[PATCH v5 04/18] PCI: designware-ep: Pre-allocate memory for MSI in dw_pcie_ep_init

Niklas Cassel
2017-11-20T13:33:00Z

Certain SoCs need to map the MSI address in raise_irq.
To map an address, you first need to call pci_epc_mem_alloc_addr(),
however, pci_epc_mem_alloc_addr() calls ioremap() (which can sleep).

Since raise_irq is only called from atomic context, we can't call
pci_epc_mem_alloc_addr() from raise_irq.

Pre-allocate a page in dw_pcie_ep_init(), so that this page can later
be used to map/unmap the MSI address in raise_irq.

Signed-off-by: Niklas Cassel <niklas.cassel@axis.com>
---
drivers/pci/dwc/pcie-designware-ep.c | 10 ++++++++++
drivers/pci/dwc/pcie-designware.h | 2 ++
2 files changed, 12 insertions(+)

diff --git a/drivers/pci/dwc/pcie-designware-ep.c b/drivers/pci/dwc/pcie-designware-ep.c
index 3fb34be99715..8d8019cdff2a 100644
--- a/drivers/pci/dwc/pcie-designware-ep.c
+++ b/drivers/pci/dwc/pcie-designware-ep.c
@@ -286,6 +286,9 @@ void dw_pcie_ep_exit(struct dw_pcie_ep *ep)
{
struct pci_epc *epc = ep->epc;

+ pci_epc_mem_free_addr(epc, ep->msi_mem_phys, ep->msi_mem,
+ epc->mem->page_size);
+
pci_epc_mem_exit(epc);
}

@@ -341,6 +344,13 @@ int dw_pcie_ep_init(struct dw_pcie_ep *ep)
return ret;
}

+ ep->msi_mem = pci_epc_mem_alloc_addr(epc, &ep->msi_mem_phys,
+ epc->mem->page_size);
+ if (!ep->msi_mem) {
+ dev_err(dev, "Failed to reserve memory for MSI\n");
+ return -ENOMEM;
+ }
+
ep->epc = epc;
epc_set_drvdata(epc, ep);
dw_pcie_setup(pci);
diff --git a/drivers/pci/dwc/pcie-designware.h b/drivers/pci/dwc/pcie-designware.h
index 9aaf0cd04dd6..5a1da459eda5 100644
--- a/drivers/pci/dwc/pcie-designware.h
+++ b/drivers/pci/dwc/pcie-designware.h
@@ -198,6 +198,8 @@ struct dw_pcie_ep {
unsigned long ob_window_map;
u32 num_ib_windows;
u32 num_ob_windows;
+ void __iomem *msi_mem;
+ phys_addr_t msi_mem_phys;
};

struct dw_pcie_ops {
--
2.14.2