[PATCH] cpufreq support for 7447A on 2004 iBooks

[PATCH] cpufreq support for 7447A on 2004 iBooks

[John Steele Scott]

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Okay, thanks to some tips from Benjamin Herrenschmidt, I now have a patch 
against 2.6.6 which lets you control dynamic frequency scaling on the latest 
model iBook G4. I imagine that this same method would apply to the new 
PowerBooks as well.

cheers,

John

diff -upr -X dontdiff linux/arch/ppc/kernel/misc.S 
linux-2.6.6-dfs/arch/ppc/kernel/misc.S
- --- linux/arch/ppc/kernel/misc.S	2004-06-05 18:02:48.000000000 +0930
+++ linux-2.6.6-dfs/arch/ppc/kernel/misc.S	2004-05-28 12:47:22.000000000 +0930
@@ -253,6 +253,24 @@ _GLOBAL(low_choose_750fx_pll)
 	mtmsr	r7
 	blr
 
+_GLOBAL(choose_7447a_dfs)
+	/* Clear MSR:EE */
+	mfmsr	r7
+	rlwinm	r0,r7,0,17,15
+	mtmsr	r0
+	
+	/* Calc new HID1 value */
+	mfspr	r4,SPRN_HID1
+	insrwi	r4,r3,1,9	/* insert parameter into bit 9 */
+	sync
+	mtspr	SPRN_HID1,r4
+	sync
+	isync
+
+	/* Return */
+	mtmsr	r7
+	blr
+
 #endif /* CONFIG_CPU_FREQ_PMAC && CONFIG_6xx */
 
 /* void local_save_flags_ptr(unsigned long *flags) */
diff -upr -X dontdiff linux/arch/ppc/platforms/pmac_cpufreq.c 
linux-2.6.6-dfs/arch/ppc/platforms/pmac_cpufreq.c
- --- linux/arch/ppc/platforms/pmac_cpufreq.c	2004-06-05 18:02:48.000000000 
+0930
+++ linux-2.6.6-dfs/arch/ppc/platforms/pmac_cpufreq.c	2004-06-05 
18:08:06.000000000 +0930
@@ -47,6 +47,7 @@
 #warning "WARNING, CPUFREQ not recommended on SMP kernels"
 #endif
 
+extern void choose_7447a_dfs(int dfs);
 extern void low_choose_750fx_pll(int pll);
 extern void low_sleep_handler(void);
 extern void openpic_suspend(struct sys_device *sysdev, u32 state);
@@ -61,6 +62,7 @@ static unsigned int cur_freq;
 /* Clean that up some day ... use a func ptr or at least an enum... */
 static int cpufreq_uses_pmu;
 static int cpufreq_uses_gpios;
+static int cpufreq_uses_dfs;
 
 static u32 voltage_gpio;
 static u32 frequency_gpio;
@@ -123,6 +125,29 @@ static int __pmac cpu_750fx_cpu_speed(in
 	return 0;
 }
 
+/* Switch CPU speed using DFS */
+static int __pmac dfs_set_cpu_speed(int low_speed)
+{
+	/* If ramping up, set voltage first */
+	if (low_speed == 0) {
+		pmac_call_feature(PMAC_FTR_WRITE_GPIO, NULL, voltage_gpio, 0x05);
+		set_current_state(TASK_UNINTERRUPTIBLE);
+		schedule_timeout(HZ/1000);
+	}
+
+	/* set frequency */
+	choose_7447a_dfs(low_speed);
+
+	/* If ramping down, set voltage last */
+	if (low_speed == 1) {
+		pmac_call_feature(PMAC_FTR_WRITE_GPIO, NULL, voltage_gpio, 0x04);
+		set_current_state(TASK_UNINTERRUPTIBLE);
+		schedule_timeout(HZ/1000);
+	}
+
+	return 0;
+}
+
 /* Switch CPU speed using slewing GPIOs
  */
 static int __pmac gpios_set_cpu_speed(unsigned int low_speed)
@@ -273,6 +298,8 @@ static int __pmac do_set_cpu_speed(int s
 		rc = pmu_set_cpu_speed(speed_mode);
 	else if (cpufreq_uses_gpios)
 		rc = gpios_set_cpu_speed(speed_mode);
+	else if (cpufreq_uses_dfs)
+		rc = dfs_set_cpu_speed(speed_mode);
 	else
 		rc = cpu_750fx_cpu_speed(speed_mode);
 	cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
@@ -346,6 +373,7 @@ static struct cpufreq_driver pmac_cpufre
  *  - iBook2 500 (PMU based, 400Mhz & 500Mhz)
  *  - iBook2 700 (CPU based, 400Mhz & 700Mhz, support low voltage)
  *  - Recent MacRISC3 machines
+ *  - iBook G4s with 7447A CPUs
  */
 static int __init pmac_cpufreq_setup(void)
 {
@@ -375,6 +403,32 @@ static int __init pmac_cpufreq_setup(voi
 		struct device_node *freq_gpio_np = of_find_node_by_name(NULL, 
"frequency-gpio");
 		struct device_node *slew_done_gpio_np = of_find_node_by_name(NULL, 
"slewing-done");
 
+		/*  Check for 7447A based iBook G4 */
+		if (machine_is_compatible("PowerBook6,5")) {
+			/* OF only reports the high frequency */
+			hi_freq = cur_freq;
+			low_freq = cur_freq/2;
+			if(mfspr(HID1) & HID1_DFS)
+				cur_freq = low_freq;
+			else
+				cur_freq = hi_freq;
+
+			volt_gpio_np = of_find_node_by_name(NULL, "cpu-vcore-select");
+			if (!volt_gpio_np){
+				printk(KERN_ERR "cpufreq: missing cpu-vcore-select gpio\n");
+				goto out;
+			}
+
+			u32 *reg = (u32 *)get_property(volt_gpio_np, "reg", NULL);
+			voltage_gpio = *reg;
+
+			cpufreq_uses_pmu = 0;
+			cpufreq_uses_gpios = 0;
+			cpufreq_uses_dfs = 1;
+			has_freq_ctl = 1;
+			goto out;
+		}
+
 		/*
 		 * Check to see if it's GPIO driven or PMU only
 		 *
@@ -497,7 +551,7 @@ out:
 	printk(KERN_INFO "Registering PowerMac CPU frequency driver\n");
 	printk(KERN_INFO "Low: %d Mhz, High: %d Mhz, Boot: %d Mhz, switch method: 
%s\n",
 	       low_freq/1000, hi_freq/1000, cur_freq/1000,
- -	       cpufreq_uses_pmu ? "PMU" : (cpufreq_uses_gpios ? "GPIOs" : "CPU"));
+	       cpufreq_uses_pmu ? "PMU" : (cpufreq_uses_gpios ? "GPIOs" : 
(cpufreq_uses_dfs ? "DFS" : "CPU")));
 
 	return cpufreq_register_driver(&pmac_cpufreq_driver);
 }
diff -upr -X dontdiff linux/include/asm-ppc/reg.h 
linux-2.6.6-dfs/include/asm-ppc/reg.h
- --- linux/include/asm-ppc/reg.h	2004-06-05 18:02:48.000000000 +0930
+++ linux-2.6.6-dfs/include/asm-ppc/reg.h	2004-06-05 18:37:00.778149544 +0930
@@ -174,6 +174,7 @@
 
 #define SPRN_HID1	0x3F1		/* Hardware Implementation Register 1 */
 #define HID1_EMCP	(1<<31)		/* 7450 Machine Check Pin Enable */
+#define HID1_DFS	(1<<22)		/* 7447A Dynamic Frequency Scaling */
 #define HID1_PC0	(1<<16)		/* 7450 PLL_CFG[0] */
 #define HID1_PC1	(1<<15)		/* 7450 PLL_CFG[1] */
 #define HID1_PC2	(1<<14)		/* 7450 PLL_CFG[2] */
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Re: [PATCH] cpufreq support for 7447A on 2004 iBooks

[John Steele Scott]

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Sorry, it seems that my mailer and I broke the last important line of the 
patch. I have uploaded a copy here which has the long lines preserved:

http://www.toojays.net/~toojays/misc/7447a_cpufreq_20040605.patch

cheers,

John
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Re: [PATCH] cpufreq support for 7447A on 2004 iBooks

[Benjamin Herrenschmidt]

On Sat, 2004-06-05 at 04:15, John Steele Scott wrote:
> -----BEGIN PGP SIGNED MESSAGE-----
> Hash: SHA1
> 
> Okay, thanks to some tips from Benjamin Herrenschmidt, I now have a patch 
> against 2.6.6 which lets you control dynamic frequency scaling on the latest 
> model iBook G4. I imagine that this same method would apply to the new 
> PowerBooks as well.

I suggest you also look at the latest Darwin code Apple released, more
sepecifically AppleMacRISC2PE. There is some new bits including something
about tweaking a bus delay when changing the frequency on these models.

Ben.

Re: [PATCH] cpufreq support for 7447A on 2004 iBooks

[Colin LEROY]

Hi,

> model iBook G4. I imagine that this same method would apply to the new
> PowerBooks as well.

According to the posts in this forum, it does.
http://forums.gentoo.org/viewtopic.php?t=177205

-- 
Colin

Re: [PATCH] cpufreq support for 7447A on 2004 iBooks

[John Steele Scott]

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Hash: SHA1

On Sun, 6 Jun 2004 01:51 am, Benjamin Herrenschmidt wrote:
> I suggest you also look at the latest Darwin code Apple released, more
> sepecifically AppleMacRISC2PE. There is some new bits including something
> about tweaking a bus delay when changing the frequency on these models.

I had time to have a look at this today (actually, I didn't have time, but I 
looked at it anyway :). There is a register in the UniNorth which controls 
whether the address acknowledge will be delayed or not. This delay is not 
required when running at high speed.

I have made a new patch for this, available from:
http://www.toojays.net/~toojays/misc/7447a_cpufreq_20040610.patch

This is a fair bit larger than the previous patch, as I have added a function 
to the intrepid feature table to control the AACK delay. There is a slight 
performance improvement for processes which are bound by memory latency (e.g. 
repeatedly cat'ing a 180MB file to /dev/null takes 0.270s with this patch 
versus 0.277s with the last one).

This patch also accepts the PowerBook5,4 models. One thing that needs checking 
as that the revision of UniNorth on this model is high enough for 
intrepid_aack_delay_enable to do its thing. I just assumed that they have the 
same UniNorth, but I will ask in the forum thread which Colin pointed to 
earlier tonight.

cheers,

John
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Re: [PATCH] cpufreq support for 7447A on 2004 iBooks

[Benjamin Herrenschmidt]

> I have made a new patch for this, available from:
> http://www.toojays.net/~toojays/misc/7447a_cpufreq_20040610.patch

Looks good except for some coding style issues ;)

Use spaces between } and else for example, there's also an if without a 
space before the ( and please, name the low level asm function low_* like
the other ones, for consistency.

Ben.

Re: [PATCH] cpufreq support for 7447A on 2004 iBooks

[John Steele Scott]

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Hash: SHA1

On Fri, 11 Jun 2004 01:42 am, Benjamin Herrenschmidt wrote:
> > I have made a new patch for this, available from:
> > http://www.toojays.net/~toojays/misc/7447a_cpufreq_20040610.patch
>
> Looks good except for some coding style issues ;)
>
> Use spaces between } and else for example, there's also an if without a
> space before the ( and please, name the low level asm function low_* like
> the other ones, for consistency.

A new patch which addresses these issues is at:
http://www.toojays.net/~toojays/misc/7447a_cpufreq_20040616.patch

This is functionally identical to the previous patch.

cheers,

John
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