realtek: add support for the RTL9300 timer

this adds support for the SoC timer of the RTL9300 chips, it
provides 6 independent timer/counters, of which the first one
is used as a clocksource and the second one as event timer.

Signed-off-by: Birger Koblitz <git@birger-koblitz.de>

target/linux/realtek/config-5.4

@@ -2,7 +2,6 @@ CONFIG_ARCH_32BIT_OFF_T=y
 CONFIG_ARCH_CLOCKSOURCE_DATA=y
 CONFIG_ARCH_HIBERNATION_POSSIBLE=y
 CONFIG_ARCH_MMAP_RND_BITS_MAX=15
-CONFIG_ARCH_MMAP_RND_COMPAT_BITS_MAX=15
 CONFIG_ARCH_SUSPEND_POSSIBLE=y
 CONFIG_BLK_DEV_RAM=y
 CONFIG_BLK_DEV_RAM_COUNT=16
@@ -10,6 +9,10 @@ CONFIG_BLK_DEV_RAM_SIZE=4096
 CONFIG_CEVT_R4K=y
 CONFIG_CLONE_BACKWARDS=y
 CONFIG_COMPAT_32BIT_TIME=y
+CONFIG_HAVE_CLK=y
+CONFIG_CLKDEV_LOOKUP=y
+CONFIG_COMMON_CLK=y
+CONFIG_COMMON_CLK_BOSTON=y
 CONFIG_CONSOLE_LOGLEVEL_DEFAULT=15
 CONFIG_CPU_BIG_ENDIAN=y
 CONFIG_CPU_GENERIC_DUMP_TLB=y
@@ -160,6 +163,7 @@ CONFIG_REGMAP=y
 CONFIG_REGMAP_MMIO=y
 CONFIG_RESET_CONTROLLER=y
 CONFIG_RTL838X=y
+CONFIG_RTL9300_TIMER=y
 CONFIG_SERIAL_MCTRL_GPIO=y
 CONFIG_SERIAL_OF_PLATFORM=y
 CONFIG_SFP=y
@@ -168,7 +172,7 @@ CONFIG_SPI_MASTER=y
 CONFIG_SPI_MEM=y
 CONFIG_SPI_RTL838X=y
 CONFIG_SRCU=y
-CONFIG_SWCONFIG=y
+CONFIG_SWAP_IO_SPACE=y
 CONFIG_SWPHY=y
 CONFIG_SYSCTL_EXCEPTION_TRACE=y
 CONFIG_SYS_HAS_CPU_MIPS32_R1=y

target/linux/realtek/files-5.4/arch/mips/rtl838x/setup.c

@@ -11,23 +11,21 @@
 
 #include <linux/console.h>
 #include <linux/init.h>
-#include <linux/clk.h>
 #include <linux/clkdev.h>
 #include <linux/clk-provider.h>
+#include <linux/delay.h>
+#include <linux/of_fdt.h>
 
 #include <asm/addrspace.h>
 #include <asm/io.h>
-
 #include <asm/bootinfo.h>
-#include <linux/of_fdt.h>
 #include <asm/reboot.h>
-#include <asm/time.h>		/* for mips_hpt_frequency */
+#include <asm/time.h>
 #include <asm/prom.h>
 #include <asm/smp-ops.h>
 
 #include "mach-rtl83xx.h"
 
-extern int rtl838x_serial_init(void);
 extern struct rtl83xx_soc_info soc_info;
 
 u32 pll_reset_value;
@@ -35,30 +33,109 @@ u32 pll_reset_value;
 static void rtl838x_restart(char *command)
 {
 	u32 pll = sw_r32(RTL838X_PLL_CML_CTRL);
-	 /* SoC reset vector (in flash memory): on RTL839x platform preferred way to reset */
-	void (*f)(void) = (void *) 0xbfc00000;
 
 	pr_info("System restart.\n");
-	if (soc_info.family == RTL8390_FAMILY_ID) {
-		f();
-		/* If calling reset vector fails, reset entire chip */
-		sw_w32(0xFFFFFFFF, RTL839X_RST_GLB_CTRL);
-		/* If this fails, halt the CPU */
-		while
-			(1);
-	}
-
 	pr_info("PLL control register: %x, applying reset value %x\n",
 		pll, pll_reset_value);
+
 	sw_w32(3, RTL838X_INT_RW_CTRL);
 	sw_w32(pll_reset_value, RTL838X_PLL_CML_CTRL);
 	sw_w32(0, RTL838X_INT_RW_CTRL);
 
-	pr_info("Resetting RTL838X SoC\n");
 	/* Reset Global Control1 Register */
 	sw_w32(1, RTL838X_RST_GLB_CTRL_1);
 }
 
+static void rtl839x_restart(char *command)
+{
+	/* SoC reset vector (in flash memory): on RTL839x platform preferred way to reset */
+	void (*f)(void) = (void *) 0xbfc00000;
+
+	pr_info("System restart.\n");
+	/* Reset SoC */
+	sw_w32(0xFFFFFFFF, RTL839X_RST_GLB_CTRL);
+	/* and call reset vector */
+	f();
+	/* If this fails, halt the CPU */
+	while
+		(1);
+}
+
+static void rtl930x_restart(char *command)
+{
+	pr_info("System restart.\n");
+	sw_w32(0x1, RTL930X_RST_GLB_CTRL_0);
+	while
+		(1);
+}
+
+static void rtl931x_restart(char *command)
+{
+	u32 v;
+
+	pr_info("System restart.\n");
+	sw_w32(1, RTL931X_RST_GLB_CTRL);
+	v = sw_r32(RTL931X_RST_GLB_CTRL);
+	sw_w32(0x101, RTL931X_RST_GLB_CTRL);
+	msleep(15);
+	sw_w32(v, RTL931X_RST_GLB_CTRL);
+	msleep(15);
+	sw_w32(0x101, RTL931X_RST_GLB_CTRL);
+}
+
+static void rtl838x_halt(void)
+{
+	pr_info("System halted.\n");
+	while
+		(1);
+}
+
+static void __init rtl838x_setup(void)
+{
+	pr_info("Registering _machine_restart\n");
+	_machine_restart = rtl838x_restart;
+	_machine_halt = rtl838x_halt;
+
+	/* This PLL value needs to be restored before a reset and will then be
+	 * preserved over a SoC reset. A wrong value prevents the SoC from
+	 * connecting to the SPI flash controller at boot and reading the
+	 * reset routine */
+	pll_reset_value = sw_r32(RTL838X_PLL_CML_CTRL);
+
+	/* Setup System LED. Bit 15 then allows to toggle it */
+	sw_w32_mask(0, 3 << 16, RTL838X_LED_GLB_CTRL);
+}
+
+static void __init rtl839x_setup(void)
+{
+	pr_info("Registering _machine_restart\n");
+	_machine_restart = rtl839x_restart;
+	_machine_halt = rtl838x_halt;
+
+	/* Setup System LED. Bit 14 of RTL839X_LED_GLB_CTRL then allows to toggle it */
+	sw_w32_mask(0, 3 << 15, RTL839X_LED_GLB_CTRL);
+}
+
+static void __init rtl930x_setup(void)
+{
+	pr_info("Registering _machine_restart\n");
+	_machine_restart = rtl930x_restart;
+	_machine_halt = rtl838x_halt;
+
+	if (soc_info.id == 0x9302)
+		sw_w32_mask(0, 3 << 13, RTL9302_LED_GLB_CTRL);
+	else
+		sw_w32_mask(0, 3 << 13, RTL930X_LED_GLB_CTRL);
+}
+
+static void __init rtl931x_setup(void)
+{
+	pr_info("Registering _machine_restart\n");
+	_machine_restart = rtl931x_restart;
+	_machine_halt = rtl838x_halt;
+	sw_w32_mask(0, 3 << 12, RTL931X_LED_GLB_CTRL);
+}
+
 void __init plat_mem_setup(void)
 {
 	void *dtb;
@@ -78,6 +155,21 @@ void __init plat_mem_setup(void)
 	 * parsed resulting in our memory appearing
 	 */
 	__dt_setup_arch(dtb);
+
+	switch (soc_info.family) {
+	case RTL8380_FAMILY_ID:
+		rtl838x_setup();
+		break;
+	case RTL8390_FAMILY_ID:
+		rtl839x_setup();
+		break;
+	case RTL9300_FAMILY_ID:
+		rtl930x_setup();
+		break;
+	case RTL9310_FAMILY_ID:
+		rtl931x_setup();
+		break;
+	}
 }
 
 void __init plat_time_init(void)
@@ -85,6 +177,9 @@ void __init plat_time_init(void)
 	struct device_node *np;
 	u32 freq = 500000000;
 
+	of_clk_init(NULL);
+	timer_probe();
+
 	np = of_find_node_by_name(NULL, "cpus");
 	if (!np) {
 		pr_err("Missing 'cpus' DT node, using default frequency.");
@@ -92,11 +187,9 @@ void __init plat_time_init(void)
 		if (of_property_read_u32(np, "frequency", &freq) < 0)
 			pr_err("No 'frequency' property in DT, using default.");
 		else
-			pr_info("CPU frequency from device tree: %d", freq);
+			pr_info("CPU frequency from device tree: %dMHz", freq / 1000000);
 		of_node_put(np);
 	}
 
 	mips_hpt_frequency = freq / 2;
-
-	pll_reset_value = sw_r32(RTL838X_PLL_CML_CTRL);
 }

target/linux/realtek/files-5.4/drivers/clocksource/timer-rtl9300.c

+// SPDX-License-Identifier: GPL-2.0-only
+
+#include <linux/clockchips.h>
+#include <linux/init.h>
+#include <asm/time.h>
+#include <linux/interrupt.h>
+#include <linux/of_address.h>
+#include <linux/of_irq.h>
+#include <linux/sched_clock.h>
+#include "timer-of.h"
+
+#include <mach-rtl83xx.h>
+
+/* 
+ * Timer registers
+ * the RTL9300/9310 SoCs have 6 timers, each register block 0x10 apart
+ */
+#define RTL9300_TC_DATA		0x0
+#define RTL9300_TC_CNT		0x4
+#define RTL9300_TC_CTRL		0x8
+#define RTL9300_TC_CTRL_MODE	BIT(24)
+#define RTL9300_TC_CTRL_EN	BIT(28)
+#define RTL9300_TC_INT		0xc
+#define RTL9300_TC_INT_IP	BIT(16)
+#define RTL9300_TC_INT_IE	BIT(20)
+
+// Clocksource is using timer 0, clock event uses timer 1
+#define TIMER_CLK_SRC		0
+#define TIMER_CLK_EVT		1
+#define TIMER_BLK_EVT		(TIMER_CLK_EVT << 4)
+
+// Timer modes
+#define TIMER_MODE_REPEAT	1
+#define TIMER_MODE_ONCE		0
+
+// Minimum divider is 2
+#define DIVISOR_RTL9300		2
+
+#define N_BITS			28
+
+static void __iomem *rtl9300_sched_reg __read_mostly;
+
+static u64 notrace rtl9300_sched_clock_read(void)
+{
+/*	pr_info("In %s: %x\n", __func__, readl_relaxed(rtl9300_sched_reg));
+	dump_stack();*/
+	return readl_relaxed(rtl9300_sched_reg);
+}
+
+static irqreturn_t rtl9300_timer_interrupt(int irq, void *dev_id)
+{
+	struct clock_event_device *clk = dev_id;
+	struct timer_of *to = to_timer_of(clk);
+	u32 v = readl(timer_of_base(to) + TIMER_BLK_EVT + RTL9300_TC_INT);
+
+	// Acknowledge the IRQ
+	v |= RTL9300_TC_INT_IP;
+	writel(v, timer_of_base(to) + TIMER_BLK_EVT + RTL9300_TC_INT);
+
+	clk->event_handler(clk);
+	return IRQ_HANDLED;
+}
+
+static void rtl9300_timer_stop(struct timer_of *to)
+{
+	u32 v;
+
+	writel(0, timer_of_base(to) + TIMER_BLK_EVT + RTL9300_TC_CTRL);
+
+	// Acknowledge possibly pending IRQ
+	v = readl(timer_of_base(to) + TIMER_BLK_EVT + RTL9300_TC_INT);
+	if (v & RTL9300_TC_INT_IP)
+		writel(v, timer_of_base(to) + TIMER_BLK_EVT + RTL9300_TC_INT);
+}
+
+static void rtl9300_timer_start(struct timer_of *to, int timer, bool periodic)
+{
+	u32 v = (periodic ? RTL9300_TC_CTRL_MODE : 0) | RTL9300_TC_CTRL_EN | DIVISOR_RTL9300;
+	writel(v, timer_of_base(to) + timer * 0x10 + RTL9300_TC_CTRL);
+}
+
+static int rtl9300_set_next_event(unsigned long delta, struct clock_event_device *clk)
+{
+	struct timer_of *to = to_timer_of(clk);
+
+	rtl9300_timer_stop(to);
+	writel(delta, timer_of_base(to) + TIMER_BLK_EVT + RTL9300_TC_DATA);
+	rtl9300_timer_start(to, TIMER_CLK_EVT, TIMER_MODE_ONCE);
+	return 0;
+}
+
+static int rtl9300_set_state_periodic(struct clock_event_device *clk)
+{
+	struct timer_of *to = to_timer_of(clk);
+
+	rtl9300_timer_stop(to);
+	writel(to->of_clk.period, timer_of_base(to) + TIMER_BLK_EVT + RTL9300_TC_DATA);
+	rtl9300_timer_start(to, TIMER_CLK_EVT, TIMER_MODE_REPEAT);
+	return 0;
+}
+
+static int rtl9300_set_state_oneshot(struct clock_event_device *clk)
+{
+	struct timer_of *to = to_timer_of(clk);
+
+	rtl9300_timer_stop(to);
+	writel(to->of_clk.period, timer_of_base(to) + TIMER_BLK_EVT + RTL9300_TC_DATA);
+	rtl9300_timer_start(to, TIMER_CLK_EVT, TIMER_MODE_ONCE);
+	return 0;
+}
+
+static int rtl9300_set_state_shutdown(struct clock_event_device *clk)
+{
+	struct timer_of *to = to_timer_of(clk);
+
+	rtl9300_timer_stop(to);
+	return 0;
+}
+
+static struct timer_of t_of = {
+	.flags = TIMER_OF_BASE | TIMER_OF_IRQ | TIMER_OF_CLOCK,
+
+	.clkevt = {
+		.name = "rtl9300_timer",
+		.rating = 350,
+		.features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT,
+		.set_next_event	= rtl9300_set_next_event,
+		.set_state_oneshot = rtl9300_set_state_oneshot,
+		.set_state_periodic = rtl9300_set_state_periodic,
+		.set_state_shutdown = rtl9300_set_state_shutdown,
+	},
+
+	.of_irq = {
+		.name = "ostimer",
+		.handler = rtl9300_timer_interrupt,
+		.flags = IRQF_TIMER,
+	},
+};
+
+static void __init rtl9300_timer_setup(u8 timer)
+{
+	u32 v;
+
+	// Disable timer
+	writel(0, timer_of_base(&t_of) + 0x10 * timer + RTL9300_TC_CTRL);
+
+	// Acknowledge possibly pending IRQ
+	v = readl(timer_of_base(&t_of) + 0x10 * timer + RTL9300_TC_INT);
+	if (v & RTL9300_TC_INT_IP)
+		writel(v, timer_of_base(&t_of) + 0x10 * timer + RTL9300_TC_INT);
+
+	// Setup maximum period (for use as clock-source)
+	writel(0x0fffffff, timer_of_base(&t_of) + 0x10 * timer + RTL9300_TC_DATA);
+}
+
+
+static int __init rtl9300_timer_init(struct device_node *node)
+{
+	int err = 0;
+	unsigned long rate;
+
+	pr_info("%s: setting up timer\n", __func__);
+
+	err = timer_of_init(node, &t_of);
+	if (err)
+		return err;
+
+	rate = timer_of_rate(&t_of) / DIVISOR_RTL9300;
+	pr_info("Frequency in dts: %ld, my rate is %ld, period %ld\n",
+		timer_of_rate(&t_of), rate, timer_of_period(&t_of));
+	pr_info("With base %08x IRQ: %d\n", (u32)timer_of_base(&t_of), timer_of_irq(&t_of));
+
+	// Configure clock source and register it for scheduling
+	rtl9300_timer_setup(TIMER_CLK_SRC);
+	rtl9300_timer_start(&t_of, TIMER_CLK_SRC, TIMER_MODE_REPEAT);
+
+	rtl9300_sched_reg = timer_of_base(&t_of) + TIMER_CLK_SRC * 0x10 + RTL9300_TC_CNT;
+
+	err = clocksource_mmio_init(rtl9300_sched_reg, node->name, rate , 100, N_BITS,
+				    clocksource_mmio_readl_up);
+	if (err)
+		return err;
+
+	sched_clock_register(rtl9300_sched_clock_read, N_BITS, rate);
+
+	// Configure clock event source
+	rtl9300_timer_setup(TIMER_CLK_EVT);
+	clockevents_config_and_register(&t_of.clkevt, rate, 100, 0x0fffffff);
+
+	// Enable interrupt
+	writel(RTL9300_TC_INT_IE, timer_of_base(&t_of) + TIMER_BLK_EVT + RTL9300_TC_INT);
+
+	return err;
+}
+
+TIMER_OF_DECLARE(rtl9300_timer, "realtek,rtl9300-timer", rtl9300_timer_init);

target/linux/realtek/patches-5.4/302-clocksource-add-rtl9300-driver.patch

+--- a/drivers/clocksource/Kconfig
++++ b/drivers/clocksource/Kconfig
+@@ -126,6 +126,15 @@
+ 	help
+ 	  Enables the support for the RDA Micro timer driver.
+ 
++config RTL9300_TIMER
++	bool "Clocksource/timer for the Realtek RTL9300 family of SoCs"
++	depends on MIPS
++	select COMMON_CLK
++	select TIMER_OF
++	select CLKSRC_MMIO
++	help
++	  Enables support for the Realtek RTL9300 timer driver.
++
+ config SUN4I_TIMER
+ 	bool "Sun4i timer driver" if COMPILE_TEST
+ 	depends on HAS_IOMEM
+@@ -695,5 +704,4 @@
+ 	select IRQ_DOMAIN
+ 	help
+ 	  Support for the timer/counter unit of the Ingenic JZ SoCs.
+-
+ endmenu
+--- a/drivers/clocksource/Makefile
++++ b/drivers/clocksource/Makefile
+@@ -61,6 +61,7 @@
+ obj-$(CONFIG_SPRD_TIMER)	+= timer-sprd.o
+ obj-$(CONFIG_NPCM7XX_TIMER)	+= timer-npcm7xx.o
+ obj-$(CONFIG_RDA_TIMER)		+= timer-rda.o
++obj-$(CONFIG_RTL9300_TIMER)	+= timer-rtl9300.o
+ 
+ obj-$(CONFIG_ARC_TIMERS)		+= arc_timer.o
+ obj-$(CONFIG_ARM_ARCH_TIMER)		+= arm_arch_timer.o