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* [PATCH v7 0/4] Dedicated CLINT timer driver
@ 2020-08-17 12:42 Anup Patel
  2020-08-17 12:42 ` [PATCH v7 1/4] RISC-V: Add mechanism to provide custom IPI operations Anup Patel
                   ` (4 more replies)
  0 siblings, 5 replies; 6+ messages in thread
From: Anup Patel @ 2020-08-17 12:42 UTC (permalink / raw)
  To: Palmer Dabbelt, Paul Walmsley, Albert Ou, Rob Herring,
	Daniel Lezcano, Thomas Gleixner
  Cc: Damien Le Moal, Atish Patra, Alistair Francis, Anup Patel,
	linux-riscv, linux-kernel, devicetree, Anup Patel

The current RISC-V timer driver is convoluted and implements two
distinct timers:
 1. S-mode timer: This is for Linux RISC-V S-mode with MMU. The
    clocksource is implemented using TIME CSR and clockevent device
    is implemented using SBI Timer calls.
 2. M-mode timer: This is for Linux RISC-V M-mode without MMU. The
    clocksource is implemented using CLINT MMIO time register and
    clockevent device is implemented using CLINT MMIO timecmp registers.

This patchset removes clint related code from RISC-V timer driver and
arch/riscv directory. Instead, the series adds a dedicated MMIO based
CLINT driver under drivers/clocksource directory which can be used by
Linux RISC-V M-mode (i.e NoMMU Linux RISC-V).

The patchset is based up Linux-5.9-rc1 and can be found at riscv_clint_v7
branch of: https://github.com/avpatel/linux.git

This series is tested on:
 1. QEMU RV64 virt machine using Linux RISC-V S-mode
 2. QEMU RV32 virt machine using Linux RISC-V S-mode
 3. QEMU RV64 virt machine using Linux RISC-V M-mode (i.e. NoMMU)

Changes since v6:
 - Rebased series on Linux-5.9-rc1

Changes since v5:
 - Fixed order of compatible strings in PATCH4
 - Added "additionalProperties: false" in PATCH4
 - Fixed register space size for example DT node in PATCH4

Changes since v4:
 - Rebased series on Linux-5.8-rc6
 - Updated Kconfig option as suggested by Daniel in PATCH2
 - Removed per-CPU registered flag in PATCH2
 - Addressed nit comments from Atish in PATCH2

Changes since v3:
 - Updated commit description of PATCH2
 - Use clint_get_cycles64() in clint_rdtime() of PATCH2
 - Call clockevents_config_and_register() only once for each CPU in
   clint_timer_starting_cpu of PATCH2
 - Select CLINT timer driver from platform Kconfig in PATCH3
 - Fixed 'make dt_binding_check' for PATCH4

Changes since v2:
 - Rebased series on Linux-5.8-rc5
 - Squashed PATCH3 onto PATCH2 to preserve GIT bisectability
 - Moved PATCH4 before PATCH2 to preserve GIT bisectability
 - Replaced CLINT dt-bindings text document with YAML schema
 - Use SiFive CLINT compatible string as per SiFive IP block versioning

Changes since v1:
 - Rebased series on Linux-5.8-rc2
 - Added pr_warn() for case where ipi_ops not available in PATCH1
 - Updated ipi_inject() prototype to use "struct cpumask *" in PATCH1
 - Updated CLINT_TIMER kconfig option to depend on RISCV_M_MODE in PATCH4
 - Added riscv,clint0 compatible string in DT bindings document

Anup Patel (4):
  RISC-V: Add mechanism to provide custom IPI operations
  clocksource/drivers: Add CLINT timer driver
  RISC-V: Remove CLINT related code from timer and arch
  dt-bindings: timer: Add CLINT bindings

 .../bindings/timer/sifive,clint.yaml          |  60 +++++
 arch/riscv/Kconfig                            |   2 +-
 arch/riscv/Kconfig.socs                       |   2 +
 arch/riscv/configs/nommu_virt_defconfig       |   7 +-
 arch/riscv/include/asm/clint.h                |  39 ---
 arch/riscv/include/asm/smp.h                  |  19 ++
 arch/riscv/include/asm/timex.h                |  28 +--
 arch/riscv/kernel/Makefile                    |   2 +-
 arch/riscv/kernel/clint.c                     |  44 ----
 arch/riscv/kernel/sbi.c                       |  14 ++
 arch/riscv/kernel/setup.c                     |   2 -
 arch/riscv/kernel/smp.c                       |  44 ++--
 arch/riscv/kernel/smpboot.c                   |   4 +-
 drivers/clocksource/Kconfig                   |  12 +-
 drivers/clocksource/Makefile                  |   1 +
 drivers/clocksource/timer-clint.c             | 226 ++++++++++++++++++
 drivers/clocksource/timer-riscv.c             |  17 +-
 include/linux/cpuhotplug.h                    |   1 +
 18 files changed, 371 insertions(+), 153 deletions(-)
 create mode 100644 Documentation/devicetree/bindings/timer/sifive,clint.yaml
 delete mode 100644 arch/riscv/include/asm/clint.h
 delete mode 100644 arch/riscv/kernel/clint.c
 create mode 100644 drivers/clocksource/timer-clint.c

-- 
2.25.1


^ permalink raw reply	[flat|nested] 6+ messages in thread

* [PATCH v7 1/4] RISC-V: Add mechanism to provide custom IPI operations
  2020-08-17 12:42 [PATCH v7 0/4] Dedicated CLINT timer driver Anup Patel
@ 2020-08-17 12:42 ` Anup Patel
  2020-08-17 12:42 ` [PATCH v7 2/4] clocksource/drivers: Add CLINT timer driver Anup Patel
                   ` (3 subsequent siblings)
  4 siblings, 0 replies; 6+ messages in thread
From: Anup Patel @ 2020-08-17 12:42 UTC (permalink / raw)
  To: Palmer Dabbelt, Paul Walmsley, Albert Ou, Rob Herring,
	Daniel Lezcano, Thomas Gleixner
  Cc: Damien Le Moal, Atish Patra, Alistair Francis, Anup Patel,
	linux-riscv, linux-kernel, devicetree, Anup Patel,
	Emil Renner Berhing, Palmer Dabbelt

We add mechanism to set custom IPI operations so that CLINT driver
from drivers directory can provide custom IPI operations.

Signed-off-by: Anup Patel <anup.patel@wdc.com>
Tested-by: Emil Renner Berhing <kernel@esmil.dk>
Reviewed-by: Atish Patra <atish.patra@wdc.com>
Reviewed-by: Palmer Dabbelt <palmerdabbelt@google.com>
---
 arch/riscv/include/asm/clint.h | 25 --------------------
 arch/riscv/include/asm/smp.h   | 19 +++++++++++++++
 arch/riscv/kernel/clint.c      | 23 ++++++++++++++++--
 arch/riscv/kernel/sbi.c        | 14 +++++++++++
 arch/riscv/kernel/smp.c        | 43 +++++++++++++++++++---------------
 arch/riscv/kernel/smpboot.c    |  3 +--
 6 files changed, 79 insertions(+), 48 deletions(-)

diff --git a/arch/riscv/include/asm/clint.h b/arch/riscv/include/asm/clint.h
index a279b17a6aad..adaba98a7d6c 100644
--- a/arch/riscv/include/asm/clint.h
+++ b/arch/riscv/include/asm/clint.h
@@ -6,34 +6,9 @@
 #include <linux/smp.h>
 
 #ifdef CONFIG_RISCV_M_MODE
-extern u32 __iomem *clint_ipi_base;
-
 void clint_init_boot_cpu(void);
-
-static inline void clint_send_ipi_single(unsigned long hartid)
-{
-	writel(1, clint_ipi_base + hartid);
-}
-
-static inline void clint_send_ipi_mask(const struct cpumask *mask)
-{
-	int cpu;
-
-	for_each_cpu(cpu, mask)
-		clint_send_ipi_single(cpuid_to_hartid_map(cpu));
-}
-
-static inline void clint_clear_ipi(unsigned long hartid)
-{
-	writel(0, clint_ipi_base + hartid);
-}
 #else /* CONFIG_RISCV_M_MODE */
 #define clint_init_boot_cpu()	do { } while (0)
-
-/* stubs to for code is only reachable under IS_ENABLED(CONFIG_RISCV_M_MODE): */
-void clint_send_ipi_single(unsigned long hartid);
-void clint_send_ipi_mask(const struct cpumask *hartid_mask);
-void clint_clear_ipi(unsigned long hartid);
 #endif /* CONFIG_RISCV_M_MODE */
 
 #endif /* _ASM_RISCV_CLINT_H */
diff --git a/arch/riscv/include/asm/smp.h b/arch/riscv/include/asm/smp.h
index 6dfd2a1446d5..df1f7c4cd433 100644
--- a/arch/riscv/include/asm/smp.h
+++ b/arch/riscv/include/asm/smp.h
@@ -15,6 +15,11 @@
 struct seq_file;
 extern unsigned long boot_cpu_hartid;
 
+struct riscv_ipi_ops {
+	void (*ipi_inject)(const struct cpumask *target);
+	void (*ipi_clear)(void);
+};
+
 #ifdef CONFIG_SMP
 /*
  * Mapping between linux logical cpu index and hartid.
@@ -40,6 +45,12 @@ void arch_send_call_function_single_ipi(int cpu);
 int riscv_hartid_to_cpuid(int hartid);
 void riscv_cpuid_to_hartid_mask(const struct cpumask *in, struct cpumask *out);
 
+/* Set custom IPI operations */
+void riscv_set_ipi_ops(struct riscv_ipi_ops *ops);
+
+/* Clear IPI for current CPU */
+void riscv_clear_ipi(void);
+
 /* Secondary hart entry */
 asmlinkage void smp_callin(void);
 
@@ -81,6 +92,14 @@ static inline void riscv_cpuid_to_hartid_mask(const struct cpumask *in,
 	cpumask_set_cpu(boot_cpu_hartid, out);
 }
 
+static inline void riscv_set_ipi_ops(struct riscv_ipi_ops *ops)
+{
+}
+
+static inline void riscv_clear_ipi(void)
+{
+}
+
 #endif /* CONFIG_SMP */
 
 #if defined(CONFIG_HOTPLUG_CPU) && (CONFIG_SMP)
diff --git a/arch/riscv/kernel/clint.c b/arch/riscv/kernel/clint.c
index 3647980d14c3..a9845ee023e2 100644
--- a/arch/riscv/kernel/clint.c
+++ b/arch/riscv/kernel/clint.c
@@ -5,11 +5,11 @@
 
 #include <linux/io.h>
 #include <linux/of_address.h>
+#include <linux/smp.h>
 #include <linux/types.h>
 #include <asm/clint.h>
 #include <asm/csr.h>
 #include <asm/timex.h>
-#include <asm/smp.h>
 
 /*
  * This is the layout used by the SiFive clint, which is also shared by the qemu
@@ -21,6 +21,24 @@
 
 u32 __iomem *clint_ipi_base;
 
+static void clint_send_ipi(const struct cpumask *target)
+{
+	unsigned int cpu;
+
+	for_each_cpu(cpu, target)
+		writel(1, clint_ipi_base + cpuid_to_hartid_map(cpu));
+}
+
+static void clint_clear_ipi(void)
+{
+	writel(0, clint_ipi_base + cpuid_to_hartid_map(smp_processor_id()));
+}
+
+static struct riscv_ipi_ops clint_ipi_ops = {
+	.ipi_inject = clint_send_ipi,
+	.ipi_clear = clint_clear_ipi,
+};
+
 void clint_init_boot_cpu(void)
 {
 	struct device_node *np;
@@ -40,5 +58,6 @@ void clint_init_boot_cpu(void)
 	riscv_time_cmp = base + CLINT_TIME_CMP_OFF;
 	riscv_time_val = base + CLINT_TIME_VAL_OFF;
 
-	clint_clear_ipi(boot_cpu_hartid);
+	clint_clear_ipi();
+	riscv_set_ipi_ops(&clint_ipi_ops);
 }
diff --git a/arch/riscv/kernel/sbi.c b/arch/riscv/kernel/sbi.c
index f383ef5672b2..226ccce0f9e0 100644
--- a/arch/riscv/kernel/sbi.c
+++ b/arch/riscv/kernel/sbi.c
@@ -547,6 +547,18 @@ static inline long sbi_get_firmware_version(void)
 	return __sbi_base_ecall(SBI_EXT_BASE_GET_IMP_VERSION);
 }
 
+static void sbi_send_cpumask_ipi(const struct cpumask *target)
+{
+	struct cpumask hartid_mask;
+
+	riscv_cpuid_to_hartid_mask(target, &hartid_mask);
+
+	sbi_send_ipi(cpumask_bits(&hartid_mask));
+}
+
+static struct riscv_ipi_ops sbi_ipi_ops = {
+	.ipi_inject = sbi_send_cpumask_ipi
+};
 
 int __init sbi_init(void)
 {
@@ -587,5 +599,7 @@ int __init sbi_init(void)
 		__sbi_rfence	= __sbi_rfence_v01;
 	}
 
+	riscv_set_ipi_ops(&sbi_ipi_ops);
+
 	return 0;
 }
diff --git a/arch/riscv/kernel/smp.c b/arch/riscv/kernel/smp.c
index 554b0fb47060..cf9acb43604c 100644
--- a/arch/riscv/kernel/smp.c
+++ b/arch/riscv/kernel/smp.c
@@ -86,9 +86,25 @@ static void ipi_stop(void)
 		wait_for_interrupt();
 }
 
+static struct riscv_ipi_ops *ipi_ops;
+
+void riscv_set_ipi_ops(struct riscv_ipi_ops *ops)
+{
+	ipi_ops = ops;
+}
+EXPORT_SYMBOL_GPL(riscv_set_ipi_ops);
+
+void riscv_clear_ipi(void)
+{
+	if (ipi_ops && ipi_ops->ipi_clear)
+		ipi_ops->ipi_clear();
+
+	csr_clear(CSR_IP, IE_SIE);
+}
+EXPORT_SYMBOL_GPL(riscv_clear_ipi);
+
 static void send_ipi_mask(const struct cpumask *mask, enum ipi_message_type op)
 {
-	struct cpumask hartid_mask;
 	int cpu;
 
 	smp_mb__before_atomic();
@@ -96,33 +112,22 @@ static void send_ipi_mask(const struct cpumask *mask, enum ipi_message_type op)
 		set_bit(op, &ipi_data[cpu].bits);
 	smp_mb__after_atomic();
 
-	riscv_cpuid_to_hartid_mask(mask, &hartid_mask);
-	if (IS_ENABLED(CONFIG_RISCV_SBI))
-		sbi_send_ipi(cpumask_bits(&hartid_mask));
+	if (ipi_ops && ipi_ops->ipi_inject)
+		ipi_ops->ipi_inject(mask);
 	else
-		clint_send_ipi_mask(mask);
+		pr_warn("SMP: IPI inject method not available\n");
 }
 
 static void send_ipi_single(int cpu, enum ipi_message_type op)
 {
-	int hartid = cpuid_to_hartid_map(cpu);
-
 	smp_mb__before_atomic();
 	set_bit(op, &ipi_data[cpu].bits);
 	smp_mb__after_atomic();
 
-	if (IS_ENABLED(CONFIG_RISCV_SBI))
-		sbi_send_ipi(cpumask_bits(cpumask_of(hartid)));
-	else
-		clint_send_ipi_single(hartid);
-}
-
-static inline void clear_ipi(void)
-{
-	if (IS_ENABLED(CONFIG_RISCV_SBI))
-		csr_clear(CSR_IP, IE_SIE);
+	if (ipi_ops && ipi_ops->ipi_inject)
+		ipi_ops->ipi_inject(cpumask_of(cpu));
 	else
-		clint_clear_ipi(cpuid_to_hartid_map(smp_processor_id()));
+		pr_warn("SMP: IPI inject method not available\n");
 }
 
 #ifdef CONFIG_IRQ_WORK
@@ -140,7 +145,7 @@ void handle_IPI(struct pt_regs *regs)
 
 	irq_enter();
 
-	clear_ipi();
+	riscv_clear_ipi();
 
 	while (true) {
 		unsigned long ops;
diff --git a/arch/riscv/kernel/smpboot.c b/arch/riscv/kernel/smpboot.c
index 356825a57551..12033d71ba0c 100644
--- a/arch/riscv/kernel/smpboot.c
+++ b/arch/riscv/kernel/smpboot.c
@@ -147,8 +147,7 @@ asmlinkage __visible void smp_callin(void)
 	struct mm_struct *mm = &init_mm;
 	unsigned int curr_cpuid = smp_processor_id();
 
-	if (!IS_ENABLED(CONFIG_RISCV_SBI))
-		clint_clear_ipi(cpuid_to_hartid_map(smp_processor_id()));
+	riscv_clear_ipi();
 
 	/* All kernel threads share the same mm context.  */
 	mmgrab(mm);
-- 
2.25.1


^ permalink raw reply related	[flat|nested] 6+ messages in thread

* [PATCH v7 2/4] clocksource/drivers: Add CLINT timer driver
  2020-08-17 12:42 [PATCH v7 0/4] Dedicated CLINT timer driver Anup Patel
  2020-08-17 12:42 ` [PATCH v7 1/4] RISC-V: Add mechanism to provide custom IPI operations Anup Patel
@ 2020-08-17 12:42 ` Anup Patel
  2020-08-17 12:42 ` [PATCH v7 3/4] RISC-V: Remove CLINT related code from timer and arch Anup Patel
                   ` (2 subsequent siblings)
  4 siblings, 0 replies; 6+ messages in thread
From: Anup Patel @ 2020-08-17 12:42 UTC (permalink / raw)
  To: Palmer Dabbelt, Paul Walmsley, Albert Ou, Rob Herring,
	Daniel Lezcano, Thomas Gleixner
  Cc: Damien Le Moal, Atish Patra, Alistair Francis, Anup Patel,
	linux-riscv, linux-kernel, devicetree, Anup Patel,
	Emil Renner Berhing, Palmer Dabbelt

We add a separate CLINT timer driver for Linux RISC-V M-mode (i.e.
RISC-V NoMMU kernel).

The CLINT MMIO device provides three things:
1. 64bit free running counter register
2. 64bit per-CPU time compare registers
3. 32bit per-CPU inter-processor interrupt registers

Unlike other timer devices, CLINT provides IPI registers along with
timer registers. To use CLINT IPI registers, the CLINT timer driver
provides IPI related callbacks to arch/riscv.

Signed-off-by: Anup Patel <anup.patel@wdc.com>
Tested-by: Emil Renner Berhing <kernel@esmil.dk>
Acked-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Reviewed-by: Atish Patra <atish.patra@wdc.com>
Reviewed-by: Palmer Dabbelt <palmerdabbelt@google.com>
---
 drivers/clocksource/Kconfig       |   9 ++
 drivers/clocksource/Makefile      |   1 +
 drivers/clocksource/timer-clint.c | 226 ++++++++++++++++++++++++++++++
 include/linux/cpuhotplug.h        |   1 +
 4 files changed, 237 insertions(+)
 create mode 100644 drivers/clocksource/timer-clint.c

diff --git a/drivers/clocksource/Kconfig b/drivers/clocksource/Kconfig
index 3576ad7bd380..d95cc7234a66 100644
--- a/drivers/clocksource/Kconfig
+++ b/drivers/clocksource/Kconfig
@@ -663,6 +663,15 @@ config RISCV_TIMER
 	  is accessed via both the SBI and the rdcycle instruction.  This is
 	  required for all RISC-V systems.
 
+config CLINT_TIMER
+	bool "CLINT Timer for the RISC-V platform" if COMPILE_TEST
+	depends on GENERIC_SCHED_CLOCK && RISCV
+	select TIMER_PROBE
+	select TIMER_OF
+	help
+	  This option enables the CLINT timer for RISC-V systems.  The CLINT
+	  driver is usually used for NoMMU RISC-V systems.
+
 config CSKY_MP_TIMER
 	bool "SMP Timer for the C-SKY platform" if COMPILE_TEST
 	depends on CSKY
diff --git a/drivers/clocksource/Makefile b/drivers/clocksource/Makefile
index eaedb7240ae7..1c444cc3bb44 100644
--- a/drivers/clocksource/Makefile
+++ b/drivers/clocksource/Makefile
@@ -89,6 +89,7 @@ obj-$(CONFIG_CLKSRC_ST_LPC)		+= clksrc_st_lpc.o
 obj-$(CONFIG_X86_NUMACHIP)		+= numachip.o
 obj-$(CONFIG_ATCPIT100_TIMER)		+= timer-atcpit100.o
 obj-$(CONFIG_RISCV_TIMER)		+= timer-riscv.o
+obj-$(CONFIG_CLINT_TIMER)		+= timer-clint.o
 obj-$(CONFIG_CSKY_MP_TIMER)		+= timer-mp-csky.o
 obj-$(CONFIG_GX6605S_TIMER)		+= timer-gx6605s.o
 obj-$(CONFIG_HYPERV_TIMER)		+= hyperv_timer.o
diff --git a/drivers/clocksource/timer-clint.c b/drivers/clocksource/timer-clint.c
new file mode 100644
index 000000000000..8eeafa82c03d
--- /dev/null
+++ b/drivers/clocksource/timer-clint.c
@@ -0,0 +1,226 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2020 Western Digital Corporation or its affiliates.
+ *
+ * Most of the M-mode (i.e. NoMMU) RISC-V systems usually have a
+ * CLINT MMIO timer device.
+ */
+
+#define pr_fmt(fmt) "clint: " fmt
+#include <linux/bitops.h>
+#include <linux/clocksource.h>
+#include <linux/clockchips.h>
+#include <linux/cpu.h>
+#include <linux/delay.h>
+#include <linux/module.h>
+#include <linux/of_address.h>
+#include <linux/sched_clock.h>
+#include <linux/io-64-nonatomic-lo-hi.h>
+#include <linux/interrupt.h>
+#include <linux/of_irq.h>
+#include <linux/smp.h>
+
+#define CLINT_IPI_OFF		0
+#define CLINT_TIMER_CMP_OFF	0x4000
+#define CLINT_TIMER_VAL_OFF	0xbff8
+
+/* CLINT manages IPI and Timer for RISC-V M-mode  */
+static u32 __iomem *clint_ipi_base;
+static u64 __iomem *clint_timer_cmp;
+static u64 __iomem *clint_timer_val;
+static unsigned long clint_timer_freq;
+static unsigned int clint_timer_irq;
+
+static void clint_send_ipi(const struct cpumask *target)
+{
+	unsigned int cpu;
+
+	for_each_cpu(cpu, target)
+		writel(1, clint_ipi_base + cpuid_to_hartid_map(cpu));
+}
+
+static void clint_clear_ipi(void)
+{
+	writel(0, clint_ipi_base + cpuid_to_hartid_map(smp_processor_id()));
+}
+
+static struct riscv_ipi_ops clint_ipi_ops = {
+	.ipi_inject = clint_send_ipi,
+	.ipi_clear = clint_clear_ipi,
+};
+
+#ifdef CONFIG_64BIT
+#define clint_get_cycles()	readq_relaxed(clint_timer_val)
+#else
+#define clint_get_cycles()	readl_relaxed(clint_timer_val)
+#define clint_get_cycles_hi()	readl_relaxed(((u32 *)clint_timer_val) + 1)
+#endif
+
+#ifdef CONFIG_64BIT
+static u64 notrace clint_get_cycles64(void)
+{
+	return clint_get_cycles();
+}
+#else /* CONFIG_64BIT */
+static u64 notrace clint_get_cycles64(void)
+{
+	u32 hi, lo;
+
+	do {
+		hi = clint_get_cycles_hi();
+		lo = clint_get_cycles();
+	} while (hi != clint_get_cycles_hi());
+
+	return ((u64)hi << 32) | lo;
+}
+#endif /* CONFIG_64BIT */
+
+static u64 clint_rdtime(struct clocksource *cs)
+{
+	return clint_get_cycles64();
+}
+
+static struct clocksource clint_clocksource = {
+	.name		= "clint_clocksource",
+	.rating		= 300,
+	.mask		= CLOCKSOURCE_MASK(64),
+	.flags		= CLOCK_SOURCE_IS_CONTINUOUS,
+	.read		= clint_rdtime,
+};
+
+static int clint_clock_next_event(unsigned long delta,
+				   struct clock_event_device *ce)
+{
+	void __iomem *r = clint_timer_cmp +
+			  cpuid_to_hartid_map(smp_processor_id());
+
+	csr_set(CSR_IE, IE_TIE);
+	writeq_relaxed(clint_get_cycles64() + delta, r);
+	return 0;
+}
+
+static DEFINE_PER_CPU(struct clock_event_device, clint_clock_event) = {
+	.name		= "clint_clockevent",
+	.features	= CLOCK_EVT_FEAT_ONESHOT,
+	.rating		= 100,
+	.set_next_event	= clint_clock_next_event,
+};
+
+static int clint_timer_starting_cpu(unsigned int cpu)
+{
+	struct clock_event_device *ce = per_cpu_ptr(&clint_clock_event, cpu);
+
+	ce->cpumask = cpumask_of(cpu);
+	clockevents_config_and_register(ce, clint_timer_freq, 100, 0x7fffffff);
+
+	enable_percpu_irq(clint_timer_irq,
+			  irq_get_trigger_type(clint_timer_irq));
+	return 0;
+}
+
+static int clint_timer_dying_cpu(unsigned int cpu)
+{
+	disable_percpu_irq(clint_timer_irq);
+	return 0;
+}
+
+static irqreturn_t clint_timer_interrupt(int irq, void *dev_id)
+{
+	struct clock_event_device *evdev = this_cpu_ptr(&clint_clock_event);
+
+	csr_clear(CSR_IE, IE_TIE);
+	evdev->event_handler(evdev);
+
+	return IRQ_HANDLED;
+}
+
+static int __init clint_timer_init_dt(struct device_node *np)
+{
+	int rc;
+	u32 i, nr_irqs;
+	void __iomem *base;
+	struct of_phandle_args oirq;
+
+	/*
+	 * Ensure that CLINT device interrupts are either RV_IRQ_TIMER or
+	 * RV_IRQ_SOFT. If it's anything else then we ignore the device.
+	 */
+	nr_irqs = of_irq_count(np);
+	for (i = 0; i < nr_irqs; i++) {
+		if (of_irq_parse_one(np, i, &oirq)) {
+			pr_err("%pOFP: failed to parse irq %d.\n", np, i);
+			continue;
+		}
+
+		if ((oirq.args_count != 1) ||
+		    (oirq.args[0] != RV_IRQ_TIMER &&
+		     oirq.args[0] != RV_IRQ_SOFT)) {
+			pr_err("%pOFP: invalid irq %d (hwirq %d)\n",
+			       np, i, oirq.args[0]);
+			return -ENODEV;
+		}
+
+		/* Find parent irq domain and map timer irq */
+		if (!clint_timer_irq &&
+		    oirq.args[0] == RV_IRQ_TIMER &&
+		    irq_find_host(oirq.np))
+			clint_timer_irq = irq_of_parse_and_map(np, i);
+	}
+
+	/* If CLINT timer irq not found then fail */
+	if (!clint_timer_irq) {
+		pr_err("%pOFP: timer irq not found\n", np);
+		return -ENODEV;
+	}
+
+	base = of_iomap(np, 0);
+	if (!base) {
+		pr_err("%pOFP: could not map registers\n", np);
+		return -ENODEV;
+	}
+
+	clint_ipi_base = base + CLINT_IPI_OFF;
+	clint_timer_cmp = base + CLINT_TIMER_CMP_OFF;
+	clint_timer_val = base + CLINT_TIMER_VAL_OFF;
+	clint_timer_freq = riscv_timebase;
+
+	pr_info("%pOFP: timer running at %ld Hz\n", np, clint_timer_freq);
+
+	rc = clocksource_register_hz(&clint_clocksource, clint_timer_freq);
+	if (rc) {
+		pr_err("%pOFP: clocksource register failed [%d]\n", np, rc);
+		goto fail_iounmap;
+	}
+
+	sched_clock_register(clint_get_cycles64, 64, clint_timer_freq);
+
+	rc = request_percpu_irq(clint_timer_irq, clint_timer_interrupt,
+				 "clint-timer", &clint_clock_event);
+	if (rc) {
+		pr_err("registering percpu irq failed [%d]\n", rc);
+		goto fail_iounmap;
+	}
+
+	rc = cpuhp_setup_state(CPUHP_AP_CLINT_TIMER_STARTING,
+				"clockevents/clint/timer:starting",
+				clint_timer_starting_cpu,
+				clint_timer_dying_cpu);
+	if (rc) {
+		pr_err("%pOFP: cpuhp setup state failed [%d]\n", np, rc);
+		goto fail_free_irq;
+	}
+
+	riscv_set_ipi_ops(&clint_ipi_ops);
+	clint_clear_ipi();
+
+	return 0;
+
+fail_free_irq:
+	free_irq(clint_timer_irq, &clint_clock_event);
+fail_iounmap:
+	iounmap(base);
+	return rc;
+}
+
+TIMER_OF_DECLARE(clint_timer, "riscv,clint0", clint_timer_init_dt);
+TIMER_OF_DECLARE(clint_timer1, "sifive,clint0", clint_timer_init_dt);
diff --git a/include/linux/cpuhotplug.h b/include/linux/cpuhotplug.h
index a2710e654b64..3215023d4852 100644
--- a/include/linux/cpuhotplug.h
+++ b/include/linux/cpuhotplug.h
@@ -132,6 +132,7 @@ enum cpuhp_state {
 	CPUHP_AP_MIPS_GIC_TIMER_STARTING,
 	CPUHP_AP_ARC_TIMER_STARTING,
 	CPUHP_AP_RISCV_TIMER_STARTING,
+	CPUHP_AP_CLINT_TIMER_STARTING,
 	CPUHP_AP_CSKY_TIMER_STARTING,
 	CPUHP_AP_HYPERV_TIMER_STARTING,
 	CPUHP_AP_KVM_STARTING,
-- 
2.25.1


^ permalink raw reply related	[flat|nested] 6+ messages in thread

* [PATCH v7 3/4] RISC-V: Remove CLINT related code from timer and arch
  2020-08-17 12:42 [PATCH v7 0/4] Dedicated CLINT timer driver Anup Patel
  2020-08-17 12:42 ` [PATCH v7 1/4] RISC-V: Add mechanism to provide custom IPI operations Anup Patel
  2020-08-17 12:42 ` [PATCH v7 2/4] clocksource/drivers: Add CLINT timer driver Anup Patel
@ 2020-08-17 12:42 ` Anup Patel
  2020-08-17 12:42 ` [PATCH v7 4/4] dt-bindings: timer: Add CLINT bindings Anup Patel
  2020-08-20 17:59 ` [PATCH v7 0/4] Dedicated CLINT timer driver Palmer Dabbelt
  4 siblings, 0 replies; 6+ messages in thread
From: Anup Patel @ 2020-08-17 12:42 UTC (permalink / raw)
  To: Palmer Dabbelt, Paul Walmsley, Albert Ou, Rob Herring,
	Daniel Lezcano, Thomas Gleixner
  Cc: Damien Le Moal, Atish Patra, Alistair Francis, Anup Patel,
	linux-riscv, linux-kernel, devicetree, Anup Patel,
	Emil Renner Berhing, Palmer Dabbelt

Right now the RISC-V timer driver is convoluted to support:
1. Linux RISC-V S-mode (with MMU) where it will use TIME CSR for
   clocksource and SBI timer calls for clockevent device.
2. Linux RISC-V M-mode (without MMU) where it will use CLINT MMIO
   counter register for clocksource and CLINT MMIO compare register
   for clockevent device.

We now have a separate CLINT timer driver which also provide CLINT
based IPI operations so let's remove CLINT MMIO related code from
arch/riscv directory and RISC-V timer driver.

Signed-off-by: Anup Patel <anup.patel@wdc.com>
Tested-by: Emil Renner Berhing <kernel@esmil.dk>
Acked-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Reviewed-by: Atish Patra <atish.patra@wdc.com>
Reviewed-by: Palmer Dabbelt <palmerdabbelt@google.com>
---
 arch/riscv/Kconfig                      |  2 +-
 arch/riscv/Kconfig.socs                 |  2 +
 arch/riscv/configs/nommu_virt_defconfig |  7 +--
 arch/riscv/include/asm/clint.h          | 14 ------
 arch/riscv/include/asm/timex.h          | 28 +++--------
 arch/riscv/kernel/Makefile              |  2 +-
 arch/riscv/kernel/clint.c               | 63 -------------------------
 arch/riscv/kernel/setup.c               |  2 -
 arch/riscv/kernel/smp.c                 |  1 -
 arch/riscv/kernel/smpboot.c             |  1 -
 drivers/clocksource/Kconfig             |  3 +-
 drivers/clocksource/timer-riscv.c       | 17 +------
 12 files changed, 16 insertions(+), 126 deletions(-)
 delete mode 100644 arch/riscv/include/asm/clint.h
 delete mode 100644 arch/riscv/kernel/clint.c

diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
index 520bf04cf04b..a8f20141f506 100644
--- a/arch/riscv/Kconfig
+++ b/arch/riscv/Kconfig
@@ -82,7 +82,7 @@ config RISCV
 	select PCI_DOMAINS_GENERIC if PCI
 	select PCI_MSI if PCI
 	select RISCV_INTC
-	select RISCV_TIMER
+	select RISCV_TIMER if RISCV_SBI
 	select SPARSEMEM_STATIC if 32BIT
 	select SPARSE_IRQ
 	select SYSCTL_EXCEPTION_TRACE
diff --git a/arch/riscv/Kconfig.socs b/arch/riscv/Kconfig.socs
index 6c88148f1b9b..8a55f6156661 100644
--- a/arch/riscv/Kconfig.socs
+++ b/arch/riscv/Kconfig.socs
@@ -12,6 +12,7 @@ config SOC_SIFIVE
 
 config SOC_VIRT
 	bool "QEMU Virt Machine"
+	select CLINT_TIMER if RISCV_M_MODE
 	select POWER_RESET
 	select POWER_RESET_SYSCON
 	select POWER_RESET_SYSCON_POWEROFF
@@ -24,6 +25,7 @@ config SOC_VIRT
 config SOC_KENDRYTE
 	bool "Kendryte K210 SoC"
 	depends on !MMU
+	select CLINT_TIMER if RISCV_M_MODE
 	select SERIAL_SIFIVE if TTY
 	select SERIAL_SIFIVE_CONSOLE if TTY
 	select SIFIVE_PLIC
diff --git a/arch/riscv/configs/nommu_virt_defconfig b/arch/riscv/configs/nommu_virt_defconfig
index f27596e9663e..e046a0babde4 100644
--- a/arch/riscv/configs/nommu_virt_defconfig
+++ b/arch/riscv/configs/nommu_virt_defconfig
@@ -26,6 +26,7 @@ CONFIG_EXPERT=y
 CONFIG_SLOB=y
 # CONFIG_SLAB_MERGE_DEFAULT is not set
 # CONFIG_MMU is not set
+CONFIG_SOC_VIRT=y
 CONFIG_MAXPHYSMEM_2GB=y
 CONFIG_SMP=y
 CONFIG_CMDLINE="root=/dev/vda rw earlycon=uart8250,mmio,0x10000000,115200n8 console=ttyS0"
@@ -49,7 +50,6 @@ CONFIG_VIRTIO_BLK=y
 # CONFIG_SERIO is not set
 # CONFIG_LEGACY_PTYS is not set
 # CONFIG_LDISC_AUTOLOAD is not set
-# CONFIG_DEVMEM is not set
 CONFIG_SERIAL_8250=y
 # CONFIG_SERIAL_8250_DEPRECATED_OPTIONS is not set
 CONFIG_SERIAL_8250_CONSOLE=y
@@ -57,16 +57,13 @@ CONFIG_SERIAL_8250_NR_UARTS=1
 CONFIG_SERIAL_8250_RUNTIME_UARTS=1
 CONFIG_SERIAL_OF_PLATFORM=y
 # CONFIG_HW_RANDOM is not set
+# CONFIG_DEVMEM is not set
 # CONFIG_HWMON is not set
-# CONFIG_LCD_CLASS_DEVICE is not set
-# CONFIG_BACKLIGHT_CLASS_DEVICE is not set
 # CONFIG_VGA_CONSOLE is not set
 # CONFIG_HID is not set
 # CONFIG_USB_SUPPORT is not set
 CONFIG_VIRTIO_MMIO=y
 CONFIG_VIRTIO_MMIO_CMDLINE_DEVICES=y
-CONFIG_SIFIVE_PLIC=y
-# CONFIG_VALIDATE_FS_PARSER is not set
 CONFIG_EXT2_FS=y
 # CONFIG_DNOTIFY is not set
 # CONFIG_INOTIFY_USER is not set
diff --git a/arch/riscv/include/asm/clint.h b/arch/riscv/include/asm/clint.h
deleted file mode 100644
index adaba98a7d6c..000000000000
--- a/arch/riscv/include/asm/clint.h
+++ /dev/null
@@ -1,14 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0 */
-#ifndef _ASM_RISCV_CLINT_H
-#define _ASM_RISCV_CLINT_H 1
-
-#include <linux/io.h>
-#include <linux/smp.h>
-
-#ifdef CONFIG_RISCV_M_MODE
-void clint_init_boot_cpu(void);
-#else /* CONFIG_RISCV_M_MODE */
-#define clint_init_boot_cpu()	do { } while (0)
-#endif /* CONFIG_RISCV_M_MODE */
-
-#endif /* _ASM_RISCV_CLINT_H */
diff --git a/arch/riscv/include/asm/timex.h b/arch/riscv/include/asm/timex.h
index bad2a7c2cda5..a3fb85d505d4 100644
--- a/arch/riscv/include/asm/timex.h
+++ b/arch/riscv/include/asm/timex.h
@@ -7,41 +7,27 @@
 #define _ASM_RISCV_TIMEX_H
 
 #include <asm/csr.h>
-#include <asm/mmio.h>
 
 typedef unsigned long cycles_t;
 
-extern u64 __iomem *riscv_time_val;
-extern u64 __iomem *riscv_time_cmp;
-
-#ifdef CONFIG_64BIT
-#define mmio_get_cycles()	readq_relaxed(riscv_time_val)
-#else
-#define mmio_get_cycles()	readl_relaxed(riscv_time_val)
-#define mmio_get_cycles_hi()	readl_relaxed(((u32 *)riscv_time_val) + 1)
-#endif
-
 static inline cycles_t get_cycles(void)
 {
-	if (IS_ENABLED(CONFIG_RISCV_SBI))
-		return csr_read(CSR_TIME);
-	return mmio_get_cycles();
+	return csr_read(CSR_TIME);
 }
 #define get_cycles get_cycles
 
+static inline u32 get_cycles_hi(void)
+{
+	return csr_read(CSR_TIMEH);
+}
+#define get_cycles_hi get_cycles_hi
+
 #ifdef CONFIG_64BIT
 static inline u64 get_cycles64(void)
 {
 	return get_cycles();
 }
 #else /* CONFIG_64BIT */
-static inline u32 get_cycles_hi(void)
-{
-	if (IS_ENABLED(CONFIG_RISCV_SBI))
-		return csr_read(CSR_TIMEH);
-	return mmio_get_cycles_hi();
-}
-
 static inline u64 get_cycles64(void)
 {
 	u32 hi, lo;
diff --git a/arch/riscv/kernel/Makefile b/arch/riscv/kernel/Makefile
index a5287ab9f7f2..dc93710f0b2f 100644
--- a/arch/riscv/kernel/Makefile
+++ b/arch/riscv/kernel/Makefile
@@ -31,7 +31,7 @@ obj-y	+= cacheinfo.o
 obj-y	+= patch.o
 obj-$(CONFIG_MMU) += vdso.o vdso/
 
-obj-$(CONFIG_RISCV_M_MODE)	+= clint.o traps_misaligned.o
+obj-$(CONFIG_RISCV_M_MODE)	+= traps_misaligned.o
 obj-$(CONFIG_FPU)		+= fpu.o
 obj-$(CONFIG_SMP)		+= smpboot.o
 obj-$(CONFIG_SMP)		+= smp.o
diff --git a/arch/riscv/kernel/clint.c b/arch/riscv/kernel/clint.c
deleted file mode 100644
index a9845ee023e2..000000000000
--- a/arch/riscv/kernel/clint.c
+++ /dev/null
@@ -1,63 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0
-/*
- * Copyright (c) 2019 Christoph Hellwig.
- */
-
-#include <linux/io.h>
-#include <linux/of_address.h>
-#include <linux/smp.h>
-#include <linux/types.h>
-#include <asm/clint.h>
-#include <asm/csr.h>
-#include <asm/timex.h>
-
-/*
- * This is the layout used by the SiFive clint, which is also shared by the qemu
- * virt platform, and the Kendryte KD210 at least.
- */
-#define CLINT_IPI_OFF		0
-#define CLINT_TIME_CMP_OFF	0x4000
-#define CLINT_TIME_VAL_OFF	0xbff8
-
-u32 __iomem *clint_ipi_base;
-
-static void clint_send_ipi(const struct cpumask *target)
-{
-	unsigned int cpu;
-
-	for_each_cpu(cpu, target)
-		writel(1, clint_ipi_base + cpuid_to_hartid_map(cpu));
-}
-
-static void clint_clear_ipi(void)
-{
-	writel(0, clint_ipi_base + cpuid_to_hartid_map(smp_processor_id()));
-}
-
-static struct riscv_ipi_ops clint_ipi_ops = {
-	.ipi_inject = clint_send_ipi,
-	.ipi_clear = clint_clear_ipi,
-};
-
-void clint_init_boot_cpu(void)
-{
-	struct device_node *np;
-	void __iomem *base;
-
-	np = of_find_compatible_node(NULL, NULL, "riscv,clint0");
-	if (!np) {
-		panic("clint not found");
-		return;
-	}
-
-	base = of_iomap(np, 0);
-	if (!base)
-		panic("could not map CLINT");
-
-	clint_ipi_base = base + CLINT_IPI_OFF;
-	riscv_time_cmp = base + CLINT_TIME_CMP_OFF;
-	riscv_time_val = base + CLINT_TIME_VAL_OFF;
-
-	clint_clear_ipi();
-	riscv_set_ipi_ops(&clint_ipi_ops);
-}
diff --git a/arch/riscv/kernel/setup.c b/arch/riscv/kernel/setup.c
index f04373be54a6..2c6dd329312b 100644
--- a/arch/riscv/kernel/setup.c
+++ b/arch/riscv/kernel/setup.c
@@ -18,7 +18,6 @@
 #include <linux/swiotlb.h>
 #include <linux/smp.h>
 
-#include <asm/clint.h>
 #include <asm/cpu_ops.h>
 #include <asm/setup.h>
 #include <asm/sections.h>
@@ -79,7 +78,6 @@ void __init setup_arch(char **cmdline_p)
 #else
 	unflatten_device_tree();
 #endif
-	clint_init_boot_cpu();
 
 #ifdef CONFIG_SWIOTLB
 	swiotlb_init(1);
diff --git a/arch/riscv/kernel/smp.c b/arch/riscv/kernel/smp.c
index cf9acb43604c..ea028d9e0d24 100644
--- a/arch/riscv/kernel/smp.c
+++ b/arch/riscv/kernel/smp.c
@@ -18,7 +18,6 @@
 #include <linux/delay.h>
 #include <linux/irq_work.h>
 
-#include <asm/clint.h>
 #include <asm/sbi.h>
 #include <asm/tlbflush.h>
 #include <asm/cacheflush.h>
diff --git a/arch/riscv/kernel/smpboot.c b/arch/riscv/kernel/smpboot.c
index 12033d71ba0c..96167d55ed98 100644
--- a/arch/riscv/kernel/smpboot.c
+++ b/arch/riscv/kernel/smpboot.c
@@ -24,7 +24,6 @@
 #include <linux/of.h>
 #include <linux/sched/task_stack.h>
 #include <linux/sched/mm.h>
-#include <asm/clint.h>
 #include <asm/cpu_ops.h>
 #include <asm/irq.h>
 #include <asm/mmu_context.h>
diff --git a/drivers/clocksource/Kconfig b/drivers/clocksource/Kconfig
index d95cc7234a66..68b087bff59c 100644
--- a/drivers/clocksource/Kconfig
+++ b/drivers/clocksource/Kconfig
@@ -653,9 +653,8 @@ config ATCPIT100_TIMER
 	  This option enables support for the Andestech ATCPIT100 timers.
 
 config RISCV_TIMER
-	bool "Timer for the RISC-V platform"
+	bool "Timer for the RISC-V platform" if COMPILE_TEST
 	depends on GENERIC_SCHED_CLOCK && RISCV
-	default y
 	select TIMER_PROBE
 	select TIMER_OF
 	help
diff --git a/drivers/clocksource/timer-riscv.c b/drivers/clocksource/timer-riscv.c
index 9de1dabfb126..c51c5ed15aa7 100644
--- a/drivers/clocksource/timer-riscv.c
+++ b/drivers/clocksource/timer-riscv.c
@@ -19,26 +19,13 @@
 #include <linux/of_irq.h>
 #include <asm/smp.h>
 #include <asm/sbi.h>
-
-u64 __iomem *riscv_time_cmp;
-u64 __iomem *riscv_time_val;
-
-static inline void mmio_set_timer(u64 val)
-{
-	void __iomem *r;
-
-	r = riscv_time_cmp + cpuid_to_hartid_map(smp_processor_id());
-	writeq_relaxed(val, r);
-}
+#include <asm/timex.h>
 
 static int riscv_clock_next_event(unsigned long delta,
 		struct clock_event_device *ce)
 {
 	csr_set(CSR_IE, IE_TIE);
-	if (IS_ENABLED(CONFIG_RISCV_SBI))
-		sbi_set_timer(get_cycles64() + delta);
-	else
-		mmio_set_timer(get_cycles64() + delta);
+	sbi_set_timer(get_cycles64() + delta);
 	return 0;
 }
 
-- 
2.25.1


^ permalink raw reply related	[flat|nested] 6+ messages in thread

* [PATCH v7 4/4] dt-bindings: timer: Add CLINT bindings
  2020-08-17 12:42 [PATCH v7 0/4] Dedicated CLINT timer driver Anup Patel
                   ` (2 preceding siblings ...)
  2020-08-17 12:42 ` [PATCH v7 3/4] RISC-V: Remove CLINT related code from timer and arch Anup Patel
@ 2020-08-17 12:42 ` Anup Patel
  2020-08-20 17:59 ` [PATCH v7 0/4] Dedicated CLINT timer driver Palmer Dabbelt
  4 siblings, 0 replies; 6+ messages in thread
From: Anup Patel @ 2020-08-17 12:42 UTC (permalink / raw)
  To: Palmer Dabbelt, Paul Walmsley, Albert Ou, Rob Herring,
	Daniel Lezcano, Thomas Gleixner
  Cc: Damien Le Moal, Atish Patra, Alistair Francis, Anup Patel,
	linux-riscv, linux-kernel, devicetree, Anup Patel,
	Palmer Dabbelt, Emil Renner Berhing, Rob Herring

We add DT bindings documentation for CLINT device.

Signed-off-by: Anup Patel <anup.patel@wdc.com>
Reviewed-by: Palmer Dabbelt <palmerdabbelt@google.com>
Tested-by: Emil Renner Berhing <kernel@esmil.dk>
Reviewed-by: Atish Patra <atish.patra@wdc.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Reviewed-by: Palmer Dabbelt <palmerdabbelt@google.com>
---
 .../bindings/timer/sifive,clint.yaml          | 60 +++++++++++++++++++
 1 file changed, 60 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/timer/sifive,clint.yaml

diff --git a/Documentation/devicetree/bindings/timer/sifive,clint.yaml b/Documentation/devicetree/bindings/timer/sifive,clint.yaml
new file mode 100644
index 000000000000..2a0e9cd9fbcf
--- /dev/null
+++ b/Documentation/devicetree/bindings/timer/sifive,clint.yaml
@@ -0,0 +1,60 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/timer/sifive,clint.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: SiFive Core Local Interruptor
+
+maintainers:
+  - Palmer Dabbelt <palmer@dabbelt.com>
+  - Anup Patel <anup.patel@wdc.com>
+
+description:
+  SiFive (and other RISC-V) SOCs include an implementation of the SiFive
+  Core Local Interruptor (CLINT) for M-mode timer and M-mode inter-processor
+  interrupts. It directly connects to the timer and inter-processor interrupt
+  lines of various HARTs (or CPUs) so RISC-V per-HART (or per-CPU) local
+  interrupt controller is the parent interrupt controller for CLINT device.
+  The clock frequency of CLINT is specified via "timebase-frequency" DT
+  property of "/cpus" DT node. The "timebase-frequency" DT property is
+  described in Documentation/devicetree/bindings/riscv/cpus.yaml
+
+properties:
+  compatible:
+    items:
+      - const: sifive,fu540-c000-clint
+      - const: sifive,clint0
+
+    description:
+      Should be "sifive,<chip>-clint" and "sifive,clint<version>".
+      Supported compatible strings are -
+      "sifive,fu540-c000-clint" for the SiFive CLINT v0 as integrated
+      onto the SiFive FU540 chip, and "sifive,clint0" for the SiFive
+      CLINT v0 IP block with no chip integration tweaks.
+      Please refer to sifive-blocks-ip-versioning.txt for details
+
+  reg:
+    maxItems: 1
+
+  interrupts-extended:
+    minItems: 1
+
+additionalProperties: false
+
+required:
+  - compatible
+  - reg
+  - interrupts-extended
+
+examples:
+  - |
+    timer@2000000 {
+      compatible = "sifive,fu540-c000-clint", "sifive,clint0";
+      interrupts-extended = <&cpu1intc 3 &cpu1intc 7
+                             &cpu2intc 3 &cpu2intc 7
+                             &cpu3intc 3 &cpu3intc 7
+                             &cpu4intc 3 &cpu4intc 7>;
+       reg = <0x2000000 0x10000>;
+    };
+...
-- 
2.25.1


^ permalink raw reply related	[flat|nested] 6+ messages in thread

* Re: [PATCH v7 0/4] Dedicated CLINT timer driver
  2020-08-17 12:42 [PATCH v7 0/4] Dedicated CLINT timer driver Anup Patel
                   ` (3 preceding siblings ...)
  2020-08-17 12:42 ` [PATCH v7 4/4] dt-bindings: timer: Add CLINT bindings Anup Patel
@ 2020-08-20 17:59 ` Palmer Dabbelt
  4 siblings, 0 replies; 6+ messages in thread
From: Palmer Dabbelt @ 2020-08-20 17:59 UTC (permalink / raw)
  To: Anup Patel
  Cc: Paul Walmsley, aou, robh+dt, daniel.lezcano, tglx,
	Damien Le Moal, Atish Patra, Alistair Francis, anup, linux-riscv,
	linux-kernel, devicetree, Anup Patel

On Mon, 17 Aug 2020 05:42:47 PDT (-0700), Anup Patel wrote:
> The current RISC-V timer driver is convoluted and implements two
> distinct timers:
>  1. S-mode timer: This is for Linux RISC-V S-mode with MMU. The
>     clocksource is implemented using TIME CSR and clockevent device
>     is implemented using SBI Timer calls.
>  2. M-mode timer: This is for Linux RISC-V M-mode without MMU. The
>     clocksource is implemented using CLINT MMIO time register and
>     clockevent device is implemented using CLINT MMIO timecmp registers.
>
> This patchset removes clint related code from RISC-V timer driver and
> arch/riscv directory. Instead, the series adds a dedicated MMIO based
> CLINT driver under drivers/clocksource directory which can be used by
> Linux RISC-V M-mode (i.e NoMMU Linux RISC-V).
>
> The patchset is based up Linux-5.9-rc1 and can be found at riscv_clint_v7
> branch of: https://github.com/avpatel/linux.git
>
> This series is tested on:
>  1. QEMU RV64 virt machine using Linux RISC-V S-mode
>  2. QEMU RV32 virt machine using Linux RISC-V S-mode
>  3. QEMU RV64 virt machine using Linux RISC-V M-mode (i.e. NoMMU)
>
> Changes since v6:
>  - Rebased series on Linux-5.9-rc1
>
> Changes since v5:
>  - Fixed order of compatible strings in PATCH4
>  - Added "additionalProperties: false" in PATCH4
>  - Fixed register space size for example DT node in PATCH4
>
> Changes since v4:
>  - Rebased series on Linux-5.8-rc6
>  - Updated Kconfig option as suggested by Daniel in PATCH2
>  - Removed per-CPU registered flag in PATCH2
>  - Addressed nit comments from Atish in PATCH2
>
> Changes since v3:
>  - Updated commit description of PATCH2
>  - Use clint_get_cycles64() in clint_rdtime() of PATCH2
>  - Call clockevents_config_and_register() only once for each CPU in
>    clint_timer_starting_cpu of PATCH2
>  - Select CLINT timer driver from platform Kconfig in PATCH3
>  - Fixed 'make dt_binding_check' for PATCH4
>
> Changes since v2:
>  - Rebased series on Linux-5.8-rc5
>  - Squashed PATCH3 onto PATCH2 to preserve GIT bisectability
>  - Moved PATCH4 before PATCH2 to preserve GIT bisectability
>  - Replaced CLINT dt-bindings text document with YAML schema
>  - Use SiFive CLINT compatible string as per SiFive IP block versioning
>
> Changes since v1:
>  - Rebased series on Linux-5.8-rc2
>  - Added pr_warn() for case where ipi_ops not available in PATCH1
>  - Updated ipi_inject() prototype to use "struct cpumask *" in PATCH1
>  - Updated CLINT_TIMER kconfig option to depend on RISCV_M_MODE in PATCH4
>  - Added riscv,clint0 compatible string in DT bindings document
>
> Anup Patel (4):
>   RISC-V: Add mechanism to provide custom IPI operations
>   clocksource/drivers: Add CLINT timer driver
>   RISC-V: Remove CLINT related code from timer and arch
>   dt-bindings: timer: Add CLINT bindings
>
>  .../bindings/timer/sifive,clint.yaml          |  60 +++++
>  arch/riscv/Kconfig                            |   2 +-
>  arch/riscv/Kconfig.socs                       |   2 +
>  arch/riscv/configs/nommu_virt_defconfig       |   7 +-
>  arch/riscv/include/asm/clint.h                |  39 ---
>  arch/riscv/include/asm/smp.h                  |  19 ++
>  arch/riscv/include/asm/timex.h                |  28 +--
>  arch/riscv/kernel/Makefile                    |   2 +-
>  arch/riscv/kernel/clint.c                     |  44 ----
>  arch/riscv/kernel/sbi.c                       |  14 ++
>  arch/riscv/kernel/setup.c                     |   2 -
>  arch/riscv/kernel/smp.c                       |  44 ++--
>  arch/riscv/kernel/smpboot.c                   |   4 +-
>  drivers/clocksource/Kconfig                   |  12 +-
>  drivers/clocksource/Makefile                  |   1 +
>  drivers/clocksource/timer-clint.c             | 226 ++++++++++++++++++
>  drivers/clocksource/timer-riscv.c             |  17 +-
>  include/linux/cpuhotplug.h                    |   1 +
>  18 files changed, 371 insertions(+), 153 deletions(-)
>  create mode 100644 Documentation/devicetree/bindings/timer/sifive,clint.yaml
>  delete mode 100644 arch/riscv/include/asm/clint.h
>  delete mode 100644 arch/riscv/kernel/clint.c
>  create mode 100644 drivers/clocksource/timer-clint.c

Thanks.  These are on fixes.

^ permalink raw reply	[flat|nested] 6+ messages in thread

end of thread, other threads:[~2020-08-20 17:59 UTC | newest]

Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2020-08-17 12:42 [PATCH v7 0/4] Dedicated CLINT timer driver Anup Patel
2020-08-17 12:42 ` [PATCH v7 1/4] RISC-V: Add mechanism to provide custom IPI operations Anup Patel
2020-08-17 12:42 ` [PATCH v7 2/4] clocksource/drivers: Add CLINT timer driver Anup Patel
2020-08-17 12:42 ` [PATCH v7 3/4] RISC-V: Remove CLINT related code from timer and arch Anup Patel
2020-08-17 12:42 ` [PATCH v7 4/4] dt-bindings: timer: Add CLINT bindings Anup Patel
2020-08-20 17:59 ` [PATCH v7 0/4] Dedicated CLINT timer driver Palmer Dabbelt

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