanks !

> On Sun, Jan 5, 2014 at 7:25 AM, Aurelien Jarno <aurelien@aurel32.net> wrote:
> 
> > On Sun, Dec 15, 2013 at 08:14:34PM +0800, Huacai Chen wrote:
> > > IPI registers of Loongson-3 include IPI_SET, IPI_CLEAR, IPI_STATUS,
> > > IPI_EN and IPI_MAILBOX_BUF. Each bit of IPI_STATUS indicate a type of
> > > IPI and IPI_EN indicate whether the IPI is enabled. The sender write 1
> > > to IPI_SET bits generate IPIs in IPI_STATUS, and receiver write 1 to
> > > bits of IPI_CLEAR to clear IPIs. IPI_MAILBOX_BUF are used to deliver
> > > more information about IPIs.
> > >
> > > Why we change code in arch/mips/loongson/common/setup.c?
> > >
> > > If without this change, when SMP configured, system cannot boot since
> > > it hang at printk() in cgroup_init_early(). The root cause is:
> > >
> > > console_trylock()
> > >   \-->down_trylock(&console_sem)
> > >     \-->raw_spin_unlock_irqrestore(&sem->lock, flags)
> > >       \-->_raw_spin_unlock_irqrestore()(SMP/UP have different versions)
> > >         \-->__raw_spin_unlock_irqrestore()  (following is the SMP case)
> > >           \-->do_raw_spin_unlock()
> > >             \-->arch_spin_unlock()
> > >               \-->nudge_writes()
> > >                 \-->mb()
> > >                   \-->wbflush()
> > >                     \-->__wbflush()
> > >
> > > In previous code __wbflush() is initialized in plat_mem_setup(), but
> > > cgroup_init_early() is called before plat_mem_setup(). Therefore, In
> > > this patch we make changes to avoid boot failure.
> > >
> > > Signed-off-by: Huacai Chen <chenhc@lemote.com>
> > > Signed-off-by: Hongliang Tao <taohl@lemote.com>
> > > Signed-off-by: Hua Yan <yanh@lemote.com>
> > > ---
> > >  arch/mips/loongson/common/init.c       |    5 +
> > >  arch/mips/loongson/common/setup.c      |    8 +-
> > >  arch/mips/loongson/loongson-3/Makefile |    2 +
> > >  arch/mips/loongson/loongson-3/irq.c    |   16 ++
> > >  arch/mips/loongson/loongson-3/smp.c    |  280
> > ++++++++++++++++++++++++++++++++
> > >  arch/mips/loongson/loongson-3/smp.h    |   24 +++
> > >  6 files changed, 330 insertions(+), 5 deletions(-)
> > >  create mode 100644 arch/mips/loongson/loongson-3/smp.c
> > >  create mode 100644 arch/mips/loongson/loongson-3/smp.h
> > >
> > > diff --git a/arch/mips/loongson/common/init.c
> > b/arch/mips/loongson/common/init.c
> > > index 81ba3b4..d6c501b 100644
> > > --- a/arch/mips/loongson/common/init.c
> > > +++ b/arch/mips/loongson/common/init.c
> > > @@ -12,6 +12,8 @@
> > >
> > >  #include <loongson.h>
> > >
> > > +extern struct plat_smp_ops loongson3_smp_ops;
> > > +
> > >  /* Loongson CPU address windows config space base address */
> > >  unsigned long __maybe_unused _loongson_addrwincfg_base;
> > >
> > > @@ -33,6 +35,9 @@ void __init prom_init(void)
> > >
> > >       /*init the uart base address */
> > >       prom_init_uart_base();
> > > +#if defined(CONFIG_SMP)
> > > +     register_smp_ops(&loongson3_smp_ops);
> > > +#endif
> > >  }
> > >
> > >  void __init prom_free_prom_memory(void)
> > > diff --git a/arch/mips/loongson/common/setup.c
> > b/arch/mips/loongson/common/setup.c
> > > index 8223f8a..bb4ac92 100644
> > > --- a/arch/mips/loongson/common/setup.c
> > > +++ b/arch/mips/loongson/common/setup.c
> > > @@ -18,9 +18,6 @@
> > >  #include <linux/screen_info.h>
> > >  #endif
> > >
> > > -void (*__wbflush)(void);
> > > -EXPORT_SYMBOL(__wbflush);
> > > -
> > >  static void wbflush_loongson(void)
> > >  {
> > >       asm(".set\tpush\n\t"
> > > @@ -32,10 +29,11 @@ static void wbflush_loongson(void)
> > >           ".set mips0\n\t");
> > >  }
> > >
> > > +void (*__wbflush)(void) = wbflush_loongson;
> > > +EXPORT_SYMBOL(__wbflush);
> > > +
> > >  void __init plat_mem_setup(void)
> > >  {
> > > -     __wbflush = wbflush_loongson;
> > > -
> > >  #ifdef CONFIG_VT
> > >  #if defined(CONFIG_VGA_CONSOLE)
> > >       conswitchp = &vga_con;
> > > diff --git a/arch/mips/loongson/loongson-3/Makefile
> > b/arch/mips/loongson/loongson-3/Makefile
> > > index b9968cd..70152b2 100644
> > > --- a/arch/mips/loongson/loongson-3/Makefile
> > > +++ b/arch/mips/loongson/loongson-3/Makefile
> > > @@ -2,3 +2,5 @@
> > >  # Makefile for Loongson-3 family machines
> > >  #
> > >  obj-y                        += irq.o
> > > +
> > > +obj-$(CONFIG_SMP)    += smp.o
> > > diff --git a/arch/mips/loongson/loongson-3/irq.c
> > b/arch/mips/loongson/loongson-3/irq.c
> > > index aaf18c2..11467ca 100644
> > > --- a/arch/mips/loongson/loongson-3/irq.c
> > > +++ b/arch/mips/loongson/loongson-3/irq.c
> > > @@ -61,10 +61,26 @@ static inline void mask_loongson_irq(struct irq_data
> > *d)
> > >  {
> > >       clear_c0_status(0x100 << (d->irq - MIPS_CPU_IRQ_BASE));
> > >       irq_disable_hazard();
> > > +
> > > +     /* Workaround: UART IRQ may deliver to any core */
> > > +     if (d->irq == LOONGSON_UART_IRQ) {
> > > +             int cpu = smp_processor_id();
> > > +
> > > +             LOONGSON_INT_ROUTER_INTENCLR = 1 << 10;
> > > +             LOONGSON_INT_ROUTER_LPC = 0x10 + (1<<cpu);
> > > +     }
> > >  }
> > >
> > >  static inline void unmask_loongson_irq(struct irq_data *d)
> > >  {
> > > +     /* Workaround: UART IRQ may deliver to any core */
> > > +     if (d->irq == LOONGSON_UART_IRQ) {
> > > +             int cpu = smp_processor_id();
> > > +
> > > +             LOONGSON_INT_ROUTER_INTENSET = 1 << 10;
> > > +             LOONGSON_INT_ROUTER_LPC = 0x10 + (1<<cpu);
> > > +     }
> > > +
> > >       set_c0_status(0x100 << (d->irq - MIPS_CPU_IRQ_BASE));
> > >       irq_enable_hazard();
> > >  }
> > > diff --git a/arch/mips/loongson/loongson-3/smp.c
> > b/arch/mips/loongson/loongson-3/smp.c
> > > new file mode 100644
> > > index 0000000..3c52565
> > > --- /dev/null
> > > +++ b/arch/mips/loongson/loongson-3/smp.c
> > > @@ -0,0 +1,280 @@
> > > +/*
> > > + * Copyright (C) 2010, 2011, 2012, Lemote, Inc.
> > > + * Author: Chen Huacai, chenhc@lemote.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.
> > > + *
> > > + * This program is distributed in the hope that it will be useful,
> > > + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> > > + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> > > + * GNU General Public License for more details.
> > > + *
> > > + * You should have received a copy of the GNU General Public License
> > > + * along with this program; if not, write to the Free Software
> > > + * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
> >  02111-1307, USA.
> > > + */
> > > +
> > > +#include <linux/init.h>
> > > +#include <linux/cpu.h>
> > > +#include <linux/sched.h>
> > > +#include <linux/smp.h>
> > > +#include <linux/cpufreq.h>
> > > +#include <asm/processor.h>
> > > +#include <asm/time.h>
> > > +#include <asm/clock.h>
> > > +#include <asm/tlbflush.h>
> > > +#include <loongson.h>
> > > +
> > > +#include "smp.h"
> > > +
> > > +/* read a 64bit value from ipi register */
> > > +uint64_t loongson3_ipi_read64(void * addr)
> > > +{
> > > +     return *((volatile uint64_t *)addr);
> > > +};
> > > +
> > > +/* write a 64bit value to ipi register */
> > > +void loongson3_ipi_write64(uint64_t action, void * addr)
> > > +{
> > > +     *((volatile uint64_t *)addr) = action;
> > > +     __wbflush();
> > > +};
> > > +
> > > +/* read a 32bit value from ipi register */
> > > +uint32_t loongson3_ipi_read32(void * addr)
> > > +{
> > > +     return *((volatile uint32_t *)addr);
> > > +};
> > > +
> > > +/* write a 32bit value to ipi register */
> > > +void loongson3_ipi_write32(uint32_t action, void * addr)
> > > +{
> > > +     *((volatile uint32_t *)addr) = action;
> > > +     __wbflush();
> > > +};
> >
> > For all these functions, you should use read/write l/q instead of
> > volatile.
> >
> > > +static void *ipi_set0_regs[] = {
> > > +     (void *)(smp_core_group0_base + smp_core0_offset + SET0),
> > > +     (void *)(smp_core_group0_base + smp_core1_offset + SET0),
> > > +     (void *)(smp_core_group0_base + smp_core2_offset + SET0),
> > > +     (void *)(smp_core_group0_base + smp_core3_offset + SET0),
> > > +     (void *)(smp_core_group1_base + smp_core0_offset + SET0),
> > > +     (void *)(smp_core_group1_base + smp_core1_offset + SET0),
> > > +     (void *)(smp_core_group1_base + smp_core2_offset + SET0),
> > > +     (void *)(smp_core_group1_base + smp_core3_offset + SET0),
> > > +     (void *)(smp_core_group2_base + smp_core0_offset + SET0),
> > > +     (void *)(smp_core_group2_base + smp_core1_offset + SET0),
> > > +     (void *)(smp_core_group2_base + smp_core2_offset + SET0),
> > > +     (void *)(smp_core_group2_base + smp_core3_offset + SET0),
> > > +     (void *)(smp_core_group3_base + smp_core0_offset + SET0),
> > > +     (void *)(smp_core_group3_base + smp_core1_offset + SET0),
> > > +     (void *)(smp_core_group3_base + smp_core2_offset + SET0),
> > > +     (void *)(smp_core_group3_base + smp_core3_offset + SET0),
> > > +};
> > > +
> > > +static void *ipi_clear0_regs[] = {
> > > +     (void *)(smp_core_group0_base + smp_core0_offset + CLEAR0),
> > > +     (void *)(smp_core_group0_base + smp_core1_offset + CLEAR0),
> > > +     (void *)(smp_core_group0_base + smp_core2_offset + CLEAR0),
> > > +     (void *)(smp_core_group0_base + smp_core3_offset + CLEAR0),
> > > +     (void *)(smp_core_group1_base + smp_core0_offset + CLEAR0),
> > > +     (void *)(smp_core_group1_base + smp_core1_offset + CLEAR0),
> > > +     (void *)(smp_core_group1_base + smp_core2_offset + CLEAR0),
> > > +     (void *)(smp_core_group1_base + smp_core3_offset + CLEAR0),
> > > +     (void *)(smp_core_group2_base + smp_core0_offset + CLEAR0),
> > > +     (void *)(smp_core_group2_base + smp_core1_offset + CLEAR0),
> > > +     (void *)(smp_core_group2_base + smp_core2_offset + CLEAR0),
> > > +     (void *)(smp_core_group2_base + smp_core3_offset + CLEAR0),
> > > +     (void *)(smp_core_group3_base + smp_core0_offset + CLEAR0),
> > > +     (void *)(smp_core_group3_base + smp_core1_offset + CLEAR0),
> > > +     (void *)(smp_core_group3_base + smp_core2_offset + CLEAR0),
> > > +     (void *)(smp_core_group3_base + smp_core3_offset + CLEAR0),
> > > +};
> > > +
> > > +static void *ipi_status0_regs[] = {
> > > +     (void *)(smp_core_group0_base + smp_core0_offset + STATUS0),
> > > +     (void *)(smp_core_group0_base + smp_core1_offset + STATUS0),
> > > +     (void *)(smp_core_group0_base + smp_core2_offset + STATUS0),
> > > +     (void *)(smp_core_group0_base + smp_core3_offset + STATUS0),
> > > +     (void *)(smp_core_group1_base + smp_core0_offset + STATUS0),
> > > +     (void *)(smp_core_group1_base + smp_core1_offset + STATUS0),
> > > +     (void *)(smp_core_group1_base + smp_core2_offset + STATUS0),
> > > +     (void *)(smp_core_group1_base + smp_core3_offset + STATUS0),
> > > +     (void *)(smp_core_group2_base + smp_core0_offset + STATUS0),
> > > +     (void *)(smp_core_group2_base + smp_core1_offset + STATUS0),
> > > +     (void *)(smp_core_group2_base + smp_core2_offset + STATUS0),
> > > +     (void *)(smp_core_group2_base + smp_core3_offset + STATUS0),
> > > +     (void *)(smp_core_group3_base + smp_core0_offset + STATUS0),
> > > +     (void *)(smp_core_group3_base + smp_core1_offset + STATUS0),
> > > +     (void *)(smp_core_group3_base + smp_core2_offset + STATUS0),
> > > +     (void *)(smp_core_group3_base + smp_core3_offset + STATUS0),
> > > +};
> > > +
> > > +static void *ipi_en0_regs[] = {
> > > +     (void *)(smp_core_group0_base + smp_core0_offset + EN0),
> > > +     (void *)(smp_core_group0_base + smp_core1_offset + EN0),
> > > +     (void *)(smp_core_group0_base + smp_core2_offset + EN0),
> > > +     (void *)(smp_core_group0_base + smp_core3_offset + EN0),
> > > +     (void *)(smp_core_group1_base + smp_core0_offset + EN0),
> > > +     (void *)(smp_core_group1_base + smp_core1_offset + EN0),
> > > +     (void *)(smp_core_group1_base + smp_core2_offset + EN0),
> > > +     (void *)(smp_core_group1_base + smp_core3_offset + EN0),
> > > +     (void *)(smp_core_group2_base + smp_core0_offset + EN0),
> > > +     (void *)(smp_core_group2_base + smp_core1_offset + EN0),
> > > +     (void *)(smp_core_group2_base + smp_core2_offset + EN0),
> > > +     (void *)(smp_core_group2_base + smp_core3_offset + EN0),
> > > +     (void *)(smp_core_group3_base + smp_core0_offset + EN0),
> > > +     (void *)(smp_core_group3_base + smp_core1_offset + EN0),
> > > +     (void *)(smp_core_group3_base + smp_core2_offset + EN0),
> > > +     (void *)(smp_core_group3_base + smp_core3_offset + EN0),
> > > +};
> > > +
> > > +static volatile void *ipi_mailbox_buf[] = {
> > > +     (void *)(smp_core_group0_base + smp_core0_offset + BUF),
> > > +     (void *)(smp_core_group0_base + smp_core1_offset + BUF),
> > > +     (void *)(smp_core_group0_base + smp_core2_offset + BUF),
> > > +     (void *)(smp_core_group0_base + smp_core3_offset + BUF),
> > > +     (void *)(smp_core_group1_base + smp_core0_offset + BUF),
> > > +     (void *)(smp_core_group1_base + smp_core1_offset + BUF),
> > > +     (void *)(smp_core_group1_base + smp_core2_offset + BUF),
> > > +     (void *)(smp_core_group1_base + smp_core3_offset + BUF),
> > > +     (void *)(smp_core_group2_base + smp_core0_offset + BUF),
> > > +     (void *)(smp_core_group2_base + smp_core1_offset + BUF),
> > > +     (void *)(smp_core_group2_base + smp_core2_offset + BUF),
> > > +     (void *)(smp_core_group2_base + smp_core3_offset + BUF),
> > > +     (void *)(smp_core_group3_base + smp_core0_offset + BUF),
> > > +     (void *)(smp_core_group3_base + smp_core1_offset + BUF),
> > > +     (void *)(smp_core_group3_base + smp_core2_offset + BUF),
> > > +     (void *)(smp_core_group3_base + smp_core3_offset + BUF),
> > > +};
> > > +
> > > +/*
> > > + * Simple enough, just poke the appropriate ipi register
> > > + */
> > > +static void loongson3_send_ipi_single(int cpu, unsigned int action)
> > > +{
> > > +     loongson3_ipi_write32((u32)action, ipi_set0_regs[cpu]);
> > > +}
> > > +
> > > +static void loongson3_send_ipi_mask(const struct cpumask *mask,
> > unsigned int action)
> > > +{
> > > +     unsigned int i;
> > > +
> > > +     for_each_cpu(i, mask)
> > > +             loongson3_ipi_write32((u32)action, ipi_set0_regs[i]);
> > > +}
> > > +
> > > +void loongson3_ipi_interrupt(struct pt_regs *regs)
> > > +{
> > > +     int cpu = smp_processor_id();
> > > +     unsigned int action;
> > > +
> > > +     /* Load the ipi register to figure out what we're supposed to do */
> > > +     action = loongson3_ipi_read32(ipi_status0_regs[cpu]);
> > > +
> > > +     /* Clear the ipi register to clear the interrupt */
> > > +     loongson3_ipi_write32((u32)action, ipi_clear0_regs[cpu]);
> > > +
> > > +     if (action & SMP_RESCHEDULE_YOURSELF) {
> > > +             scheduler_ipi();
> > > +     }
> > > +
> > > +     if (action & SMP_CALL_FUNCTION) {
> > > +             smp_call_function_interrupt();
> > > +     }
> > > +}
> > > +
> > > +/*
> > > + * SMP init and finish on secondary CPUs
> > > + */
> > > +void loongson3_init_secondary(void)
> > > +{
> > > +     int i;
> > > +     unsigned int imask = STATUSF_IP7 | STATUSF_IP6 |
> > > +                          STATUSF_IP3 | STATUSF_IP2;
> > > +
> > > +     /* Set interrupt mask, but don't enable */
> > > +     change_c0_status(ST0_IM, imask);
> > > +
> > > +     for (i = 0; i < nr_cpus_loongson; i++) {
> > > +             loongson3_ipi_write32(0xffffffff, ipi_en0_regs[i]);
> > > +     }
> > > +}
> > > +
> > > +void loongson3_smp_finish(void)
> > > +{
> > > +     write_c0_compare(read_c0_count() + mips_hpt_frequency/HZ);
> > > +     local_irq_enable();
> > > +     loongson3_ipi_write64(0, (void
> > *)(ipi_mailbox_buf[smp_processor_id()]+0x0));
> > > +     printk(KERN_INFO "CPU#%d finished, CP0_ST=%x\n",
> > > +                     smp_processor_id(), read_c0_status());
> > > +}
> > > +
> > > +void __init loongson3_smp_setup(void)
> > > +{
> > > +     int i, num;
> > > +
> > > +     init_cpu_possible(cpu_none_mask);
> > > +     set_cpu_possible(0, true);
> > > +
> > > +     __cpu_number_map[0] = 0;
> > > +     __cpu_logical_map[0] = 0;
> > > +
> > > +     /* For unified kernel, NR_CPUS is the maximum possible value,
> > > +      * nr_cpus_loongson is the really present value */
> > > +     for (i = 1, num = 0; i < nr_cpus_loongson; i++) {
> > > +             set_cpu_possible(i, true);
> > > +             __cpu_number_map[i] = ++num;
> > > +             __cpu_logical_map[num] = i;
> > > +     }
> > > +     printk(KERN_INFO "Detected %i available secondary CPU(s)\n", num);
> > > +}
> > > +
> > > +void __init loongson3_prepare_cpus(unsigned int max_cpus)
> > > +{
> > > +}
> > > +
> > > +/*
> > > + * Setup the PC, SP, and GP of a secondary processor and start it
> > runing!
> > > + */
> > > +void loongson3_boot_secondary(int cpu, struct task_struct *idle)
> > > +{
> > > +     volatile unsigned long startargs[4];
> >
> > Do we really need volatile here?
> >
> > > +
> > > +     printk(KERN_INFO "Booting CPU#%d...\n", cpu);
> > > +
> > > +     /* startargs[] are initial PC, SP and GP for secondary CPU */
> > > +     startargs[0] = (unsigned long)&smp_bootstrap;
> > > +     startargs[1] = (unsigned long)__KSTK_TOS(idle);
> > > +     startargs[2] = (unsigned long)task_thread_info(idle);
> > > +     startargs[3] = 0;
> > > +
> > > +     printk(KERN_DEBUG "CPU#%d, func_pc=%lx, sp=%lx, gp=%lx\n",
> > > +                     cpu, startargs[0], startargs[1], startargs[2]);
> > > +
> > > +     loongson3_ipi_write64(startargs[3], (void
> > *)(ipi_mailbox_buf[cpu]+0x18));
> > > +     loongson3_ipi_write64(startargs[2], (void
> > *)(ipi_mailbox_buf[cpu]+0x10));
> > > +     loongson3_ipi_write64(startargs[1], (void
> > *)(ipi_mailbox_buf[cpu]+0x8));
> > > +     loongson3_ipi_write64(startargs[0], (void
> > *)(ipi_mailbox_buf[cpu]+0x0));
> > > +}
> > > +
> > > +/*
> > > + * Final cleanup after all secondaries booted
> > > + */
> > > +void __init loongson3_cpus_done(void)
> > > +{
> > > +}
> > > +
> > > +struct plat_smp_ops loongson3_smp_ops = {
> > > +     .send_ipi_single = loongson3_send_ipi_single,
> > > +     .send_ipi_mask = loongson3_send_ipi_mask,
> > > +     .init_secondary = loongson3_init_secondary,
> > > +     .smp_finish = loongson3_smp_finish,
> > > +     .cpus_done = loongson3_cpus_done,
> > > +     .boot_secondary = loongson3_boot_secondary,
> > > +     .smp_setup = loongson3_smp_setup,
> > > +     .prepare_cpus = loongson3_prepare_cpus,
> > > +};
> > > diff --git a/arch/mips/loongson/loongson-3/smp.h
> > b/arch/mips/loongson/loongson-3/smp.h
> > > new file mode 100644
> > > index 0000000..dc9ce69
> > > --- /dev/null
> > > +++ b/arch/mips/loongson/loongson-3/smp.h
> > > @@ -0,0 +1,24 @@
> > > +/* for Loongson-3A smp support */
> > > +
> > > +/* 4 groups(nodes) in maximum in numa case */
> > > +#define  smp_core_group0_base    0x900000003ff01000
> > > +#define  smp_core_group1_base    0x900010003ff01000
> > > +#define  smp_core_group2_base    0x900020003ff01000
> > > +#define  smp_core_group3_base    0x900030003ff01000
> > > +
> > > +/* 4 cores in each group(node) */
> > > +#define  smp_core0_offset  0x000
> > > +#define  smp_core1_offset  0x100
> > > +#define  smp_core2_offset  0x200
> > > +#define  smp_core3_offset  0x300
> > > +
> > > +/* ipi registers offsets */
> > > +#define  STATUS0  0x00
> > > +#define  EN0      0x04
> > > +#define  SET0     0x08
> > > +#define  CLEAR0   0x0c
> > > +#define  STATUS1  0x10
> > > +#define  MASK1    0x14
> > > +#define  SET1     0x18
> > > +#define  CLEAR1   0x1c
> > > +#define  BUF      0x20
> > > --
> > > 1.7.7.3
> > >
> > >
> > >
> >
> > --
> > Aurelien Jarno                          GPG: 1024D/F1BCDB73
> > aurelien@aurel32.net                 http://www.aurel32.net
> >
> >

-- 
Aurelien Jarno                          GPG: 1024D/F1BCDB73
aurelien@aurel32.net                 http://www.aurel32.net