[PATCH 0/8] iommu/omap: misc fixes

[PATCH 0/8] iommu/omap: misc fixes

[Tero Kristo via iommu]

Hi Joerg,

Here are a few fixes for OMAP IOMMU. These are mostly towards getting
runtime PM support functional again for the IOMMU.

-Tero

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[PATCH 1/8] iommu/omap: fix boot issue on remoteprocs with AMMU/Unicache

[Tero Kristo via iommu]

From: Suman Anna <s-anna@ti.com>

Support has been added to the OMAP IOMMU driver to fix a boot hang
issue on OMAP remoteprocs with AMMU/Unicache, caused by an improper
AMMU/Unicache state upon initial deassertion of the processor reset.
The issue is described in detail in the next three paragraphs.

All the Cortex M3/M4 IPU processor subsystems in OMAP SoCs have a
AMMU/Unicache IP that dictates the memory attributes for addresses
seen by the processor cores. The AMMU/Unicache is configured/enabled
by the SCACHE_CONFIG.BYPASS bit - a value of 1 enables the cache and
mandates all addresses accessed by M3/M4 be defined in the AMMU. This
bit is not programmable from the host processor. The M3/M4 boot
sequence starts out with the AMMU/Unicache in disabled state, and
SYS/BIOS programs the AMMU regions and enables the Unicache during
one of its initial boot steps. This SCACHE_CONFIG.BYPASS bit is
however enabled by default whenever a RET reset is applied to the IP,
irrespective of whether it was previously enabled or not. The AMMU
registers lose their context whenever this reset is applied. The reset
is effective as long as the MMU portion of the subsystem is enabled
and clocked. This behavior is common to all the IPU and DSP subsystems
that have an AMMU/Unicache.

The IPU boot sequence involves enabling and programming the MMU, and
loading the processor and releasing the reset(s) for the processor.
The PM setup code currently sets the target state for most of the
power domains to RET. The L2 MMU can be enabled, programmed and
accessed properly just fine with the domain in hardware supervised
mode, while the power domain goes through a RET->ON->RET transition
during the programming sequence. However, the ON->RET transition
asserts a RET reset, and the SCACHE_CONFIG.BYPASS bit gets auto-set.
An AMMU fault is thrown immediately when the M3/M4 core's reset is
released since the first instruction address itself will not be
defined in any valid AMMU regions. The ON->RET transition happens
automatically on the power domain after enabling the iommu due to
the hardware supervised mode.

This patch adds and invokes the .set_pwrdm_constraint pdata ops, if
present, during the OMAP IOMMU enable and disable functions to resolve
the above boot hang issue. The ops will allow to invoke a mach-omap2
layer API pwrdm_set_next_pwrst() in a multi-arch kernel environment.
The ops also returns the current power domain state while enforcing
the constraint so that the driver can store it and use it to set back
the power domain state while releasing the constraint. The pdata ops
implementation restricts the target power domain to ON during enable,
and back to the original power domain state during disable, and thereby
eliminating the conditions for the boot issue. The implementation is
effective only when the original power domain state is either RET or
OFF, and is a no-op when it is ON or INACTIVE.

The .set_pwrdm_constraint ops need to be plugged in pdata-quirks
for the affected remote processors to be able to boot properly.

Note that the current issue is seen only on kernels with the affected
power domains programmed to enter RET. For eg., IPU1 on DRA7xx is in a
separate domain and is susceptible to this bug, while the IPU2 subsystem
is within CORE power domain, and CORE RET is not supported on this SoC.
IPUs on OMAP4 and OMAP5 are also susceptible since they are in CORE power
domain, and CORE RET is a valid power target on these SoCs.

Signed-off-by: Suman Anna <s-anna@ti.com>
---
 arch/arm/mach-omap2/Makefile             |  2 ++
 arch/arm/mach-omap2/omap-iommu.c         | 51 ++++++++++++++++++++++++++++++++
 drivers/iommu/omap-iommu.c               | 17 +++++++++++
 drivers/iommu/omap-iommu.h               |  2 ++
 include/linux/platform_data/iommu-omap.h |  2 ++
 5 files changed, 74 insertions(+)
 create mode 100644 arch/arm/mach-omap2/omap-iommu.c

diff --git a/arch/arm/mach-omap2/Makefile b/arch/arm/mach-omap2/Makefile
index 6006505..d4f11c5 100644
--- a/arch/arm/mach-omap2/Makefile
+++ b/arch/arm/mach-omap2/Makefile
@@ -229,3 +229,5 @@ include/generated/ti-pm-asm-offsets.h: arch/arm/mach-omap2/pm-asm-offsets.s FORC
 $(obj)/sleep33xx.o $(obj)/sleep43xx.o: include/generated/ti-pm-asm-offsets.h
 
 targets += pm-asm-offsets.s
+
+obj-$(CONFIG_OMAP_IOMMU)		+= omap-iommu.o
diff --git a/arch/arm/mach-omap2/omap-iommu.c b/arch/arm/mach-omap2/omap-iommu.c
new file mode 100644
index 0000000..1392a5b
--- /dev/null
+++ b/arch/arm/mach-omap2/omap-iommu.c
@@ -0,0 +1,43 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * OMAP IOMMU quirks for various TI SoCs
+ *
+ * Copyright (C) 2015-2019 Texas Instruments Incorporated - http://www.ti.com/
+ *      Suman Anna <s-anna@ti.com>
+ */
+
+#include <linux/platform_device.h>
+#include <linux/err.h>
+
+#include "omap_hwmod.h"
+#include "omap_device.h"
+#include "powerdomain.h"
+
+int omap_iommu_set_pwrdm_constraint(struct platform_device *pdev, bool request,
+				    u8 *pwrst)
+{
+	struct powerdomain *pwrdm;
+	struct omap_device *od;
+	u8 next_pwrst;
+
+	od = to_omap_device(pdev);
+	if (!od)
+		return -ENODEV;
+
+	if (od->hwmods_cnt != 1)
+		return -EINVAL;
+
+	pwrdm = omap_hwmod_get_pwrdm(od->hwmods[0]);
+	if (!pwrdm)
+		return -EINVAL;
+
+	if (request)
+		*pwrst = pwrdm_read_next_pwrst(pwrdm);
+
+	if (*pwrst > PWRDM_POWER_RET)
+		return 0;
+
+	next_pwrst = request ? PWRDM_POWER_ON : *pwrst;
+
+	return pwrdm_set_next_pwrst(pwrdm, next_pwrst);
+}
diff --git a/drivers/iommu/omap-iommu.c b/drivers/iommu/omap-iommu.c
index dfb961d..84b99d5 100644
--- a/drivers/iommu/omap-iommu.c
+++ b/drivers/iommu/omap-iommu.c
@@ -190,6 +190,14 @@ static int iommu_enable(struct omap_iommu *obj)
 	struct platform_device *pdev = to_platform_device(obj->dev);
 	struct iommu_platform_data *pdata = dev_get_platdata(&pdev->dev);
 
+	if (pdata && pdata->set_pwrdm_constraint) {
+		err = pdata->set_pwrdm_constraint(pdev, true, &obj->pwrst);
+		if (err) {
+			dev_warn(obj->dev, "pwrdm_constraint failed to be set, status = %d\n",
+				 err);
+		}
+	}
+
 	if (pdata && pdata->deassert_reset) {
 		err = pdata->deassert_reset(pdev, pdata->reset_name);
 		if (err) {
@@ -209,6 +217,7 @@ static void iommu_disable(struct omap_iommu *obj)
 {
 	struct platform_device *pdev = to_platform_device(obj->dev);
 	struct iommu_platform_data *pdata = dev_get_platdata(&pdev->dev);
+	int ret;
 
 	omap2_iommu_disable(obj);
 
@@ -216,6 +225,14 @@ static void iommu_disable(struct omap_iommu *obj)
 
 	if (pdata && pdata->assert_reset)
 		pdata->assert_reset(pdev, pdata->reset_name);
+
+	if (pdata && pdata->set_pwrdm_constraint) {
+		ret = pdata->set_pwrdm_constraint(pdev, false, &obj->pwrst);
+		if (ret) {
+			dev_warn(obj->dev, "pwrdm_constraint failed to be reset, status = %d\n",
+				 ret);
+		}
+	}
 }
 
 /*
diff --git a/drivers/iommu/omap-iommu.h b/drivers/iommu/omap-iommu.h
index 09968a0..aac1ca6 100644
--- a/drivers/iommu/omap-iommu.h
+++ b/drivers/iommu/omap-iommu.h
@@ -78,6 +78,8 @@ struct omap_iommu {
 
 	struct iommu_device iommu;
 	struct iommu_group *group;
+
+	u8 pwrst;
 };
 
 /**
diff --git a/include/linux/platform_data/iommu-omap.h b/include/linux/platform_data/iommu-omap.h
index 44d913a..1ed6026 100644
--- a/include/linux/platform_data/iommu-omap.h
+++ b/include/linux/platform_data/iommu-omap.h
@@ -13,4 +13,6 @@ struct iommu_platform_data {
 	const char *reset_name;
 	int (*assert_reset)(struct platform_device *pdev, const char *name);
 	int (*deassert_reset)(struct platform_device *pdev, const char *name);
+	int (*set_pwrdm_constraint)(struct platform_device *pdev, bool request,
+				    u8 *pwrst);
 };
-- 
1.9.1

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[PATCH 2/8] iommu/omap: add pdata ops for omap_device_enable/idle

[Tero Kristo via iommu]

From: Suman Anna <s-anna@ti.com>

Add two new platform data ops to allow the OMAP iommu driver to
be able to invoke the omap_device_enable and omap_device_idle
from within the driver. These are being added to streamline the
sequence between managing the hard reset lines and the clocks
during the suspend path, as the default device pm_domain callback
sequences in omap_device layer are not conducive for the OMAP
IOMMU driver.

This could have been done by expanding the existing pdata ops
for reset management (like in the OMAP remoteproc driver), but
this was chosen to avoid adding additional code in the separate
file in the mach-omap2 layer.

Signed-off-by: Suman Anna <s-anna@ti.com>
---
 include/linux/platform_data/iommu-omap.h | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/include/linux/platform_data/iommu-omap.h b/include/linux/platform_data/iommu-omap.h
index 1ed6026..8474a02 100644
--- a/include/linux/platform_data/iommu-omap.h
+++ b/include/linux/platform_data/iommu-omap.h
@@ -13,6 +13,8 @@ struct iommu_platform_data {
 	const char *reset_name;
 	int (*assert_reset)(struct platform_device *pdev, const char *name);
 	int (*deassert_reset)(struct platform_device *pdev, const char *name);
+	int (*device_enable)(struct platform_device *pdev);
+	int (*device_idle)(struct platform_device *pdev);
 	int (*set_pwrdm_constraint)(struct platform_device *pdev, bool request,
 				    u8 *pwrst);
 };
-- 
1.9.1

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[PATCH 3/8] iommu/omap: streamline enable/disable through runtime pm callbacks

[Tero Kristo via iommu]

From: Suman Anna <s-anna@ti.com>

The OMAP IOMMU devices are typically present within the respective
client processor subsystem and have their own dedicated hard-reset
line. Enabling an IOMMU requires the reset line to be deasserted
and the clocks to be enabled before programming the necessary IOMMU
registers. The IOMMU disable sequence follow the reverse order of
enabling. The OMAP IOMMU driver programs the reset lines through
pdata ops to invoke the omap_device_assert/deassert_hardreset API.
The clocks are managed through the pm_runtime framework, and the
callbacks associated with the device's pm_domain, implemented in
the omap_device layer.

Streamline the enable and disable sequences in the OMAP IOMMU
driver by implementing all the above operations within the
runtime pm callbacks. All the OMAP devices have device pm_domain
callbacks plugged in the omap_device layer for automatic runtime
management of the clocks. Invoking the reset management functions
within the runtime pm callbacks in OMAP IOMMU driver therefore
requires that the default device's pm domain callbacks in the
omap_device layer be reset, as the ordering sequence for managing
the reset lines and clocks from the pm_domain callbacks don't gel
well with the implementation in the IOMMU driver callbacks. The
omap_device_enable/omap_device_idle functions are invoked through
the newly added pdata ops.

Consolidating all the device management sequences within the
runtime pm callbacks allows the driver to easily support both
system suspend/resume and runtime suspend/resume using common
code.

Signed-off-by: Suman Anna <s-anna@ti.com>
---
 drivers/iommu/omap-iommu.c | 139 ++++++++++++++++++++++++++++++++-------------
 1 file changed, 99 insertions(+), 40 deletions(-)

diff --git a/drivers/iommu/omap-iommu.c b/drivers/iommu/omap-iommu.c
index 84b99d5..fbceae3 100644
--- a/drivers/iommu/omap-iommu.c
+++ b/drivers/iommu/omap-iommu.c
@@ -186,53 +186,18 @@ static void omap2_iommu_disable(struct omap_iommu *obj)
 
 static int iommu_enable(struct omap_iommu *obj)
 {
-	int err;
-	struct platform_device *pdev = to_platform_device(obj->dev);
-	struct iommu_platform_data *pdata = dev_get_platdata(&pdev->dev);
-
-	if (pdata && pdata->set_pwrdm_constraint) {
-		err = pdata->set_pwrdm_constraint(pdev, true, &obj->pwrst);
-		if (err) {
-			dev_warn(obj->dev, "pwrdm_constraint failed to be set, status = %d\n",
-				 err);
-		}
-	}
-
-	if (pdata && pdata->deassert_reset) {
-		err = pdata->deassert_reset(pdev, pdata->reset_name);
-		if (err) {
-			dev_err(obj->dev, "deassert_reset failed: %d\n", err);
-			return err;
-		}
-	}
-
-	pm_runtime_get_sync(obj->dev);
+	int ret;
 
-	err = omap2_iommu_enable(obj);
+	ret = pm_runtime_get_sync(obj->dev);
+	if (ret < 0)
+		pm_runtime_put_noidle(obj->dev);
 
-	return err;
+	return ret < 0 ? ret : 0;
 }
 
 static void iommu_disable(struct omap_iommu *obj)
 {
-	struct platform_device *pdev = to_platform_device(obj->dev);
-	struct iommu_platform_data *pdata = dev_get_platdata(&pdev->dev);
-	int ret;
-
-	omap2_iommu_disable(obj);
-
 	pm_runtime_put_sync(obj->dev);
-
-	if (pdata && pdata->assert_reset)
-		pdata->assert_reset(pdev, pdata->reset_name);
-
-	if (pdata && pdata->set_pwrdm_constraint) {
-		ret = pdata->set_pwrdm_constraint(pdev, false, &obj->pwrst);
-		if (ret) {
-			dev_warn(obj->dev, "pwrdm_constraint failed to be reset, status = %d\n",
-				 ret);
-		}
-	}
 }
 
 /*
@@ -927,6 +892,85 @@ static void omap_iommu_detach(struct omap_iommu *obj)
 	dev_dbg(obj->dev, "%s: %s\n", __func__, obj->name);
 }
 
+/**
+ * omap_iommu_runtime_suspend - disable an iommu device
+ * @dev:	iommu device
+ *
+ * This function performs all that is necessary to disable an
+ * IOMMU device, either during final detachment from a client
+ * device, or during system/runtime suspend of the device. This
+ * includes programming all the appropriate IOMMU registers, and
+ * managing the associated omap_hwmod's state and the device's
+ * reset line.
+ **/
+static int omap_iommu_runtime_suspend(struct device *dev)
+{
+	struct platform_device *pdev = to_platform_device(dev);
+	struct iommu_platform_data *pdata = dev_get_platdata(dev);
+	struct omap_iommu *obj = to_iommu(dev);
+	int ret;
+
+	omap2_iommu_disable(obj);
+
+	if (pdata && pdata->device_idle)
+		pdata->device_idle(pdev);
+
+	if (pdata && pdata->assert_reset)
+		pdata->assert_reset(pdev, pdata->reset_name);
+
+	if (pdata && pdata->set_pwrdm_constraint) {
+		ret = pdata->set_pwrdm_constraint(pdev, false, &obj->pwrst);
+		if (ret) {
+			dev_warn(obj->dev, "pwrdm_constraint failed to be reset, status = %d\n",
+				 ret);
+		}
+	}
+
+	return 0;
+}
+
+/**
+ * omap_iommu_runtime_resume - enable an iommu device
+ * @dev:	iommu device
+ *
+ * This function performs all that is necessary to enable an
+ * IOMMU device, either during initial attachment to a client
+ * device, or during system/runtime resume of the device. This
+ * includes programming all the appropriate IOMMU registers, and
+ * managing the associated omap_hwmod's state and the device's
+ * reset line.
+ **/
+static int omap_iommu_runtime_resume(struct device *dev)
+{
+	struct platform_device *pdev = to_platform_device(dev);
+	struct iommu_platform_data *pdata = dev_get_platdata(dev);
+	struct omap_iommu *obj = to_iommu(dev);
+	int ret = 0;
+
+	if (pdata && pdata->set_pwrdm_constraint) {
+		ret = pdata->set_pwrdm_constraint(pdev, true, &obj->pwrst);
+		if (ret) {
+			dev_warn(obj->dev, "pwrdm_constraint failed to be set, status = %d\n",
+				 ret);
+		}
+	}
+
+	if (pdata && pdata->deassert_reset) {
+		ret = pdata->deassert_reset(pdev, pdata->reset_name);
+		if (ret) {
+			dev_err(dev, "deassert_reset failed: %d\n", ret);
+			return ret;
+		}
+	}
+
+	if (pdata && pdata->device_enable)
+		pdata->device_enable(pdev);
+
+	ret = omap2_iommu_enable(obj);
+
+	return ret;
+}
+
 static bool omap_iommu_can_register(struct platform_device *pdev)
 {
 	struct device_node *np = pdev->dev.of_node;
@@ -1001,6 +1045,15 @@ static int omap_iommu_probe(struct platform_device *pdev)
 	if (!obj)
 		return -ENOMEM;
 
+	/*
+	 * self-manage the ordering dependencies between omap_device_enable/idle
+	 * and omap_device_assert/deassert_hardreset API
+	 */
+	if (pdev->dev.pm_domain) {
+		dev_dbg(&pdev->dev, "device pm_domain is being reset\n");
+		pdev->dev.pm_domain = NULL;
+	}
+
 	obj->name = dev_name(&pdev->dev);
 	obj->nr_tlb_entries = 32;
 	err = of_property_read_u32(of, "ti,#tlb-entries", &obj->nr_tlb_entries);
@@ -1089,6 +1142,11 @@ static int omap_iommu_remove(struct platform_device *pdev)
 	return 0;
 }
 
+static const struct dev_pm_ops omap_iommu_pm_ops = {
+	SET_RUNTIME_PM_OPS(omap_iommu_runtime_suspend,
+			   omap_iommu_runtime_resume, NULL)
+};
+
 static const struct of_device_id omap_iommu_of_match[] = {
 	{ .compatible = "ti,omap2-iommu" },
 	{ .compatible = "ti,omap4-iommu" },
@@ -1102,6 +1160,7 @@ static int omap_iommu_remove(struct platform_device *pdev)
 	.remove	= omap_iommu_remove,
 	.driver	= {
 		.name	= "omap-iommu",
+		.pm	= &omap_iommu_pm_ops,
 		.of_match_table = of_match_ptr(omap_iommu_of_match),
 	},
 };
-- 
1.9.1

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[PATCH 4/8] iommu/omap: add logic to save/restore locked TLBs

[Tero Kristo via iommu]

From: Suman Anna <s-anna@ti.com>

The MMUs provide a mechanism to lock TLB entries to avoid
eviction and fetching of frequently used page table entries.
These TLBs lose context when the MMUs are turned OFF. Add the
logic to save and restore these locked TLBS during suspend
and resume respectively. There are no locked TLBs during
initial power ON, and they need not be saved during final
shutdown.

Signed-off-by: Suman Anna <s-anna@ti.com>
---
 drivers/iommu/omap-iommu.c | 61 +++++++++++++++++++++++++++++++++++++++++++---
 drivers/iommu/omap-iommu.h |  3 +++
 2 files changed, 61 insertions(+), 3 deletions(-)

diff --git a/drivers/iommu/omap-iommu.c b/drivers/iommu/omap-iommu.c
index fbceae3..51bf9d7 100644
--- a/drivers/iommu/omap-iommu.c
+++ b/drivers/iommu/omap-iommu.c
@@ -883,15 +883,55 @@ static void omap_iommu_detach(struct omap_iommu *obj)
 
 	dma_unmap_single(obj->dev, obj->pd_dma, IOPGD_TABLE_SIZE,
 			 DMA_TO_DEVICE);
-	iommu_disable(obj);
 	obj->pd_dma = 0;
 	obj->iopgd = NULL;
+	iommu_disable(obj);
 
 	spin_unlock(&obj->iommu_lock);
 
 	dev_dbg(obj->dev, "%s: %s\n", __func__, obj->name);
 }
 
+static void omap_iommu_save_tlb_entries(struct omap_iommu *obj)
+{
+	struct iotlb_lock lock;
+	struct cr_regs cr;
+	struct cr_regs *tmp;
+	int i;
+
+	/* check if there are any locked tlbs to save */
+	iotlb_lock_get(obj, &lock);
+	obj->num_cr_ctx = lock.base;
+	if (!obj->num_cr_ctx)
+		return;
+
+	tmp = obj->cr_ctx;
+	for_each_iotlb_cr(obj, obj->num_cr_ctx, i, cr)
+		* tmp++ = cr;
+}
+
+static void omap_iommu_restore_tlb_entries(struct omap_iommu *obj)
+{
+	struct iotlb_lock l;
+	struct cr_regs *tmp;
+	int i;
+
+	/* no locked tlbs to restore */
+	if (!obj->num_cr_ctx)
+		return;
+
+	l.base = 0;
+	tmp = obj->cr_ctx;
+	for (i = 0; i < obj->num_cr_ctx; i++, tmp++) {
+		l.vict = i;
+		iotlb_lock_set(obj, &l);
+		iotlb_load_cr(obj, tmp);
+	}
+	l.base = obj->num_cr_ctx;
+	l.vict = i;
+	iotlb_lock_set(obj, &l);
+}
+
 /**
  * omap_iommu_runtime_suspend - disable an iommu device
  * @dev:	iommu device
@@ -901,7 +941,8 @@ static void omap_iommu_detach(struct omap_iommu *obj)
  * device, or during system/runtime suspend of the device. This
  * includes programming all the appropriate IOMMU registers, and
  * managing the associated omap_hwmod's state and the device's
- * reset line.
+ * reset line. This function also saves the context of any
+ * locked TLBs if suspending.
  **/
 static int omap_iommu_runtime_suspend(struct device *dev)
 {
@@ -910,6 +951,10 @@ static int omap_iommu_runtime_suspend(struct device *dev)
 	struct omap_iommu *obj = to_iommu(dev);
 	int ret;
 
+	/* save the TLBs only during suspend, and not for power down */
+	if (obj->domain && obj->iopgd)
+		omap_iommu_save_tlb_entries(obj);
+
 	omap2_iommu_disable(obj);
 
 	if (pdata && pdata->device_idle)
@@ -938,7 +983,8 @@ static int omap_iommu_runtime_suspend(struct device *dev)
  * device, or during system/runtime resume of the device. This
  * includes programming all the appropriate IOMMU registers, and
  * managing the associated omap_hwmod's state and the device's
- * reset line.
+ * reset line. The function also restores any locked TLBs if
+ * resuming after a suspend.
  **/
 static int omap_iommu_runtime_resume(struct device *dev)
 {
@@ -966,6 +1012,10 @@ static int omap_iommu_runtime_resume(struct device *dev)
 	if (pdata && pdata->device_enable)
 		pdata->device_enable(pdev);
 
+	/* restore the TLBs only during resume, and not for power up */
+	if (obj->domain)
+		omap_iommu_restore_tlb_entries(obj);
+
 	ret = omap2_iommu_enable(obj);
 
 	return ret;
@@ -1066,6 +1116,11 @@ static int omap_iommu_probe(struct platform_device *pdev)
 
 	obj->dev = &pdev->dev;
 	obj->ctx = (void *)obj + sizeof(*obj);
+	obj->cr_ctx = devm_kzalloc(&pdev->dev,
+				   sizeof(*obj->cr_ctx) * obj->nr_tlb_entries,
+				   GFP_KERNEL);
+	if (!obj->cr_ctx)
+		return -ENOMEM;
 
 	spin_lock_init(&obj->iommu_lock);
 	spin_lock_init(&obj->page_table_lock);
diff --git a/drivers/iommu/omap-iommu.h b/drivers/iommu/omap-iommu.h
index aac1ca6..1d15aa8 100644
--- a/drivers/iommu/omap-iommu.h
+++ b/drivers/iommu/omap-iommu.h
@@ -73,6 +73,9 @@ struct omap_iommu {
 
 	void *ctx; /* iommu context: registres saved area */
 
+	struct cr_regs *cr_ctx;
+	u32 num_cr_ctx;
+
 	int has_bus_err_back;
 	u32 id;
 
-- 
1.9.1

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[PATCH 5/8] iommu/omap: Add system suspend/resume support

[Tero Kristo via iommu]

From: Suman Anna <s-anna@ti.com>

The MMU registers for the remote processors lose their context
in Open Switch Retention (OSWR) or device OFF modes. Hence, the
context of the IOMMU needs to be saved before it is put into any
of these lower power state (OSWR/OFF) and restored before it is
powered up to ON again. The IOMMUs need to be active as long as
the client devices that are present behind the IOMMU are active.

This patch adds the dev_pm_ops callbacks to provide the system
suspend/resume functionality through the appropriate runtime
PM callbacks. The PM runtime_resume and runtime_suspend callbacks
are already used to enable, configure and disable the IOMMUs during
the attaching and detaching of the client devices to the IOMMUs,
and the new PM callbacks reuse the same code by invoking the
pm_runtime_force_suspend() and pm_runtime_force_resume() API. The
functionality in dev_pm_ops .prepare() checks if the IOMMU device
was already runtime suspended, and skips invoking the suspend/resume
PM callbacks. The suspend/resume PM callbacks are plugged in through
the 'late' pm ops to ensure that the IOMMU devices will be suspended
only after its master devices (remoteproc devices) are suspended and
restored before them.

NOTE:
There are two other existing API, omap_iommu_save_ctx() and
omap_iommu_restore_ctx(). These are left as is to support
suspend/resume of devices on legacy OMAP3 SoC.

Signed-off-by: Suman Anna <s-anna@ti.com>
---
 drivers/iommu/omap-iommu.c | 26 ++++++++++++++++++++++++++
 1 file changed, 26 insertions(+)

diff --git a/drivers/iommu/omap-iommu.c b/drivers/iommu/omap-iommu.c
index 51bf9d7..694cd38 100644
--- a/drivers/iommu/omap-iommu.c
+++ b/drivers/iommu/omap-iommu.c
@@ -65,6 +65,9 @@ static struct omap_iommu_domain *to_omap_domain(struct iommu_domain *dom)
 /**
  * omap_iommu_save_ctx - Save registers for pm off-mode support
  * @dev:	client device
+ *
+ * This should be treated as an deprecated API. It is preserved only
+ * to maintain existing functionality for OMAP3 ISP driver.
  **/
 void omap_iommu_save_ctx(struct device *dev)
 {
@@ -92,6 +95,9 @@ void omap_iommu_save_ctx(struct device *dev)
 /**
  * omap_iommu_restore_ctx - Restore registers for pm off-mode support
  * @dev:	client device
+ *
+ * This should be treated as an deprecated API. It is preserved only
+ * to maintain existing functionality for OMAP3 ISP driver.
  **/
 void omap_iommu_restore_ctx(struct device *dev)
 {
@@ -1021,6 +1027,23 @@ static int omap_iommu_runtime_resume(struct device *dev)
 	return ret;
 }
 
+/**
+ * omap_iommu_suspend_prepare - prepare() dev_pm_ops implementation
+ * @dev:	iommu device
+ *
+ * This function performs the necessary checks to determine if the IOMMU
+ * device needs suspending or not. The function checks if the runtime_pm
+ * status of the device is suspended, and returns 1 in that case. This
+ * results in the PM core to skip invoking any of the Sleep PM callbacks
+ * (suspend, suspend_late, resume, resume_early etc).
+ */
+static int omap_iommu_prepare(struct device *dev)
+{
+	if (pm_runtime_status_suspended(dev))
+		return 1;
+	return 0;
+}
+
 static bool omap_iommu_can_register(struct platform_device *pdev)
 {
 	struct device_node *np = pdev->dev.of_node;
@@ -1198,6 +1221,9 @@ static int omap_iommu_remove(struct platform_device *pdev)
 }
 
 static const struct dev_pm_ops omap_iommu_pm_ops = {
+	.prepare = omap_iommu_prepare,
+	SET_LATE_SYSTEM_SLEEP_PM_OPS(pm_runtime_force_suspend,
+				     pm_runtime_force_resume)
 	SET_RUNTIME_PM_OPS(omap_iommu_runtime_suspend,
 			   omap_iommu_runtime_resume, NULL)
 };
-- 
1.9.1

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[PATCH 6/8] iommu/omap: introduce new API for runtime suspend/resume control

[Tero Kristo via iommu]

From: Suman Anna <s-anna@ti.com>

This patch adds the support for the OMAP IOMMUs to be suspended
during the auto suspend/resume of the OMAP remoteproc devices. The
remote processors are auto suspended after a certain time of idle
or inactivity period. This is done by introducing two new API,
omap_iommu_domain_deactivate() and omap_iommu_domain_activate()
to allow the client users/master devices of the IOMMU devices to
deactivate & activate the IOMMU devices from their runtime
suspend/resume operations. There is no API exposed by the IOMMU
layer at present, and so these new API are added directly in the
OMAP IOMMU driver to minimize framework changes.

The API simply decrements and increments the runtime usage count
of the IOMMU devices and let the context be saved/restored using
the existing runtime pm callbacks.

Signed-off-by: Suman Anna <s-anna@ti.com>
---
 drivers/iommu/omap-iommu.c | 58 ++++++++++++++++++++++++++++++++++++++++++++++
 include/linux/omap-iommu.h |  8 +++++++
 2 files changed, 66 insertions(+)

diff --git a/drivers/iommu/omap-iommu.c b/drivers/iommu/omap-iommu.c
index 694cd38..5e0dfca 100644
--- a/drivers/iommu/omap-iommu.c
+++ b/drivers/iommu/omap-iommu.c
@@ -939,6 +939,64 @@ static void omap_iommu_restore_tlb_entries(struct omap_iommu *obj)
 }
 
 /**
+ * omap_iommu_domain_deactivate - deactivate attached iommu devices
+ * @domain: iommu domain attached to the target iommu device
+ *
+ * This API allows the client devices of IOMMU devices to suspend
+ * the IOMMUs they control at runtime, after they are idled and
+ * suspended all activity. System Suspend will leverage the PM
+ * driver late callbacks.
+ **/
+int omap_iommu_domain_deactivate(struct iommu_domain *domain)
+{
+	struct omap_iommu_domain *omap_domain = to_omap_domain(domain);
+	struct omap_iommu_device *iommu;
+	struct omap_iommu *oiommu;
+	int i;
+
+	if (!omap_domain->dev)
+		return 0;
+
+	iommu = omap_domain->iommus;
+	iommu += (omap_domain->num_iommus - 1);
+	for (i = 0; i < omap_domain->num_iommus; i++, iommu--) {
+		oiommu = iommu->iommu_dev;
+		pm_runtime_put_sync(oiommu->dev);
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(omap_iommu_domain_deactivate);
+
+/**
+ * omap_iommu_domain_activate - activate attached iommu devices
+ * @domain: iommu domain attached to the target iommu device
+ *
+ * This API allows the client devices of IOMMU devices to resume the
+ * IOMMUs they control at runtime, before they can resume operations.
+ * System Resume will leverage the PM driver late callbacks.
+ **/
+int omap_iommu_domain_activate(struct iommu_domain *domain)
+{
+	struct omap_iommu_domain *omap_domain = to_omap_domain(domain);
+	struct omap_iommu_device *iommu;
+	struct omap_iommu *oiommu;
+	int i;
+
+	if (!omap_domain->dev)
+		return 0;
+
+	iommu = omap_domain->iommus;
+	for (i = 0; i < omap_domain->num_iommus; i++, iommu++) {
+		oiommu = iommu->iommu_dev;
+		pm_runtime_get_sync(oiommu->dev);
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(omap_iommu_domain_activate);
+
+/**
  * omap_iommu_runtime_suspend - disable an iommu device
  * @dev:	iommu device
  *
diff --git a/include/linux/omap-iommu.h b/include/linux/omap-iommu.h
index 153bf25..36b6457 100644
--- a/include/linux/omap-iommu.h
+++ b/include/linux/omap-iommu.h
@@ -10,12 +10,20 @@
 #ifndef _OMAP_IOMMU_H_
 #define _OMAP_IOMMU_H_
 
+struct iommu_domain;
+
 #ifdef CONFIG_OMAP_IOMMU
 extern void omap_iommu_save_ctx(struct device *dev);
 extern void omap_iommu_restore_ctx(struct device *dev);
+
+int omap_iommu_domain_deactivate(struct iommu_domain *domain);
+int omap_iommu_domain_activate(struct iommu_domain *domain);
 #else
 static inline void omap_iommu_save_ctx(struct device *dev) {}
 static inline void omap_iommu_restore_ctx(struct device *dev) {}
+
+static inline int omap_iommu_domain_deactivate(struct iommu_domain *domain) {}
+static inline int omap_iommu_domain_activate(struct iommu_domain *domain) {}
 #endif
 
 #endif
-- 
1.9.1

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[PATCH 7/8] iommu/omap: add support for late attachment of iommu devices

[Tero Kristo via iommu]

Current implementation of OMAP IOMMU enforces strict ordering of device
probe, initiated by iommu and followed by remoteproc later. This doesn't
work too well with the new setup done with ti-sysc changes which may
have the devices probed at pretty much any order. To overcome this limitation,
if iommu has not been probed yet when a consumer tries to attach to it,
add the device to orphan device list which will be parsed during iommu
probe to see if any orphan devices should be attached.

Signed-off-by: Tero Kristo <t-kristo@ti.com>
---
 drivers/iommu/omap-iommu.c | 56 +++++++++++++++++++++++++++++++++++++++++++---
 drivers/iommu/omap-iommu.h |  4 +++-
 2 files changed, 56 insertions(+), 4 deletions(-)

diff --git a/drivers/iommu/omap-iommu.c b/drivers/iommu/omap-iommu.c
index 5e0dfca..1beb318 100644
--- a/drivers/iommu/omap-iommu.c
+++ b/drivers/iommu/omap-iommu.c
@@ -35,6 +35,15 @@
 
 static const struct iommu_ops omap_iommu_ops;
 
+struct orphan_dev {
+	struct device *dev;
+	struct list_head node;
+};
+
+static LIST_HEAD(orphan_dev_list);
+
+static DEFINE_SPINLOCK(orphan_lock);
+
 #define to_iommu(dev)	((struct omap_iommu *)dev_get_drvdata(dev))
 
 /* bitmap of the page sizes currently supported */
@@ -53,6 +62,8 @@
 static struct platform_driver omap_iommu_driver;
 static struct kmem_cache *iopte_cachep;
 
+static int _omap_iommu_add_device(struct device *dev);
+
 /**
  * to_omap_domain - Get struct omap_iommu_domain from generic iommu_domain
  * @dom:	generic iommu domain handle
@@ -1166,6 +1177,7 @@ static int omap_iommu_probe(struct platform_device *pdev)
 	struct omap_iommu *obj;
 	struct resource *res;
 	struct device_node *of = pdev->dev.of_node;
+	struct orphan_dev *orphan_dev, *tmp;
 
 	if (!of) {
 		pr_err("%s: only DT-based devices are supported\n", __func__);
@@ -1249,6 +1261,14 @@ static int omap_iommu_probe(struct platform_device *pdev)
 
 	dev_info(&pdev->dev, "%s registered\n", obj->name);
 
+	list_for_each_entry_safe(orphan_dev, tmp, &orphan_dev_list, node) {
+		err = _omap_iommu_add_device(orphan_dev->dev);
+		if (!err) {
+			list_del(&orphan_dev->node);
+			kfree(orphan_dev);
+		}
+	}
+
 	return 0;
 
 out_sysfs:
@@ -1638,7 +1658,7 @@ static phys_addr_t omap_iommu_iova_to_phys(struct iommu_domain *domain,
 	return ret;
 }
 
-static int omap_iommu_add_device(struct device *dev)
+static int _omap_iommu_add_device(struct device *dev)
 {
 	struct omap_iommu_arch_data *arch_data, *tmp;
 	struct omap_iommu *oiommu;
@@ -1647,6 +1667,8 @@ static int omap_iommu_add_device(struct device *dev)
 	struct platform_device *pdev;
 	int num_iommus, i;
 	int ret;
+	struct orphan_dev *orphan_dev;
+	unsigned long flags;
 
 	/*
 	 * Allocate the archdata iommu structure for DT-based devices.
@@ -1678,10 +1700,26 @@ static int omap_iommu_add_device(struct device *dev)
 		}
 
 		pdev = of_find_device_by_node(np);
-		if (WARN_ON(!pdev)) {
+		if (!pdev) {
 			of_node_put(np);
 			kfree(arch_data);
-			return -EINVAL;
+			spin_lock_irqsave(&orphan_lock, flags);
+			list_for_each_entry(orphan_dev, &orphan_dev_list,
+					    node) {
+				if (orphan_dev->dev == dev)
+					break;
+			}
+			spin_unlock_irqrestore(&orphan_lock, flags);
+
+			if (orphan_dev && orphan_dev->dev == dev)
+				return -EPROBE_DEFER;
+
+			orphan_dev = kzalloc(sizeof(*orphan_dev), GFP_KERNEL);
+			orphan_dev->dev = dev;
+			spin_lock_irqsave(&orphan_lock, flags);
+			list_add(&orphan_dev->node, &orphan_dev_list);
+			spin_unlock_irqrestore(&orphan_lock, flags);
+			return -EPROBE_DEFER;
 		}
 
 		oiommu = platform_get_drvdata(pdev);
@@ -1692,6 +1730,7 @@ static int omap_iommu_add_device(struct device *dev)
 		}
 
 		tmp->iommu_dev = oiommu;
+		tmp->dev = &pdev->dev;
 
 		of_node_put(np);
 	}
@@ -1726,6 +1765,17 @@ static int omap_iommu_add_device(struct device *dev)
 	return 0;
 }
 
+static int omap_iommu_add_device(struct device *dev)
+{
+	int ret;
+
+	ret = _omap_iommu_add_device(dev);
+	if (ret == -EPROBE_DEFER)
+		return 0;
+
+	return ret;
+}
+
 static void omap_iommu_remove_device(struct device *dev)
 {
 	struct omap_iommu_arch_data *arch_data = dev->archdata.iommu;
diff --git a/drivers/iommu/omap-iommu.h b/drivers/iommu/omap-iommu.h
index 1d15aa8..18ee713 100644
--- a/drivers/iommu/omap-iommu.h
+++ b/drivers/iommu/omap-iommu.h
@@ -87,7 +87,8 @@ struct omap_iommu {
 
 /**
  * struct omap_iommu_arch_data - omap iommu private data
- * @iommu_dev: handle of the iommu device
+ * @iommu_dev: handle of the OMAP iommu device
+ * @dev: handle of the iommu device
  *
  * This is an omap iommu private data object, which binds an iommu user
  * to its iommu device. This object should be placed at the iommu user's
@@ -96,6 +97,7 @@ struct omap_iommu {
  */
 struct omap_iommu_arch_data {
 	struct omap_iommu *iommu_dev;
+	struct device *dev;
 };
 
 struct cr_regs {
-- 
1.9.1

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[PATCH 8/8] iommu/omap: remove pm_runtime_irq_safe flag for OMAP IOMMUs

[Tero Kristo via iommu]

This is not needed for anything, and prevents proper PM transitions for
parent devices which is bad in case of ti-sysc; this effectively kills
PM completely. Thus, remove the flag.

Signed-off-by: Tero Kristo <t-kristo@ti.com>
---
 drivers/iommu/omap-iommu.c | 1 -
 1 file changed, 1 deletion(-)

diff --git a/drivers/iommu/omap-iommu.c b/drivers/iommu/omap-iommu.c
index 1beb318..c8a2142 100644
--- a/drivers/iommu/omap-iommu.c
+++ b/drivers/iommu/omap-iommu.c
@@ -1254,7 +1254,6 @@ static int omap_iommu_probe(struct platform_device *pdev)
 			goto out_sysfs;
 	}
 
-	pm_runtime_irq_safe(obj->dev);
 	pm_runtime_enable(obj->dev);
 
 	omap_iommu_debugfs_add(obj);
-- 
1.9.1

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Re: [PATCH 0/8] iommu/omap: misc fixes

[Joerg Roedel]

On Wed, Aug 07, 2019 at 11:26:44AM +0300, Tero Kristo wrote:
> Here are a few fixes for OMAP IOMMU. These are mostly towards getting
> runtime PM support functional again for the IOMMU.

Applied all, thanks.
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[PATCH] iommu/omap: Fix compilation warnings suspend/resume control

[Joerg Roedel]

On Wed, Aug 07, 2019 at 11:26:50AM +0300, Tero Kristo wrote:
> +static inline int omap_iommu_domain_deactivate(struct iommu_domain *domain) {}
> +static inline int omap_iommu_domain_activate(struct iommu_domain *domain) {}

This caused compilation warnings, I queued the fix below.

From 70c8a42adf482fba35e9e39ccd441a5ff8ffb657 Mon Sep 17 00:00:00 2001
From: Joerg Roedel <jroedel@suse.de>
Date: Fri, 9 Aug 2019 18:09:13 +0200
Subject: [PATCH] iommu/omap: Fix compilation warnings

A recent patches introduced a new compiler warning because
two functions with non-void return type have no return
statement in omap-iommu.h for CONFIG_OMAP_IOMMU=n.

Fix this by adding return statements to these functions.

Fixes: d9c4d8a6cc0f8 ('iommu/omap: introduce new API for runtime suspend/resume control')
Signed-off-by: Joerg Roedel <jroedel@suse.de>
---
 include/linux/omap-iommu.h | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/include/linux/omap-iommu.h b/include/linux/omap-iommu.h
index 36b645726813..2c32ca09df02 100644
--- a/include/linux/omap-iommu.h
+++ b/include/linux/omap-iommu.h
@@ -22,8 +22,15 @@ int omap_iommu_domain_activate(struct iommu_domain *domain);
 static inline void omap_iommu_save_ctx(struct device *dev) {}
 static inline void omap_iommu_restore_ctx(struct device *dev) {}
 
-static inline int omap_iommu_domain_deactivate(struct iommu_domain *domain) {}
-static inline int omap_iommu_domain_activate(struct iommu_domain *domain) {}
+static inline int omap_iommu_domain_deactivate(struct iommu_domain *domain)
+{
+	return -ENODEV;
+}
+
+static inline int omap_iommu_domain_activate(struct iommu_domain *domain)
+{
+	return -ENODEV;
+}
 #endif
 
 #endif
-- 
2.16.4

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Re: [PATCH] iommu/omap: Fix compilation warnings suspend/resume control

[Suman Anna via iommu]

On 8/9/19 11:13 AM, Joerg Roedel wrote:
> On Wed, Aug 07, 2019 at 11:26:50AM +0300, Tero Kristo wrote:
>> +static inline int omap_iommu_domain_deactivate(struct iommu_domain *domain) {}
>> +static inline int omap_iommu_domain_activate(struct iommu_domain *domain) {}
> 
> This caused compilation warnings, I queued the fix below.
> 
> From 70c8a42adf482fba35e9e39ccd441a5ff8ffb657 Mon Sep 17 00:00:00 2001
> From: Joerg Roedel <jroedel@suse.de>
> Date: Fri, 9 Aug 2019 18:09:13 +0200
> Subject: [PATCH] iommu/omap: Fix compilation warnings
> 
> A recent patches introduced a new compiler warning because
> two functions with non-void return type have no return
> statement in omap-iommu.h for CONFIG_OMAP_IOMMU=n.
> 
> Fix this by adding return statements to these functions.

Thanks Joerg, looks like Tero missed them when he forward-ported the
patches.

regards
Suman

> 
> Fixes: d9c4d8a6cc0f8 ('iommu/omap: introduce new API for runtime suspend/resume control')
> Signed-off-by: Joerg Roedel <jroedel@suse.de>
> ---
>  include/linux/omap-iommu.h | 11 +++++++++--
>  1 file changed, 9 insertions(+), 2 deletions(-)
> 
> diff --git a/include/linux/omap-iommu.h b/include/linux/omap-iommu.h
> index 36b645726813..2c32ca09df02 100644
> --- a/include/linux/omap-iommu.h
> +++ b/include/linux/omap-iommu.h
> @@ -22,8 +22,15 @@ int omap_iommu_domain_activate(struct iommu_domain *domain);
>  static inline void omap_iommu_save_ctx(struct device *dev) {}
>  static inline void omap_iommu_restore_ctx(struct device *dev) {}
>  
> -static inline int omap_iommu_domain_deactivate(struct iommu_domain *domain) {}
> -static inline int omap_iommu_domain_activate(struct iommu_domain *domain) {}
> +static inline int omap_iommu_domain_deactivate(struct iommu_domain *domain)
> +{
> +	return -ENODEV;
> +}
> +
> +static inline int omap_iommu_domain_activate(struct iommu_domain *domain)
> +{
> +	return -ENODEV;
> +}
>  #endif
>  
>  #endif
> 

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