diff mbox series

[v5,2/2] PCI: dwc: Fix MSI page leakage in suspend/resume

Message ID 20200930091449.50ae0caf@xhacker.debian
State Superseded
Headers show
Series PCI: dwc: fix two MSI issues | expand

Commit Message

Jisheng Zhang Sept. 30, 2020, 1:15 a.m. UTC 
Currently, dw_pcie_msi_init() allocates and maps page for msi, then
program the PCIE_MSI_ADDR_LO and PCIE_MSI_ADDR_HI. The Root Complex
may lose power during suspend-to-RAM, so when we resume, we want to
redo the latter but not the former. If designware based driver (for
example, pcie-tegra194.c) calls dw_pcie_msi_init() in resume path, the
msi page will be leaked.

As pointed out by Rob and Ard, there's no need to allocate a page for
the MSI address, we could use an address in the driver data.

To avoid map the MSI msg again during resume, we move the map MSI msg
from dw_pcie_msi_init() to dw_pcie_host_init().

Signed-off-by: Jisheng Zhang <Jisheng.Zhang@synaptics.com>
---
 drivers/pci/controller/dwc/pci-dra7xx.c       | 18 ++++++++++-
 .../pci/controller/dwc/pcie-designware-host.c | 32 +++++++++----------
 drivers/pci/controller/dwc/pcie-designware.h  |  2 +-
 3 files changed, 34 insertions(+), 18 deletions(-)

Comments

Rob Herring (Arm) Oct. 7, 2020, 5:41 p.m. UTC | #1 
On Wed, Sep 30, 2020 at 09:15:25AM +0800, Jisheng Zhang wrote:
> Currently, dw_pcie_msi_init() allocates and maps page for msi, then

> program the PCIE_MSI_ADDR_LO and PCIE_MSI_ADDR_HI. The Root Complex

> may lose power during suspend-to-RAM, so when we resume, we want to

> redo the latter but not the former. If designware based driver (for

> example, pcie-tegra194.c) calls dw_pcie_msi_init() in resume path, the

> msi page will be leaked.

> 

> As pointed out by Rob and Ard, there's no need to allocate a page for

> the MSI address, we could use an address in the driver data.

> 

> To avoid map the MSI msg again during resume, we move the map MSI msg

> from dw_pcie_msi_init() to dw_pcie_host_init().

> 

> Signed-off-by: Jisheng Zhang <Jisheng.Zhang@synaptics.com>

> ---

>  drivers/pci/controller/dwc/pci-dra7xx.c       | 18 ++++++++++-

>  .../pci/controller/dwc/pcie-designware-host.c | 32 +++++++++----------

>  drivers/pci/controller/dwc/pcie-designware.h  |  2 +-

>  3 files changed, 34 insertions(+), 18 deletions(-)


I'm working on some larger MSI clean-ups which should eliminate the 
dra7xx addition, but this is good enough for now.

Reviewed-by: Rob Herring <robh@kernel.org>
diff mbox series

Patch

diff --git a/drivers/pci/controller/dwc/pci-dra7xx.c b/drivers/pci/controller/dwc/pci-dra7xx.c
index dc387724cf08..a0b2deb7f628 100644
--- a/drivers/pci/controller/dwc/pci-dra7xx.c
+++ b/drivers/pci/controller/dwc/pci-dra7xx.c
@@ -490,7 +490,9 @@  static struct irq_chip dra7xx_pci_msi_bottom_irq_chip = {
 static int dra7xx_pcie_msi_host_init(struct pcie_port *pp)
 {
 	struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
+	struct device *dev = pci->dev;
 	u32 ctrl, num_ctrls;
+	int ret;
 
 	pp->msi_irq_chip = &dra7xx_pci_msi_bottom_irq_chip;
 
@@ -506,7 +508,21 @@  static int dra7xx_pcie_msi_host_init(struct pcie_port *pp)
 				    ~0);
 	}
 
-	return dw_pcie_allocate_domains(pp);
+	ret = dw_pcie_allocate_domains(pp);
+	if (ret)
+		return ret;
+
+	pp->msi_data = dma_map_single_attrs(dev, &pp->msi_msg,
+					   sizeof(pp->msi_msg),
+					   DMA_FROM_DEVICE,
+					   DMA_ATTR_SKIP_CPU_SYNC);
+	ret = dma_mapping_error(dev, pp->msi_data);
+	if (ret) {
+		dev_err(dev, "Failed to map MSI data\n");
+		pp->msi_data = 0;
+		dw_pcie_free_msi(pp);
+	}
+	return ret;
 }
 
 static const struct dw_pcie_host_ops dra7xx_pcie_host_ops = {
diff --git a/drivers/pci/controller/dwc/pcie-designware-host.c b/drivers/pci/controller/dwc/pcie-designware-host.c
index f08f4d97f321..27bbeee5718f 100644
--- a/drivers/pci/controller/dwc/pcie-designware-host.c
+++ b/drivers/pci/controller/dwc/pcie-designware-host.c
@@ -288,26 +288,17 @@  void dw_pcie_free_msi(struct pcie_port *pp)
 	irq_domain_remove(pp->msi_domain);
 	irq_domain_remove(pp->irq_domain);
 
-	if (pp->msi_page)
-		__free_page(pp->msi_page);
+	if (pp->msi_data) {
+		struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
+		struct device *dev = pci->dev;
+		dma_unmap_single_attrs(dev, pp->msi_data, sizeof(pp->msi_msg),
+				       DMA_FROM_DEVICE, DMA_ATTR_SKIP_CPU_SYNC);
+	}
 }
 
 void dw_pcie_msi_init(struct pcie_port *pp)
 {
-	struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
-	struct device *dev = pci->dev;
-	u64 msi_target;
-
-	pp->msi_page = alloc_page(GFP_KERNEL);
-	pp->msi_data = dma_map_page(dev, pp->msi_page, 0, PAGE_SIZE,
-				    DMA_FROM_DEVICE);
-	if (dma_mapping_error(dev, pp->msi_data)) {
-		dev_err(dev, "Failed to map MSI data\n");
-		__free_page(pp->msi_page);
-		pp->msi_page = NULL;
-		return;
-	}
-	msi_target = (u64)pp->msi_data;
+	u64 msi_target = (u64)pp->msi_data;
 
 	/* Program the msi_data */
 	dw_pcie_wr_own_conf(pp, PCIE_MSI_ADDR_LO, 4,
@@ -440,6 +431,15 @@  int dw_pcie_host_init(struct pcie_port *pp)
 				irq_set_chained_handler_and_data(pp->msi_irq,
 							    dw_chained_msi_isr,
 							    pp);
+			pp->msi_data = dma_map_single_attrs(pci->dev, &pp->msi_msg,
+						      sizeof(pp->msi_msg),
+						      DMA_FROM_DEVICE,
+						      DMA_ATTR_SKIP_CPU_SYNC);
+			if (dma_mapping_error(pci->dev, pp->msi_data)) {
+				dev_err(pci->dev, "Failed to map MSI data\n");
+				pp->msi_data = 0;
+				goto err_free_msi;
+			}
 		} else {
 			ret = pp->ops->msi_host_init(pp);
 			if (ret < 0)
diff --git a/drivers/pci/controller/dwc/pcie-designware.h b/drivers/pci/controller/dwc/pcie-designware.h
index f911760dcc69..cd9e76904c58 100644
--- a/drivers/pci/controller/dwc/pcie-designware.h
+++ b/drivers/pci/controller/dwc/pcie-designware.h
@@ -194,8 +194,8 @@  struct pcie_port {
 	int			msi_irq;
 	struct irq_domain	*irq_domain;
 	struct irq_domain	*msi_domain;
+	u16			msi_msg;
 	dma_addr_t		msi_data;
-	struct page		*msi_page;
 	struct irq_chip		*msi_irq_chip;
 	u32			num_vectors;
 	u32			irq_mask[MAX_MSI_CTRLS];