[PATCH v4 0/2] PCI: dwc: fix two MSI issues

[PATCH v4 0/2] PCI: dwc: fix two MSI issues

[Jisheng Zhang]

Fix two MSI issues. One to skip PCIE_MSI_INTR0* programming if MSI is
disabled, another to use an address in the driver data for MSI address,
to fix the MSI page leakage during suspend/resume.

Since v3:
  - add Acked-by tag
  - change patch2 commit msg to make it more clear
  - map the MSI msg with dma_map_single_attrs() for some platforms
    which either has seperate addrs for dma and phy or has mem access
    limitation for the PCIe.

Since v2:
  - add Acked-by tag
  - use an address in the driver data for MSI address. Thank Ard and Rob
    for pointing out this correct direction.
  - Since the MSI page has gone, the leak issue doesn't exist anymore,
    remove unnecessary patches.
  - Remove dw_pcie_free_msi rename and the last patch. They could be
    targeted to next. So will send out patches in a separate series.

Since v1:
  - add proper error handling patches.
  - solve the msi page leakage by moving dw_pcie_msi_init() from each
    users to designware host



Jisheng Zhang (2):
  PCI: dwc: Skip PCIE_MSI_INTR0* programming if MSI is disabled
  PCI: dwc: Fix MSI page leakage in suspend/resume

 drivers/pci/controller/dwc/pci-dra7xx.c       | 16 ++++++++-
 .../pci/controller/dwc/pcie-designware-host.c | 34 +++++++++----------
 drivers/pci/controller/dwc/pcie-designware.h  |  2 +-
 3 files changed, 33 insertions(+), 19 deletions(-)

-- 
2.28.0

[PATCH v4 1/2] PCI: dwc: Skip PCIE_MSI_INTR0* programming if MSI is disabled

[Jisheng Zhang]

If MSI is disabled, there's no need to program PCIE_MSI_INTR0_MASK
and PCIE_MSI_INTR0_ENABLE registers.

Signed-off-by: Jisheng Zhang <Jisheng.Zhang@synaptics.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Acked-by: Gustavo Pimentel <gustavo.pimentel@synopsys.com>
---
 drivers/pci/controller/dwc/pcie-designware-host.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/pci/controller/dwc/pcie-designware-host.c b/drivers/pci/controller/dwc/pcie-designware-host.c
index 9dafecba347f..f08f4d97f321 100644
--- a/drivers/pci/controller/dwc/pcie-designware-host.c
+++ b/drivers/pci/controller/dwc/pcie-designware-host.c
@@ -632,7 +632,7 @@ void dw_pcie_setup_rc(struct pcie_port *pp)
 
 	dw_pcie_setup(pci);
 
-	if (!pp->ops->msi_host_init) {
+	if (pci_msi_enabled() && !pp->ops->msi_host_init) {
 		num_ctrls = pp->num_vectors / MAX_MSI_IRQS_PER_CTRL;
 
 		/* Initialize IRQ Status array */
-- 
2.28.0

[PATCH v4 2/2] PCI: dwc: Fix MSI page leakage in suspend/resume

[Jisheng Zhang]

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       | 16 +++++++++-
 .../pci/controller/dwc/pcie-designware-host.c | 32 +++++++++----------
 drivers/pci/controller/dwc/pcie-designware.h  |  2 +-
 3 files changed, 32 insertions(+), 18 deletions(-)

diff --git a/drivers/pci/controller/dwc/pci-dra7xx.c b/drivers/pci/controller/dwc/pci-dra7xx.c
index dc387724cf08..688e5e88784e 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 +508,19 @@ 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(dev, pp->msi_msg, sizeof(pp->msi_msg),
+				      DMA_FROM_DEVICE);
+	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];
-- 
2.28.0