timer: Add Cadence TTC timer counter support

This driver was tested on Xilinx ZynqMP SoC.

Signed-off-by: Michal Simek <michal.simek@xilinx.com>

MAINTAINERS

@@ -288,6 +288,7 @@ F:	drivers/net/zynq_gem.c
 F:	drivers/serial/serial_zynq.c
 F:	drivers/spi/zynq_qspi.c
 F:	drivers/spi/zynq_spi.c
+F:	drivers/timer/cadence-ttc.c
 F:	drivers/usb/host/ehci-zynq.c
 F:	drivers/watchdog/cdns_wdt.c
 F:	include/zynqmppl.h

drivers/timer/Kconfig

@@ -52,6 +52,13 @@ config ATMEL_PIT_TIMER
 	  it is designed to offer maximum accuracy and efficient management,
 	  even for systems with long response time.
 
+config CADENCE_TTC_TIMER
+	bool "Cadence TTC (Triple Timer Counter)"
+	depends on TIMER
+	help
+	  Enables support for the cadence ttc driver. This driver is present
+	  on Xilinx Zynq and ZynqMP SoCs.
+
 config SANDBOX_TIMER
 	bool "Sandbox timer support"
 	depends on SANDBOX && TIMER

drivers/timer/Makefile

@@ -4,6 +4,7 @@
 
 obj-y += timer-uclass.o
 obj-$(CONFIG_ALTERA_TIMER)	+= altera_timer.o
+obj-$(CONFIG_CADENCE_TTC_TIMER)	+= cadence-ttc.o
 obj-$(CONFIG_SANDBOX_TIMER)	+= sandbox_timer.o
 obj-$(CONFIG_X86_TSC_TIMER)	+= tsc_timer.o
 obj-$(CONFIG_OMAP_TIMER)	+= omap-timer.o

drivers/timer/cadence-ttc.c

@@ -0,0 +1,91 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2018 Xilinx, Inc. (Michal Simek)
+ */
+
+#include <common.h>
+#include <dm.h>
+#include <errno.h>
+#include <timer.h>
+#include <asm/io.h>
+
+#define CNT_CNTRL_RESET		BIT(4)
+
+struct cadence_ttc_regs {
+	u32 clk_cntrl1; /* 0x0 - Clock Control 1 */
+	u32 clk_cntrl2; /* 0x4 - Clock Control 2 */
+	u32 clk_cntrl3; /* 0x8 - Clock Control 3 */
+	u32 counter_cntrl1; /* 0xC - Counter Control 1 */
+	u32 counter_cntrl2; /* 0x10 - Counter Control 2 */
+	u32 counter_cntrl3; /* 0x14 - Counter Control 3 */
+	u32 counter_val1; /* 0x18 - Counter Control 1 */
+	u32 counter_val2; /* 0x1C - Counter Control 2 */
+	u32 counter_val3; /* 0x20 - Counter Control 3 */
+	u32 reserved[15];
+	u32 interrupt_enable1; /* 0x60 - Interrupt Enable 1 */
+	u32 interrupt_enable2; /* 0x64 - Interrupt Enable 2 */
+	u32 interrupt_enable3; /* 0x68 - Interrupt Enable 3 */
+};
+
+struct cadence_ttc_priv {
+	struct cadence_ttc_regs *regs;
+};
+
+static int cadence_ttc_get_count(struct udevice *dev, u64 *count)
+{
+	struct cadence_ttc_priv *priv = dev_get_priv(dev);
+
+	*count = readl(&priv->regs->counter_val1);
+
+	return 0;
+}
+
+static int cadence_ttc_probe(struct udevice *dev)
+{
+	struct cadence_ttc_priv *priv = dev_get_priv(dev);
+
+	/* Disable interrupts for sure */
+	writel(0, &priv->regs->interrupt_enable1);
+	writel(0, &priv->regs->interrupt_enable2);
+	writel(0, &priv->regs->interrupt_enable3);
+
+	/* Make sure that clocks are configured properly without prescaller */
+	writel(0, &priv->regs->clk_cntrl1);
+	writel(0, &priv->regs->clk_cntrl2);
+	writel(0, &priv->regs->clk_cntrl3);
+
+	/* Reset and enable this counter */
+	writel(CNT_CNTRL_RESET, &priv->regs->counter_cntrl1);
+
+	return 0;
+}
+
+static int cadence_ttc_ofdata_to_platdata(struct udevice *dev)
+{
+	struct cadence_ttc_priv *priv = dev_get_priv(dev);
+
+	priv->regs = map_physmem(devfdt_get_addr(dev),
+				 sizeof(struct cadence_ttc_regs), MAP_NOCACHE);
+
+	return 0;
+}
+
+static const struct timer_ops cadence_ttc_ops = {
+	.get_count = cadence_ttc_get_count,
+};
+
+static const struct udevice_id cadence_ttc_ids[] = {
+	{ .compatible = "cdns,ttc" },
+	{}
+};
+
+U_BOOT_DRIVER(cadence_ttc) = {
+	.name = "cadence_ttc",
+	.id = UCLASS_TIMER,
+	.of_match = cadence_ttc_ids,
+	.ofdata_to_platdata = cadence_ttc_ofdata_to_platdata,
+	.priv_auto_alloc_size = sizeof(struct cadence_ttc_priv),
+	.probe = cadence_ttc_probe,
+	.ops = &cadence_ttc_ops,
+	.flags = DM_FLAG_PRE_RELOC,
+};