[PATCH] zynq: Convert arm twd timer to DM driver

Stefan Herbrechtsmeier stefan.herbrechtsmeier-oss at weidmueller.com
Fri Aug 5 08:16:28 CEST 2022 

From: Stefan Herbrechtsmeier <stefan.herbrechtsmeier at weidmueller.com>

Move arm twd timer driver from zynq to generic location.

DM timer drivers are designed differently to original driver. Timer is
counting up and not down.
Information about clock rates are find out in timer_pre_probe() that's
why there is no need to get any additional information from DT in the
driver itself (only register offset).

Signed-off-by: Stefan Herbrechtsmeier <stefan.herbrechtsmeier at weidmueller.com>

---

 arch/arm/Kconfig              |   3 +
 arch/arm/dts/zynq-7000.dtsi   |   1 +
 arch/arm/mach-zynq/Makefile   |   1 -
 arch/arm/mach-zynq/clk.c      |   6 +-
 arch/arm/mach-zynq/timer.c    | 113 ----------------------------------
 drivers/timer/Kconfig         |   6 ++
 drivers/timer/Makefile        |   1 +
 drivers/timer/arm_twd_timer.c | 108 ++++++++++++++++++++++++++++++++
 8 files changed, 123 insertions(+), 116 deletions(-)
 delete mode 100644 arch/arm/mach-zynq/timer.c
 create mode 100644 drivers/timer/arm_twd_timer.c

diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index 949ebb46ba..bccdc6dfd8 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -1249,6 +1249,7 @@ config ARCH_VF610
 
 config ARCH_ZYNQ
 	bool "Xilinx Zynq based platform"
+	select ARM_TWD_TIMER
 	select CLK
 	select CLK_ZYNQ
 	select CPU_V7A
@@ -1268,7 +1269,9 @@ config ARCH_ZYNQ
 	select SPL_DM_SPI_FLASH if SPL
 	select SPL_OF_CONTROL if SPL
 	select SPL_SEPARATE_BSS if SPL
+	select SPL_TIMER if SPL
 	select SUPPORT_SPL
+	select TIMER
 	imply ARCH_EARLY_INIT_R
 	imply BOARD_LATE_INIT
 	imply CMD_CLK
diff --git a/arch/arm/dts/zynq-7000.dtsi b/arch/arm/dts/zynq-7000.dtsi
index 37155df0fd..a7ca00fb76 100644
--- a/arch/arm/dts/zynq-7000.dtsi
+++ b/arch/arm/dts/zynq-7000.dtsi
@@ -416,6 +416,7 @@
 		};
 
 		scutimer: timer at f8f00600 {
+			u-boot,dm-pre-reloc;
 			interrupt-parent = <&intc>;
 			interrupts = <1 13 0x301>;
 			compatible = "arm,cortex-a9-twd-timer";
diff --git a/arch/arm/mach-zynq/Makefile b/arch/arm/mach-zynq/Makefile
index 8737f434d9..d9b2b999e1 100644
--- a/arch/arm/mach-zynq/Makefile
+++ b/arch/arm/mach-zynq/Makefile
@@ -6,7 +6,6 @@
 # (C) Copyright 2008
 # Guennadi Liakhovetki, DENX Software Engineering, <lg at denx.de>
 
-obj-y	:= timer.o
 obj-y	+= cpu.o
 obj-y	+= ddrc.o
 obj-y	+= slcr.o
diff --git a/arch/arm/mach-zynq/clk.c b/arch/arm/mach-zynq/clk.c
index 27f6bf2183..1945f60e08 100644
--- a/arch/arm/mach-zynq/clk.c
+++ b/arch/arm/mach-zynq/clk.c
@@ -52,10 +52,12 @@ int set_cpu_clk_info(void)
 			return ret;
 
 		rate = clk_get_rate(&clk) / 1000000;
-		if (i)
+		if (i) {
 			gd->bd->bi_ddr_freq = rate;
-		else
+		} else {
 			gd->bd->bi_arm_freq = rate;
+			gd->cpu_clk = clk_get_rate(&clk);
+		}
 
 		clk_free(&clk);
 	}
diff --git a/arch/arm/mach-zynq/timer.c b/arch/arm/mach-zynq/timer.c
deleted file mode 100644
index a51822a530..0000000000
--- a/arch/arm/mach-zynq/timer.c
+++ /dev/null
@@ -1,113 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0+
-/*
- * Copyright (C) 2017 Weidmüller Interface GmbH & Co. KG
- * Stefan Herbrechtsmeier <stefan.herbrechtsmeier at weidmueller.com>
- *
- * Copyright (C) 2012 Michal Simek <monstr at monstr.eu>
- * Copyright (C) 2011-2017 Xilinx, Inc. All rights reserved.
- *
- * (C) Copyright 2008
- * Guennadi Liakhovetki, DENX Software Engineering, <lg at denx.de>
- *
- * (C) Copyright 2004
- * Philippe Robin, ARM Ltd. <philippe.robin at arm.com>
- *
- * (C) Copyright 2002-2004
- * Gary Jennejohn, DENX Software Engineering, <gj at denx.de>
- *
- * (C) Copyright 2003
- * Texas Instruments <www.ti.com>
- *
- * (C) Copyright 2002
- * Sysgo Real-Time Solutions, GmbH <www.elinos.com>
- * Marius Groeger <mgroeger at sysgo.de>
- *
- * (C) Copyright 2002
- * Sysgo Real-Time Solutions, GmbH <www.elinos.com>
- * Alex Zuepke <azu at sysgo.de>
- */
-
-#include <clk.h>
-#include <common.h>
-#include <div64.h>
-#include <dm.h>
-#include <init.h>
-#include <time.h>
-#include <malloc.h>
-#include <asm/global_data.h>
-#include <asm/io.h>
-#include <asm/arch/hardware.h>
-#include <asm/arch/clk.h>
-
-DECLARE_GLOBAL_DATA_PTR;
-
-struct scu_timer {
-	u32 load; /* Timer Load Register */
-	u32 counter; /* Timer Counter Register */
-	u32 control; /* Timer Control Register */
-};
-
-static struct scu_timer *timer_base =
-			      (struct scu_timer *)ZYNQ_SCUTIMER_BASEADDR;
-
-#define SCUTIMER_CONTROL_PRESCALER_MASK	0x0000FF00 /* Prescaler */
-#define SCUTIMER_CONTROL_PRESCALER_SHIFT	8
-#define SCUTIMER_CONTROL_AUTO_RELOAD_MASK	0x00000002 /* Auto-reload */
-#define SCUTIMER_CONTROL_ENABLE_MASK		0x00000001 /* Timer enable */
-
-#define TIMER_LOAD_VAL 0xFFFFFFFF
-#define TIMER_PRESCALE 255
-
-int timer_init(void)
-{
-	const u32 emask = SCUTIMER_CONTROL_AUTO_RELOAD_MASK |
-			(TIMER_PRESCALE << SCUTIMER_CONTROL_PRESCALER_SHIFT) |
-			SCUTIMER_CONTROL_ENABLE_MASK;
-
-	struct udevice *dev;
-	struct clk clk;
-	int ret;
-
-	ret = uclass_get_device_by_driver(UCLASS_CLK,
-		DM_DRIVER_GET(zynq_clk), &dev);
-	if (ret)
-		return ret;
-
-	clk.id = cpu_6or4x_clk;
-	ret = clk_request(dev, &clk);
-	if (ret < 0)
-		return ret;
-
-	gd->cpu_clk = clk_get_rate(&clk);
-
-	clk_free(&clk);
-
-	gd->arch.timer_rate_hz = (gd->cpu_clk / 2) / (TIMER_PRESCALE + 1);
-
-	/* Load the timer counter register */
-	writel(0xFFFFFFFF, &timer_base->load);
-
-	/*
-	 * Start the A9Timer device
-	 * Enable Auto reload mode, Clear prescaler control bits
-	 * Set prescaler value, Enable the decrementer
-	 */
-	clrsetbits_le32(&timer_base->control, SCUTIMER_CONTROL_PRESCALER_MASK,
-								emask);
-
-	/* Reset time */
-	gd->arch.lastinc = readl(&timer_base->counter) /
-				(gd->arch.timer_rate_hz / CONFIG_SYS_HZ);
-	gd->arch.tbl = 0;
-
-	return 0;
-}
-
-/*
- * This function is derived from PowerPC code (timebase clock frequency).
- * On ARM it returns the number of timer ticks per second.
- */
-ulong get_tbclk(void)
-{
-	return gd->arch.timer_rate_hz;
-}
diff --git a/drivers/timer/Kconfig b/drivers/timer/Kconfig
index 20b5af7e26..1e2b6566c6 100644
--- a/drivers/timer/Kconfig
+++ b/drivers/timer/Kconfig
@@ -73,6 +73,12 @@ config ARC_TIMER
 	  usually at least one of them exists. Either of them is supported
 	  in U-Boot.
 
+config ARM_TWD_TIMER
+	bool "ARM timer watchdog (TWD) timer support"
+	depends on TIMER && CLK
+	help
+	  Select this to enable support for the ARM global timer watchdog timer.
+
 config AST_TIMER
 	bool "Aspeed ast2400/ast2500 timer support"
 	depends on TIMER
diff --git a/drivers/timer/Makefile b/drivers/timer/Makefile
index d9822a5370..4db03fe09c 100644
--- a/drivers/timer/Makefile
+++ b/drivers/timer/Makefile
@@ -6,6 +6,7 @@ obj-y += timer-uclass.o
 obj-$(CONFIG_ALTERA_TIMER)	+= altera_timer.o
 obj-$(CONFIG_ANDES_PLMT_TIMER) += andes_plmt_timer.o
 obj-$(CONFIG_ARC_TIMER)	+= arc_timer.o
+obj-$(CONFIG_ARM_TWD_TIMER)	+= arm_twd_timer.o
 obj-$(CONFIG_AST_TIMER)	+= ast_timer.o
 obj-$(CONFIG_ATCPIT100_TIMER) += atcpit100_timer.o
 obj-$(CONFIG_$(SPL_)ATMEL_PIT_TIMER) += atmel_pit_timer.o
diff --git a/drivers/timer/arm_twd_timer.c b/drivers/timer/arm_twd_timer.c
new file mode 100644
index 0000000000..40ccd16587
--- /dev/null
+++ b/drivers/timer/arm_twd_timer.c
@@ -0,0 +1,108 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (C) 2017-2022 Weidmüller Interface GmbH & Co. KG
+ * Stefan Herbrechtsmeier <stefan.herbrechtsmeier at weidmueller.com>
+ *
+ * Copyright (C) 2012 Michal Simek <monstr at monstr.eu>
+ * Copyright (C) 2011-2017 Xilinx, Inc. All rights reserved.
+ *
+ * (C) Copyright 2008
+ * Guennadi Liakhovetki, DENX Software Engineering, <lg at denx.de>
+ *
+ * (C) Copyright 2004
+ * Philippe Robin, ARM Ltd. <philippe.robin at arm.com>
+ *
+ * (C) Copyright 2002-2004
+ * Gary Jennejohn, DENX Software Engineering, <gj at denx.de>
+ *
+ * (C) Copyright 2003
+ * Texas Instruments <www.ti.com>
+ *
+ * (C) Copyright 2002
+ * Sysgo Real-Time Solutions, GmbH <www.elinos.com>
+ * Marius Groeger <mgroeger at sysgo.de>
+ *
+ * (C) Copyright 2002
+ * Sysgo Real-Time Solutions, GmbH <www.elinos.com>
+ * Alex Zuepke <azu at sysgo.de>
+ */
+
+#include <common.h>
+#include <dm.h>
+#include <fdtdec.h>
+#include <timer.h>
+#include <linux/bitops.h>
+
+#include <asm/io.h>
+
+#define SCUTIMER_CONTROL_PRESCALER_MASK		0x0000FF00 /* Prescaler */
+#define SCUTIMER_CONTROL_AUTO_RELOAD_MASK	0x00000002 /* Auto-reload */
+#define SCUTIMER_CONTROL_ENABLE_MASK		0x00000001 /* Timer enable */
+
+#define TIMER_LOAD_VAL 0xFFFFFFFF
+
+struct arm_twd_timer_regs {
+	u32 load; /* Timer Load Register */
+	u32 counter; /* Timer Counter Register */
+	u32 control; /* Timer Control Register */
+};
+
+struct arm_twd_timer_priv {
+	struct arm_twd_timer_regs *base;
+};
+
+static u64 arm_twd_timer_get_count(struct udevice *dev)
+{
+	struct arm_twd_timer_priv *priv = dev_get_priv(dev);
+	struct arm_twd_timer_regs *regs = priv->base;
+	u32 count = TIMER_LOAD_VAL - readl(&regs->counter);
+
+	return timer_conv_64(count);
+}
+
+static int arm_twd_timer_probe(struct udevice *dev)
+{
+	struct arm_twd_timer_priv *priv = dev_get_priv(dev);
+	struct arm_twd_timer_regs *regs;
+	fdt_addr_t addr;
+
+	addr = dev_read_addr(dev);
+	if (addr == FDT_ADDR_T_NONE)
+		return -EINVAL;
+
+	priv->base = (struct arm_twd_timer_regs *)addr;
+
+	regs = priv->base;
+
+	/* Load the timer counter register */
+	writel(0xFFFFFFFF, &regs->load);
+
+	/*
+	 * Start the A9Timer device
+	 * Enable Auto reload mode, Clear prescaler control bits
+	 * Set prescaler value, Enable the decrementer
+	 */
+	clrsetbits_le32(&regs->control, SCUTIMER_CONTROL_PRESCALER_MASK,
+			SCUTIMER_CONTROL_AUTO_RELOAD_MASK |
+			SCUTIMER_CONTROL_ENABLE_MASK);
+
+	return 0;
+}
+
+static const struct timer_ops arm_twd_timer_ops = {
+	.get_count = arm_twd_timer_get_count,
+};
+
+static const struct udevice_id arm_twd_timer_ids[] = {
+	{ .compatible = "arm,cortex-a9-twd-timer" },
+	{}
+};
+
+U_BOOT_DRIVER(arm_twd_timer) = {
+	.name = "arm_twd_timer",
+	.id = UCLASS_TIMER,
+	.of_match = arm_twd_timer_ids,
+	.priv_auto	= sizeof(struct arm_twd_timer_priv),
+	.probe = arm_twd_timer_probe,
+	.ops = &arm_twd_timer_ops,
+};
-- 
2.30.2

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