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Commit 3fc7c5c0 authored by Marc Zyngier's avatar Marc Zyngier Committed by Olof Johansson
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iommu/rockchip: Handle errors returned from PM framework 



pm_runtime_get_if_in_use can fail: either PM has been disabled
altogether (-EINVAL), or the device hasn't been enabled yet (0).
Sadly, the Rockchip IOMMU driver tends to conflate the two things
by considering a non-zero return value as successful.

This has the consequence of hiding other bugs, so let's handle this
case throughout the driver, with a WARN_ON_ONCE so that we can try
and work out what happened.

Fixes: 0f181d3c ("iommu/rockchip: Add runtime PM support")
Reviewed-by: default avatarHeiko Stuebner <heiko@sntech.de>
Signed-off-by: default avatarMarc Zyngier <marc.zyngier@arm.com>
Signed-off-by: default avatarOlof Johansson <olof@lixom.net>
parent 7db7a8f5

drivers/iommu/rockchip-iommu.c

+15 −6
Original line number Diff line number Diff line
@@ -521,10 +521,11 @@ static irqreturn_t rk_iommu_irq(int irq, void *dev_id) 
	u32 int_status;

	dma_addr_t iova;

	irqreturn_t ret = IRQ_NONE;

	int i;

	int i, err;



	if (WARN_ON(!pm_runtime_get_if_in_use(iommu->dev)))

		return 0;

	err = pm_runtime_get_if_in_use(iommu->dev);

	if (WARN_ON_ONCE(err <= 0))

		return ret;



	if (WARN_ON(clk_bulk_enable(iommu->num_clocks, iommu->clocks)))

		goto out;
@@ -620,11 +621,15 @@ static void rk_iommu_zap_iova(struct rk_iommu_domain *rk_domain, 
	spin_lock_irqsave(&rk_domain->iommus_lock, flags);

	list_for_each(pos, &rk_domain->iommus) {

		struct rk_iommu *iommu;

		int ret;



		iommu = list_entry(pos, struct rk_iommu, node);



		/* Only zap TLBs of IOMMUs that are powered on. */

		if (pm_runtime_get_if_in_use(iommu->dev)) {

		ret = pm_runtime_get_if_in_use(iommu->dev);

		if (WARN_ON_ONCE(ret < 0))

			continue;

		if (ret) {

			WARN_ON(clk_bulk_enable(iommu->num_clocks,

						iommu->clocks));

			rk_iommu_zap_lines(iommu, iova, size);
@@ -891,6 +896,7 @@ static void rk_iommu_detach_device(struct iommu_domain *domain, 
	struct rk_iommu *iommu;

	struct rk_iommu_domain *rk_domain = to_rk_domain(domain);

	unsigned long flags;

	int ret;



	/* Allow 'virtual devices' (eg drm) to detach from domain */

	iommu = rk_iommu_from_dev(dev);
@@ -909,7 +915,9 @@ static void rk_iommu_detach_device(struct iommu_domain *domain, 
	list_del_init(&iommu->node);

	spin_unlock_irqrestore(&rk_domain->iommus_lock, flags);



	if (pm_runtime_get_if_in_use(iommu->dev)) {

	ret = pm_runtime_get_if_in_use(iommu->dev);

	WARN_ON_ONCE(ret < 0);

	if (ret > 0) {

		rk_iommu_disable(iommu);

		pm_runtime_put(iommu->dev);

	}
@@ -946,7 +954,8 @@ static int rk_iommu_attach_device(struct iommu_domain *domain, 
	list_add_tail(&iommu->node, &rk_domain->iommus);

	spin_unlock_irqrestore(&rk_domain->iommus_lock, flags);



	if (!pm_runtime_get_if_in_use(iommu->dev))

	ret = pm_runtime_get_if_in_use(iommu->dev);

	if (!ret || WARN_ON_ONCE(ret < 0))

		return 0;



	ret = rk_iommu_enable(iommu);