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From: Antony Pavlov <antonynpavlov@gmail.com>
To: barebox@lists.infradead.org
Cc: Ahmad Fatoum <a.fatoum@pengutronix.de>
Subject: [PATCH RESEND v4 1/8] clocksource: timer-riscv: select CSR from device tree
Date: Tue, 17 Aug 2021 13:10:57 +0300
Message-ID: <20210817101104.114945-2-antonynpavlov@gmail.com> (raw)
In-Reply-To: <20210817101104.114945-1-antonynpavlov@gmail.com>

barebox timer-riscv driver supports one of user counters:

  * 'cycle', counter for RDCYCLE instruction (CSR 0xc00);
  * 'time', timer for RDTIME instruction (CSR 0xc01).

At the moment in M-mode timer-riscv uses the 'cycle' counter,
and in S-mode timer-riscv uses the 'time' timer.

Alas picorv32 CPU core supports only the 'cycle' counter.
VexRiscV CPU core in M-mode supports only the 'time' timer.

This patch makes it possible to use the 'time' timer
for VexRiscV CPU in M-mode.

See also http://lists.infradead.org/pipermail/barebox/2021-May/036067.html

Signed-off-by: Antony Pavlov <antonynpavlov@gmail.com>
---
 arch/riscv/dts/erizo.dtsi         |  2 ++
 drivers/clocksource/timer-riscv.c | 24 ++++++++++++------------
 2 files changed, 14 insertions(+), 12 deletions(-)

diff --git a/arch/riscv/dts/erizo.dtsi b/arch/riscv/dts/erizo.dtsi
index 228711bd69..4eb92ae6f1 100644
--- a/arch/riscv/dts/erizo.dtsi
+++ b/arch/riscv/dts/erizo.dtsi
@@ -22,6 +22,8 @@
 
 		timebase-frequency = <24000000>;
 
+		barebox,csr-cycle;
+
 		cpu@0 {
 			device_type = "cpu";
 			compatible = "cliffordwolf,picorv32", "riscv";
diff --git a/drivers/clocksource/timer-riscv.c b/drivers/clocksource/timer-riscv.c
index 5a517fe6b4..96637f988a 100644
--- a/drivers/clocksource/timer-riscv.c
+++ b/drivers/clocksource/timer-riscv.c
@@ -12,9 +12,8 @@
 #include <clock.h>
 #include <asm/timer.h>
 #include <asm/csr.h>
-#include <asm/system.h>
 
-static u64 notrace riscv_timer_get_count_sbi(void)
+static u64 notrace riscv_timer_get_count_time(void)
 {
 	__maybe_unused u32 hi, lo;
 
@@ -29,7 +28,7 @@ static u64 notrace riscv_timer_get_count_sbi(void)
 	return ((u64)hi << 32) | lo;
 }
 
-static u64 notrace riscv_timer_get_count_rdcycle(void)
+static u64 notrace riscv_timer_get_count_cycle(void)
 {
 	__maybe_unused u32 hi, lo;
 
@@ -44,24 +43,25 @@ static u64 notrace riscv_timer_get_count_rdcycle(void)
 	return ((u64)hi << 32) | lo;
 }
 
-static u64 notrace riscv_timer_get_count(void)
-{
-	if (riscv_mode() == RISCV_S_MODE)
-		return riscv_timer_get_count_sbi();
-	else
-		return riscv_timer_get_count_rdcycle();
-}
-
 static struct clocksource riscv_clocksource = {
-	.read		= riscv_timer_get_count,
 	.mask		= CLOCKSOURCE_MASK(64),
 	.priority	= 100,
 };
 
 static int riscv_timer_init(struct device_d* dev)
 {
+	struct device_node *cpu;
+
 	dev_dbg(dev, "running at %lu Hz\n", riscv_timebase);
 
+	cpu = of_find_node_by_path("/cpus");
+
+	if (of_property_read_bool(cpu, "barebox,csr-cycle")) {
+		riscv_clocksource.read = riscv_timer_get_count_cycle;
+	} else {
+		riscv_clocksource.read = riscv_timer_get_count_time;
+	}
+
 	riscv_clocksource.mult = clocksource_hz2mult(riscv_timebase, riscv_clocksource.shift);
 
 	return init_clock(&riscv_clocksource);
-- 
2.32.0


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  reply	other threads:[~2021-08-17 10:13 UTC|newest]

Thread overview: 23+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-08-17 10:10 [PATCH RESEND v4 0/8] RISC-V: add LiteX SoC support Antony Pavlov
2021-08-17 10:10 ` Antony Pavlov [this message]
2021-08-23 12:08   ` [PATCH RESEND v4 1/8] clocksource: timer-riscv: select CSR from device tree Ahmad Fatoum
2021-08-31  4:07     ` Antony Pavlov
2021-10-01 10:12       ` Ahmad Fatoum
2021-08-17 10:10 ` [PATCH RESEND v4 2/8] serial: add litex UART driver Antony Pavlov
2021-08-23 11:58   ` Ahmad Fatoum
2021-08-17 10:10 ` [PATCH RESEND v4 3/8] console: support set baudrate for fixed baudrate drivers Antony Pavlov
2021-08-23 12:01   ` Ahmad Fatoum
2021-08-17 10:11 ` [PATCH RESEND v4 4/8] gpio: add driver for 74xx-ICs with MMIO access Antony Pavlov
2021-10-01 10:13   ` Ahmad Fatoum
2021-08-17 10:11 ` [PATCH RESEND v4 5/8] spi: add litex spiflash driver Antony Pavlov
2021-08-23 11:57   ` [PATCH] fixup! " Ahmad Fatoum
2021-10-01 10:13   ` [PATCH RESEND v4 5/8] " Ahmad Fatoum
2021-08-17 10:11 ` [PATCH RESEND v4 6/8] net: add LiteEth driver Antony Pavlov
2021-10-01 10:14   ` Ahmad Fatoum
2021-08-17 10:11 ` [PATCH RESEND v4 7/8] RISC-V: add LiteX SoC and linux-on-litex-vexriscv support Antony Pavlov
2021-08-23 12:06   ` Ahmad Fatoum
2021-08-31  4:38     ` Antony Pavlov
2021-10-01 10:21       ` Ahmad Fatoum
2021-08-17 10:11 ` [PATCH RESEND v4 8/8] RISC-V: add litex_linux_defconfig Antony Pavlov
2021-10-01 10:18   ` Ahmad Fatoum
2021-10-04 12:02 ` [PATCH RESEND v4 0/8] RISC-V: add LiteX SoC support Sascha Hauer

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