[PATCH v4 00/12] coordinate cht i2c-pmic and i915-punit accesses

[PATCH v4 00/12] coordinate cht i2c-pmic and i915-punit accesses

[Hans de Goede]

Hi All,

Here is v4 of my "coordinate cht i2c-pmic and i915-punit accesses" patch-set
this version adds a #include <linux/notifier.h>" to asm/iosf_mbi.h fixing
a compile warning in arch/x86/platform/intel-quark/imr.c .

Otherwise there are no changes, here is the cover-letter from v3 with
more background info on this patch-set:

Here is v3 of my cht i2c-pmic and i915-punit access coordination
patchset. New in this version is the dropping of the punit_acquire /
_release calls around punit accesses in the i915 driver, these seem
to be unnecessary in this case acquiring the pmic-bus semaphore in
the punit seems to be enough. We do definitely need the forcewake stuff
done by "drm/i915: Listen for PMIC bus access notifications", without
that cht devices which have a pmic which makes the kernel share the bus
with the punit see forcewake timeouts followed by a lockup.

Also new in this version is some renames + extra comments in patch 11 and 12
as reqested by Ville.

This patch-set includes 6 i2c patches, these patches are ready for merging,
they have Wolfram's (the i2c maintainer's) ack. The problem is the 6th i2c
patch which fixes the punit semaphore support in i2c-designware-baytrail.c,
which fixes the i2c-designware not binding to the pmic (axp288) i2c bus.
But with this fixed we actually start triggering the coordination problems
the rest of this patch-set addresses.

So the plan (again with Wolfram's ack) is for all these patches
including the i2c-designware ones to go upstream through the drm-intel
tree, to avoid an intermediate state were things don't work.

As for the how and why of this patchset, let me copy and paste the
cover letter of v1 of this set which is still mostly valid:

### being v1 cover letter ###

This series fixes an issue where the following messages are shown in dmesg:
[drm:fw_domains_get [i915]] *ERROR* render: timed out waiting for forcewake ack request.
[drm:fw_domains_get [i915]] *MEDIA* render: timed out waiting for forcewake ack request.
i2c_designware 808622C1:06: punit semaphore timed out, resetting
i2c_designware 808622C1:06: PUNIT SEM: 2
i2c_designware 808622C1:06: couldn't acquire bus ownership

Usually followed by a gfx or system freeze, this is happening both on my
cherrytrail tablet as well as being seen by an user commenting on:
https://bugzilla.kernel.org/show_bug.cgi?id=155241

This problem is triggered by my patch series to fix the punit i2c bus
semaphore code in drivers/i2c/busses/designware-baytrail.c .

Which actually allows i2c access to pmic-s wich need bus-access arbritration
for the first time on cherrytrail, combined with patches from me to actually
make the axp288_fuel_gauge driver load, which leads to regular pmic i2c
accesses (when userspace checks the battery level).

The fix / workaround
====================

Testing has shown that just taking the punit i2c bus semaphore on
i2c accesses to a shared pmic i2c bus is not enough to avoid problem,
e.g. besides this series to coordinate i915 access, we also need:
https://patchwork.ozlabs.org/patch/710070/

This series introduces 2 mechanisms to coordinate direct pmic accesses
vs punit requests which lead to pmic accesses. The first mechanism is
a simple mutex, which works well for the direct punit accesses the i915
code does. However testing has shown this is not enough, we also need
to avoid doing a forcewake when a driver is directly accessing the pmic
i2c bus, otherwise we get the timeout errors quoted above, the fact
that after the forcewake errors the designware-baytrail.c code also
fails to acquire the lock, suggests that doing forcewakes during the
access window causes the i2c bus to get stuck (or the punit to get
confused).

The deal with the forcewake issue a notifier is introduced which allows
drivers to get notified before any pmic i2c transfer begins (and after
it ends). This is used in the i915 driver to do a
forcewake_get(FORCEWAKE_ALL) before the access begins avoiding needing to
it while the access is in progress.

Testing has shown that this avoids the problem for both me and the user,
where as before it could be reproduced at will.

The implementation of the fix
=============================

I've decided to put the mutex and the notifier in the iosf_mbi code,
as that is somewhat of a common middle ground between the i915 driver and
the designware-baytrail.c code, with the latter already depending on the
iosf_mbi code. I'm open for moving them if someone has a suggestion for a
better place to put them.

If iosf_mbi support is not enabled then all the functions used will become
static inline NOPs and nothing changes on the i915 side.

If the code is enabled and runs on a system which does not need pmic i2c
bus arbritration, then the mutex lock / unlock calls added to the i915 code
will still be made, but there won't be any contention, so other then the
overhead of the lock / unlock there will not be any delays. These calls are
not made in any hot paths.

The biggest downside IMHO is that taking FORCEWAKE_ALL before each bus
access will cause extra GPU wakeups, and thus powerdrain. I plan to make
the impact of this minimal by modifying any drivers (axp288 code, with
which I'm quite familiar by now) to limit their i2c accesses to a bare
minimum. Specifically I plan to e.g. cache the battery level and wait
at least 15 seconds (max 4 times a minute) before getting a fresh reading
even if userspace asks for it more often, combined with some mechanism
to only do 1 access-begin and 1 access-end notification for i2c accesses
in quick succession.

Alternatives
============

It would be tempting to say that this is not worth the trouble and we
should just disallow direct i2c accesses to the pmic bus. Unfortunately
that will cause some major issues on affected devices:
-No battery monitoring
-No "AC" plugged in monitoring
-If booted with a normal USB-A -> micro-USB cable, or no cable, plugged
 in and then the user replaces the cable with an otg USB-host cable /
 adapter, the id-pin shorting will enable a 5v boost convertor, but we
 need to disable the pmic's USB-Vbus path otherwise it will start drawing
 current from the boost convertor, leading to aprox 300mA of extra
 battery drain, this is done by the axp288_charger driver, which needs
 direct i2c access to the pmic bus

Way forward
===========

I realize the workaround this patch-set adds is not the prettiest code
ever seen, but I see no otherway to get things like battery monitoring
and proper OTG support working on affected devices without breaking
drm/i915 support. So I would like to see this merged in some form, I'm
happy to make any kind of requested changes; and/or to try alternative
fixes.

### end v1 cover letter ###

Regards,

Hans
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[PATCH v4 01/12] x86/platform/intel/iosf_mbi: Add a mutex for P-Unit access

[Hans de Goede]

One some systems the P-Unit accesses the PMIC to change various voltages
through the same bus as other kernel drivers use for e.g. battery
monitoring.

If a driver sends requests to the P-Unit which require the P-Unit to access
the PMIC bus while another driver is also accessing the PMIC bus various
bad things happen.

This commit adds a mutex to protect the P-Unit against simultaneous
accesses and 2 functions to lock / unlock this mutex.

Note on these systems the i2c-bus driver will request a sempahore from the
P-Unit for exclusive access to the PMIC bus when i2c drivers are accessing
it, but this does not appear to be sufficient, we still need to avoid
making certain P-Unit requests during the access window to avoid problems.

BugLink: https://bugzilla.kernel.org/show_bug.cgi?id=155241
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Tested-by: tagorereddy <tagore.chandan@gmail.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
---
Changes in v2:
-Rename iosf_mbi_punit_lock/_unlock to _acquire/_release rename
-Spelling: P-Unit, PMIC
---
 arch/x86/include/asm/iosf_mbi.h    | 31 +++++++++++++++++++++++++++++++
 arch/x86/platform/intel/iosf_mbi.c | 13 +++++++++++++
 2 files changed, 44 insertions(+)

diff --git a/arch/x86/include/asm/iosf_mbi.h b/arch/x86/include/asm/iosf_mbi.h
index b41ee16..f6119d0 100644
--- a/arch/x86/include/asm/iosf_mbi.h
+++ b/arch/x86/include/asm/iosf_mbi.h
@@ -88,6 +88,33 @@ int iosf_mbi_write(u8 port, u8 opcode, u32 offset, u32 mdr);
  */
 int iosf_mbi_modify(u8 port, u8 opcode, u32 offset, u32 mdr, u32 mask);
 
+/**
+ * iosf_mbi_punit_acquire() - Acquire access to the P-Unit
+ *
+ * One some systems the P-Unit accesses the PMIC to change various voltages
+ * through the same bus as other kernel drivers use for e.g. battery monitoring.
+ *
+ * If a driver sends requests to the P-Unit which require the P-Unit to access
+ * the PMIC bus while another driver is also accessing the PMIC bus various bad
+ * things happen.
+ *
+ * To avoid these problems this function must be called before accessing the
+ * P-Unit or the PMIC, be it through iosf_mbi* functions or through other means.
+ *
+ * Note on these systems the i2c-bus driver will request a sempahore from the
+ * P-Unit for exclusive access to the PMIC bus when i2c drivers are accessing
+ * it, but this does not appear to be sufficient, we still need to avoid making
+ * certain P-Unit requests during the access window to avoid problems.
+ *
+ * This function locks a mutex, as such it may sleep.
+ */
+void iosf_mbi_punit_acquire(void);
+
+/**
+ * iosf_mbi_punit_release() - Release access to the P-Unit
+ */
+void iosf_mbi_punit_release(void);
+
 #else /* CONFIG_IOSF_MBI is not enabled */
 static inline
 bool iosf_mbi_available(void)
@@ -115,6 +142,10 @@ int iosf_mbi_modify(u8 port, u8 opcode, u32 offset, u32 mdr, u32 mask)
 	WARN(1, "IOSF_MBI driver not available");
 	return -EPERM;
 }
+
+static inline void iosf_mbi_punit_acquire(void) {}
+static inline void iosf_mbi_punit_release(void) {}
+
 #endif /* CONFIG_IOSF_MBI */
 
 #endif /* IOSF_MBI_SYMS_H */
diff --git a/arch/x86/platform/intel/iosf_mbi.c b/arch/x86/platform/intel/iosf_mbi.c
index edf2c54..ed24fa9f 100644
--- a/arch/x86/platform/intel/iosf_mbi.c
+++ b/arch/x86/platform/intel/iosf_mbi.c
@@ -34,6 +34,7 @@
 
 static struct pci_dev *mbi_pdev;
 static DEFINE_SPINLOCK(iosf_mbi_lock);
+static DEFINE_MUTEX(iosf_mbi_punit_mutex);
 
 static inline u32 iosf_mbi_form_mcr(u8 op, u8 port, u8 offset)
 {
@@ -190,6 +191,18 @@ bool iosf_mbi_available(void)
 }
 EXPORT_SYMBOL(iosf_mbi_available);
 
+void iosf_mbi_punit_acquire(void)
+{
+	mutex_lock(&iosf_mbi_punit_mutex);
+}
+EXPORT_SYMBOL(iosf_mbi_punit_acquire);
+
+void iosf_mbi_punit_release(void)
+{
+	mutex_unlock(&iosf_mbi_punit_mutex);
+}
+EXPORT_SYMBOL(iosf_mbi_punit_release);
+
 #ifdef CONFIG_IOSF_MBI_DEBUG
 static u32	dbg_mdr;
 static u32	dbg_mcr;
-- 
2.9.3

[PATCH v4 02/12] x86/platform/intel/iosf_mbi: Add a PMIC bus access notifier

[Hans de Goede]

Some drivers may need to acquire P-Unit managed resources from interrupt
context, where they cannot call iosf_mbi_punit_acquire().

This commit adds a notifier chain which allows a driver to get notified
(in a process context) before other drivers start accessing the PMIC bus,
so that the driver can acquire any resources, which it may need during
the window the other driver is accessing the PMIC, before hand.

BugLink: https://bugzilla.kernel.org/show_bug.cgi?id=155241
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Tested-by: tagorereddy <tagore.chandan@gmail.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
---
Changes in v2:
-Spelling: P-Unit, PMIC
-Adjust for iosf_mbi_punit_lock/_unlock to _acquire/_release rename
Changes in v4:
-Include <linux/notifier.h> from asm/iosf_mbi.h
---
 arch/x86/include/asm/iosf_mbi.h    | 56 ++++++++++++++++++++++++++++++++++++++
 arch/x86/platform/intel/iosf_mbi.c | 36 ++++++++++++++++++++++++
 2 files changed, 92 insertions(+)

diff --git a/arch/x86/include/asm/iosf_mbi.h b/arch/x86/include/asm/iosf_mbi.h
index f6119d0..c313cac 100644
--- a/arch/x86/include/asm/iosf_mbi.h
+++ b/arch/x86/include/asm/iosf_mbi.h
@@ -5,6 +5,8 @@
 #ifndef IOSF_MBI_SYMS_H
 #define IOSF_MBI_SYMS_H
 
+#include <linux/notifier.h>
+
 #define MBI_MCR_OFFSET		0xD0
 #define MBI_MDR_OFFSET		0xD4
 #define MBI_MCRX_OFFSET		0xD8
@@ -47,6 +49,10 @@
 #define QRK_MBI_UNIT_MM		0x05
 #define QRK_MBI_UNIT_SOC	0x31
 
+/* Action values for the pmic_bus_access_notifier functions */
+#define MBI_PMIC_BUS_ACCESS_BEGIN	1
+#define MBI_PMIC_BUS_ACCESS_END		2
+
 #if IS_ENABLED(CONFIG_IOSF_MBI)
 
 bool iosf_mbi_available(void);
@@ -115,6 +121,38 @@ void iosf_mbi_punit_acquire(void);
  */
 void iosf_mbi_punit_release(void);
 
+/**
+ * iosf_mbi_register_pmic_bus_access_notifier - Register PMIC bus notifier
+ *
+ * This function can be used by drivers which may need to acquire P-Unit
+ * managed resources from interrupt context, where iosf_mbi_punit_acquire()
+ * can not be used.
+ *
+ * This function allows a driver to register a notifier to get notified (in a
+ * process context) before other drivers start accessing the PMIC bus.
+ *
+ * This allows the driver to acquire any resources, which it may need during
+ * the window the other driver is accessing the PMIC, before hand.
+ *
+ * @nb: notifier_block to register
+ */
+int iosf_mbi_register_pmic_bus_access_notifier(struct notifier_block *nb);
+
+/**
+ * iosf_mbi_register_pmic_bus_access_notifier - Unregister PMIC bus notifier
+ *
+ * @nb: notifier_block to unregister
+ */
+int iosf_mbi_unregister_pmic_bus_access_notifier(struct notifier_block *nb);
+
+/**
+ * iosf_mbi_call_pmic_bus_access_notifier_chain - Call PMIC bus notifier chain
+ *
+ * @val: action to pass into listener's notifier_call function
+ * @v: data pointer to pass into listener's notifier_call function
+ */
+int iosf_mbi_call_pmic_bus_access_notifier_chain(unsigned long val, void *v);
+
 #else /* CONFIG_IOSF_MBI is not enabled */
 static inline
 bool iosf_mbi_available(void)
@@ -146,6 +184,24 @@ int iosf_mbi_modify(u8 port, u8 opcode, u32 offset, u32 mdr, u32 mask)
 static inline void iosf_mbi_punit_acquire(void) {}
 static inline void iosf_mbi_punit_release(void) {}
 
+static inline
+int iosf_mbi_register_pmic_bus_access_notifier(struct notifier_block *nb)
+{
+	return 0;
+}
+
+static inline
+int iosf_mbi_unregister_pmic_bus_access_notifier(struct notifier_block *nb)
+{
+	return 0;
+}
+
+static inline
+int iosf_mbi_call_pmic_bus_access_notifier_chain(unsigned long val, void *v)
+{
+	return 0;
+}
+
 #endif /* CONFIG_IOSF_MBI */
 
 #endif /* IOSF_MBI_SYMS_H */
diff --git a/arch/x86/platform/intel/iosf_mbi.c b/arch/x86/platform/intel/iosf_mbi.c
index ed24fa9f..a952ac1 100644
--- a/arch/x86/platform/intel/iosf_mbi.c
+++ b/arch/x86/platform/intel/iosf_mbi.c
@@ -35,6 +35,7 @@
 static struct pci_dev *mbi_pdev;
 static DEFINE_SPINLOCK(iosf_mbi_lock);
 static DEFINE_MUTEX(iosf_mbi_punit_mutex);
+static BLOCKING_NOTIFIER_HEAD(iosf_mbi_pmic_bus_access_notifier);
 
 static inline u32 iosf_mbi_form_mcr(u8 op, u8 port, u8 offset)
 {
@@ -203,6 +204,41 @@ void iosf_mbi_punit_release(void)
 }
 EXPORT_SYMBOL(iosf_mbi_punit_release);
 
+int iosf_mbi_register_pmic_bus_access_notifier(struct notifier_block *nb)
+{
+	int ret;
+
+	/* Wait for the bus to go inactive before registering */
+	mutex_lock(&iosf_mbi_punit_mutex);
+	ret = blocking_notifier_chain_register(
+				&iosf_mbi_pmic_bus_access_notifier, nb);
+	mutex_unlock(&iosf_mbi_punit_mutex);
+
+	return ret;
+}
+EXPORT_SYMBOL(iosf_mbi_register_pmic_bus_access_notifier);
+
+int iosf_mbi_unregister_pmic_bus_access_notifier(struct notifier_block *nb)
+{
+	int ret;
+
+	/* Wait for the bus to go inactive before unregistering */
+	mutex_lock(&iosf_mbi_punit_mutex);
+	ret = blocking_notifier_chain_unregister(
+				&iosf_mbi_pmic_bus_access_notifier, nb);
+	mutex_unlock(&iosf_mbi_punit_mutex);
+
+	return ret;
+}
+EXPORT_SYMBOL(iosf_mbi_unregister_pmic_bus_access_notifier);
+
+int iosf_mbi_call_pmic_bus_access_notifier_chain(unsigned long val, void *v)
+{
+	return blocking_notifier_call_chain(
+				&iosf_mbi_pmic_bus_access_notifier, val, v);
+}
+EXPORT_SYMBOL(iosf_mbi_call_pmic_bus_access_notifier_chain);
+
 #ifdef CONFIG_IOSF_MBI_DEBUG
 static u32	dbg_mdr;
 static u32	dbg_mcr;
-- 
2.9.3

[PATCH v4 03/12] i2c: designware: Rename accessor_flags to flags

[Hans de Goede]

Rename accessor_flags to flags, so that we can use the field for
other flags too. This is a preparation patch for adding cherrytrail
support to the punit semaphore code.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: Jarkko Nikula <jarkko.nikula@linux.intel.com>
Tested-by: Takashi Iwai <tiwai@suse.de>
Acked-by: Wolfram Sang <wsa@the-dreams.de>
---
 drivers/i2c/busses/i2c-designware-core.c    | 14 +++++++-------
 drivers/i2c/busses/i2c-designware-core.h    |  2 +-
 drivers/i2c/busses/i2c-designware-platdrv.c |  2 +-
 3 files changed, 9 insertions(+), 9 deletions(-)

diff --git a/drivers/i2c/busses/i2c-designware-core.c b/drivers/i2c/busses/i2c-designware-core.c
index 6d81c56..8c3ba42 100644
--- a/drivers/i2c/busses/i2c-designware-core.c
+++ b/drivers/i2c/busses/i2c-designware-core.c
@@ -177,13 +177,13 @@ static u32 dw_readl(struct dw_i2c_dev *dev, int offset)
 {
 	u32 value;
 
-	if (dev->accessor_flags & ACCESS_16BIT)
+	if (dev->flags & ACCESS_16BIT)
 		value = readw_relaxed(dev->base + offset) |
 			(readw_relaxed(dev->base + offset + 2) << 16);
 	else
 		value = readl_relaxed(dev->base + offset);
 
-	if (dev->accessor_flags & ACCESS_SWAP)
+	if (dev->flags & ACCESS_SWAP)
 		return swab32(value);
 	else
 		return value;
@@ -191,10 +191,10 @@ static u32 dw_readl(struct dw_i2c_dev *dev, int offset)
 
 static void dw_writel(struct dw_i2c_dev *dev, u32 b, int offset)
 {
-	if (dev->accessor_flags & ACCESS_SWAP)
+	if (dev->flags & ACCESS_SWAP)
 		b = swab32(b);
 
-	if (dev->accessor_flags & ACCESS_16BIT) {
+	if (dev->flags & ACCESS_16BIT) {
 		writew_relaxed((u16)b, dev->base + offset);
 		writew_relaxed((u16)(b >> 16), dev->base + offset + 2);
 	} else {
@@ -339,10 +339,10 @@ int i2c_dw_init(struct dw_i2c_dev *dev)
 	reg = dw_readl(dev, DW_IC_COMP_TYPE);
 	if (reg == ___constant_swab32(DW_IC_COMP_TYPE_VALUE)) {
 		/* Configure register endianess access */
-		dev->accessor_flags |= ACCESS_SWAP;
+		dev->flags |= ACCESS_SWAP;
 	} else if (reg == (DW_IC_COMP_TYPE_VALUE & 0x0000ffff)) {
 		/* Configure register access mode 16bit */
-		dev->accessor_flags |= ACCESS_16BIT;
+		dev->flags |= ACCESS_16BIT;
 	} else if (reg != DW_IC_COMP_TYPE_VALUE) {
 		dev_err(dev->dev, "Unknown Synopsys component type: "
 			"0x%08x\n", reg);
@@ -926,7 +926,7 @@ static irqreturn_t i2c_dw_isr(int this_irq, void *dev_id)
 tx_aborted:
 	if ((stat & (DW_IC_INTR_TX_ABRT | DW_IC_INTR_STOP_DET)) || dev->msg_err)
 		complete(&dev->cmd_complete);
-	else if (unlikely(dev->accessor_flags & ACCESS_INTR_MASK)) {
+	else if (unlikely(dev->flags & ACCESS_INTR_MASK)) {
 		/* workaround to trigger pending interrupt */
 		stat = dw_readl(dev, DW_IC_INTR_MASK);
 		i2c_dw_disable_int(dev);
diff --git a/drivers/i2c/busses/i2c-designware-core.h b/drivers/i2c/busses/i2c-designware-core.h
index 26250b4..2c50571 100644
--- a/drivers/i2c/busses/i2c-designware-core.h
+++ b/drivers/i2c/busses/i2c-designware-core.h
@@ -103,7 +103,7 @@ struct dw_i2c_dev {
 	unsigned int		status;
 	u32			abort_source;
 	int			irq;
-	u32			accessor_flags;
+	u32			flags;
 	struct i2c_adapter	adapter;
 	u32			functionality;
 	u32			master_cfg;
diff --git a/drivers/i2c/busses/i2c-designware-platdrv.c b/drivers/i2c/busses/i2c-designware-platdrv.c
index 6ce4313..3eede7b 100644
--- a/drivers/i2c/busses/i2c-designware-platdrv.c
+++ b/drivers/i2c/busses/i2c-designware-platdrv.c
@@ -112,7 +112,7 @@ static int dw_i2c_acpi_configure(struct platform_device *pdev)
 
 	id = acpi_match_device(pdev->dev.driver->acpi_match_table, &pdev->dev);
 	if (id && id->driver_data)
-		dev->accessor_flags |= (u32)id->driver_data;
+		dev->flags |= (u32)id->driver_data;
 
 	return 0;
 }
-- 
2.9.3

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[PATCH v4 04/12] i2c: designware-baytrail: Pass dw_i2c_dev into helper functions

[Hans de Goede]

Pass dw_i2c_dev into the helper functions, this is a preparation patch
for the punit semaphore fixes done in the other patches in this set.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Reviewed-by: Takashi Iwai <tiwai@suse.de>
Tested-by: Takashi Iwai <tiwai@suse.de>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: Jarkko Nikula <jarkko.nikula@linux.intel.com>
Acked-by: Wolfram Sang <wsa@the-dreams.de>
---
 drivers/i2c/busses/i2c-designware-baytrail.c | 16 ++++++++--------
 1 file changed, 8 insertions(+), 8 deletions(-)

diff --git a/drivers/i2c/busses/i2c-designware-baytrail.c b/drivers/i2c/busses/i2c-designware-baytrail.c
index 1590ad0..a3f581c 100644
--- a/drivers/i2c/busses/i2c-designware-baytrail.c
+++ b/drivers/i2c/busses/i2c-designware-baytrail.c
@@ -28,14 +28,14 @@
 
 static unsigned long acquired;
 
-static int get_sem(struct device *dev, u32 *sem)
+static int get_sem(struct dw_i2c_dev *dev, u32 *sem)
 {
 	u32 data;
 	int ret;
 
 	ret = iosf_mbi_read(BT_MBI_UNIT_PMC, MBI_REG_READ, PUNIT_SEMAPHORE, &data);
 	if (ret) {
-		dev_err(dev, "iosf failed to read punit semaphore\n");
+		dev_err(dev->dev, "iosf failed to read punit semaphore\n");
 		return ret;
 	}
 
@@ -44,18 +44,18 @@ static int get_sem(struct device *dev, u32 *sem)
 	return 0;
 }
 
-static void reset_semaphore(struct device *dev)
+static void reset_semaphore(struct dw_i2c_dev *dev)
 {
 	u32 data;
 
 	if (iosf_mbi_read(BT_MBI_UNIT_PMC, MBI_REG_READ, PUNIT_SEMAPHORE, &data)) {
-		dev_err(dev, "iosf failed to reset punit semaphore during read\n");
+		dev_err(dev->dev, "iosf failed to reset punit semaphore during read\n");
 		return;
 	}
 
 	data &= ~PUNIT_SEMAPHORE_BIT;
 	if (iosf_mbi_write(BT_MBI_UNIT_PMC, MBI_REG_WRITE, PUNIT_SEMAPHORE, data))
-		dev_err(dev, "iosf failed to reset punit semaphore during write\n");
+		dev_err(dev->dev, "iosf failed to reset punit semaphore during write\n");
 }
 
 static int baytrail_i2c_acquire(struct dw_i2c_dev *dev)
@@ -83,7 +83,7 @@ static int baytrail_i2c_acquire(struct dw_i2c_dev *dev)
 	start = jiffies;
 	end = start + msecs_to_jiffies(SEMAPHORE_TIMEOUT);
 	do {
-		ret = get_sem(dev->dev, &sem);
+		ret = get_sem(dev, &sem);
 		if (!ret && sem) {
 			acquired = jiffies;
 			dev_dbg(dev->dev, "punit semaphore acquired after %ums\n",
@@ -95,7 +95,7 @@ static int baytrail_i2c_acquire(struct dw_i2c_dev *dev)
 	} while (time_before(jiffies, end));
 
 	dev_err(dev->dev, "punit semaphore timed out, resetting\n");
-	reset_semaphore(dev->dev);
+	reset_semaphore(dev);
 
 	ret = iosf_mbi_read(BT_MBI_UNIT_PMC, MBI_REG_READ, PUNIT_SEMAPHORE, &sem);
 	if (ret)
@@ -116,7 +116,7 @@ static void baytrail_i2c_release(struct dw_i2c_dev *dev)
 	if (!dev->acquire_lock)
 		return;
 
-	reset_semaphore(dev->dev);
+	reset_semaphore(dev);
 	dev_dbg(dev->dev, "punit semaphore held for %ums\n",
 		jiffies_to_msecs(jiffies - acquired));
 }
-- 
2.9.3

[PATCH v4 05/12] i2c: designware-baytrail: Only check iosf_mbi_available() for shared hosts

[Hans de Goede]

If (!shared_host) simply return 0, this avoids delaying the probe if
iosf_mbi_available() returns false when an i2c bus is not using the
punit semaphore.

Also move the if (!iosf_mbi_available()) check to above the
dev_info, so that we do not repeat the dev_info on every probe
until iosf_mbi_available() returns true.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: Jarkko Nikula <jarkko.nikula@linux.intel.com>
Tested-by: Takashi Iwai <tiwai@suse.de>
Acked-by: Wolfram Sang <wsa@the-dreams.de>
---
Changes in v2:
-New patch in v2 of this set
Changes in v3:
-Use if (!shared_host) return 0, to simplify the non-shared_host path
 and to avoid nested ifs
---
 drivers/i2c/busses/i2c-designware-baytrail.c | 13 +++++++------
 1 file changed, 7 insertions(+), 6 deletions(-)

diff --git a/drivers/i2c/busses/i2c-designware-baytrail.c b/drivers/i2c/busses/i2c-designware-baytrail.c
index a3f581c..cf02222 100644
--- a/drivers/i2c/busses/i2c-designware-baytrail.c
+++ b/drivers/i2c/busses/i2c-designware-baytrail.c
@@ -138,15 +138,16 @@ int i2c_dw_eval_lock_support(struct dw_i2c_dev *dev)
 	if (ACPI_FAILURE(status))
 		return 0;
 
-	if (shared_host) {
-		dev_info(dev->dev, "I2C bus managed by PUNIT\n");
-		dev->acquire_lock = baytrail_i2c_acquire;
-		dev->release_lock = baytrail_i2c_release;
-		dev->pm_runtime_disabled = true;
-	}
+	if (!shared_host)
+		return 0;
 
 	if (!iosf_mbi_available())
 		return -EPROBE_DEFER;
 
+	dev_info(dev->dev, "I2C bus managed by PUNIT\n");
+	dev->acquire_lock = baytrail_i2c_acquire;
+	dev->release_lock = baytrail_i2c_release;
+	dev->pm_runtime_disabled = true;
+
 	return 0;
 }
-- 
2.9.3

[PATCH v4 06/12] i2c: designware-baytrail: Disallow the CPU to enter C6 or C7 while holding the punit semaphore

[Hans de Goede]

On my cherrytrail tablet with axp288 pmic, just doing a bunch of repeated
reads from the pmic, e.g. "i2cdump -y 14 0x34" would lookup the tablet in
1 - 3 runs guaranteed.

This seems to be causes by the cpu trying to enter C6 or C7 while we hold
the punit bus semaphore, at which point everything just hangs.

Avoid this by disallowing the CPU to enter C6 or C7 before acquiring the
punit bus semaphore.

BugLink: https://bugzilla.kernel.org/show_bug.cgi?id=109051
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Tested-by: Takashi Iwai <tiwai@suse.de>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: Jarkko Nikula <jarkko.nikula@linux.intel.com>
Acked-by: Wolfram Sang <wsa@the-dreams.de>
---
Changes in v2:
-New patch in v2 of this set
Changes in v3:
-Change commit message and comment in the code from "force the CPU to C1"
 to "Disallow the CPU to enter C6 or C7", as the CPU may still be in either
 C0 or C1 with the request pm_qos
Changes in v4:
-Rename i2c_dw_eval_lock_support to i2c_dw_probe_lock_support so that we can
 add a matching i2c_dw_remove_lock_support cleanup function
-Move qm_pos removal to new i2c_dw_remove_lock_support function
-Move pm_qos_add_request to the end of i2c_dw_probe_lock_support
Changes in v5:
-Update the pm_qos for a latency of 0 *before* requesting the semaphore,
 instead of doing it while waiting for the request to be acked
---
 drivers/i2c/busses/i2c-designware-baytrail.c | 24 ++++++++++++++++++++++--
 drivers/i2c/busses/i2c-designware-core.h     |  9 +++++++--
 drivers/i2c/busses/i2c-designware-platdrv.c  |  4 +++-
 3 files changed, 32 insertions(+), 5 deletions(-)

diff --git a/drivers/i2c/busses/i2c-designware-baytrail.c b/drivers/i2c/busses/i2c-designware-baytrail.c
index cf02222..650a700 100644
--- a/drivers/i2c/busses/i2c-designware-baytrail.c
+++ b/drivers/i2c/busses/i2c-designware-baytrail.c
@@ -16,6 +16,7 @@
 #include <linux/acpi.h>
 #include <linux/i2c.h>
 #include <linux/interrupt.h>
+#include <linux/pm_qos.h>
 
 #include <asm/iosf_mbi.h>
 
@@ -56,6 +57,8 @@ static void reset_semaphore(struct dw_i2c_dev *dev)
 	data &= ~PUNIT_SEMAPHORE_BIT;
 	if (iosf_mbi_write(BT_MBI_UNIT_PMC, MBI_REG_WRITE, PUNIT_SEMAPHORE, data))
 		dev_err(dev->dev, "iosf failed to reset punit semaphore during write\n");
+
+	pm_qos_update_request(&dev->pm_qos, PM_QOS_DEFAULT_VALUE);
 }
 
 static int baytrail_i2c_acquire(struct dw_i2c_dev *dev)
@@ -72,11 +75,18 @@ static int baytrail_i2c_acquire(struct dw_i2c_dev *dev)
 	if (!dev->release_lock)
 		return 0;
 
+	/*
+	 * Disallow the CPU to enter C6 or C7 state, entering these states
+	 * requires the punit to talk to the pmic and if this happens while
+	 * we're holding the semaphore, the SoC hangs.
+	 */
+	pm_qos_update_request(&dev->pm_qos, 0);
+
 	/* host driver writes to side band semaphore register */
 	ret = iosf_mbi_write(BT_MBI_UNIT_PMC, MBI_REG_WRITE, PUNIT_SEMAPHORE, sem);
 	if (ret) {
 		dev_err(dev->dev, "iosf punit semaphore request failed\n");
-		return ret;
+		goto out;
 	}
 
 	/* host driver waits for bit 0 to be set in semaphore register */
@@ -95,6 +105,7 @@ static int baytrail_i2c_acquire(struct dw_i2c_dev *dev)
 	} while (time_before(jiffies, end));
 
 	dev_err(dev->dev, "punit semaphore timed out, resetting\n");
+out:
 	reset_semaphore(dev);
 
 	ret = iosf_mbi_read(BT_MBI_UNIT_PMC, MBI_REG_READ, PUNIT_SEMAPHORE, &sem);
@@ -121,7 +132,7 @@ static void baytrail_i2c_release(struct dw_i2c_dev *dev)
 		jiffies_to_msecs(jiffies - acquired));
 }
 
-int i2c_dw_eval_lock_support(struct dw_i2c_dev *dev)
+int i2c_dw_probe_lock_support(struct dw_i2c_dev *dev)
 {
 	acpi_status status;
 	unsigned long long shared_host = 0;
@@ -149,5 +160,14 @@ int i2c_dw_eval_lock_support(struct dw_i2c_dev *dev)
 	dev->release_lock = baytrail_i2c_release;
 	dev->pm_runtime_disabled = true;
 
+	pm_qos_add_request(&dev->pm_qos, PM_QOS_CPU_DMA_LATENCY,
+			   PM_QOS_DEFAULT_VALUE);
+
 	return 0;
 }
+
+void i2c_dw_remove_lock_support(struct dw_i2c_dev *dev)
+{
+	if (dev->acquire_lock)
+		pm_qos_remove_request(&dev->pm_qos);
+}
diff --git a/drivers/i2c/busses/i2c-designware-core.h b/drivers/i2c/busses/i2c-designware-core.h
index 2c50571..94a5fd1 100644
--- a/drivers/i2c/busses/i2c-designware-core.h
+++ b/drivers/i2c/busses/i2c-designware-core.h
@@ -23,6 +23,7 @@
  */
 
 #include <linux/i2c.h>
+#include <linux/pm_qos.h>
 
 #define DW_IC_DEFAULT_FUNCTIONALITY (I2C_FUNC_I2C |			\
 					I2C_FUNC_SMBUS_BYTE |		\
@@ -75,6 +76,7 @@
  * @fp_lcnt: fast plus LCNT value
  * @hs_hcnt: high speed HCNT value
  * @hs_lcnt: high speed LCNT value
+ * @pm_qos: pm_qos_request used while holding a hardware lock on the bus
  * @acquire_lock: function to acquire a hardware lock on the bus
  * @release_lock: function to release a hardware lock on the bus
  * @pm_runtime_disabled: true if pm runtime is disabled
@@ -122,6 +124,7 @@ struct dw_i2c_dev {
 	u16			fp_lcnt;
 	u16			hs_hcnt;
 	u16			hs_lcnt;
+	struct pm_qos_request	pm_qos;
 	int			(*acquire_lock)(struct dw_i2c_dev *dev);
 	void			(*release_lock)(struct dw_i2c_dev *dev);
 	bool			pm_runtime_disabled;
@@ -139,7 +142,9 @@ extern u32 i2c_dw_read_comp_param(struct dw_i2c_dev *dev);
 extern int i2c_dw_probe(struct dw_i2c_dev *dev);
 
 #if IS_ENABLED(CONFIG_I2C_DESIGNWARE_BAYTRAIL)
-extern int i2c_dw_eval_lock_support(struct dw_i2c_dev *dev);
+extern int i2c_dw_probe_lock_support(struct dw_i2c_dev *dev);
+extern void i2c_dw_remove_lock_support(struct dw_i2c_dev *dev);
 #else
-static inline int i2c_dw_eval_lock_support(struct dw_i2c_dev *dev) { return 0; }
+static inline int i2c_dw_probe_lock_support(struct dw_i2c_dev *dev) { return 0; }
+static inline void i2c_dw_remove_lock_support(struct dw_i2c_dev *dev) {}
 #endif
diff --git a/drivers/i2c/busses/i2c-designware-platdrv.c b/drivers/i2c/busses/i2c-designware-platdrv.c
index 3eede7b..d474db0 100644
--- a/drivers/i2c/busses/i2c-designware-platdrv.c
+++ b/drivers/i2c/busses/i2c-designware-platdrv.c
@@ -238,7 +238,7 @@ static int dw_i2c_plat_probe(struct platform_device *pdev)
 		return -EINVAL;
 	}
 
-	r = i2c_dw_eval_lock_support(dev);
+	r = i2c_dw_probe_lock_support(dev);
 	if (r)
 		return r;
 
@@ -307,6 +307,8 @@ static int dw_i2c_plat_remove(struct platform_device *pdev)
 	if (!dev->pm_runtime_disabled)
 		pm_runtime_disable(&pdev->dev);
 
+	i2c_dw_remove_lock_support(dev);
+
 	return 0;
 }
 
-- 
2.9.3

[PATCH v4 07/12] i2c: designware-baytrail: Fix race when resetting the semaphore

[Hans de Goede]

Use iosf_mbi_modify instead of iosf_mbi_read + iosf_mbi_write so that
we keep the iosf_mbi_lock locked during the read-modify-write done to
reset the semaphore.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: Jarkko Nikula <jarkko.nikula@linux.intel.com>
Acked-by: Wolfram Sang <wsa@the-dreams.de>
---
Changes in v5:
-New patch in v5 of this patch-set
---
 drivers/i2c/busses/i2c-designware-baytrail.c | 11 ++---------
 1 file changed, 2 insertions(+), 9 deletions(-)

diff --git a/drivers/i2c/busses/i2c-designware-baytrail.c b/drivers/i2c/busses/i2c-designware-baytrail.c
index 650a700..8df529c 100644
--- a/drivers/i2c/busses/i2c-designware-baytrail.c
+++ b/drivers/i2c/busses/i2c-designware-baytrail.c
@@ -47,15 +47,8 @@ static int get_sem(struct dw_i2c_dev *dev, u32 *sem)
 
 static void reset_semaphore(struct dw_i2c_dev *dev)
 {
-	u32 data;
-
-	if (iosf_mbi_read(BT_MBI_UNIT_PMC, MBI_REG_READ, PUNIT_SEMAPHORE, &data)) {
-		dev_err(dev->dev, "iosf failed to reset punit semaphore during read\n");
-		return;
-	}
-
-	data &= ~PUNIT_SEMAPHORE_BIT;
-	if (iosf_mbi_write(BT_MBI_UNIT_PMC, MBI_REG_WRITE, PUNIT_SEMAPHORE, data))
+	if (iosf_mbi_modify(BT_MBI_UNIT_PMC, MBI_REG_READ, PUNIT_SEMAPHORE,
+			    0, PUNIT_SEMAPHORE_BIT))
 		dev_err(dev->dev, "iosf failed to reset punit semaphore during write\n");
 
 	pm_qos_update_request(&dev->pm_qos, PM_QOS_DEFAULT_VALUE);
-- 
2.9.3

_______________________________________________
Intel-gfx mailing list
Intel-gfx@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/intel-gfx

[PATCH v4 08/12] i2c: designware-baytrail: Add support for cherrytrail

[Hans de Goede]

The cherrytrail punit has the pmic i2c bus access semaphore at a
different register address.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Reviewed-by: Takashi Iwai <tiwai@suse.de>
Tested-by: Takashi Iwai <tiwai@suse.de>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: Jarkko Nikula <jarkko.nikula@linux.intel.com>
Acked-by: Wolfram Sang <wsa@the-dreams.de>
---
Changes in v2:
-Adjust for accessor_flags -> flags rename
-Add flags field to struct dw_pci_controller
-Add get_sem_addr() helper replacing MODEL_CHERRYTRAIL flag checking in
 PUNIT_SEMAPHORE macro
Changes in v3:
-Add a gap between ACCESS_* and MODEL_* flags as reserved space for
 future ACCESS_* flags
Changes in v4:
-s/CHV/CHT/
---
 drivers/i2c/busses/i2c-designware-baytrail.c | 19 +++++++++++++++----
 drivers/i2c/busses/i2c-designware-core.h     |  2 ++
 drivers/i2c/busses/i2c-designware-pcidrv.c   | 26 +++++++++++++++++++-------
 drivers/i2c/busses/i2c-designware-platdrv.c  |  2 +-
 4 files changed, 37 insertions(+), 12 deletions(-)

diff --git a/drivers/i2c/busses/i2c-designware-baytrail.c b/drivers/i2c/busses/i2c-designware-baytrail.c
index 8df529c..3effc9a 100644
--- a/drivers/i2c/busses/i2c-designware-baytrail.c
+++ b/drivers/i2c/busses/i2c-designware-baytrail.c
@@ -24,17 +24,27 @@
 
 #define SEMAPHORE_TIMEOUT	100
 #define PUNIT_SEMAPHORE		0x7
+#define PUNIT_SEMAPHORE_CHT	0x10e
 #define PUNIT_SEMAPHORE_BIT	BIT(0)
 #define PUNIT_SEMAPHORE_ACQUIRE	BIT(1)
 
 static unsigned long acquired;
 
+static u32 get_sem_addr(struct dw_i2c_dev *dev)
+{
+	if (dev->flags & MODEL_CHERRYTRAIL)
+		return PUNIT_SEMAPHORE_CHT;
+	else
+		return PUNIT_SEMAPHORE;
+}
+
 static int get_sem(struct dw_i2c_dev *dev, u32 *sem)
 {
+	u32 addr = get_sem_addr(dev);
 	u32 data;
 	int ret;
 
-	ret = iosf_mbi_read(BT_MBI_UNIT_PMC, MBI_REG_READ, PUNIT_SEMAPHORE, &data);
+	ret = iosf_mbi_read(BT_MBI_UNIT_PMC, MBI_REG_READ, addr, &data);
 	if (ret) {
 		dev_err(dev->dev, "iosf failed to read punit semaphore\n");
 		return ret;
@@ -47,7 +57,7 @@ static int get_sem(struct dw_i2c_dev *dev, u32 *sem)
 
 static void reset_semaphore(struct dw_i2c_dev *dev)
 {
-	if (iosf_mbi_modify(BT_MBI_UNIT_PMC, MBI_REG_READ, PUNIT_SEMAPHORE,
+	if (iosf_mbi_modify(BT_MBI_UNIT_PMC, MBI_REG_READ, get_sem_addr(dev),
 			    0, PUNIT_SEMAPHORE_BIT))
 		dev_err(dev->dev, "iosf failed to reset punit semaphore during write\n");
 
@@ -56,6 +66,7 @@ static void reset_semaphore(struct dw_i2c_dev *dev)
 
 static int baytrail_i2c_acquire(struct dw_i2c_dev *dev)
 {
+	u32 addr = get_sem_addr(dev);
 	u32 sem = PUNIT_SEMAPHORE_ACQUIRE;
 	int ret;
 	unsigned long start, end;
@@ -76,7 +87,7 @@ static int baytrail_i2c_acquire(struct dw_i2c_dev *dev)
 	pm_qos_update_request(&dev->pm_qos, 0);
 
 	/* host driver writes to side band semaphore register */
-	ret = iosf_mbi_write(BT_MBI_UNIT_PMC, MBI_REG_WRITE, PUNIT_SEMAPHORE, sem);
+	ret = iosf_mbi_write(BT_MBI_UNIT_PMC, MBI_REG_WRITE, addr, sem);
 	if (ret) {
 		dev_err(dev->dev, "iosf punit semaphore request failed\n");
 		goto out;
@@ -101,7 +112,7 @@ static int baytrail_i2c_acquire(struct dw_i2c_dev *dev)
 out:
 	reset_semaphore(dev);
 
-	ret = iosf_mbi_read(BT_MBI_UNIT_PMC, MBI_REG_READ, PUNIT_SEMAPHORE, &sem);
+	ret = iosf_mbi_read(BT_MBI_UNIT_PMC, MBI_REG_READ, addr, &sem);
 	if (ret)
 		dev_err(dev->dev, "iosf failed to read punit semaphore\n");
 	else
diff --git a/drivers/i2c/busses/i2c-designware-core.h b/drivers/i2c/busses/i2c-designware-core.h
index 94a5fd1..a8e74ca 100644
--- a/drivers/i2c/busses/i2c-designware-core.h
+++ b/drivers/i2c/busses/i2c-designware-core.h
@@ -135,6 +135,8 @@ struct dw_i2c_dev {
 #define ACCESS_16BIT		0x00000002
 #define ACCESS_INTR_MASK	0x00000004
 
+#define MODEL_CHERRYTRAIL	0x00000100
+
 extern int i2c_dw_init(struct dw_i2c_dev *dev);
 extern void i2c_dw_disable(struct dw_i2c_dev *dev);
 extern void i2c_dw_disable_int(struct dw_i2c_dev *dev);
diff --git a/drivers/i2c/busses/i2c-designware-pcidrv.c b/drivers/i2c/busses/i2c-designware-pcidrv.c
index d6423cf..ed485b6 100644
--- a/drivers/i2c/busses/i2c-designware-pcidrv.c
+++ b/drivers/i2c/busses/i2c-designware-pcidrv.c
@@ -45,6 +45,7 @@ enum dw_pci_ctl_id_t {
 	medfield,
 	merrifield,
 	baytrail,
+	cherrytrail,
 	haswell,
 };
 
@@ -63,6 +64,7 @@ struct dw_pci_controller {
 	u32 rx_fifo_depth;
 	u32 clk_khz;
 	u32 functionality;
+	u32 flags;
 	struct dw_scl_sda_cfg *scl_sda_cfg;
 	int (*setup)(struct pci_dev *pdev, struct dw_pci_controller *c);
 };
@@ -170,6 +172,15 @@ static struct dw_pci_controller dw_pci_controllers[] = {
 		.functionality = I2C_FUNC_10BIT_ADDR,
 		.scl_sda_cfg = &hsw_config,
 	},
+	[cherrytrail] = {
+		.bus_num = -1,
+		.bus_cfg = INTEL_MID_STD_CFG | DW_IC_CON_SPEED_FAST,
+		.tx_fifo_depth = 32,
+		.rx_fifo_depth = 32,
+		.functionality = I2C_FUNC_10BIT_ADDR,
+		.flags = MODEL_CHERRYTRAIL,
+		.scl_sda_cfg = &byt_config,
+	},
 };
 
 #ifdef CONFIG_PM
@@ -237,6 +248,7 @@ static int i2c_dw_pci_probe(struct pci_dev *pdev,
 	dev->base = pcim_iomap_table(pdev)[0];
 	dev->dev = &pdev->dev;
 	dev->irq = pdev->irq;
+	dev->flags |= controller->flags;
 
 	if (controller->setup) {
 		r = controller->setup(pdev, controller);
@@ -317,13 +329,13 @@ static const struct pci_device_id i2_designware_pci_ids[] = {
 	{ PCI_VDEVICE(INTEL, 0x9c61), haswell },
 	{ PCI_VDEVICE(INTEL, 0x9c62), haswell },
 	/* Braswell / Cherrytrail */
-	{ PCI_VDEVICE(INTEL, 0x22C1), baytrail },
-	{ PCI_VDEVICE(INTEL, 0x22C2), baytrail },
-	{ PCI_VDEVICE(INTEL, 0x22C3), baytrail },
-	{ PCI_VDEVICE(INTEL, 0x22C4), baytrail },
-	{ PCI_VDEVICE(INTEL, 0x22C5), baytrail },
-	{ PCI_VDEVICE(INTEL, 0x22C6), baytrail },
-	{ PCI_VDEVICE(INTEL, 0x22C7), baytrail },
+	{ PCI_VDEVICE(INTEL, 0x22C1), cherrytrail },
+	{ PCI_VDEVICE(INTEL, 0x22C2), cherrytrail },
+	{ PCI_VDEVICE(INTEL, 0x22C3), cherrytrail },
+	{ PCI_VDEVICE(INTEL, 0x22C4), cherrytrail },
+	{ PCI_VDEVICE(INTEL, 0x22C5), cherrytrail },
+	{ PCI_VDEVICE(INTEL, 0x22C6), cherrytrail },
+	{ PCI_VDEVICE(INTEL, 0x22C7), cherrytrail },
 	{ 0,}
 };
 MODULE_DEVICE_TABLE(pci, i2_designware_pci_ids);
diff --git a/drivers/i2c/busses/i2c-designware-platdrv.c b/drivers/i2c/busses/i2c-designware-platdrv.c
index d474db0..df0ff7d 100644
--- a/drivers/i2c/busses/i2c-designware-platdrv.c
+++ b/drivers/i2c/busses/i2c-designware-platdrv.c
@@ -123,7 +123,7 @@ static const struct acpi_device_id dw_i2c_acpi_match[] = {
 	{ "INT3432", 0 },
 	{ "INT3433", 0 },
 	{ "80860F41", 0 },
-	{ "808622C1", 0 },
+	{ "808622C1", MODEL_CHERRYTRAIL },
 	{ "AMD0010", ACCESS_INTR_MASK },
 	{ "AMDI0010", ACCESS_INTR_MASK },
 	{ "AMDI0510", 0 },
-- 
2.9.3

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[PATCH v4 09/12] i2c: designware-baytrail: Acquire P-Unit access on bus acquire

[Hans de Goede]

Acquire P-Unit access to stop others from accessing the P-Unit while the
PMIC i2c bus is in use. This is necessary because accessing the P-Unit
from the kernel may result in the P-Unit trying to access the PMIC i2c
bus, which results in a hang when it happens while we own the PMIC i2c
bus semaphore.

BugLink: https://bugzilla.kernel.org/show_bug.cgi?id=155241
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Tested-by: tagorereddy <tagore.chandan@gmail.com>
Acked-by: Wolfram Sang <wsa@the-dreams.de>
Acked-by: Jarkko Nikula <jarkko.nikula@linux.intel.com>
---
Changes in v2:
-Spelling: P-Unit, PMIC
-Adjust for iosf_mbi_punit_lock/_unlock to _acquire/_release rename
---
 drivers/i2c/busses/i2c-designware-baytrail.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/i2c/busses/i2c-designware-baytrail.c b/drivers/i2c/busses/i2c-designware-baytrail.c
index 3effc9a..7eddc3b 100644
--- a/drivers/i2c/busses/i2c-designware-baytrail.c
+++ b/drivers/i2c/busses/i2c-designware-baytrail.c
@@ -62,6 +62,8 @@ static void reset_semaphore(struct dw_i2c_dev *dev)
 		dev_err(dev->dev, "iosf failed to reset punit semaphore during write\n");
 
 	pm_qos_update_request(&dev->pm_qos, PM_QOS_DEFAULT_VALUE);
+
+	iosf_mbi_punit_release();
 }
 
 static int baytrail_i2c_acquire(struct dw_i2c_dev *dev)
@@ -79,6 +81,8 @@ static int baytrail_i2c_acquire(struct dw_i2c_dev *dev)
 	if (!dev->release_lock)
 		return 0;
 
+	iosf_mbi_punit_acquire();
+
 	/*
 	 * Disallow the CPU to enter C6 or C7 state, entering these states
 	 * requires the punit to talk to the pmic and if this happens while
-- 
2.9.3

[PATCH v4 10/12] i2c: designware-baytrail: Call pmic_bus_access_notifier_chain

[Hans de Goede]

Call the iosf_mbi pmic_bus_access_notifier_chain on bus acquire / release.

BugLink: https://bugzilla.kernel.org/show_bug.cgi?id=155241
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Tested-by: tagorereddy <tagore.chandan@gmail.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: Wolfram Sang <wsa@the-dreams.de>
Acked-by: Jarkko Nikula <jarkko.nikula@linux.intel.com>
---
Changes in v2:
-Spelling: P-Unit, PMIC
---
 drivers/i2c/busses/i2c-designware-baytrail.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/i2c/busses/i2c-designware-baytrail.c b/drivers/i2c/busses/i2c-designware-baytrail.c
index 7eddc3b..1749a0f 100644
--- a/drivers/i2c/busses/i2c-designware-baytrail.c
+++ b/drivers/i2c/busses/i2c-designware-baytrail.c
@@ -63,6 +63,8 @@ static void reset_semaphore(struct dw_i2c_dev *dev)
 
 	pm_qos_update_request(&dev->pm_qos, PM_QOS_DEFAULT_VALUE);
 
+	iosf_mbi_call_pmic_bus_access_notifier_chain(MBI_PMIC_BUS_ACCESS_END,
+						     NULL);
 	iosf_mbi_punit_release();
 }
 
@@ -82,6 +84,8 @@ static int baytrail_i2c_acquire(struct dw_i2c_dev *dev)
 		return 0;
 
 	iosf_mbi_punit_acquire();
+	iosf_mbi_call_pmic_bus_access_notifier_chain(MBI_PMIC_BUS_ACCESS_BEGIN,
+						     NULL);
 
 	/*
 	 * Disallow the CPU to enter C6 or C7 state, entering these states
-- 
2.9.3

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[PATCH v4 11/12] drm/i915: Add intel_uncore_suspend / resume functions

[Hans de Goede]

Rename intel_uncore_early_sanitize to intel_uncore_resume, dropping the
(always true) restore_forcewake argument and add a new intel_uncore_resume
function to replace the intel_uncore_forcewake_reset(dev_priv, false)
calls done from the suspend / runtime_suspend functions and make
intel_uncore_forcewake_reset private.

This is a preparation patch for adding PMIC bus access notifier support.

BugLink: https://bugzilla.kernel.org/show_bug.cgi?id=155241
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Tested-by: tagorereddy <tagore.chandan@gmail.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Acked-by: Jani Nikula <jani.nikula@intel.com>
---
Changes in v2:
-Spelling: P-Unit, PMIC
Changes in v3:
-Rename intel_uncore_resume to intel_uncore_resume_early
-Keep intel_uncore_forcewake_reset name as is
---
 drivers/gpu/drm/i915/i915_drv.c     |  6 +++---
 drivers/gpu/drm/i915/i915_drv.h     |  6 ++----
 drivers/gpu/drm/i915/intel_uncore.c | 14 +++++++++-----
 3 files changed, 14 insertions(+), 12 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c
index 747cd5d..4b413db 100644
--- a/drivers/gpu/drm/i915/i915_drv.c
+++ b/drivers/gpu/drm/i915/i915_drv.c
@@ -1515,7 +1515,7 @@ static int i915_drm_suspend(struct drm_device *dev)
 	opregion_target_state = suspend_to_idle(dev_priv) ? PCI_D1 : PCI_D3cold;
 	intel_opregion_notify_adapter(dev_priv, opregion_target_state);
 
-	intel_uncore_forcewake_reset(dev_priv, false);
+	intel_uncore_suspend(dev_priv);
 	intel_opregion_unregister(dev_priv);
 
 	intel_fbdev_set_suspend(dev, FBINFO_STATE_SUSPENDED, true);
@@ -1760,7 +1760,7 @@ static int i915_drm_resume_early(struct drm_device *dev)
 		DRM_ERROR("Resume prepare failed: %d, continuing anyway\n",
 			  ret);
 
-	intel_uncore_early_sanitize(dev_priv, true);
+	intel_uncore_resume_early(dev_priv);
 
 	if (IS_GEN9_LP(dev_priv)) {
 		if (!dev_priv->suspended_to_idle)
@@ -2405,7 +2405,7 @@ static int intel_runtime_suspend(struct device *kdev)
 		return ret;
 	}
 
-	intel_uncore_forcewake_reset(dev_priv, false);
+	intel_uncore_suspend(dev_priv);
 
 	enable_rpm_wakeref_asserts(dev_priv);
 	WARN_ON_ONCE(atomic_read(&dev_priv->pm.wakeref_count));
diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 1fe4010..ca699de 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -3028,14 +3028,12 @@ int intel_irq_install(struct drm_i915_private *dev_priv);
 void intel_irq_uninstall(struct drm_i915_private *dev_priv);
 
 extern void intel_uncore_sanitize(struct drm_i915_private *dev_priv);
-extern void intel_uncore_early_sanitize(struct drm_i915_private *dev_priv,
-					bool restore_forcewake);
 extern void intel_uncore_init(struct drm_i915_private *dev_priv);
 extern bool intel_uncore_unclaimed_mmio(struct drm_i915_private *dev_priv);
 extern bool intel_uncore_arm_unclaimed_mmio_detection(struct drm_i915_private *dev_priv);
 extern void intel_uncore_fini(struct drm_i915_private *dev_priv);
-extern void intel_uncore_forcewake_reset(struct drm_i915_private *dev_priv,
-					 bool restore);
+extern void intel_uncore_suspend(struct drm_i915_private *dev_priv);
+extern void intel_uncore_resume_early(struct drm_i915_private *dev_priv);
 const char *intel_uncore_forcewake_domain_to_str(const enum forcewake_domain_id id);
 void intel_uncore_forcewake_get(struct drm_i915_private *dev_priv,
 				enum forcewake_domains domains);
diff --git a/drivers/gpu/drm/i915/intel_uncore.c b/drivers/gpu/drm/i915/intel_uncore.c
index 441c51f..699a107 100644
--- a/drivers/gpu/drm/i915/intel_uncore.c
+++ b/drivers/gpu/drm/i915/intel_uncore.c
@@ -257,8 +257,8 @@ intel_uncore_fw_release_timer(struct hrtimer *timer)
 	return HRTIMER_NORESTART;
 }
 
-void intel_uncore_forcewake_reset(struct drm_i915_private *dev_priv,
-				  bool restore)
+static void intel_uncore_forcewake_reset(struct drm_i915_private *dev_priv,
+					 bool restore)
 {
 	unsigned long irqflags;
 	struct intel_uncore_forcewake_domain *domain;
@@ -434,10 +434,14 @@ static void __intel_uncore_early_sanitize(struct drm_i915_private *dev_priv,
 	intel_uncore_forcewake_reset(dev_priv, restore_forcewake);
 }
 
-void intel_uncore_early_sanitize(struct drm_i915_private *dev_priv,
-				 bool restore_forcewake)
+void intel_uncore_suspend(struct drm_i915_private *dev_priv)
 {
-	__intel_uncore_early_sanitize(dev_priv, restore_forcewake);
+	intel_uncore_forcewake_reset(dev_priv, false);
+}
+
+void intel_uncore_resume_early(struct drm_i915_private *dev_priv)
+{
+	__intel_uncore_early_sanitize(dev_priv, true);
 	i915_check_and_clear_faults(dev_priv);
 }
 
-- 
2.9.3

[PATCH v4 12/12] drm/i915: Listen for PMIC bus access notifications

[Hans de Goede]

Listen for PMIC bus access notifications and get FORCEWAKE_ALL while
the bus is accessed to avoid needing to do any forcewakes, which need
PMIC bus access, while the PMIC bus is busy:

This fixes errors like these showing up in dmesg, usually followed
by a gfx or system freeze:

[drm:fw_domains_get [i915]] *ERROR* render: timed out waiting for forcewake ack request.
[drm:fw_domains_get [i915]] *MEDIA* render: timed out waiting for forcewake ack request.
i2c_designware 808622C1:06: punit semaphore timed out, resetting
i2c_designware 808622C1:06: PUNIT SEM: 2
i2c_designware 808622C1:06: couldn't acquire bus ownership

Downside of this approach is that it causes wakeups whenever the PMIC
bus is accessed. Unfortunately we cannot simply wait for the PMIC bus
to go idle when we hit a race, as forcewakes may be done from interrupt
handlers where we cannot sleep to wait for the i2c PMIC bus access to
finish.

Note that the notifications and thus the wakeups will only happen on
baytrail / cherrytrail devices using PMICs with a shared i2c bus for
P-Unit and host PMIC access (i2c busses with a _SEM method in their
APCI node), e.g. an axp288 PMIC.

I plan to write some patches for drivers accessing the PMIC bus to
limit their bus accesses to a bare minimum (e.g. cache registers, do not
update battery level more often then 4 times a minute), to limit the
amount of wakeups.

BugLink: https://bugzilla.kernel.org/show_bug.cgi?id=155241
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Tested-by: tagorereddy <tagore.chandan@gmail.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Acked-by: Jani Nikula <jani.nikula@intel.com>
---
Changes in v2:
-Spelling: P-Unit, PMIC
Changes in v3:
-Improve comment explaining why we call intel_uncore_forcewake_get(ALL) on
 MBI_PMIC_BUS_ACCESS_BEGIN notification
---
 drivers/gpu/drm/i915/Kconfig        |  1 +
 drivers/gpu/drm/i915/i915_drv.h     |  1 +
 drivers/gpu/drm/i915/intel_uncore.c | 39 +++++++++++++++++++++++++++++++++++++
 3 files changed, 41 insertions(+)

diff --git a/drivers/gpu/drm/i915/Kconfig b/drivers/gpu/drm/i915/Kconfig
index 1ae0bb9..a5cd5da 100644
--- a/drivers/gpu/drm/i915/Kconfig
+++ b/drivers/gpu/drm/i915/Kconfig
@@ -20,6 +20,7 @@ config DRM_I915
 	select ACPI_VIDEO if ACPI
 	select ACPI_BUTTON if ACPI
 	select SYNC_FILE
+	select IOSF_MBI
 	help
 	  Choose this option if you have a system that has "Intel Graphics
 	  Media Accelerator" or "HD Graphics" integrated graphics,
diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index ca699de..e4af9b7 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -749,6 +749,7 @@ struct intel_uncore {
 	const struct intel_forcewake_range *fw_domains_table;
 	unsigned int fw_domains_table_entries;
 
+	struct notifier_block pmic_bus_access_nb;
 	struct intel_uncore_funcs funcs;
 
 	unsigned fifo_count;
diff --git a/drivers/gpu/drm/i915/intel_uncore.c b/drivers/gpu/drm/i915/intel_uncore.c
index 699a107..7d965e2 100644
--- a/drivers/gpu/drm/i915/intel_uncore.c
+++ b/drivers/gpu/drm/i915/intel_uncore.c
@@ -25,6 +25,7 @@
 #include "intel_drv.h"
 #include "i915_vgpu.h"
 
+#include <asm/iosf_mbi.h>
 #include <linux/pm_runtime.h>
 
 #define FORCEWAKE_ACK_TIMEOUT_MS 50
@@ -436,12 +437,16 @@ static void __intel_uncore_early_sanitize(struct drm_i915_private *dev_priv,
 
 void intel_uncore_suspend(struct drm_i915_private *dev_priv)
 {
+	iosf_mbi_unregister_pmic_bus_access_notifier(
+		&dev_priv->uncore.pmic_bus_access_nb);
 	intel_uncore_forcewake_reset(dev_priv, false);
 }
 
 void intel_uncore_resume_early(struct drm_i915_private *dev_priv)
 {
 	__intel_uncore_early_sanitize(dev_priv, true);
+	iosf_mbi_register_pmic_bus_access_notifier(
+		&dev_priv->uncore.pmic_bus_access_nb);
 	i915_check_and_clear_faults(dev_priv);
 }
 
@@ -1285,6 +1290,32 @@ static void intel_uncore_fw_domains_init(struct drm_i915_private *dev_priv)
 	dev_priv->uncore.fw_domains_table_entries = ARRAY_SIZE((d)); \
 }
 
+static int i915_pmic_bus_access_notifier(struct notifier_block *nb,
+					 unsigned long action, void *data)
+{
+	struct drm_i915_private *dev_priv = container_of(nb,
+			struct drm_i915_private, uncore.pmic_bus_access_nb);
+
+	switch (action) {
+	case MBI_PMIC_BUS_ACCESS_BEGIN:
+		/*
+		 * forcewake all now to make sure that we don't need to do a
+		 * forcewake later which on systems where this notifier gets
+		 * called requires the punit to access to the shared pmic i2c
+		 * bus, which will be busy after this notification, leading to:
+		 * "render: timed out waiting for forcewake ack request."
+		 * errors.
+		 */
+		intel_uncore_forcewake_get(dev_priv, FORCEWAKE_ALL);
+		break;
+	case MBI_PMIC_BUS_ACCESS_END:
+		intel_uncore_forcewake_put(dev_priv, FORCEWAKE_ALL);
+		break;
+	}
+
+	return NOTIFY_OK;
+}
+
 void intel_uncore_init(struct drm_i915_private *dev_priv)
 {
 	i915_check_vgpu(dev_priv);
@@ -1294,6 +1325,8 @@ void intel_uncore_init(struct drm_i915_private *dev_priv)
 	__intel_uncore_early_sanitize(dev_priv, false);
 
 	dev_priv->uncore.unclaimed_mmio_check = 1;
+	dev_priv->uncore.pmic_bus_access_nb.notifier_call =
+		i915_pmic_bus_access_notifier;
 
 	switch (INTEL_INFO(dev_priv)->gen) {
 	default:
@@ -1344,6 +1377,9 @@ void intel_uncore_init(struct drm_i915_private *dev_priv)
 		break;
 	}
 
+	iosf_mbi_register_pmic_bus_access_notifier(
+		&dev_priv->uncore.pmic_bus_access_nb);
+
 	i915_check_and_clear_faults(dev_priv);
 }
 #undef ASSIGN_WRITE_MMIO_VFUNCS
@@ -1351,6 +1387,9 @@ void intel_uncore_init(struct drm_i915_private *dev_priv)
 
 void intel_uncore_fini(struct drm_i915_private *dev_priv)
 {
+	iosf_mbi_unregister_pmic_bus_access_notifier(
+		&dev_priv->uncore.pmic_bus_access_nb);
+
 	/* Paranoia: make sure we have disabled everything before we exit. */
 	intel_uncore_sanitize(dev_priv);
 	intel_uncore_forcewake_reset(dev_priv, false);
-- 
2.9.3

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