Add suspend and resume support for arm-smmu-v3 by low-power mode.

When the smmu is suspended, it is powered off and the registers are
cleared. So saves the msi_msg context during msi interrupt initialization
of smmu. When resume happens it calls arm_smmu_device_reset() to restore
the registers.

Signed-off-by: Bixuan Cui <cuibix...@huawei.com>
Reviewed-by: Wei Yongjun <weiyongj...@huawei.com>
Reviewed-by: Zhen Lei <thunder.leiz...@huawei.com>
Reviewed-by: Ding Tianhong <dingtianh...@huawei.com>
Reviewed-by: Hanjun Guo <guohan...@huawei.com>
---
Changes in v2:
* Using get_cached_msi_msg() instead of the descriptor to resume msi_msg
  in arm_smmu_resume_msis();

* Move arm_smmu_resume_msis() from arm_smmu_setup_unique_irqs() into
  arm_smmu_setup_irqs() and rename it to arm_smmu_resume_unique_irqs();

  Call arm_smmu_setup_unique_irqs() to configure the IRQ during probe and
  call arm_smmu_resume_unique_irqs() in resume mode to restore the IRQ
  registers to make the code more reasonable.

* Call arm_smmu_device_disable() to disable smmu and clear CR0_SMMUEN on
  suspend. Then the warning about CR0_SMMUEN being enabled can be cleared
  on resume.

* Using SET_SYSTEM_SLEEP_PM_OPS();

 drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c | 69 ++++++++++++++++++---
 1 file changed, 62 insertions(+), 7 deletions(-)

diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c 
b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
index 235f9bdaeaf2..66f35d5c7a70 100644
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
@@ -40,6 +40,7 @@ MODULE_PARM_DESC(disable_bypass,
 
 static bool disable_msipolling;
 module_param(disable_msipolling, bool, 0444);
+static bool bypass;
 MODULE_PARM_DESC(disable_msipolling,
        "Disable MSI-based polling for CMD_SYNC completion.");
 
@@ -3129,11 +3130,38 @@ static void arm_smmu_write_msi_msg(struct msi_desc 
*desc, struct msi_msg *msg)
        doorbell = (((u64)msg->address_hi) << 32) | msg->address_lo;
        doorbell &= MSI_CFG0_ADDR_MASK;
 
+       /* Saves the msg context for resume if desc->msg is empty */
+       if (desc->msg.address_lo == 0x0 && desc->msg.address_hi == 0x0) {
+               desc->msg.address_lo = msg->address_lo;
+               desc->msg.address_hi = msg->address_hi;
+               desc->msg.data = msg->data;
+       }
+
        writeq_relaxed(doorbell, smmu->base + cfg[0]);
        writel_relaxed(msg->data, smmu->base + cfg[1]);
        writel_relaxed(ARM_SMMU_MEMATTR_DEVICE_nGnRE, smmu->base + cfg[2]);
 }
 
+static void arm_smmu_resume_unique_irqs(struct arm_smmu_device *smmu)
+{
+       struct msi_desc *desc;
+       struct msi_msg msg;
+
+       desc = irq_get_msi_desc(smmu->evtq.q.irq);
+       get_cached_msi_msg(smmu->evtq.q.irq, &msg);
+       arm_smmu_write_msi_msg(desc, &msg);
+
+       desc = irq_get_msi_desc(smmu->gerr_irq);
+       get_cached_msi_msg(smmu->gerr_irq, &msg);
+       arm_smmu_write_msi_msg(desc, &msg);
+
+       if (smmu->features & ARM_SMMU_FEAT_PRI) {
+               desc = irq_get_msi_desc(smmu->priq.q.irq);
+               get_cached_msi_msg(smmu->priq.q.irq, &msg);
+               arm_smmu_write_msi_msg(desc, &msg);
+       }
+}
+
 static void arm_smmu_setup_msis(struct arm_smmu_device *smmu)
 {
        struct msi_desc *desc;
@@ -3230,7 +3258,7 @@ static void arm_smmu_setup_unique_irqs(struct 
arm_smmu_device *smmu)
        }
 }
 
-static int arm_smmu_setup_irqs(struct arm_smmu_device *smmu)
+static int arm_smmu_setup_irqs(struct arm_smmu_device *smmu, bool resume_mode)
 {
        int ret, irq;
        u32 irqen_flags = IRQ_CTRL_EVTQ_IRQEN | IRQ_CTRL_GERROR_IRQEN;
@@ -3256,8 +3284,12 @@ static int arm_smmu_setup_irqs(struct arm_smmu_device 
*smmu)
                                        "arm-smmu-v3-combined-irq", smmu);
                if (ret < 0)
                        dev_warn(smmu->dev, "failed to enable combined irq\n");
-       } else
-               arm_smmu_setup_unique_irqs(smmu);
+       } else {
+               if (!resume_mode)
+                       arm_smmu_setup_unique_irqs(smmu);
+               else
+                       arm_smmu_resume_unique_irqs(smmu);
+       }
 
        if (smmu->features & ARM_SMMU_FEAT_PRI)
                irqen_flags |= IRQ_CTRL_PRIQ_IRQEN;
@@ -3282,7 +3314,7 @@ static int arm_smmu_device_disable(struct arm_smmu_device 
*smmu)
        return ret;
 }
 
-static int arm_smmu_device_reset(struct arm_smmu_device *smmu, bool bypass)
+static int arm_smmu_device_reset(struct arm_smmu_device *smmu, bool 
resume_mode)
 {
        int ret;
        u32 reg, enables;
@@ -3392,7 +3424,7 @@ static int arm_smmu_device_reset(struct arm_smmu_device 
*smmu, bool bypass)
                }
        }
 
-       ret = arm_smmu_setup_irqs(smmu);
+       ret = arm_smmu_setup_irqs(smmu, resume_mode);
        if (ret) {
                dev_err(smmu->dev, "failed to setup irqs\n");
                return ret;
@@ -3749,6 +3781,25 @@ static void __iomem *arm_smmu_ioremap(struct device 
*dev, resource_size_t start,
        return devm_ioremap_resource(dev, &res);
 }
 
+static int __maybe_unused arm_smmu_suspend(struct device *dev)
+{
+       struct arm_smmu_device *smmu = dev_get_drvdata(dev);
+
+       /* disable smmu to clear CR0 */
+       arm_smmu_device_disable(smmu);
+
+       return 0;
+}
+
+static int __maybe_unused arm_smmu_resume(struct device *dev)
+{
+       struct arm_smmu_device *smmu = dev_get_drvdata(dev);
+
+       arm_smmu_device_reset(smmu, true);
+
+       return 0;
+}
+
 static int arm_smmu_device_probe(struct platform_device *pdev)
 {
        int irq, ret;
@@ -3756,7 +3807,6 @@ static int arm_smmu_device_probe(struct platform_device 
*pdev)
        resource_size_t ioaddr;
        struct arm_smmu_device *smmu;
        struct device *dev = &pdev->dev;
-       bool bypass;
 
        smmu = devm_kzalloc(dev, sizeof(*smmu), GFP_KERNEL);
        if (!smmu)
@@ -3831,7 +3881,7 @@ static int arm_smmu_device_probe(struct platform_device 
*pdev)
        platform_set_drvdata(pdev, smmu);
 
        /* Reset the device */
-       ret = arm_smmu_device_reset(smmu, bypass);
+       ret = arm_smmu_device_reset(smmu, false);
        if (ret)
                return ret;
 
@@ -3884,6 +3934,10 @@ static const struct of_device_id arm_smmu_of_match[] = {
 };
 MODULE_DEVICE_TABLE(of, arm_smmu_of_match);
 
+static const struct dev_pm_ops arm_smmu_pm_ops = {
+       SET_SYSTEM_SLEEP_PM_OPS(arm_smmu_suspend, arm_smmu_resume)
+};
+
 static void arm_smmu_driver_unregister(struct platform_driver *drv)
 {
        arm_smmu_sva_notifier_synchronize();
@@ -3895,6 +3949,7 @@ static struct platform_driver arm_smmu_driver = {
                .name                   = "arm-smmu-v3",
                .of_match_table         = arm_smmu_of_match,
                .suppress_bind_attrs    = true,
+               .pm                     = &arm_smmu_pm_ops,
        },
        .probe  = arm_smmu_device_probe,
        .remove = arm_smmu_device_remove,
-- 
2.17.1

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