[PATCH v2 0/6] Modify some registers operations and move decode_cpucfg() to loongson_regs.h

[PATCH v2 0/6] Modify some registers operations and move decode_cpucfg() to loongson_regs.h

[Tiezhu Yang]

v2: Add some callbacks in csr_ipi probe() for patch #4

Tiezhu Yang (6):
  MIPS: Loongson64: Do not write the read only field LPA of CP0_CONFIG3
  MIPS: Loongson64: Set the field ELPA of CP0_PAGEGRAIN only once
  MIPS: Loongson64: Set IPI_Enable register per core by itself
  MIPS: Loongson64: Add Mail_Send support for 3A4000+ CPU
  MIPS: Loongson64: Make sure the PC address is correct when 3A4000+ CPU
    hotplug
  MIPS: Loongson64: Move decode_cpucfg() to loongson_regs.h

 .../asm/mach-loongson64/kernel-entry-init.h        |   8 --
 .../include/asm/mach-loongson64/loongson_regs.h    |  34 ++++++
 arch/mips/kernel/cpu-probe.c                       |  31 +-----
 arch/mips/loongson64/numa.c                        |  20 +---
 arch/mips/loongson64/smp.c                         | 123 +++++++++++++++++----
 5 files changed, 136 insertions(+), 80 deletions(-)

-- 
2.1.0

[PATCH v2 1/6] MIPS: Loongson64: Do not write the read only field LPA of CP0_CONFIG3

[Tiezhu Yang]

The field LPA of CP0_CONFIG3 register is read only for Loongson64, so the
write operations are meaningless, remove them.

Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
---

v2: No changes

 arch/mips/include/asm/mach-loongson64/kernel-entry-init.h | 8 --------
 arch/mips/loongson64/numa.c                               | 3 ---
 2 files changed, 11 deletions(-)

diff --git a/arch/mips/include/asm/mach-loongson64/kernel-entry-init.h b/arch/mips/include/asm/mach-loongson64/kernel-entry-init.h
index 87a5bfb..e4d77f4 100644
--- a/arch/mips/include/asm/mach-loongson64/kernel-entry-init.h
+++ b/arch/mips/include/asm/mach-loongson64/kernel-entry-init.h
@@ -19,10 +19,6 @@
 	.macro	kernel_entry_setup
 	.set	push
 	.set	mips64
-	/* Set LPA on LOONGSON3 config3 */
-	mfc0	t0, CP0_CONFIG3
-	or	t0, (0x1 << 7)
-	mtc0	t0, CP0_CONFIG3
 	/* Set ELPA on LOONGSON3 pagegrain */
 	mfc0	t0, CP0_PAGEGRAIN
 	or	t0, (0x1 << 29)
@@ -54,10 +50,6 @@
 	.macro	smp_slave_setup
 	.set	push
 	.set	mips64
-	/* Set LPA on LOONGSON3 config3 */
-	mfc0	t0, CP0_CONFIG3
-	or	t0, (0x1 << 7)
-	mtc0	t0, CP0_CONFIG3
 	/* Set ELPA on LOONGSON3 pagegrain */
 	mfc0	t0, CP0_PAGEGRAIN
 	or	t0, (0x1 << 29)
diff --git a/arch/mips/loongson64/numa.c b/arch/mips/loongson64/numa.c
index cf9459f..c7e3cced 100644
--- a/arch/mips/loongson64/numa.c
+++ b/arch/mips/loongson64/numa.c
@@ -40,9 +40,6 @@ static void enable_lpa(void)
 	unsigned long value;
 
 	value = __read_32bit_c0_register($16, 3);
-	value |= 0x00000080;
-	__write_32bit_c0_register($16, 3, value);
-	value = __read_32bit_c0_register($16, 3);
 	pr_info("CP0_Config3: CP0 16.3 (0x%lx)\n", value);
 
 	value = __read_32bit_c0_register($5, 1);
-- 
2.1.0

[PATCH v2 2/6] MIPS: Loongson64: Set the field ELPA of CP0_PAGEGRAIN only once

[Tiezhu Yang]

The field ELPA of CP0_PAGEGRAIN register is set at the beginning
of the kernel entry point in kernel-entry-init.h, no need to set
it again in numa.c, we can remove enable_lpa() and only print the
related information.

Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
---

v2: No changes

 arch/mips/loongson64/numa.c | 17 ++---------------
 1 file changed, 2 insertions(+), 15 deletions(-)

diff --git a/arch/mips/loongson64/numa.c b/arch/mips/loongson64/numa.c
index c7e3cced..509b360 100644
--- a/arch/mips/loongson64/numa.c
+++ b/arch/mips/loongson64/numa.c
@@ -35,20 +35,6 @@ EXPORT_SYMBOL(__node_data);
 cpumask_t __node_cpumask[MAX_NUMNODES];
 EXPORT_SYMBOL(__node_cpumask);
 
-static void enable_lpa(void)
-{
-	unsigned long value;
-
-	value = __read_32bit_c0_register($16, 3);
-	pr_info("CP0_Config3: CP0 16.3 (0x%lx)\n", value);
-
-	value = __read_32bit_c0_register($5, 1);
-	value |= 0x20000000;
-	__write_32bit_c0_register($5, 1, value);
-	value = __read_32bit_c0_register($5, 1);
-	pr_info("CP0_PageGrain: CP0 5.1 (0x%lx)\n", value);
-}
-
 static void cpu_node_probe(void)
 {
 	int i;
@@ -240,7 +226,8 @@ EXPORT_SYMBOL(pcibus_to_node);
 
 void __init prom_init_numa_memory(void)
 {
-	enable_lpa();
+	pr_info("CP0_Config3: CP0 16.3 (0x%x)\n", read_c0_config3());
+	pr_info("CP0_PageGrain: CP0 5.1 (0x%x)\n", read_c0_pagegrain());
 	prom_meminit();
 }
 EXPORT_SYMBOL(prom_init_numa_memory);
-- 
2.1.0

[PATCH v2 3/6] MIPS: Loongson64: Set IPI_Enable register per core by itself

[Tiezhu Yang]

In the current code, for example, core 1 sets Core[0, 1, 2, 3]_IPI_Enalbe
register and core 2, 3 do the same thing on the 1-way Loongson64 platform,
this is not necessary. Set IPI_Enable register per core by itself to avoid
duplicate operations and make the logic more clear.

Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
---

v2: No changes

 arch/mips/loongson64/smp.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/mips/loongson64/smp.c b/arch/mips/loongson64/smp.c
index e744e1b..7d58853 100644
--- a/arch/mips/loongson64/smp.c
+++ b/arch/mips/loongson64/smp.c
@@ -348,8 +348,7 @@ static void loongson3_init_secondary(void)
 	/* Set interrupt mask, but don't enable */
 	change_c0_status(ST0_IM, imask);
 
-	for (i = 0; i < num_possible_cpus(); i++)
-		loongson3_ipi_write32(0xffffffff, ipi_en0_regs[cpu_logical_map(i)]);
+	loongson3_ipi_write32(0xffffffff, ipi_en0_regs[cpu_logical_map(cpu)]);
 
 	per_cpu(cpu_state, cpu) = CPU_ONLINE;
 	cpu_set_core(&cpu_data[cpu],
@@ -420,6 +419,7 @@ static void __init loongson3_smp_setup(void)
 	ipi_status0_regs_init();
 	ipi_en0_regs_init();
 	ipi_mailbox_buf_init();
+	loongson3_ipi_write32(0xffffffff, ipi_en0_regs[cpu_logical_map(0)]);
 	cpu_set_core(&cpu_data[0],
 		     cpu_logical_map(0) % loongson_sysconf.cores_per_package);
 	cpu_data[0].package = cpu_logical_map(0) / loongson_sysconf.cores_per_package;
-- 
2.1.0

[PATCH v2 4/6] MIPS: Loongson64: Add Mail_Send support for 3A4000+ CPU

[Tiezhu Yang]

Loongson 3A4000+ CPU has per-core Mail_Send register to send mail,
there is no need to maintain register address of each core and node,
just simply specify cpu number.

Signed-off-by: Lu Zeng <zenglu@loongson.cn>
Signed-off-by: Jianmin Lv <lvjianmin@loongson.cn>
Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
---

v2: Add some callbacks in csr_ipi_probe()

 .../include/asm/mach-loongson64/loongson_regs.h    |  10 ++
 arch/mips/loongson64/smp.c                         | 120 +++++++++++++++++----
 2 files changed, 107 insertions(+), 23 deletions(-)

diff --git a/arch/mips/include/asm/mach-loongson64/loongson_regs.h b/arch/mips/include/asm/mach-loongson64/loongson_regs.h
index 83dbb9f..1659935 100644
--- a/arch/mips/include/asm/mach-loongson64/loongson_regs.h
+++ b/arch/mips/include/asm/mach-loongson64/loongson_regs.h
@@ -227,6 +227,16 @@ static inline void csr_writeq(u64 val, u32 reg)
 #define CSR_IPI_SEND_CPU_SHIFT	16
 #define CSR_IPI_SEND_BLOCK	BIT(31)
 
+#define LOONGSON_CSR_MAIL_BUF0		0x1020
+#define LOONGSON_CSR_MAIL_SEND		0x1048
+#define CSR_MAIL_SEND_BLOCK		BIT_ULL(31)
+#define CSR_MAIL_SEND_BOX_LOW(box)	(box << 1)
+#define CSR_MAIL_SEND_BOX_HIGH(box)	((box << 1) + 1)
+#define CSR_MAIL_SEND_BOX_SHIFT		2
+#define CSR_MAIL_SEND_CPU_SHIFT		16
+#define CSR_MAIL_SEND_BUF_SHIFT		32
+#define CSR_MAIL_SEND_H32_MASK		0xFFFFFFFF00000000ULL
+
 static inline u64 drdtime(void)
 {
 	int rID = 0;
diff --git a/arch/mips/loongson64/smp.c b/arch/mips/loongson64/smp.c
index 7d58853..736e98d 100644
--- a/arch/mips/loongson64/smp.c
+++ b/arch/mips/loongson64/smp.c
@@ -53,6 +53,29 @@ static uint32_t core0_c0count[NR_CPUS];
 
 u32 (*ipi_read_clear)(int cpu);
 void (*ipi_write_action)(int cpu, u32 action);
+void (*ipi_write_enable)(int cpu);
+void (*ipi_clear_buf)(int cpu);
+void (*ipi_write_buf)(int cpu, struct task_struct *idle);
+
+/* send mail via Mail_Send register for 3A4000+ CPU */
+static void csr_mail_send(uint64_t data, int cpu, int mailbox)
+{
+	uint64_t val;
+
+	/* send high 32 bits */
+	val = CSR_MAIL_SEND_BLOCK;
+	val |= (CSR_MAIL_SEND_BOX_HIGH(mailbox) << CSR_MAIL_SEND_BOX_SHIFT);
+	val |= (cpu << CSR_MAIL_SEND_CPU_SHIFT);
+	val |= (data & CSR_MAIL_SEND_H32_MASK);
+	csr_writeq(val, LOONGSON_CSR_MAIL_SEND);
+
+	/* send low 32 bits */
+	val = CSR_MAIL_SEND_BLOCK;
+	val |= (CSR_MAIL_SEND_BOX_LOW(mailbox) << CSR_MAIL_SEND_BOX_SHIFT);
+	val |= (cpu << CSR_MAIL_SEND_CPU_SHIFT);
+	val |= (data << CSR_MAIL_SEND_BUF_SHIFT);
+	csr_writeq(val, LOONGSON_CSR_MAIL_SEND);
+};
 
 static u32 csr_ipi_read_clear(int cpu)
 {
@@ -79,6 +102,35 @@ static void csr_ipi_write_action(int cpu, u32 action)
 	}
 }
 
+static void csr_ipi_write_enable(int cpu)
+{
+	csr_writel(0xffffffff, LOONGSON_CSR_IPI_EN);
+}
+
+static void csr_ipi_clear_buf(int cpu)
+{
+	csr_writeq(0, LOONGSON_CSR_MAIL_BUF0);
+}
+
+static void csr_ipi_write_buf(int cpu, struct task_struct *idle)
+{
+	unsigned long startargs[4];
+
+	/* 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;
+
+	pr_debug("CPU#%d, func_pc=%lx, sp=%lx, gp=%lx\n",
+		cpu, startargs[0], startargs[1], startargs[2]);
+
+	csr_mail_send(startargs[3], cpu_logical_map(cpu), 3);
+	csr_mail_send(startargs[2], cpu_logical_map(cpu), 2);
+	csr_mail_send(startargs[1], cpu_logical_map(cpu), 1);
+	csr_mail_send(startargs[0], cpu_logical_map(cpu), 0);
+}
+
 static u32 legacy_ipi_read_clear(int cpu)
 {
 	u32 action;
@@ -96,14 +148,53 @@ static void legacy_ipi_write_action(int cpu, u32 action)
 	loongson3_ipi_write32((u32)action, ipi_set0_regs[cpu]);
 }
 
+static void legacy_ipi_write_enable(int cpu)
+{
+	loongson3_ipi_write32(0xffffffff, ipi_en0_regs[cpu_logical_map(cpu)]);
+}
+
+static void legacy_ipi_clear_buf(int cpu)
+{
+	loongson3_ipi_write64(0, ipi_mailbox_buf[cpu_logical_map(cpu)] + 0x0);
+}
+
+static void legacy_ipi_write_buf(int cpu, struct task_struct *idle)
+{
+	unsigned long startargs[4];
+
+	/* 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;
+
+	pr_debug("CPU#%d, func_pc=%lx, sp=%lx, gp=%lx\n",
+			cpu, startargs[0], startargs[1], startargs[2]);
+
+	loongson3_ipi_write64(startargs[3],
+			ipi_mailbox_buf[cpu_logical_map(cpu)] + 0x18);
+	loongson3_ipi_write64(startargs[2],
+			ipi_mailbox_buf[cpu_logical_map(cpu)] + 0x10);
+	loongson3_ipi_write64(startargs[1],
+			ipi_mailbox_buf[cpu_logical_map(cpu)] + 0x8);
+	loongson3_ipi_write64(startargs[0],
+			ipi_mailbox_buf[cpu_logical_map(cpu)] + 0x0);
+}
+
 static void csr_ipi_probe(void)
 {
 	if (cpu_has_csr() && csr_readl(LOONGSON_CSR_FEATURES) & LOONGSON_CSRF_IPI) {
 		ipi_read_clear = csr_ipi_read_clear;
 		ipi_write_action = csr_ipi_write_action;
+		ipi_write_enable = csr_ipi_write_enable;
+		ipi_clear_buf = csr_ipi_clear_buf;
+		ipi_write_buf = csr_ipi_write_buf;
 	} else {
 		ipi_read_clear = legacy_ipi_read_clear;
 		ipi_write_action = legacy_ipi_write_action;
+		ipi_write_enable = legacy_ipi_write_enable;
+		ipi_clear_buf = legacy_ipi_clear_buf;
+		ipi_write_buf = legacy_ipi_write_buf;
 	}
 }
 
@@ -347,8 +438,7 @@ static void loongson3_init_secondary(void)
 
 	/* Set interrupt mask, but don't enable */
 	change_c0_status(ST0_IM, imask);
-
-	loongson3_ipi_write32(0xffffffff, ipi_en0_regs[cpu_logical_map(cpu)]);
+	ipi_write_enable(cpu);
 
 	per_cpu(cpu_state, cpu) = CPU_ONLINE;
 	cpu_set_core(&cpu_data[cpu],
@@ -380,8 +470,8 @@ static void loongson3_smp_finish(void)
 
 	write_c0_compare(read_c0_count() + mips_hpt_frequency/HZ);
 	local_irq_enable();
-	loongson3_ipi_write64(0,
-			ipi_mailbox_buf[cpu_logical_map(cpu)] + 0x0);
+	ipi_clear_buf(cpu);
+
 	pr_info("CPU#%d finished, CP0_ST=%x\n",
 			smp_processor_id(), read_c0_status());
 }
@@ -419,7 +509,8 @@ static void __init loongson3_smp_setup(void)
 	ipi_status0_regs_init();
 	ipi_en0_regs_init();
 	ipi_mailbox_buf_init();
-	loongson3_ipi_write32(0xffffffff, ipi_en0_regs[cpu_logical_map(0)]);
+	ipi_write_enable(0);
+
 	cpu_set_core(&cpu_data[0],
 		     cpu_logical_map(0) % loongson_sysconf.cores_per_package);
 	cpu_data[0].package = cpu_logical_map(0) / loongson_sysconf.cores_per_package;
@@ -439,27 +530,10 @@ static void __init loongson3_prepare_cpus(unsigned int max_cpus)
  */
 static int loongson3_boot_secondary(int cpu, struct task_struct *idle)
 {
-	unsigned long startargs[4];
-
 	pr_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;
-
-	pr_debug("CPU#%d, func_pc=%lx, sp=%lx, gp=%lx\n",
-			cpu, startargs[0], startargs[1], startargs[2]);
+	ipi_write_buf(cpu, idle);
 
-	loongson3_ipi_write64(startargs[3],
-			ipi_mailbox_buf[cpu_logical_map(cpu)] + 0x18);
-	loongson3_ipi_write64(startargs[2],
-			ipi_mailbox_buf[cpu_logical_map(cpu)] + 0x10);
-	loongson3_ipi_write64(startargs[1],
-			ipi_mailbox_buf[cpu_logical_map(cpu)] + 0x8);
-	loongson3_ipi_write64(startargs[0],
-			ipi_mailbox_buf[cpu_logical_map(cpu)] + 0x0);
 	return 0;
 }
 
-- 
2.1.0

[PATCH v2 5/6] MIPS: Loongson64: Make sure the PC address is correct when 3A4000+ CPU hotplug

[Tiezhu Yang]

In loongson3_type3_play_dead(), in order to make sure the PC address is
correct, use lw to read the low 32 bits first, if the result is not zero,
then use ld to read the whole 64 bits, otherwise there maybe exists atomic
problem due to write high 32 bits first and then low 32 bits, like this:

high 32 bits (write done)
                                  -- only read high 32-bits which is wrong
low 32 bits (not yet write done)

This problem is especially for Loongson 3A4000+ CPU due to using Mail_Send
register which can only send 32 bits data one time. Although it is hard to
reproduce, we can do something at the software level to avoid the risks for
3A4000+ CPU, this change has no influence on the other Loongson CPUs.

Signed-off-by: Lu Zeng <zenglu@loongson.cn>
Signed-off-by: Jun Yi <yijun@loongson.cn>
Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
---

v2: No changes

 arch/mips/loongson64/smp.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/arch/mips/loongson64/smp.c b/arch/mips/loongson64/smp.c
index 736e98d..e32b46e 100644
--- a/arch/mips/loongson64/smp.c
+++ b/arch/mips/loongson64/smp.c
@@ -764,9 +764,10 @@ static void loongson3_type3_play_dead(int *state_addr)
 		"1: li    %[count], 0x100             \n" /* wait for init loop */
 		"2: bnez  %[count], 2b                \n" /* limit mailbox access */
 		"   addiu %[count], -1                \n"
-		"   ld    %[initfunc], 0x20(%[base])  \n" /* get PC via mailbox */
+		"   lw    %[initfunc], 0x20(%[base])  \n" /* get PC (low 32 bits) via mailbox */
 		"   beqz  %[initfunc], 1b             \n"
 		"   nop                               \n"
+		"   ld    %[initfunc], 0x20(%[base])  \n" /* get PC (whole 64 bits) via mailbox */
 		"   ld    $sp, 0x28(%[base])          \n" /* get SP via mailbox */
 		"   ld    $gp, 0x30(%[base])          \n" /* get GP via mailbox */
 		"   ld    $a1, 0x38(%[base])          \n"
-- 
2.1.0

[PATCH v2 6/6] MIPS: Loongson64: Move decode_cpucfg() to loongson_regs.h

[Tiezhu Yang]

Since decode_cpucfg() is only used for Loongson64, just move
it to loongson_regs.h to avoid the pollution of common code
with #ifdef CONFIG_CPU_LOONGSON64.

Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
---

v2: No changes

 .../include/asm/mach-loongson64/loongson_regs.h    | 24 +++++++++++++++++
 arch/mips/kernel/cpu-probe.c                       | 31 +---------------------
 2 files changed, 25 insertions(+), 30 deletions(-)

diff --git a/arch/mips/include/asm/mach-loongson64/loongson_regs.h b/arch/mips/include/asm/mach-loongson64/loongson_regs.h
index 1659935..2d469d6 100644
--- a/arch/mips/include/asm/mach-loongson64/loongson_regs.h
+++ b/arch/mips/include/asm/mach-loongson64/loongson_regs.h
@@ -129,6 +129,30 @@ static inline u32 read_cpucfg(u32 reg)
 #define LOONGSON_CFG7_GCCAEQRP	BIT(0)
 #define LOONGSON_CFG7_UCAWINP	BIT(1)
 
+static inline void decode_cpucfg(struct cpuinfo_mips *c)
+{
+	u32 cfg1 = read_cpucfg(LOONGSON_CFG1);
+	u32 cfg2 = read_cpucfg(LOONGSON_CFG2);
+	u32 cfg3 = read_cpucfg(LOONGSON_CFG3);
+
+	if (cfg1 & LOONGSON_CFG1_MMI)
+		c->ases |= MIPS_ASE_LOONGSON_MMI;
+
+	if (cfg2 & LOONGSON_CFG2_LEXT1)
+		c->ases |= MIPS_ASE_LOONGSON_EXT;
+
+	if (cfg2 & LOONGSON_CFG2_LEXT2)
+		c->ases |= MIPS_ASE_LOONGSON_EXT2;
+
+	if (cfg2 & LOONGSON_CFG2_LSPW) {
+		c->options |= MIPS_CPU_LDPTE;
+		c->guest.options |= MIPS_CPU_LDPTE;
+	}
+
+	if (cfg3 & LOONGSON_CFG3_LCAMP)
+		c->ases |= MIPS_ASE_LOONGSON_CAM;
+}
+
 static inline bool cpu_has_csr(void)
 {
 	if (cpu_has_cfg())
diff --git a/arch/mips/kernel/cpu-probe.c b/arch/mips/kernel/cpu-probe.c
index e685369..1fa2c8b 100644
--- a/arch/mips/kernel/cpu-probe.c
+++ b/arch/mips/kernel/cpu-probe.c
@@ -31,6 +31,7 @@
 #include "fpu-probe.h"
 
 #include <asm/mach-loongson64/cpucfg-emul.h>
+#include <asm/mach-loongson64/loongson_regs.h>
 
 /* Hardware capabilities */
 unsigned int elf_hwcap __read_mostly;
@@ -1692,33 +1693,6 @@ static inline void cpu_probe_cavium(struct cpuinfo_mips *c, unsigned int cpu)
 	}
 }
 
-#ifdef CONFIG_CPU_LOONGSON64
-#include <loongson_regs.h>
-
-static inline void decode_cpucfg(struct cpuinfo_mips *c)
-{
-	u32 cfg1 = read_cpucfg(LOONGSON_CFG1);
-	u32 cfg2 = read_cpucfg(LOONGSON_CFG2);
-	u32 cfg3 = read_cpucfg(LOONGSON_CFG3);
-
-	if (cfg1 & LOONGSON_CFG1_MMI)
-		c->ases |= MIPS_ASE_LOONGSON_MMI;
-
-	if (cfg2 & LOONGSON_CFG2_LEXT1)
-		c->ases |= MIPS_ASE_LOONGSON_EXT;
-
-	if (cfg2 & LOONGSON_CFG2_LEXT2)
-		c->ases |= MIPS_ASE_LOONGSON_EXT2;
-
-	if (cfg2 & LOONGSON_CFG2_LSPW) {
-		c->options |= MIPS_CPU_LDPTE;
-		c->guest.options |= MIPS_CPU_LDPTE;
-	}
-
-	if (cfg3 & LOONGSON_CFG3_LCAMP)
-		c->ases |= MIPS_ASE_LOONGSON_CAM;
-}
-
 static inline void cpu_probe_loongson(struct cpuinfo_mips *c, unsigned int cpu)
 {
 	decode_configs(c);
@@ -1787,9 +1761,6 @@ static inline void cpu_probe_loongson(struct cpuinfo_mips *c, unsigned int cpu)
 		break;
 	}
 }
-#else
-static inline void cpu_probe_loongson(struct cpuinfo_mips *c, unsigned int cpu) { }
-#endif
 
 static inline void cpu_probe_ingenic(struct cpuinfo_mips *c, unsigned int cpu)
 {
-- 
2.1.0

Re: [PATCH v2 5/6] MIPS: Loongson64: Make sure the PC address is correct when 3A4000+ CPU hotplug

[Jiaxun Yang]

在 2020/11/3 11:15, Tiezhu Yang 写道:
> In loongson3_type3_play_dead(), in order to make sure the PC address is
> correct, use lw to read the low 32 bits first, if the result is not zero,
> then use ld to read the whole 64 bits, otherwise there maybe exists atomic
> problem due to write high 32 bits first and then low 32 bits, like this:
>
> high 32 bits (write done)
>                                    -- only read high 32-bits which is wrong
> low 32 bits (not yet write done)
>
> This problem is especially for Loongson 3A4000+ CPU due to using Mail_Send
> register which can only send 32 bits data one time. Although it is hard to
> reproduce, we can do something at the software level to avoid the risks for
> 3A4000+ CPU, this change has no influence on the other Loongson CPUs.
>
> Signed-off-by: Lu Zeng <zenglu@loongson.cn>
> Signed-off-by: Jun Yi <yijun@loongson.cn>
> Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>

Hi Tiezhu,

Sorry that I didn't look this patch carefully in previous rev, here's my 
comments,

Firstly the commit message and code comment looks bogus...

I'd prefer

---
MIPS: Loongson64: SMP: Fix up play_dead jump indicator

In play_dead function, the whole 64-bit PC mailbox was used as a indicator
to determine if the master core had written boot jump information.

However, after we introduced CSR mailsend, the 64-bit PC mailbox won't be
written atomicly. Thus we have to use the lower 32-bit, which will be 
written at
the last, as the jump indicator instead.
--

Thanks.

> ---
>
> v2: No changes
>
>   arch/mips/loongson64/smp.c | 3 ++-
>   1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/arch/mips/loongson64/smp.c b/arch/mips/loongson64/smp.c
> index 736e98d..e32b46e 100644
> --- a/arch/mips/loongson64/smp.c
> +++ b/arch/mips/loongson64/smp.c
> @@ -764,9 +764,10 @@ static void loongson3_type3_play_dead(int *state_addr)
>   		"1: li    %[count], 0x100             \n" /* wait for init loop */
>   		"2: bnez  %[count], 2b                \n" /* limit mailbox access */
>   		"   addiu %[count], -1                \n"
> -		"   ld    %[initfunc], 0x20(%[base])  \n" /* get PC via mailbox */
> +		"   lw    %[initfunc], 0x20(%[base])  \n" /* get PC (low 32 bits) via mailbox */

Here you can comment as "Check jump indicator (lower 32-bit of PC mailbox)"

Thanks.

- Jiaxun
>   		"   beqz  %[initfunc], 1b             \n"
>   		"   nop                               \n"
> +		"   ld    %[initfunc], 0x20(%[base])  \n" /* get PC (whole 64 bits) via mailbox */
>   		"   ld    $sp, 0x28(%[base])          \n" /* get SP via mailbox */
>   		"   ld    $gp, 0x30(%[base])          \n" /* get GP via mailbox */
>   		"   ld    $a1, 0x38(%[base])          \n"

Re: [PATCH v2 6/6] MIPS: Loongson64: Move decode_cpucfg() to loongson_regs.h

[Jiaxun Yang]

在 2020/11/3 11:15, Tiezhu Yang 写道:
> Since decode_cpucfg() is only used for Loongson64, just move
> it to loongson_regs.h to avoid the pollution of common code
> with #ifdef CONFIG_CPU_LOONGSON64.
>
> Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>

Hi all,

Don't know if it's a good idea to move this piece of code around...
Also I do think loongson_regs.h should be a common header while
cpucfg_decode won't be reused else where.

But I do respect Thomas's decision if it's necessary.

Thanks

- Jiaxun

> ---
>
> v2: No changes
>
>   .../include/asm/mach-loongson64/loongson_regs.h    | 24 +++++++++++++++++
>   arch/mips/kernel/cpu-probe.c                       | 31 +---------------------
>   2 files changed, 25 insertions(+), 30 deletions(-)
>
> diff --git a/arch/mips/include/asm/mach-loongson64/loongson_regs.h b/arch/mips/include/asm/mach-loongson64/loongson_regs.h
> index 1659935..2d469d6 100644
> --- a/arch/mips/include/asm/mach-loongson64/loongson_regs.h
> +++ b/arch/mips/include/asm/mach-loongson64/loongson_regs.h
> @@ -129,6 +129,30 @@ static inline u32 read_cpucfg(u32 reg)
>   #define LOONGSON_CFG7_GCCAEQRP	BIT(0)
>   #define LOONGSON_CFG7_UCAWINP	BIT(1)
>   
> +static inline void decode_cpucfg(struct cpuinfo_mips *c)
> +{
> +	u32 cfg1 = read_cpucfg(LOONGSON_CFG1);
> +	u32 cfg2 = read_cpucfg(LOONGSON_CFG2);
> +	u32 cfg3 = read_cpucfg(LOONGSON_CFG3);
> +
> +	if (cfg1 & LOONGSON_CFG1_MMI)
> +		c->ases |= MIPS_ASE_LOONGSON_MMI;
> +
> +	if (cfg2 & LOONGSON_CFG2_LEXT1)
> +		c->ases |= MIPS_ASE_LOONGSON_EXT;
> +
> +	if (cfg2 & LOONGSON_CFG2_LEXT2)
> +		c->ases |= MIPS_ASE_LOONGSON_EXT2;
> +
> +	if (cfg2 & LOONGSON_CFG2_LSPW) {
> +		c->options |= MIPS_CPU_LDPTE;
> +		c->guest.options |= MIPS_CPU_LDPTE;
> +	}
> +
> +	if (cfg3 & LOONGSON_CFG3_LCAMP)
> +		c->ases |= MIPS_ASE_LOONGSON_CAM;
> +}
> +
>   static inline bool cpu_has_csr(void)
>   {
>   	if (cpu_has_cfg())
> diff --git a/arch/mips/kernel/cpu-probe.c b/arch/mips/kernel/cpu-probe.c
> index e685369..1fa2c8b 100644
> --- a/arch/mips/kernel/cpu-probe.c
> +++ b/arch/mips/kernel/cpu-probe.c
> @@ -31,6 +31,7 @@
>   #include "fpu-probe.h"
>   
>   #include <asm/mach-loongson64/cpucfg-emul.h>
> +#include <asm/mach-loongson64/loongson_regs.h>
>   
>   /* Hardware capabilities */
>   unsigned int elf_hwcap __read_mostly;
> @@ -1692,33 +1693,6 @@ static inline void cpu_probe_cavium(struct cpuinfo_mips *c, unsigned int cpu)
>   	}
>   }
>   
> -#ifdef CONFIG_CPU_LOONGSON64
> -#include <loongson_regs.h>
> -
> -static inline void decode_cpucfg(struct cpuinfo_mips *c)
> -{
> -	u32 cfg1 = read_cpucfg(LOONGSON_CFG1);
> -	u32 cfg2 = read_cpucfg(LOONGSON_CFG2);
> -	u32 cfg3 = read_cpucfg(LOONGSON_CFG3);
> -
> -	if (cfg1 & LOONGSON_CFG1_MMI)
> -		c->ases |= MIPS_ASE_LOONGSON_MMI;
> -
> -	if (cfg2 & LOONGSON_CFG2_LEXT1)
> -		c->ases |= MIPS_ASE_LOONGSON_EXT;
> -
> -	if (cfg2 & LOONGSON_CFG2_LEXT2)
> -		c->ases |= MIPS_ASE_LOONGSON_EXT2;
> -
> -	if (cfg2 & LOONGSON_CFG2_LSPW) {
> -		c->options |= MIPS_CPU_LDPTE;
> -		c->guest.options |= MIPS_CPU_LDPTE;
> -	}
> -
> -	if (cfg3 & LOONGSON_CFG3_LCAMP)
> -		c->ases |= MIPS_ASE_LOONGSON_CAM;
> -}
> -
>   static inline void cpu_probe_loongson(struct cpuinfo_mips *c, unsigned int cpu)
>   {
>   	decode_configs(c);
> @@ -1787,9 +1761,6 @@ static inline void cpu_probe_loongson(struct cpuinfo_mips *c, unsigned int cpu)
>   		break;
>   	}
>   }
> -#else
> -static inline void cpu_probe_loongson(struct cpuinfo_mips *c, unsigned int cpu) { }
> -#endif
>   
>   static inline void cpu_probe_ingenic(struct cpuinfo_mips *c, unsigned int cpu)
>   {

Re: [PATCH v2 5/6] MIPS: Loongson64: Make sure the PC address is correct when 3A4000+ CPU hotplug

[Tiezhu Yang]

On 11/03/2020 01:28 PM, Jiaxun Yang wrote:
>
>
> 在 2020/11/3 11:15, Tiezhu Yang 写道:
>> In loongson3_type3_play_dead(), in order to make sure the PC address is
>> correct, use lw to read the low 32 bits first, if the result is not 
>> zero,
>> then use ld to read the whole 64 bits, otherwise there maybe exists 
>> atomic
>> problem due to write high 32 bits first and then low 32 bits, like this:
>>
>> high 32 bits (write done)
>>                                    -- only read high 32-bits which is 
>> wrong
>> low 32 bits (not yet write done)
>>
>> This problem is especially for Loongson 3A4000+ CPU due to using 
>> Mail_Send
>> register which can only send 32 bits data one time. Although it is 
>> hard to
>> reproduce, we can do something at the software level to avoid the 
>> risks for
>> 3A4000+ CPU, this change has no influence on the other Loongson CPUs.
>>
>> Signed-off-by: Lu Zeng <zenglu@loongson.cn>
>> Signed-off-by: Jun Yi <yijun@loongson.cn>
>> Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
>
> Hi Tiezhu,
>
> Sorry that I didn't look this patch carefully in previous rev, here's 
> my comments,
>
> Firstly the commit message and code comment looks bogus...
>
> I'd prefer

Hi Jiaxun,

Thanks for your detail review, it looks better.
Let me update it and then send v3.

Thanks,
Tiezhu

>
> ---
> MIPS: Loongson64: SMP: Fix up play_dead jump indicator
>
> In play_dead function, the whole 64-bit PC mailbox was used as a 
> indicator
> to determine if the master core had written boot jump information.
>
> However, after we introduced CSR mailsend, the 64-bit PC mailbox won't be
> written atomicly. Thus we have to use the lower 32-bit, which will be 
> written at
> the last, as the jump indicator instead.
> -- 
>
> Thanks.
>
>> ---
>>
>> v2: No changes
>>
>>   arch/mips/loongson64/smp.c | 3 ++-
>>   1 file changed, 2 insertions(+), 1 deletion(-)
>>
>> diff --git a/arch/mips/loongson64/smp.c b/arch/mips/loongson64/smp.c
>> index 736e98d..e32b46e 100644
>> --- a/arch/mips/loongson64/smp.c
>> +++ b/arch/mips/loongson64/smp.c
>> @@ -764,9 +764,10 @@ static void loongson3_type3_play_dead(int 
>> *state_addr)
>>           "1: li    %[count], 0x100             \n" /* wait for init 
>> loop */
>>           "2: bnez  %[count], 2b                \n" /* limit mailbox 
>> access */
>>           "   addiu %[count], -1                \n"
>> -        "   ld    %[initfunc], 0x20(%[base])  \n" /* get PC via 
>> mailbox */
>> +        "   lw    %[initfunc], 0x20(%[base])  \n" /* get PC (low 32 
>> bits) via mailbox */
>
> Here you can comment as "Check jump indicator (lower 32-bit of PC 
> mailbox)"
>
> Thanks.
>
> - Jiaxun
>>           "   beqz  %[initfunc], 1b             \n"
>>           "   nop                               \n"
>> +        "   ld    %[initfunc], 0x20(%[base])  \n" /* get PC (whole 
>> 64 bits) via mailbox */
>>           "   ld    $sp, 0x28(%[base])          \n" /* get SP via 
>> mailbox */
>>           "   ld    $gp, 0x30(%[base])          \n" /* get GP via 
>> mailbox */
>>           "   ld    $a1, 0x38(%[base])          \n"