[PATCH] power-management elements for 603e/fsl (version 2)

[PATCH] power-management elements for 603e/fsl (version 2)

[Guennadi Liakhovetski]

Hi all

Below is the second version of the standby patch for ppc linkstation 
systems, which also introduces suspend / resume methods for Freescale 
CPUs. It is now based on a recent (post .22-rc1) powerpc.git snapshot, and 
it depends on the "don't link timer.o for powerpc systems using generic 
rtc" patch (sorry, didn't cc maintainers on that one)
http://ozlabs.org/pipermail/linuxppc-dev/2007-May/036319.html. Also 
addressed comments from Johannes Berg. Please, consider for inclusion.

Paul, sorry, I called it standby, if you don't mind... Somehow I don't 
quite feel like calling this STR.

Thanks
Guennadi
---
Guennadi Liakhovetski

linkstation: implement standby for linkstation ppc.

We put the PCI bus and the core to SLEEP and wait for a button to be 
pressed for wake up. Requires 
http://ozlabs.org/pipermail/linuxppc-dev/2007-May/036319.html as we use 
generic rtc and its suspend/resume code. Note: PM is not enabled by 
default in linkstation_defconfig.

Signed-off-by: G. Liakhovetski <g.liakhovetski@gmx.de>

diff --git a/arch/powerpc/platforms/embedded6xx/linkstation.c b/arch/powerpc/platforms/embedded6xx/linkstation.c
index b412f00..a37ae97 100644
--- a/arch/powerpc/platforms/embedded6xx/linkstation.c
+++ b/arch/powerpc/platforms/embedded6xx/linkstation.c
@@ -11,15 +11,15 @@
  */
 
 #include <linux/kernel.h>
-#include <linux/pci.h>
 #include <linux/initrd.h>
 #include <linux/mtd/physmap.h>
+#include <linux/serial_reg.h>
+#include <sysdev/fsl_soc.h>
 
 #include <asm/time.h>
 #include <asm/prom.h>
 #include <asm/mpic.h>
 #include <asm/mpc10x.h>
-#include <asm/pci-bridge.h>
 
 static struct mtd_partition linkstation_physmap_partitions[] = {
 	{
@@ -134,6 +134,7 @@ static void __init linkstation_init_IRQ(void)
 
 extern void avr_uart_configure(void);
 extern void avr_uart_send(const char);
+extern int avr_uart_ier_swap(const char, char *);
 
 static void linkstation_restart(char *cmd)
 {
@@ -197,3 +198,73 @@ define_machine(linkstation){
 	.halt	 		= linkstation_halt,
 	.calibrate_decr 	= generic_calibrate_decr,
 };
+
+#ifdef CONFIG_PM
+
+static int ls_pm_valid(suspend_state_t state)
+{
+	switch (state) {
+	case PM_SUSPEND_STANDBY:
+		return 1;
+	default:
+		return 0;
+	}
+}
+
+static int ls_pm_enter(suspend_state_t state)
+{
+	char ier;
+	int ret = 0;
+	u64 tb;
+
+	/* Stop preemption */
+	preempt_disable();
+
+	if ((ret = fsl_suspend(state)) < 0) {
+		preempt_enable();
+		return ret;
+	}
+
+	local_irq_disable();
+
+	avr_uart_configure();
+	ret = avr_uart_ier_swap(UART_IER_RDI | UART_IER_RLSI/* | UART_IER_THRI*/, &ier);
+	if (ret < 0)
+		goto fail;
+
+	/* Get timebase */
+	tb = get_tb();
+
+	/* go zzzzz... (re-enabling interrupts) */
+	fsl_low_sleep();
+
+	local_irq_disable();
+
+	set_tb(tb >> 32, tb & 0xfffffffful);
+
+	(void)avr_uart_ier_swap(ier, NULL);
+fail:
+
+	/* Re-enable local CPU interrupts */
+	local_irq_enable();
+
+	preempt_enable();
+
+	fsl_resume(state);
+
+	return ret;
+}
+
+static struct pm_ops ls_pm_ops = {
+	.valid		= ls_pm_valid,
+	.enter		= ls_pm_enter,
+};
+
+static int __init ls_pm_init(void)
+{
+	pm_set_ops(&ls_pm_ops);
+	return 0;
+}
+
+device_initcall(ls_pm_init);
+#endif
diff --git a/arch/powerpc/platforms/embedded6xx/ls_uart.c b/arch/powerpc/platforms/embedded6xx/ls_uart.c
index d0bee9f..b1086e9 100644
--- a/arch/powerpc/platforms/embedded6xx/ls_uart.c
+++ b/arch/powerpc/platforms/embedded6xx/ls_uart.c
@@ -1,3 +1,14 @@
+/*
+ * AVR power-management chip interface for the Buffalo Linkstation /
+ * Kurobox Platform.
+ *
+ * Author: 2006 (c) G. Liakhovetski
+ *	 g.liakhovetski@gmx.de
+ *
+ * This file is licensed under the terms of the GNU General Public License
+ * version 2.  This program is licensed "as is" without any warranty of
+ * any kind, whether express or implied.
+ */
 #include <linux/workqueue.h>
 #include <linux/string.h>
 #include <linux/delay.h>
@@ -11,6 +22,7 @@
 
 static void __iomem *avr_addr;
 static unsigned long avr_clock;
+static unsigned int avr_virq;
 
 static struct work_struct wd_work;
 
@@ -42,6 +54,37 @@ static void wd_stop(struct work_struct *unused)
 	printk("\n");
 }
 
+static irqreturn_t avr_handler(int irq, void *id)
+{
+	(void) in_8(avr_addr + UART_LSR);
+	(void) in_8(avr_addr + UART_RX);
+	(void) in_8(avr_addr + UART_IIR);
+	(void) in_8(avr_addr + UART_MSR);
+
+	return IRQ_HANDLED;
+}
+
+int avr_uart_ier_swap(const char new, char *old)
+{
+	int ret = 0;
+
+	if (!avr_addr || !avr_clock || avr_virq == NO_IRQ)
+		return -EIO;
+
+	if (old)
+		ret = request_irq(avr_virq, avr_handler, 0, "avr_wakeup", NULL);
+	else
+		free_irq(avr_virq, NULL);
+
+	if (ret >= 0) {
+		if (old)
+			*old = in_8(avr_addr + UART_IER);
+		out_8(avr_addr + UART_IER, new);
+	}
+
+	return ret;
+}
+
 #define AVR_QUOT(clock) ((clock) + 8 * 9600) / (16 * 9600)
 
 void avr_uart_configure(void)
@@ -104,7 +147,7 @@ static int __init ls_uarts_init(void)
 {
 	struct device_node *avr;
 	phys_addr_t phys_addr;
-	int len;
+	int len, irq;
 
 	avr = of_find_node_by_path("/soc10x/serial@80004500");
 	if (!avr)
@@ -112,10 +155,15 @@ static int __init ls_uarts_init(void)
 
 	avr_clock = *(u32*)of_get_property(avr, "clock-frequency", &len);
 	phys_addr = ((u32*)of_get_property(avr, "reg", &len))[0];
+ 	irq = ((u32*)get_property(avr, "interrupts", &len))[0];
 
 	if (!avr_clock || !phys_addr)
 		return -EINVAL;
 
+	avr_virq = irq_find_mapping(NULL, irq);
+	if (avr_virq == NO_IRQ)
+		return -EIO;
+
 	avr_addr = ioremap(phys_addr, 32);
 	if (!avr_addr)
 		return -EFAULT;
diff --git a/arch/powerpc/sysdev/Makefile b/arch/powerpc/sysdev/Makefile
index c3ce0bd..745c6f6 100644
--- a/arch/powerpc/sysdev/Makefile
+++ b/arch/powerpc/sysdev/Makefile
@@ -13,6 +13,9 @@ obj-$(CONFIG_PPC_PMI)		+= pmi.o
 obj-$(CONFIG_U3_DART)		+= dart_iommu.o
 obj-$(CONFIG_MMIO_NVRAM)	+= mmio_nvram.o
 obj-$(CONFIG_FSL_SOC)		+= fsl_soc.o
+ifeq ($(CONFIG_PM),y)
+obj-$(CONFIG_FSL_SOC)		+= fsl_pm.o
+endif
 obj-$(CONFIG_FSL_PCIE)		+= fsl_pcie.o
 obj-$(CONFIG_TSI108_BRIDGE)	+= tsi108_pci.o tsi108_dev.o
 obj-$(CONFIG_QUICC_ENGINE)	+= qe_lib/
diff --git a/arch/powerpc/sysdev/fsl_soc.c b/arch/powerpc/sysdev/fsl_soc.c
index cad1757..9588b60 100644
--- a/arch/powerpc/sysdev/fsl_soc.c
+++ b/arch/powerpc/sysdev/fsl_soc.c
@@ -1103,3 +1103,65 @@ err:
 arch_initcall(cpm_smc_uart_of_init);
 
 #endif /* CONFIG_8xx */
+
+#ifdef CONFIG_PM
+#include <linux/pci.h>
+#include <asm/pci-bridge.h>
+
+#define	MPC10X_LP_REF_EN	(1<<12)
+#define	MPC10X_PM		(1<<7)
+#define MPC10X_DOZE		(1<<5)
+#define	MPC10X_NAP		(1<<4)
+#define	MPC10X_SLEEP		(1<<3)
+
+int fsl_suspend(suspend_state_t state)
+{
+	struct pci_dev *bridge;
+	unsigned long flags;
+	u16 pmcr1;
+
+	bridge = pci_find_slot(0, 0);
+	if (!bridge)
+		return -ENODEV;
+
+	pci_read_config_word(bridge, 0x70, &pmcr1);
+	local_irq_save(flags);
+	/* Apparently, MacOS uses NAP mode for Grackle ??? */
+	pmcr1 &= ~(MPC10X_DOZE | MPC10X_NAP);
+	pmcr1 |= MPC10X_PM | MPC10X_SLEEP | MPC10X_LP_REF_EN;
+	pci_write_config_word(bridge, 0x70, pmcr1);
+	local_irq_restore(flags);
+
+	/* Make sure the decrementer won't interrupt us */
+	asm volatile("mtdec %0" : : "r" (0x7fffffff));
+	/* Make sure any pending DEC interrupt occurring while we did
+	 * the above didn't re-enable the DEC */
+	mb();
+	asm volatile("mtdec %0" : : "r" (0x7fffffff)); /* 8 seconds */
+
+	return 0;
+}
+
+int fsl_resume(suspend_state_t state)
+{
+	struct pci_dev *bridge;
+	unsigned long flags;
+	u16 pmcr1;
+
+	bridge = pci_find_slot(0, 0);
+	if (!bridge)
+		return -ENODEV;
+
+	local_irq_save(flags);
+	/* We're awake again, stop grackle PM */
+	pci_read_config_word(bridge, 0x70, &pmcr1);
+	pmcr1 &= ~(MPC10X_PM | MPC10X_DOZE | MPC10X_SLEEP | MPC10X_NAP | MPC10X_LP_REF_EN);
+	pci_write_config_word(bridge, 0x70, pmcr1);
+	local_irq_restore(flags);
+
+	/* Restart jiffies & scheduling */
+	wakeup_decrementer();
+
+	return 0;
+}
+#endif
diff --git a/arch/powerpc/sysdev/fsl_soc.h b/arch/powerpc/sysdev/fsl_soc.h
index 04e145b..9853913 100644
--- a/arch/powerpc/sysdev/fsl_soc.h
+++ b/arch/powerpc/sysdev/fsl_soc.h
@@ -8,5 +8,12 @@ extern phys_addr_t get_immrbase(void);
 extern u32 get_brgfreq(void);
 extern u32 get_baudrate(void);
 
+#ifdef CONFIG_PM
+#include <linux/pm.h>
+extern int fsl_suspend(suspend_state_t state);
+extern int fsl_resume(suspend_state_t state);
+extern void fsl_low_sleep(void);
+#endif
+
 #endif
 #endif
diff -u /dev/null b/arch/powerpc/sysdev/fsl_pm.S
--- /dev/null	2005-08-21 16:20:22.000000000 +0200
+++ b/arch/powerpc/sysdev/fsl_pm.S	2007-05-18 19:34:22.000000000 +0200
@@ -0,0 +1,19 @@
+#include <asm/reg.h>
+#include <asm/ppc_asm.h>
+
+_GLOBAL(fsl_low_sleep)
+	isync			/* Set the HID0 and MSR for sleep. */
+	mfspr	r3,SPRN_HID0
+	rlwinm	r3,r3,0,10,7	/* clear doze, nap */
+	oris	r3,r3,HID0_SLEEP@h /* r3 |= HID0_SLEEP & (0xffff << 16) */
+	sync
+	isync
+	mtspr	SPRN_HID0,r3
+	sync
+	mfmsr	r3
+	ori	r3,r3,MSR_EE	/* Enable interrupts to wake us up */
+	oris	r3,r3,MSR_POW@h
+	sync
+	mtmsr	r3
+	isync
+	blr

Re: [PATCH] power-management elements for 603e/fsl (version 2)

[Johannes Berg]

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On Sat, 2007-05-19 at 21:22 +0200, Guennadi Liakhovetski wrote:

> +int fsl_suspend(suspend_state_t state)
> +{
> +	struct pci_dev *bridge;
> +	unsigned long flags;
> +	u16 pmcr1;
> +
> +	bridge = pci_find_slot(0, 0);
> +	if (!bridge)
> +		return -ENODEV;
> +
> +	pci_read_config_word(bridge, 0x70, &pmcr1);
> +	local_irq_save(flags);
> +	/* Apparently, MacOS uses NAP mode for Grackle ??? */

That comment seems out of place :)

> +	pmcr1 &= ~(MPC10X_DOZE | MPC10X_NAP);
> +	pmcr1 |= MPC10X_PM | MPC10X_SLEEP | MPC10X_LP_REF_EN;
> +	pci_write_config_word(bridge, 0x70, pmcr1);
> +	local_irq_restore(flags);
> +
> +	/* Make sure the decrementer won't interrupt us */
> +	asm volatile("mtdec %0" : : "r" (0x7fffffff));
> +	/* Make sure any pending DEC interrupt occurring while we did
> +	 * the above didn't re-enable the DEC */
> +	mb();
> +	asm volatile("mtdec %0" : : "r" (0x7fffffff)); /* 8 seconds */

Are you sure that's 8 seconds? Seems too fast.

Also, the whole irq handling thing in resume/suspend seems bogus. Both
resume and suspend are called with interrupts off, so the
local_irq_{save,restore} calls do nothing. You probably need to use
arch_suspend_{enable,disable}_irqs and do the decrementer magic there
(after all that's why we introduced these.)

Then again, see the other mail I'm about to send in response to a patch
from Scott Wood using these hooks.

johannes

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Re: [PATCH] power-management elements for 603e/fsl (version 2)

[Scott Wood]

On Sat, May 19, 2007 at 09:22:10PM +0200, Guennadi Liakhovetski wrote:
> +static int ls_pm_enter(suspend_state_t state)
> +{
> +	char ier;
> +	int ret = 0;
> +	u64 tb;
> +
> +	/* Stop preemption */
> +	preempt_disable();
> +
> +	if ((ret = fsl_suspend(state)) < 0) {
> +		preempt_enable();
> +		return ret;
> +	}
> +
> +	local_irq_disable();

IRQs are already disabled when this function is called.

> +	/* go zzzzz... (re-enabling interrupts) */
> +	fsl_low_sleep();

IRQs really shouldn't be enabled here without something like the "Handle
HID0_SLEEP in the TLF_NAPPING hack" patch I posted recently.

> +	/* Re-enable local CPU interrupts */
> +	local_irq_enable();

Just leave them off.

> @@ -112,10 +155,15 @@ static int __init ls_uarts_init(void)
>  
>  	avr_clock = *(u32*)of_get_property(avr, "clock-frequency", &len);
>  	phys_addr = ((u32*)of_get_property(avr, "reg", &len))[0];
> + 	irq = ((u32*)get_property(avr, "interrupts", &len))[0];

Oopsing if a property is missing isn't nice.

> +
> +#ifdef CONFIG_PM
> +#include <linux/pci.h>
> +#include <asm/pci-bridge.h>
> +
> +#define	MPC10X_LP_REF_EN	(1<<12)
> +#define	MPC10X_PM		(1<<7)
> +#define MPC10X_DOZE		(1<<5)
> +#define	MPC10X_NAP		(1<<4)
> +#define	MPC10X_SLEEP		(1<<3)
> +
> +int fsl_suspend(suspend_state_t state)
> +{
> +	struct pci_dev *bridge;
> +	unsigned long flags;
> +	u16 pmcr1;
> +
> +	bridge = pci_find_slot(0, 0);
> +	if (!bridge)
> +		return -ENODEV;
> +
> +	pci_read_config_word(bridge, 0x70, &pmcr1);
> +	local_irq_save(flags);
> +	/* Apparently, MacOS uses NAP mode for Grackle ??? */
> +	pmcr1 &= ~(MPC10X_DOZE | MPC10X_NAP);
> +	pmcr1 |= MPC10X_PM | MPC10X_SLEEP | MPC10X_LP_REF_EN;
> +	pci_write_config_word(bridge, 0x70, pmcr1);
> +	local_irq_restore(flags);

This should probably be something like mpc10x_suspend.  Also, IRQs should
already be disabled when this is called.

> +	/* Make sure the decrementer won't interrupt us */
> +	asm volatile("mtdec %0" : : "r" (0x7fffffff));
> +	/* Make sure any pending DEC interrupt occurring while we did
> +	 * the above didn't re-enable the DEC */
> +	mb();
> +	asm volatile("mtdec %0" : : "r" (0x7fffffff)); /* 8 seconds */

IRQs are already disabled here, so if it was pending it still will be (at
least with some cores).  It needs to be done with the arch suspend hook.

-Scott

Re: [PATCH] power-management elements for 603e/fsl (version 2)

[Guennadi Liakhovetski]

On Mon, 21 May 2007, Scott Wood wrote:

> On Sat, May 19, 2007 at 09:22:10PM +0200, Guennadi Liakhovetski wrote:
> > +	local_irq_disable();
> 
> IRQs are already disabled when this function is called.

ok

> > +	/* go zzzzz... (re-enabling interrupts) */
> > +	fsl_low_sleep();
> 
> IRQs really shouldn't be enabled here without something like the "Handle
> HID0_SLEEP in the TLF_NAPPING hack" patch I posted recently.

Ok, I'd be happy to rely on those your patches... as long as they make it 
into the kernel. Paulus, what's the plan? I'll try to apply them locally 
for now and adjust my code accordingly. A recent powerpc.git should be 
fine, I guess - the arch_suspend_{disable,enable}_irqs hooks are already 
there, or are there any further dependencies?

> > +	/* Re-enable local CPU interrupts */
> > +	local_irq_enable();
> 
> Just leave them off.

ok

> > @@ -112,10 +155,15 @@ static int __init ls_uarts_init(void)
> >  
> >  	avr_clock = *(u32*)of_get_property(avr, "clock-frequency", &len);
> >  	phys_addr = ((u32*)of_get_property(avr, "reg", &len))[0];
> > + 	irq = ((u32*)get_property(avr, "interrupts", &len))[0];
> 
> Oopsing if a property is missing isn't nice.

Hm, it is in .dts in the kernel tree, do I still have to care a possible 
non-compliant version? Probably, you're right, will fix.

> > +	local_irq_save(flags);
> > +	/* Apparently, MacOS uses NAP mode for Grackle ??? */
> > +	pmcr1 &= ~(MPC10X_DOZE | MPC10X_NAP);
> > +	pmcr1 |= MPC10X_PM | MPC10X_SLEEP | MPC10X_LP_REF_EN;
> > +	pci_write_config_word(bridge, 0x70, pmcr1);
> > +	local_irq_restore(flags);
> 
> This should probably be something like mpc10x_suspend.  Also, IRQs should
> already be disabled when this is called.

well, I'd also prefer a more specific namespace than "fsl." Would it be ok 
to call them with mpc10x (has been discussed on irc, I remember there have 
been objections against this as mpc10x are just some host-pci bridges from 
older Apple (not only?) machines)? And if we use mpc10x, is it ok to leave 
them in fsl_soc.c?

> > +	/* Make sure the decrementer won't interrupt us */
> > +	asm volatile("mtdec %0" : : "r" (0x7fffffff));
> > +	/* Make sure any pending DEC interrupt occurring while we did
> > +	 * the above didn't re-enable the DEC */
> > +	mb();
> > +	asm volatile("mtdec %0" : : "r" (0x7fffffff)); /* 8 seconds */
> 
> IRQs are already disabled here, so if it was pending it still will be (at
> least with some cores).  It needs to be done with the arch suspend hook.

as above, will test with your patches.

Thanks for comments!
Guennadi
---
Guennadi Liakhovetski

Re: [PATCH] power-management elements for 603e/fsl (version 2)

[Guennadi Liakhovetski]

On Mon, 21 May 2007, Guennadi Liakhovetski wrote:

> On Mon, 21 May 2007, Scott Wood wrote:
> 
> > IRQs really shouldn't be enabled here without something like the "Handle
> > HID0_SLEEP in the TLF_NAPPING hack" patch I posted recently.
> 
> Ok, I'd be happy to rely on those your patches... as long as they make it 
> into the kernel. Paulus, what's the plan? I'll try to apply them locally 
> for now and adjust my code accordingly. A recent powerpc.git should be 
> fine, I guess - the arch_suspend_{disable,enable}_irqs hooks are already 
> there, or are there any further dependencies?

Took some time, but now I did rebase my linkstation standby code on your 
patches, and also used your mpc83xx_enter_sleep / ret_from_sleep functions 
(former with a single modification - removed the first mtmsr to set EE and 
POW in MSR with one insn) - all worked. So, we could put them into 
something like arch/powerpc/sysdev/fsl_pm.S and name accordingly. That 
could be an incremental patch after the present versions make it into some 
tree.

Of course, I needed other your patches to, e.g., bypass calling the ISR on 
resume too.

Thanks
Guennadi
---
Guennadi Liakhovetski