Re: [PATCH] PCI: dwc: Move allocate and map page for msi out of dw_pcie_msi_init()
From: Ard Biesheuvel <ardb@kernel.org>
Date: 2020-09-24 11:00:41
Also in:
linux-omap, linux-pci, lkml
On Wed, 23 Sep 2020 at 08:28, Jisheng Zhang [off-list ref] 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
previous msi page will be leaked.
Move the allocate and map msi page from dw_pcie_msi_init() to
dw_pcie_host_init() to fix this problem.
Fixes: 56e15a238d92 ("PCI: tegra: Add Tegra194 PCIe support")
Signed-off-by: Jisheng Zhang <redacted>Why do you allocate a page for this in the first place? Isn't PCIE_MSI_ADDR_HI:PCIE_MSI_ADDR_LO simply a magic DMA address that never gets forwarded across to the CPU side of the host bridge, and triggers a SPI instead, which gets handled by reading PCIE_MSI_INTR0_STATUS ? Couldn't you just map the zero page instead?
quoted hunk ↗ jump to hunk
--- drivers/pci/controller/dwc/pci-dra7xx.c | 18 ++++++++++++- .../pci/controller/dwc/pcie-designware-host.c | 27 +++++++++---------- 2 files changed, 30 insertions(+), 15 deletions(-)diff --git a/drivers/pci/controller/dwc/pci-dra7xx.c b/drivers/pci/controller/dwc/pci-dra7xx.c index dc387724cf08..4301cf844a4c 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_page = alloc_page(GFP_KERNEL); + pp->msi_data = dma_map_page(dev, pp->msi_page, 0, PAGE_SIZE, + DMA_FROM_DEVICE); + ret = dma_mapping_error(dev, pp->msi_data); + if (ret) { + dev_err(dev, "Failed to map MSI data\n"); + __free_page(pp->msi_page); + pp->msi_page = NULL; + 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 9dafecba347f..c23ba64f64fe 100644 --- a/drivers/pci/controller/dwc/pcie-designware-host.c +++ b/drivers/pci/controller/dwc/pcie-designware-host.c@@ -294,20 +294,7 @@ void dw_pcie_free_msi(struct pcie_port *pp) 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 +427,18 @@ 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_page = alloc_page(GFP_KERNEL); + pp->msi_data = dma_map_page(pci->dev, pp->msi_page, + 0, PAGE_SIZE, + DMA_FROM_DEVICE); + ret = dma_mapping_error(pci->dev, pp->msi_data); + if (ret) { + dev_err(pci->dev, "Failed to map MSI data\n"); + __free_page(pp->msi_page); + pp->msi_page = NULL; + goto err_free_msi; + } } else { ret = pp->ops->msi_host_init(pp); if (ret < 0) --2.28.0 _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
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