realtek: Replace the RTL9300 generic timer with a CEVT timer

The RTL9300 has a broken R4K MIPS timer interrupt, however, the
R4K clocksource works. We replace the RTL9300 timer with a
Clock Event Timer (CEVT), which is VSMP aware and can be instantiated
as part of brining a VSMTP cpu up instead of the R4K CEVT source.
For this we place the RTL9300 CEVT timer in arch/mips/kernel
together with other MIPS CEVT timers, initialize the SoC IRQs
from a modified smp-mt.c and instantiate each timer as part
of the MIPS time setup in arch/mips/include/asm/time.h instead
of the R4K CEVT, similarly as is done by other MIPS CEVT timers.

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

2 files changed, 54 insertions, 28 deletions

diff --git a/target/linux/realtek/patches-5.10/302-clocksource-add-rtl9300-driver.patch b/target/linux/realtek/patches-5.10/302-clocksource-add-rtl9300-driver.patch
deleted file mode 100644
index 365a62bf30..0000000000
--- a/target/linux/realtek/patches-5.10/302-clocksource-add-rtl9300-driver.patch
+++ /dev/null
@@ -1,28 +0,0 @@
---- a/drivers/clocksource/Kconfig
-+++ b/drivers/clocksource/Kconfig
-@@ -127,6 +127,15 @@ config RDA_TIMER
- 	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
---- a/drivers/clocksource/Makefile
-+++ b/drivers/clocksource/Makefile
-@@ -63,6 +63,7 @@ obj-$(CONFIG_MILBEAUT_TIMER)	+= timer-mi
- obj-$(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-$(CONFIG_ARM_ARCH_TIMER)		+= arm_arch_timer.o
diff --git a/target/linux/realtek/patches-5.10/309-cevt-rtl9300-support.patch b/target/linux/realtek/patches-5.10/309-cevt-rtl9300-support.patch
new file mode 100644
index 0000000000..6a0038d86b
--- /dev/null
+++ b/target/linux/realtek/patches-5.10/309-cevt-rtl9300-support.patch
@@ -0,0 +1,54 @@
+--- a/arch/mips/kernel/Makefile
++++ b/arch/mips/kernel/Makefile
+@@ -27,6 +27,7 @@ obj-$(CONFIG_CEVT_BCM1480)	+= cevt-bcm14
+ obj-$(CONFIG_CEVT_R4K)		+= cevt-r4k.o
+ obj-$(CONFIG_CEVT_DS1287)	+= cevt-ds1287.o
+ obj-$(CONFIG_CEVT_GT641XX)	+= cevt-gt641xx.o
++obj-$(CONFIG_CEVT_RTL9300)	+= cevt-rtl9300.o
+ obj-$(CONFIG_CEVT_SB1250)	+= cevt-sb1250.o
+ obj-$(CONFIG_CEVT_TXX9)		+= cevt-txx9.o
+ obj-$(CONFIG_CSRC_BCM1480)	+= csrc-bcm1480.o
+--- a/arch/mips/include/asm/time.h
++++ b/arch/mips/include/asm/time.h
+@@ -15,6 +15,8 @@
+ #include <linux/clockchips.h>
+ #include <linux/clocksource.h>
+ 
++extern void rtl9300_clockevent_init(void);
++
+ extern spinlock_t rtc_lock;
+ 
+ /*
+@@ -43,6 +45,11 @@ extern int r4k_clockevent_init(void);
+ 
+ static inline int mips_clockevent_init(void)
+ {
++#ifdef CONFIG_CEVT_RTL9300
++	rtl9300_clockevent_init();
++	return 0;
++#endif
++
+ #ifdef CONFIG_CEVT_R4K
+ 	return r4k_clockevent_init();
+ #else
+--- a/arch/mips/kernel/smp-mt.c
++++ b/arch/mips/kernel/smp-mt.c
+@@ -108,12 +108,18 @@ static void __init smvp_tc_init(unsigned
+ static void vsmp_init_secondary(void)
+ {
+ 	/* This is Malta specific: IPI,performance and timer interrupts */
++
++	/* RTL9300 Clear internal timer interrupt */
++	write_c0_compare(0);
++
+ 	if (mips_gic_present())
+ 		change_c0_status(ST0_IM, STATUSF_IP2 | STATUSF_IP3 |
+ 					 STATUSF_IP4 | STATUSF_IP5 |
+ 					 STATUSF_IP6 | STATUSF_IP7);
+ 	else
+ 		change_c0_status(ST0_IM, STATUSF_IP0 | STATUSF_IP1 |
++					 STATUSF_IP2 | STATUSF_IP3 |
++					 STATUSF_IP4 | STATUSF_IP5 |
+ 					 STATUSF_IP6 | STATUSF_IP7);
+ }
+