[PATCH v10 0/5] iommu/arm-smmu: Add runtime pm/sleep support

[PATCH v10 0/5] iommu/arm-smmu: Add runtime pm/sleep support

[Vivek Gautam]

This series provides the support for turning on the arm-smmu's
clocks/power domains using runtime pm. This is done using the
recently introduced device links patches, which lets the smmu's
runtime to follow the master's runtime pm, so the smmu remains
powered only when the masters use it.
As not all implementations support clock/power gating, we are checking
for a valid 'smmu->dev's pm_domain' to conditionally enable the runtime
power management for such smmu implementations that can support it.

This series also adds support for Qcom's arm-smmu-v2 variant that
has different clocks and power requirements.

Took some reference from the exynos runtime patches [1].

With conditional runtime pm now, we avoid touching dev->power.lock
in fastpaths for smmu implementations that don't need to do anything
useful with pm_runtime.
This lets us to use the much-argued pm_runtime_get_sync/put_sync()
calls in map/unmap callbacks so that the clients do not have to
worry about handling any of the arm-smmu's power.

Previous version of this patch series is @ [5].

[v10]
   * Introduce device_link_del_dev() API to delete the link between
     given consumer and supplier devices. The users of device link
     do not need to store link pointer to delete the link later.
     They can straightaway use this API by passing consumer and
     supplier devices.
   * Made corresponding changes to arm-smmu driver patch handling the
     device links.
   * Dropped the patch [9] that was adding device_link_find() API to
     device core layer. device_link_del_dev() serves the purpose to
     directly delete the link between two given devices.

[v9]
   * Removed 'rpm_supported' flag, instead checking on pm_domain
     to enable runtime pm.
   * Creating device link only when the runtime pm is enabled, as we
     don't need a device link besides managing the power dependency
     between supplier and consumer devices.
   * Introducing a patch to add device_link_find() API that finds
     and existing link between supplier and consumer devices.
     Also, made necessary change to device_link_add() to use this API.
   * arm_smmu_remove_device() now uses this device_link_find() to find
     the device link between smmu device and the master device, and then
     delete this link.
   * Dropped the destroy_domain_context() fix [8] as it was rather,
     introducing catastrophically bad problem by destroying
     'good dev's domain context.
   * Added 'Reviwed-by' tag for Tomasz's review.

[v8]
   * Major change -
     - Added a flag 'rpm_supported' which each platform that supports
       runtime pm, can enable, and we enable runtime_pm over arm-smmu
       only when this flag is set.
     - Adding the conditional pm_runtime_get/put() calls to .map, .unmap
       and .attach_dev ops.
     - Dropped the patch [6] that exported pm_runtim_get/put_suupliers(),
       and also dropped the user driver patch [7] for these APIs.

   * Clock code further cleanup
     - doing only clk_bulk_enable() and clk_bulk_disable() in runtime pm
       callbacks. We shouldn't be taking a slow path (clk_prepare/unprepare())
       from these runtime pm callbacks. Thereby, moved clk_bulk_prepare() to
       arm_smmu_device_probe(), and clk_bulk_unprepare() to
       arm_smmu_device_remove().
     - clk data filling to a common method arm_smmu_fill_clk_data() that
       fills the clock ids and number of clocks.

   * Addressed other nits and comments
     - device_link_add() error path fixed.
     - Fix for checking negative error value from pm_runtime_get_sync().
     - Documentation redo.

   * Added another patch fixing the error path in arm_smmu_attach_dev()
     to destroy allocated domain context.

[v7]
   * Addressed review comments given by Robin Murphy -
     - Added device_link_del() in .remove_device path.
     - Error path cleanup in arm_smmu_add_device().
     - Added pm_runtime_get/put_sync() in .remove path, and replaced
        pm_runtime_force_suspend() with pm_runtime_disable().
     - clk_names cleanup in arm_smmu_init_clks()
   * Added 'Reviewed-by' given by Rob H.

[V6]
   * Added Ack given by Rafael to first patch in the series.
   * Addressed Rob Herring's comment for adding soc specific compatible
     string as well besides 'qcom,smmu-v2'.

[V5]
   * Dropped runtime pm calls from "arm_smmu_unmap" op as discussed over
     the list [3] for the last patch series.
   * Added a patch to export pm_runtime_get/put_suppliers() APIs to the
     series as agreed with Rafael [4].
   * Added the related patch for msm drm iommu layer to use
     pm_runtime_get/put_suppliers() APIs in msm_mmu_funcs.
   * Dropped arm-mmu500 clock patch since that would break existing
     platforms.
   * Changed compatible 'qcom,msm8996-smmu-v2' to 'qcom,smmu-v2' to reflect
     the IP version rather than the platform on which it is used.
     The same IP is used across multiple platforms including msm8996,
     and sdm845 etc.
   * Using clock bulk APIs to handle the clocks available to the IP as
     suggested by Stephen Boyd.
   * The first patch in v4 version of the patch-series:
     ("iommu/arm-smmu: Fix the error path in arm_smmu_add_device") has
     already made it to mainline.

[V4]
   * Reworked the clock handling part. We now take clock names as data
     in the driver for supported compatible versions, and loop over them
     to get, enable, and disable the clocks.
   * Using qcom,msm8996 based compatibles for bindings instead of a generic
     qcom compatible.
   * Refactor MMU500 patch to just add the necessary clock names data and
     corresponding bindings.
   * Added the pm_runtime_get/put() calls in .unmap iommu op (fix added by
     Stanimir on top of previous patch version.
   * Added a patch to fix error path in arm_smmu_add_device()
   * Removed patch 3/5 of V3 patch series that added qcom,smmu-v2 bindings.

[V3]
   * Reworked the patches to keep the clocks init/enabling function
     separately for each compatible.

   * Added clocks bindings for MMU40x/500.

   * Added a new compatible for qcom,smmu-v2 implementation and
     the clock bindings for the same.

   * Rebased on top of 4.11-rc1

[V2]
   * Split the patches little differently.

   * Addressed comments.

   * Removed the patch #4 [2] from previous post
     for arm-smmu context save restore. Planning to
     post this separately after reworking/addressing Robin's
     feedback.

   * Reversed the sequence to disable clocks than enabling.
     This was required for those cases where the
     clocks are populated in a dependent order from DT.

[1] https://lkml.org/lkml/2016/10/20/70
[2] https://patchwork.kernel.org/patch/9389717/
[3] https://patchwork.kernel.org/patch/10204925/
[4] https://patchwork.kernel.org/patch/10102445/
[5] https://lkml.org/lkml/2018/3/13/170
[6] https://patchwork.kernel.org/patch/10204945/
[7] https://patchwork.kernel.org/patch/10204925/
[8] https://patchwork.kernel.org/patch/10254105/
[9] https://patchwork.kernel.org/patch/10277975/

Sricharan R (3):
  iommu/arm-smmu: Add pm_runtime/sleep ops
  iommu/arm-smmu: Invoke pm_runtime during probe, add/remove device
  iommu/arm-smmu: Add the device_link between masters and smmu

Vivek Gautam (2):
  driver core: Delete the link between two given devices
  iommu/arm-smmu: Add support for qcom,smmu-v2 variant

 .../devicetree/bindings/iommu/arm,smmu.txt         |  42 +++++
 drivers/base/core.c                                |  31 ++++
 drivers/iommu/arm-smmu.c                           | 193 +++++++++++++++++++--
 include/linux/device.h                             |   1 +
 4 files changed, 257 insertions(+), 10 deletions(-)

-- 
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of Code Aurora Forum, hosted by The Linux Foundation

[PATCH v10 1/5] driver core: Delete the link between two given devices

[Vivek Gautam]

Given the consumer and supplier devices, add an API to
delete the link between them.

Suggested-by: Tomasz Figa <tfiga@chromium.org>
Signed-off-by: Vivek Gautam <vivek.gautam@codeaurora.org>
Cc: Rafael J. Wysocki <rjw@rjwysocki.net>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

 - This patch replaces an earlier patch [1] that was adding
   device_link_find() API.
   [1] https://patchwork.kernel.org/patch/10277975/

 drivers/base/core.c    | 31 +++++++++++++++++++++++++++++++
 include/linux/device.h |  1 +
 2 files changed, 32 insertions(+)

diff --git a/drivers/base/core.c b/drivers/base/core.c
index 5847364f25d9..e13d904e1e12 100644
--- a/drivers/base/core.c
+++ b/drivers/base/core.c
@@ -336,6 +336,37 @@ void device_link_del(struct device_link *link)
 }
 EXPORT_SYMBOL_GPL(device_link_del);
 
+/**
+ * device_link_del_dev - Delete a link between two given devices
+ * @consumer: Consumer end of the link.
+ * @supplier: Supplier end of the link.
+ *
+ * The caller must ensure proper synchronization of this function with runtime
+ * PM.
+ */
+void device_link_del_dev(struct device *consumer, struct device *supplier)
+{
+	struct device_link *link;
+
+	if (!consumer || !supplier)
+		return;
+
+	device_links_write_lock();
+	device_pm_lock();
+
+	list_for_each_entry(link, &supplier->links.consumers, s_node) {
+		if (link->consumer == consumer) {
+			__device_link_del(link);
+			/* just one link between the devices */
+			break;
+		}
+	}
+
+	device_pm_unlock();
+	device_links_write_unlock();
+}
+EXPORT_SYMBOL_GPL(device_link_del_dev);
+
 static void device_links_missing_supplier(struct device *dev)
 {
 	struct device_link *link;
diff --git a/include/linux/device.h b/include/linux/device.h
index b093405ed525..14508d843f67 100644
--- a/include/linux/device.h
+++ b/include/linux/device.h
@@ -1278,6 +1278,7 @@ extern const char *dev_driver_string(const struct device *dev);
 struct device_link *device_link_add(struct device *consumer,
 				    struct device *supplier, u32 flags);
 void device_link_del(struct device_link *link);
+void device_link_del_dev(struct device *consumer, struct device *supplier);
 
 #ifdef CONFIG_PRINTK
 
-- 
QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member
of Code Aurora Forum, hosted by The Linux Foundation

[PATCH v10 2/5] iommu/arm-smmu: Add pm_runtime/sleep ops

[Vivek Gautam]

From: Sricharan R <sricharan@codeaurora.org>

The smmu needs to be functional only when the respective
master's using it are active. The device_link feature
helps to track such functional dependencies, so that the
iommu gets powered when the master device enables itself
using pm_runtime. So by adapting the smmu driver for
runtime pm, above said dependency can be addressed.

This patch adds the pm runtime/sleep callbacks to the
driver and also the functions to parse the smmu clocks
from DT and enable them in resume/suspend.

Signed-off-by: Sricharan R <sricharan@codeaurora.org>
Signed-off-by: Archit Taneja <architt@codeaurora.org>
[vivek: Clock rework to request bulk of clocks]
Signed-off-by: Vivek Gautam <vivek.gautam@codeaurora.org>
Reviewed-by: Tomasz Figa <tfiga@chromium.org>
---

 - No change since v9.

 drivers/iommu/arm-smmu.c | 60 ++++++++++++++++++++++++++++++++++++++++++++++--
 1 file changed, 58 insertions(+), 2 deletions(-)

diff --git a/drivers/iommu/arm-smmu.c b/drivers/iommu/arm-smmu.c
index 69e7c60792a8..d5873d545024 100644
--- a/drivers/iommu/arm-smmu.c
+++ b/drivers/iommu/arm-smmu.c
@@ -48,6 +48,7 @@
 #include <linux/of_iommu.h>
 #include <linux/pci.h>
 #include <linux/platform_device.h>
+#include <linux/pm_runtime.h>
 #include <linux/slab.h>
 #include <linux/spinlock.h>
 
@@ -205,6 +206,8 @@ struct arm_smmu_device {
 	u32				num_global_irqs;
 	u32				num_context_irqs;
 	unsigned int			*irqs;
+	struct clk_bulk_data		*clks;
+	int				num_clks;
 
 	u32				cavium_id_base; /* Specific to Cavium */
 
@@ -1897,10 +1900,12 @@ static int arm_smmu_device_cfg_probe(struct arm_smmu_device *smmu)
 struct arm_smmu_match_data {
 	enum arm_smmu_arch_version version;
 	enum arm_smmu_implementation model;
+	const char * const *clks;
+	int num_clks;
 };
 
 #define ARM_SMMU_MATCH_DATA(name, ver, imp)	\
-static struct arm_smmu_match_data name = { .version = ver, .model = imp }
+static const struct arm_smmu_match_data name = { .version = ver, .model = imp }
 
 ARM_SMMU_MATCH_DATA(smmu_generic_v1, ARM_SMMU_V1, GENERIC_SMMU);
 ARM_SMMU_MATCH_DATA(smmu_generic_v2, ARM_SMMU_V2, GENERIC_SMMU);
@@ -1919,6 +1924,23 @@ static const struct of_device_id arm_smmu_of_match[] = {
 };
 MODULE_DEVICE_TABLE(of, arm_smmu_of_match);
 
+static void arm_smmu_fill_clk_data(struct arm_smmu_device *smmu,
+				   const char * const *clks)
+{
+	int i;
+
+	if (smmu->num_clks < 1)
+		return;
+
+	smmu->clks = devm_kcalloc(smmu->dev, smmu->num_clks,
+				  sizeof(*smmu->clks), GFP_KERNEL);
+	if (!smmu->clks)
+		return;
+
+	for (i = 0; i < smmu->num_clks; i++)
+		smmu->clks[i].id = clks[i];
+}
+
 #ifdef CONFIG_ACPI
 static int acpi_smmu_get_data(u32 model, struct arm_smmu_device *smmu)
 {
@@ -2001,6 +2023,9 @@ static int arm_smmu_device_dt_probe(struct platform_device *pdev,
 	data = of_device_get_match_data(dev);
 	smmu->version = data->version;
 	smmu->model = data->model;
+	smmu->num_clks = data->num_clks;
+
+	arm_smmu_fill_clk_data(smmu, data->clks);
 
 	parse_driver_options(smmu);
 
@@ -2099,6 +2124,14 @@ static int arm_smmu_device_probe(struct platform_device *pdev)
 		smmu->irqs[i] = irq;
 	}
 
+	err = devm_clk_bulk_get(smmu->dev, smmu->num_clks, smmu->clks);
+	if (err)
+		return err;
+
+	err = clk_bulk_prepare(smmu->num_clks, smmu->clks);
+	if (err)
+		return err;
+
 	err = arm_smmu_device_cfg_probe(smmu);
 	if (err)
 		return err;
@@ -2181,6 +2214,9 @@ static int arm_smmu_device_remove(struct platform_device *pdev)
 
 	/* Turn the thing off */
 	writel(sCR0_CLIENTPD, ARM_SMMU_GR0_NS(smmu) + ARM_SMMU_GR0_sCR0);
+
+	clk_bulk_unprepare(smmu->num_clks, smmu->clks);
+
 	return 0;
 }
 
@@ -2197,7 +2233,27 @@ static int __maybe_unused arm_smmu_pm_resume(struct device *dev)
 	return 0;
 }
 
-static SIMPLE_DEV_PM_OPS(arm_smmu_pm_ops, NULL, arm_smmu_pm_resume);
+static int __maybe_unused arm_smmu_runtime_resume(struct device *dev)
+{
+	struct arm_smmu_device *smmu = dev_get_drvdata(dev);
+
+	return clk_bulk_enable(smmu->num_clks, smmu->clks);
+}
+
+static int __maybe_unused arm_smmu_runtime_suspend(struct device *dev)
+{
+	struct arm_smmu_device *smmu = dev_get_drvdata(dev);
+
+	clk_bulk_disable(smmu->num_clks, smmu->clks);
+
+	return 0;
+}
+
+static const struct dev_pm_ops arm_smmu_pm_ops = {
+	SET_SYSTEM_SLEEP_PM_OPS(NULL, arm_smmu_pm_resume)
+	SET_RUNTIME_PM_OPS(arm_smmu_runtime_suspend,
+			   arm_smmu_runtime_resume, NULL)
+};
 
 static struct platform_driver arm_smmu_driver = {
 	.driver	= {
-- 
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of Code Aurora Forum, hosted by The Linux Foundation

[PATCH v10 3/5] iommu/arm-smmu: Invoke pm_runtime during probe, add/remove device

[Vivek Gautam]

From: Sricharan R <sricharan@codeaurora.org>

The smmu device probe/remove and add/remove master device callbacks
gets called when the smmu is not linked to its master, that is without
the context of the master device. So calling runtime apis in those places
separately.

Signed-off-by: Sricharan R <sricharan@codeaurora.org>
[vivek: Cleanup pm runtime calls]
Signed-off-by: Vivek Gautam <vivek.gautam@codeaurora.org>
Reviewed-by: Tomasz Figa <tfiga@chromium.org>
---

 - No change since v9.

 drivers/iommu/arm-smmu.c | 95 ++++++++++++++++++++++++++++++++++++++++++++----
 1 file changed, 87 insertions(+), 8 deletions(-)

diff --git a/drivers/iommu/arm-smmu.c b/drivers/iommu/arm-smmu.c
index d5873d545024..56a04ae80bf3 100644
--- a/drivers/iommu/arm-smmu.c
+++ b/drivers/iommu/arm-smmu.c
@@ -268,6 +268,20 @@ static struct arm_smmu_option_prop arm_smmu_options[] = {
 	{ 0, NULL},
 };
 
+static inline int arm_smmu_rpm_get(struct arm_smmu_device *smmu)
+{
+	if (pm_runtime_enabled(smmu->dev))
+		return pm_runtime_get_sync(smmu->dev);
+
+	return 0;
+}
+
+static inline void arm_smmu_rpm_put(struct arm_smmu_device *smmu)
+{
+	if (pm_runtime_enabled(smmu->dev))
+		pm_runtime_put(smmu->dev);
+}
+
 static struct arm_smmu_domain *to_smmu_domain(struct iommu_domain *dom)
 {
 	return container_of(dom, struct arm_smmu_domain, domain);
@@ -913,11 +927,15 @@ static void arm_smmu_destroy_domain_context(struct iommu_domain *domain)
 	struct arm_smmu_domain *smmu_domain = to_smmu_domain(domain);
 	struct arm_smmu_device *smmu = smmu_domain->smmu;
 	struct arm_smmu_cfg *cfg = &smmu_domain->cfg;
-	int irq;
+	int ret, irq;
 
 	if (!smmu || domain->type == IOMMU_DOMAIN_IDENTITY)
 		return;
 
+	ret = arm_smmu_rpm_get(smmu);
+	if (ret < 0)
+		return;
+
 	/*
 	 * Disable the context bank and free the page tables before freeing
 	 * it.
@@ -932,6 +950,8 @@ static void arm_smmu_destroy_domain_context(struct iommu_domain *domain)
 
 	free_io_pgtable_ops(smmu_domain->pgtbl_ops);
 	__arm_smmu_free_bitmap(smmu->context_map, cfg->cbndx);
+
+	arm_smmu_rpm_put(smmu);
 }
 
 static struct iommu_domain *arm_smmu_domain_alloc(unsigned type)
@@ -1213,10 +1233,15 @@ static int arm_smmu_attach_dev(struct iommu_domain *domain, struct device *dev)
 		return -ENODEV;
 
 	smmu = fwspec_smmu(fwspec);
+
+	ret = arm_smmu_rpm_get(smmu);
+	if (ret < 0)
+		return ret;
+
 	/* Ensure that the domain is finalised */
 	ret = arm_smmu_init_domain_context(domain, smmu);
 	if (ret < 0)
-		return ret;
+		goto rpm_put;
 
 	/*
 	 * Sanity check the domain. We don't support domains across
@@ -1230,29 +1255,47 @@ static int arm_smmu_attach_dev(struct iommu_domain *domain, struct device *dev)
 	}
 
 	/* Looks ok, so add the device to the domain */
-	return arm_smmu_domain_add_master(smmu_domain, fwspec);
+	ret = arm_smmu_domain_add_master(smmu_domain, fwspec);
+
+rpm_put:
+	arm_smmu_rpm_put(smmu);
+	return ret;
 }
 
 static int arm_smmu_map(struct iommu_domain *domain, unsigned long iova,
 			phys_addr_t paddr, size_t size, int prot)
 {
 	struct io_pgtable_ops *ops = to_smmu_domain(domain)->pgtbl_ops;
+	struct arm_smmu_domain *smmu_domain = to_smmu_domain(domain);
+	struct arm_smmu_device *smmu = smmu_domain->smmu;
+	int ret;
 
 	if (!ops)
 		return -ENODEV;
 
-	return ops->map(ops, iova, paddr, size, prot);
+	arm_smmu_rpm_get(smmu);
+	ret = ops->map(ops, iova, paddr, size, prot);
+	arm_smmu_rpm_put(smmu);
+
+	return ret;
 }
 
 static size_t arm_smmu_unmap(struct iommu_domain *domain, unsigned long iova,
 			     size_t size)
 {
 	struct io_pgtable_ops *ops = to_smmu_domain(domain)->pgtbl_ops;
+	struct arm_smmu_domain *smmu_domain = to_smmu_domain(domain);
+	struct arm_smmu_device *smmu = smmu_domain->smmu;
+	size_t ret;
 
 	if (!ops)
 		return 0;
 
-	return ops->unmap(ops, iova, size);
+	arm_smmu_rpm_get(smmu);
+	ret = ops->unmap(ops, iova, size);
+	arm_smmu_rpm_put(smmu);
+
+	return ret;
 }
 
 static void arm_smmu_iotlb_sync(struct iommu_domain *domain)
@@ -1407,14 +1450,22 @@ static int arm_smmu_add_device(struct device *dev)
 	while (i--)
 		cfg->smendx[i] = INVALID_SMENDX;
 
+	ret = arm_smmu_rpm_get(smmu);
+	if (ret < 0)
+		goto out_cfg_free;
+
 	ret = arm_smmu_master_alloc_smes(dev);
 	if (ret)
-		goto out_cfg_free;
+		goto out_rpm_put;
 
 	iommu_device_link(&smmu->iommu, dev);
 
+	arm_smmu_rpm_put(smmu);
+
 	return 0;
 
+out_rpm_put:
+	arm_smmu_rpm_put(smmu);
 out_cfg_free:
 	kfree(cfg);
 out_free:
@@ -1427,7 +1478,7 @@ static void arm_smmu_remove_device(struct device *dev)
 	struct iommu_fwspec *fwspec = dev->iommu_fwspec;
 	struct arm_smmu_master_cfg *cfg;
 	struct arm_smmu_device *smmu;
-
+	int ret;
 
 	if (!fwspec || fwspec->ops != &arm_smmu_ops)
 		return;
@@ -1435,8 +1486,15 @@ static void arm_smmu_remove_device(struct device *dev)
 	cfg  = fwspec->iommu_priv;
 	smmu = cfg->smmu;
 
+	ret = arm_smmu_rpm_get(smmu);
+	if (ret < 0)
+		return;
+
 	iommu_device_unlink(&smmu->iommu, dev);
 	arm_smmu_master_free_smes(fwspec);
+
+	arm_smmu_rpm_put(smmu);
+
 	iommu_group_remove_device(dev);
 	kfree(fwspec->iommu_priv);
 	iommu_fwspec_free(dev);
@@ -2124,6 +2182,8 @@ static int arm_smmu_device_probe(struct platform_device *pdev)
 		smmu->irqs[i] = irq;
 	}
 
+	platform_set_drvdata(pdev, smmu);
+
 	err = devm_clk_bulk_get(smmu->dev, smmu->num_clks, smmu->clks);
 	if (err)
 		return err;
@@ -2132,6 +2192,19 @@ static int arm_smmu_device_probe(struct platform_device *pdev)
 	if (err)
 		return err;
 
+	/*
+	 * We want to avoid touching dev->power.lock in fastpaths unless
+	 * it's really going to do something useful - pm_runtime_enabled()
+	 * can serve as an ideal proxy for that decision. So, conditionally
+	 * enable pm_runtime.
+	 */
+	if (dev->pm_domain)
+		pm_runtime_enable(dev);
+
+	err = arm_smmu_rpm_get(smmu);
+	if (err < 0)
+		return err;
+
 	err = arm_smmu_device_cfg_probe(smmu);
 	if (err)
 		return err;
@@ -2173,10 +2246,11 @@ static int arm_smmu_device_probe(struct platform_device *pdev)
 		return err;
 	}
 
-	platform_set_drvdata(pdev, smmu);
 	arm_smmu_device_reset(smmu);
 	arm_smmu_test_smr_masks(smmu);
 
+	arm_smmu_rpm_put(smmu);
+
 	/*
 	 * For ACPI and generic DT bindings, an SMMU will be probed before
 	 * any device which might need it, so we want the bus ops in place
@@ -2212,8 +2286,13 @@ static int arm_smmu_device_remove(struct platform_device *pdev)
 	if (!bitmap_empty(smmu->context_map, ARM_SMMU_MAX_CBS))
 		dev_err(&pdev->dev, "removing device with active domains!\n");
 
+	arm_smmu_rpm_get(smmu);
 	/* Turn the thing off */
 	writel(sCR0_CLIENTPD, ARM_SMMU_GR0_NS(smmu) + ARM_SMMU_GR0_sCR0);
+	arm_smmu_rpm_put(smmu);
+
+	if (pm_runtime_enabled(smmu->dev))
+		pm_runtime_disable(smmu->dev);
 
 	clk_bulk_unprepare(smmu->num_clks, smmu->clks);
 
-- 
QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member
of Code Aurora Forum, hosted by The Linux Foundation

[PATCH v10 4/5] iommu/arm-smmu: Add the device_link between masters and smmu

[Vivek Gautam]

From: Sricharan R <sricharan@codeaurora.org>

Finally add the device link between the master device and
smmu, so that the smmu gets runtime enabled/disabled only when the
master needs it. This is done from add_device callback which gets
called once when the master is added to the smmu.

Signed-off-by: Sricharan R <sricharan@codeaurora.org>
Signed-off-by: Vivek Gautam <vivek.gautam@codeaurora.org>
Reviewed-by: Tomasz Figa <tfiga@chromium.org>
---

Changes since v9:
 - Using device_link_del_dev() to delete the device link, instead of
   doing it in two steps - device_link_find() to first find the link, and
   then calling device_link_del().

 drivers/iommu/arm-smmu.c | 24 ++++++++++++++++++++++++
 1 file changed, 24 insertions(+)

diff --git a/drivers/iommu/arm-smmu.c b/drivers/iommu/arm-smmu.c
index 56a04ae80bf3..4cf270ffd449 100644
--- a/drivers/iommu/arm-smmu.c
+++ b/drivers/iommu/arm-smmu.c
@@ -1460,10 +1460,31 @@ static int arm_smmu_add_device(struct device *dev)
 
 	iommu_device_link(&smmu->iommu, dev);
 
+	if (pm_runtime_enabled(smmu->dev)) {
+		struct device_link *link;
+
+		/*
+		 * Establish the link between smmu and master, so that the
+		 * smmu gets runtime enabled/disabled as per the master's
+		 * needs.
+		 */
+		link = device_link_add(dev, smmu->dev, DL_FLAG_PM_RUNTIME);
+		if (!link) {
+			dev_warn(smmu->dev,
+				 "Unable to add link to the consumer %s\n",
+				 dev_name(dev));
+			ret = -ENODEV;
+			goto out_unlink;
+		}
+	}
+
 	arm_smmu_rpm_put(smmu);
 
 	return 0;
 
+out_unlink:
+	iommu_device_unlink(&smmu->iommu, dev);
+	arm_smmu_master_free_smes(fwspec);
 out_rpm_put:
 	arm_smmu_rpm_put(smmu);
 out_cfg_free:
@@ -1486,6 +1507,9 @@ static void arm_smmu_remove_device(struct device *dev)
 	cfg  = fwspec->iommu_priv;
 	smmu = cfg->smmu;
 
+	if (pm_runtime_enabled(smmu->dev))
+		device_link_del_dev(dev, smmu->dev);
+
 	ret = arm_smmu_rpm_get(smmu);
 	if (ret < 0)
 		return;
-- 
QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member
of Code Aurora Forum, hosted by The Linux Foundation

[PATCH v10 5/5] iommu/arm-smmu: Add support for qcom,smmu-v2 variant

[Vivek Gautam]

qcom,smmu-v2 is an arm,smmu-v2 implementation with specific
clock and power requirements. This smmu core is used with
multiple masters on msm8996, viz. mdss, video, etc.
Add bindings for the same.

Signed-off-by: Vivek Gautam <vivek.gautam@codeaurora.org>
Reviewed-by: Rob Herring <robh@kernel.org>
Reviewed-by: Tomasz Figa <tfiga@chromium.org>
---

 - No change since v9.

 .../devicetree/bindings/iommu/arm,smmu.txt         | 42 ++++++++++++++++++++++
 drivers/iommu/arm-smmu.c                           | 14 ++++++++
 2 files changed, 56 insertions(+)

diff --git a/Documentation/devicetree/bindings/iommu/arm,smmu.txt b/Documentation/devicetree/bindings/iommu/arm,smmu.txt
index 8a6ffce12af5..7c71a6ed465a 100644
--- a/Documentation/devicetree/bindings/iommu/arm,smmu.txt
+++ b/Documentation/devicetree/bindings/iommu/arm,smmu.txt
@@ -17,10 +17,19 @@ conditions.
                         "arm,mmu-401"
                         "arm,mmu-500"
                         "cavium,smmu-v2"
+                        "qcom,<soc>-smmu-v2", "qcom,smmu-v2"
 
                   depending on the particular implementation and/or the
                   version of the architecture implemented.
 
+                  A number of Qcom SoCs use qcom,smmu-v2 version of the IP.
+                  "qcom,<soc>-smmu-v2" represents a soc specific compatible
+                  string that should be present along with the "qcom,smmu-v2"
+                  to facilitate SoC specific clocks/power connections and to
+                  address specific bug fixes.
+                  An example string would be -
+                  "qcom,msm8996-smmu-v2", "qcom,smmu-v2".
+
 - reg           : Base address and size of the SMMU.
 
 - #global-interrupts : The number of global interrupts exposed by the
@@ -71,6 +80,22 @@ conditions.
                   or using stream matching with #iommu-cells = <2>, and
                   may be ignored if present in such cases.
 
+- clock-names:    List of the names of clocks input to the device. The
+                  required list depends on particular implementation and
+                  is as follows:
+                  - for "qcom,smmu-v2":
+                    - "bus": clock required for downstream bus access and
+                             for the smmu ptw,
+                    - "iface": clock required to access smmu's registers
+                               through the TCU's programming interface.
+                  - unspecified for other implementations.
+
+- clocks:         Specifiers for all clocks listed in the clock-names property,
+                  as per generic clock bindings.
+
+- power-domains:  Specifiers for power domains required to be powered on for
+                  the SMMU to operate, as per generic power domain bindings.
+
 ** Deprecated properties:
 
 - mmu-masters (deprecated in favour of the generic "iommus" binding) :
@@ -137,3 +162,20 @@ conditions.
                 iommu-map = <0 &smmu3 0 0x400>;
                 ...
         };
+
+	/* Qcom's arm,smmu-v2 implementation */
+	smmu4: iommu {
+		compatible = "qcom,msm8996-smmu-v2", "qcom,smmu-v2";
+		reg = <0xd00000 0x10000>;
+
+		#global-interrupts = <1>;
+		interrupts = <GIC_SPI 73 IRQ_TYPE_LEVEL_HIGH>,
+			     <GIC_SPI 320 IRQ_TYPE_LEVEL_HIGH>,
+			     <GIC_SPI 321 IRQ_TYPE_LEVEL_HIGH>;
+		#iommu-cells = <1>;
+		power-domains = <&mmcc MDSS_GDSC>;
+
+		clocks = <&mmcc SMMU_MDP_AXI_CLK>,
+			 <&mmcc SMMU_MDP_AHB_CLK>;
+		clock-names = "bus", "iface";
+	};
diff --git a/drivers/iommu/arm-smmu.c b/drivers/iommu/arm-smmu.c
index 4cf270ffd449..03750ba15224 100644
--- a/drivers/iommu/arm-smmu.c
+++ b/drivers/iommu/arm-smmu.c
@@ -119,6 +119,7 @@ enum arm_smmu_implementation {
 	GENERIC_SMMU,
 	ARM_MMU500,
 	CAVIUM_SMMUV2,
+	QCOM_SMMUV2,
 };
 
 struct arm_smmu_s2cr {
@@ -1995,6 +1996,17 @@ ARM_SMMU_MATCH_DATA(arm_mmu401, ARM_SMMU_V1_64K, GENERIC_SMMU);
 ARM_SMMU_MATCH_DATA(arm_mmu500, ARM_SMMU_V2, ARM_MMU500);
 ARM_SMMU_MATCH_DATA(cavium_smmuv2, ARM_SMMU_V2, CAVIUM_SMMUV2);
 
+static const char * const qcom_smmuv2_clks[] = {
+	"bus", "iface",
+};
+
+static const struct arm_smmu_match_data qcom_smmuv2 = {
+	.version = ARM_SMMU_V2,
+	.model = QCOM_SMMUV2,
+	.clks = qcom_smmuv2_clks,
+	.num_clks = ARRAY_SIZE(qcom_smmuv2_clks),
+};
+
 static const struct of_device_id arm_smmu_of_match[] = {
 	{ .compatible = "arm,smmu-v1", .data = &smmu_generic_v1 },
 	{ .compatible = "arm,smmu-v2", .data = &smmu_generic_v2 },
@@ -2002,6 +2014,7 @@ static const struct of_device_id arm_smmu_of_match[] = {
 	{ .compatible = "arm,mmu-401", .data = &arm_mmu401 },
 	{ .compatible = "arm,mmu-500", .data = &arm_mmu500 },
 	{ .compatible = "cavium,smmu-v2", .data = &cavium_smmuv2 },
+	{ .compatible = "qcom,smmu-v2", .data = &qcom_smmuv2 },
 	{ },
 };
 MODULE_DEVICE_TABLE(of, arm_smmu_of_match);
@@ -2376,6 +2389,7 @@ IOMMU_OF_DECLARE(arm_mmu400, "arm,mmu-400");
 IOMMU_OF_DECLARE(arm_mmu401, "arm,mmu-401");
 IOMMU_OF_DECLARE(arm_mmu500, "arm,mmu-500");
 IOMMU_OF_DECLARE(cavium_smmuv2, "cavium,smmu-v2");
+IOMMU_OF_DECLARE(qcom_smmuv2, "qcom,smmu-v2");
 
 MODULE_DESCRIPTION("IOMMU API for ARM architected SMMU implementations");
 MODULE_AUTHOR("Will Deacon <will.deacon@arm.com>");
-- 
QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member
of Code Aurora Forum, hosted by The Linux Foundation

Re: [PATCH v10 4/5] iommu/arm-smmu: Add the device_link between masters and smmu

[Tomasz Figa]

Hi Vivek,

On Wed, Mar 14, 2018 at 5:14 PM, Vivek Gautam
<vivek.gautam@codeaurora.org> wrote:
> From: Sricharan R <sricharan@codeaurora.org>
>
> Finally add the device link between the master device and
> smmu, so that the smmu gets runtime enabled/disabled only when the
> master needs it. This is done from add_device callback which gets
> called once when the master is added to the smmu.
>
> Signed-off-by: Sricharan R <sricharan@codeaurora.org>
> Signed-off-by: Vivek Gautam <vivek.gautam@codeaurora.org>
> Reviewed-by: Tomasz Figa <tfiga@chromium.org>
> ---
>
> Changes since v9:
>  - Using device_link_del_dev() to delete the device link, instead of
>    doing it in two steps - device_link_find() to first find the link, and
>    then calling device_link_del().
>
>  drivers/iommu/arm-smmu.c | 24 ++++++++++++++++++++++++
>  1 file changed, 24 insertions(+)
>
> diff --git a/drivers/iommu/arm-smmu.c b/drivers/iommu/arm-smmu.c
> index 56a04ae80bf3..4cf270ffd449 100644
> --- a/drivers/iommu/arm-smmu.c
> +++ b/drivers/iommu/arm-smmu.c
> @@ -1460,10 +1460,31 @@ static int arm_smmu_add_device(struct device *dev)
>
>         iommu_device_link(&smmu->iommu, dev);
>
> +       if (pm_runtime_enabled(smmu->dev)) {
> +               struct device_link *link;
> +
> +               /*
> +                * Establish the link between smmu and master, so that the
> +                * smmu gets runtime enabled/disabled as per the master's
> +                * needs.
> +                */
> +               link = device_link_add(dev, smmu->dev, DL_FLAG_PM_RUNTIME);
> +               if (!link) {
> +                       dev_warn(smmu->dev,
> +                                "Unable to add link to the consumer %s\n",
> +                                dev_name(dev));
> +                       ret = -ENODEV;
> +                       goto out_unlink;
> +               }
> +       }

If it's an error, we should use dev_err(). Also, as per Robin's
comment for v9 could we make it as follows?

if (pm_runtime_enabled(smmu->dev) &&
    !device_link_add(dev, smmu->dev, DL_FLAG_PM_RUNTIME)) {
        dev_err(smmu->dev,
                         "Unable to add link to the consumer %s\n",
dev_name(dev));
        ret = -ENODEV;
        goto out_unlink;
}

Best regards,
Tomasz