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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: 0f181d3cf7 ("iommu/rockchip: Add runtime PM support")
Reviewed-by: Heiko Stuebner <heiko@sntech.de>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Olof Johansson <olof@lixom.net>
This commit is contained in:
Marc Zyngier 2018-08-24 16:06:36 +01:00 committed by Olof Johansson
parent 7db7a8f563
commit 3fc7c5c0cf
1 changed files with 15 additions and 6 deletions
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21
drivers/iommu/rockchip-iommu.c
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@ -521,10 +521,11 @@ static irqreturn_t rk_iommu_irq(int irq, void *dev_id)
u32 int_status; u32 int_status;
dma_addr_t iova; dma_addr_t iova;
irqreturn_t ret = IRQ_NONE; irqreturn_t ret = IRQ_NONE;
int i; int i, err;
if (WARN_ON(!pm_runtime_get_if_in_use(iommu->dev))) err = pm_runtime_get_if_in_use(iommu->dev);
return 0; if (WARN_ON_ONCE(err <= 0))
return ret;
if (WARN_ON(clk_bulk_enable(iommu->num_clocks, iommu->clocks))) if (WARN_ON(clk_bulk_enable(iommu->num_clocks, iommu->clocks)))
goto out; 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); spin_lock_irqsave(&rk_domain->iommus_lock, flags);
list_for_each(pos, &rk_domain->iommus) { list_for_each(pos, &rk_domain->iommus) {
struct rk_iommu *iommu; struct rk_iommu *iommu;
int ret;
iommu = list_entry(pos, struct rk_iommu, node); iommu = list_entry(pos, struct rk_iommu, node);
/* Only zap TLBs of IOMMUs that are powered on. */ /* 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, WARN_ON(clk_bulk_enable(iommu->num_clocks,
iommu->clocks)); iommu->clocks));
rk_iommu_zap_lines(iommu, iova, size); 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 *iommu;
struct rk_iommu_domain *rk_domain = to_rk_domain(domain); struct rk_iommu_domain *rk_domain = to_rk_domain(domain);
unsigned long flags; unsigned long flags;
int ret;
/* Allow 'virtual devices' (eg drm) to detach from domain */ /* Allow 'virtual devices' (eg drm) to detach from domain */
iommu = rk_iommu_from_dev(dev); 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); list_del_init(&iommu->node);
spin_unlock_irqrestore(&rk_domain->iommus_lock, flags); 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); rk_iommu_disable(iommu);
pm_runtime_put(iommu->dev); 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); list_add_tail(&iommu->node, &rk_domain->iommus);
spin_unlock_irqrestore(&rk_domain->iommus_lock, flags); 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; return 0;
ret = rk_iommu_enable(iommu); ret = rk_iommu_enable(iommu);