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

[Aurelien Jarno <aurelien@aurel32.net>]

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