Add CPUFreq support for loongson2f

This patchset adds CPUFreq support for loongson2f, 'Cause loongson2f doesn't have a fixed MIPS Timer(relative to cpu frequency), If we enable CPUFreq, the system time will be broken. So, an external Timer is needed, Herein, In Lemote loongson2f family machine, there is a CS5536 MFGPT Timer, in Dexxon Gdium, it use i8253.

This v1 revision have incorporated with the feedbacks from "Dominik Brodowski" and Ralf. And this Thread have replied more feedbacks from Ralf:

http://www.linux-mips.org/archives/linux-mips/2009-11/msg00292.html

Best Regards,
Wu Zhangjin

Wu Zhangjin (3):
[loongson] lemote-2f: add cs5536 MFGPT timer support
MIPS: add basic options for CPUFreq support [loongson] 2f: add CPUFreq support

 arch/mips/Kconfig                                  |    3 +
 arch/mips/include/asm/clock.h                      |   64 ++++++
 .../asm/mach-loongson/cs5536/cs5536_mfgpt.h        |   35 +++
 arch/mips/include/asm/mach-loongson/loongson.h     |    6 +-
 arch/mips/kernel/Makefile                          |    2 +
 arch/mips/kernel/cpu-probe.c                       |    2 +
 arch/mips/kernel/cpufreq/Kconfig                   |   41 ++++
 arch/mips/kernel/cpufreq/Makefile                  |    5 +
 arch/mips/kernel/cpufreq/loongson2_clock.c         |  166 +++++++++++++++
 arch/mips/kernel/cpufreq/loongson2_cpufreq.c       |  202 ++++++++++++++++++
 arch/mips/loongson/Kconfig                         |   16 ++-
 arch/mips/loongson/common/cs5536/Makefile          |    5 +
 arch/mips/loongson/common/cs5536/cs5536_mfgpt.c    |  217 ++++++++++++++++++++
 arch/mips/loongson/common/env.c                    |    3 +
 arch/mips/loongson/common/time.c                   |    3 +
 15 files changed, 767 insertions(+), 3 deletions(-)
 create mode 100644 arch/mips/include/asm/clock.h
 create mode 100644 arch/mips/include/asm/mach-loongson/cs5536/cs5536_mfgpt.h
 create mode 100644 arch/mips/kernel/cpufreq/Kconfig
 create mode 100644 arch/mips/kernel/cpufreq/Makefile
 create mode 100644 arch/mips/kernel/cpufreq/loongson2_clock.c
 create mode 100644 arch/mips/kernel/cpufreq/loongson2_cpufreq.c
 create mode 100644 arch/mips/loongson/common/cs5536/cs5536_mfgpt.c

When we want to enable CPUFreq support for loongson2f, it need an external timer, this patch add it.

'Cause the frequency of the MIPS Timer is half of the cpu frequency, if we use it with Cpufreq support, the sytem time will become not accuracy.

And we export the mfgpt0 counter disable/enable operations for the coming suspend support to suspend/resume the timer.

---
 .../asm/mach-loongson/cs5536/cs5536_mfgpt.h        |   35 +++
 arch/mips/loongson/Kconfig                         |   11 +
 arch/mips/loongson/common/cs5536/Makefile          |    5 +
 arch/mips/loongson/common/cs5536/cs5536_mfgpt.c    |  217 ++++++++++++++++++++
 arch/mips/loongson/common/time.c                   |    3 +
 5 files changed, 271 insertions(+), 0 deletions(-)
 create mode 100644 arch/mips/include/asm/mach-loongson/cs5536/cs5536_mfgpt.h
 create mode 100644 arch/mips/loongson/common/cs5536/cs5536_mfgpt.c

new file mode 100644
index 0000000..4b493d6
@@ -0,0 +1,35 @@
+/*
+ * cs5536 mfgpt header file
+ */
+
+#ifndef _CS5536_MFGPT_H
+#define _CS5536_MFGPT_H
+
+#include <cs5536/cs5536.h>
+#include <cs5536/cs5536_pci.h>
+
+#ifdef CONFIG_CS5536_MFGPT
+extern void setup_mfgpt0_timer(void);
+extern void disable_mfgpt0_counter(void);
+extern void enable_mfgpt0_counter(void);
+#else
+static inline void __maybe_unused setup_mfgpt0_timer(void)
+{
+}
+static inline void __maybe_unused disable_mfgpt0_counter(void)
+{
+}
+static inline void __maybe_unused enable_mfgpt0_counter(void)
+{
+}
+#endif
+
+#define MFGPT_TICK_RATE 14318000
+#define COMPARE  ((MFGPT_TICK_RATE + HZ/2) / HZ)
+
+#define MFGPT_BASE	mfgpt_base
+#define MFGPT0_CMP2	(MFGPT_BASE + 2)
+#define MFGPT0_CNT	(MFGPT_BASE + 4)
+#define MFGPT0_SETUP	(MFGPT_BASE + 6)
+
+#endif /*!_CS5536_MFGPT_H */

index 17e72fd..8b5cc13 100644
@@ -62,6 +62,17 @@ endchoice
 config CS5536
 	bool
 
+config CS5536_MFGPT
+	bool "CS5536 MFGPT Timer"
+	depends on CS5536
+	help
+	  This option enables the mfgpt0 timer of AMD CS5536.
+
+	  If you want to enable the Loongson2 CPUFreq Driver, Please enable
+	  this option at first, otherwise, You will get wrong system time.
+
+	  If unsure, say Yes.
+
 config LOONGSON_SUSPEND
 	bool
 	default y

index 31657ee..510d4cd 100644
@@ -5,4 +5,9 @@
 obj-$(CONFIG_CS5536) += cs5536_pci.o cs5536_ide.o cs5536_acc.o cs5536_ohci.o \
 			cs5536_isa.o cs5536_ehci.o
 
+#
+# Enable cs5536 mfgpt Timer
+#
+obj-$(CONFIG_CS5536_MFGPT) += cs5536_mfgpt.o
+
 EXTRA_CFLAGS += -Werror

index 6e08c82..35f0b66 100644
@@ -14,11 +14,14 @@
 #include <asm/time.h>
 
 #include <loongson.h>
+#include <cs5536/cs5536_mfgpt.h>
 
 void __init plat_time_init(void)
 {
 	/* setup mips r4k timer */
 	mips_hpt_frequency = cpu_clock_freq / 2;
+
+	setup_mfgpt0_timer();
 }
 
 void read_persistent_clock(struct timespec *ts)

1.6.2.1

This patch adds basic options for MIPS CPUFreq support.

Since MIPS Timer's frequency is relative to the processor's frequency, So, MIPS CPUFreq support not only need the processor's CPUFreq support but also need an external timer. otherwise, we will make the system time "mussy".

---
 arch/mips/Kconfig                |    3 +++
 arch/mips/kernel/cpufreq/Kconfig |   27 +++++++++++++++++++++++++++
 2 files changed, 30 insertions(+), 0 deletions(-)
 create mode 100644 arch/mips/kernel/cpufreq/Kconfig

index 0e4b510..bfe8c39 100644
@@ -2146,6 +2146,7 @@ config MMU
 
 config I8253
 	bool
+	select MIPS_EXTERNAL_TIMER
 
 config ZONE_DMA32
 	bool

@@ -2222,6 +2223,8 @@ source "kernel/power/Kconfig"
 
 endmenu
 
+source "arch/mips/kernel/cpufreq/Kconfig"
+
 source "net/Kconfig"
 
 source "drivers/Kconfig"

new file mode 100644
index 0000000..37983a1
@@ -0,0 +1,27 @@
+#
+# CPU Frequency scaling
+#
+
+config MIPS_EXTERNAL_TIMER
+	bool
+
+config MIPS_CPUFREQ
+	bool
+	default y
+	depends on CPU_SUPPORTS_CPUFREQ && MIPS_EXTERNAL_TIMER
+
+if MIPS_CPUFREQ
+
+menu "CPU Frequency scaling"
+
+source "drivers/cpufreq/Kconfig"
+
+if CPU_FREQ
+
+comment "CPUFreq processor drivers"
+
+endif	# CPU_FREQ
+
+endmenu
+
+endif	# MIPS_CPUFREQ

1.6.2.1

Loongson2f add a new capability to dynamicly scale cpu frequency. And when we put it into wait mode via setting the frequency as ZERO, it will wait there until an external interrupt take place, which will help saving power for us.

And as the last patch described, to enable this support, an external timer is needed to avoid getting wrong system time when using the MIPS Timer, 'Cause the MIPS Timer's frequency is half of the cpu frequency, when the cpu frequency is changed, the MIPS Timer will be not accuracy.

This version incorporates the feedback from "Dominik Brodowski <[email protected]>" to register transition notifier before register_driver().

---
 arch/mips/include/asm/clock.h                  |   64 ++++++++
 arch/mips/include/asm/mach-loongson/loongson.h |    6 +-
 arch/mips/kernel/Makefile                      |    2 +
 arch/mips/kernel/cpu-probe.c                   |    2 +
 arch/mips/kernel/cpufreq/Kconfig               |   14 ++
 arch/mips/kernel/cpufreq/Makefile              |    5 +
 arch/mips/kernel/cpufreq/loongson2_clock.c     |  166 +++++++++++++++++++
 arch/mips/kernel/cpufreq/loongson2_cpufreq.c   |  202 ++++++++++++++++++++++++
 arch/mips/loongson/Kconfig                     |    5 +-
 arch/mips/loongson/common/env.c                |    3 +
 10 files changed, 466 insertions(+), 3 deletions(-)
 create mode 100644 arch/mips/include/asm/clock.h
 create mode 100644 arch/mips/kernel/cpufreq/Makefile
 create mode 100644 arch/mips/kernel/cpufreq/loongson2_clock.c
 create mode 100644 arch/mips/kernel/cpufreq/loongson2_cpufreq.c

new file mode 100644
index 0000000..83894aa
@@ -0,0 +1,64 @@
+#ifndef __ASM_MIPS_CLOCK_H
+#define __ASM_MIPS_CLOCK_H
+
+#include <linux/kref.h>
+#include <linux/list.h>
+#include <linux/seq_file.h>
+#include <linux/clk.h>
+
+extern void (*cpu_wait) (void);
+
+struct clk;
+
+struct clk_ops {
+	void (*init) (struct clk *clk);
+	void (*enable) (struct clk *clk);
+	void (*disable) (struct clk *clk);
+	void (*recalc) (struct clk *clk);
+	int (*set_rate) (struct clk *clk, unsigned long rate, int algo_id);
+	long (*round_rate) (struct clk *clk, unsigned long rate);
+};
+
+struct clk {
+	struct list_head node;
+	const char *name;
+	int id;
+	struct module *owner;
+
+	struct clk *parent;
+	struct clk_ops *ops;
+
+	struct kref kref;
+
+	unsigned long rate;
+	unsigned long flags;
+};
+
+#define CLK_ALWAYS_ENABLED	(1 << 0)
+#define CLK_RATE_PROPAGATES	(1 << 1)
+
+/* Should be defined by processor-specific code */
+void arch_init_clk_ops(struct clk_ops **, int type);
+
+int clk_init(void);
+
+int __clk_enable(struct clk *);
+void __clk_disable(struct clk *);
+
+void clk_recalc_rate(struct clk *);
+
+int clk_register(struct clk *);
+void clk_unregister(struct clk *);
+
+/* the exported API, in addition to clk_set_rate */
+/**
+ * clk_set_rate_ex - set the clock rate for a clock source, with additional parameter
+ * @clk: clock source
+ * @rate: desired clock rate in Hz
+ * @algo_id: algorithm id to be passed down to ops->set_rate
+ *
+ * Returns success (0) or negative errno.
+ */
+int clk_set_rate_ex(struct clk *clk, unsigned long rate, int algo_id);
+
+#endif				/* __ASM_MIPS_CLOCK_H */

index 9ee40df..daf7041 100644
@@ -226,8 +226,12 @@ extern void mach_irq_dispatch(unsigned int pending);
 #define LOONGSON_PCIMAP_WIN(WIN, ADDR)	\
 	((((ADDR)>>26) & LOONGSON_PCIMAP_PCIMAP_LO0) << ((WIN)*6))
 
-/* Chip Config */
 #ifdef CONFIG_CPU_SUPPORTS_CPUFREQ
+#include <linux/cpufreq.h>
+extern void loongson2_cpu_wait(void);
+extern struct cpufreq_frequency_table loongson2_clockmod_table[];
+
+/* Chip Config */
 #define LOONGSON_CHIPCFG0		LOONGSON_REG(LOONGSON_REGBASE + 0x80)
 #endif
 

index e953c6d..6a9adff 100644
@@ -91,6 +91,8 @@ CFLAGS_cpu-bugs64.o	= $(shell if $(CC) $(KBUILD_CFLAGS) -Wa,-mdaddi -c -o /dev/n
 
 obj-$(CONFIG_HAVE_STD_PC_SERIAL_PORT)	+= 8250-platform.o
 
+obj-$(CONFIG_MIPS_CPUFREQ)	+= cpufreq/
+
 EXTRA_CFLAGS += -Werror
 
 CPPFLAGS_vmlinux.lds		:= $(KBUILD_CFLAGS)

index 7a51866..80e202e 100644
@@ -16,6 +16,7 @@
 #include <linux/ptrace.h>
 #include <linux/smp.h>
 #include <linux/stddef.h>
+#include <linux/module.h>
 
 #include <asm/bugs.h>
 #include <asm/cpu.h>

@@ -32,6 +33,7 @@
  * the CPU very much.
  */
 void (*cpu_wait)(void);
+EXPORT_SYMBOL(cpu_wait);
 
 static void r3081_wait(void)
 {

index 37983a1..58c601e 100644
@@ -20,6 +20,20 @@ if CPU_FREQ
 
 comment "CPUFreq processor drivers"
 
+config LOONGSON2_CPUFREQ
+	tristate "Loongson2 CPUFreq Driver"
+	select CPU_FREQ_TABLE
+	depends on MIPS_CPUFREQ
+	help
+	  This option adds a CPUFreq driver for loongson processors which
+	  support software configurable cpu frequency.
+
+	  Loongson2F and it's successors support this feature.
+
+	  For details, take a look at <file:Documentation/cpu-freq/>.
+
+	  If in doubt, say N.
+
 endif	# CPU_FREQ
 
 endmenu

new file mode 100644
index 0000000..c3479a4
@@ -0,0 +1,5 @@
+#
+# Makefile for the Linux/MIPS cpufreq.
+#
+
+obj-$(CONFIG_LOONGSON2_CPUFREQ) += loongson2_cpufreq.o loongson2_clock.o

index 8b5cc13..7a86987 100644
@@ -34,10 +34,10 @@ config LEMOTE_MACH2F
 	select ARCH_SPARSEMEM_ENABLE
 	select BOARD_SCACHE
 	select BOOT_ELF32
-	select CEVT_R4K
+	select CEVT_R4K if ! MIPS_EXTERNAL_TIMER
 	select CPU_HAS_WB
 	select CS5536
-	select CSRC_R4K
+	select CSRC_R4K if ! MIPS_EXTERNAL_TIMER
 	select DMA_NONCOHERENT
 	select GENERIC_HARDIRQS_NO__DO_IRQ
 	select GENERIC_ISA_DMA_SUPPORT_BROKEN

@@ -65,6 +65,7 @@ config CS5536
 config CS5536_MFGPT
 	bool "CS5536 MFGPT Timer"
 	depends on CS5536
+	select MIPS_EXTERNAL_TIMER
 	help
 	  This option enables the mfgpt0 timer of AMD CS5536.
 

index b9ef503..196d947 100644
@@ -17,11 +17,14 @@
  * Free Software Foundation;  either version 2 of the  License, or (at your
  * option) any later version.
  */
+#include <linux/module.h>
+
 #include <asm/bootinfo.h>
 
 #include <loongson.h>
 
 unsigned long bus_clock, cpu_clock_freq;
+EXPORT_SYMBOL(cpu_clock_freq);
 unsigned long memsize, highmemsize;
 
 /* pmon passes arguments in 32bit pointers */

1.6.2.1

Thanks, queue for 2.6.33.

Ralf

Thanks, queue for 2.6.33.

Ralf

Thanks, queue for 2.6.33.

Ralf