[RFC PATCH 1/2] pci: Allow platforms to modify BAR adresses

[Mykyta Poturai <Mykyta_Poturai@xxxxxxxx>]

This patch is a preparatory work for adding Region ID support on Renesas
R-Car series boards. Add new host bridge op "fixup_bar" that allows
platforms to modify BAR addresses before they are mapped.

Because x86 don't have support for PCI Host Bridge drivers, add another
level of indirection in form of platform_pci_fixup_bar() function, that
will call host bridge op on ARM and do nothing on x86.

Signed-off-by: Mykyta Poturai <mykyta_poturai@xxxxxxxx>
---
 xen/arch/arm/include/asm/pci.h  |  3 +++
 xen/arch/arm/include/asm/vpci.h |  9 +++++++++
 xen/arch/arm/vpci.c             | 12 ++++++++++++
 xen/arch/x86/include/asm/vpci.h |  6 ++++++
 xen/drivers/vpci/header.c       |  2 ++
 5 files changed, 32 insertions(+)

diff --git a/xen/arch/arm/include/asm/pci.h b/xen/arch/arm/include/asm/pci.h
index 7c3211823f..398a4eb746 100644
--- a/xen/arch/arm/include/asm/pci.h
+++ b/xen/arch/arm/include/asm/pci.h
@@ -80,6 +80,9 @@ struct pci_ops {
     void (*init_bus_range)(struct dt_device_node *dev,
                            struct pci_host_bridge *bridge,
                            struct pci_config_window *cfg);
+    void (*fixup_bar)(struct pci_host_bridge *bridge,
+                      unsigned int bar_num,
+                      paddr_t *addr);
 };
 
 /*
diff --git a/xen/arch/arm/include/asm/vpci.h b/xen/arch/arm/include/asm/vpci.h
index 0cc6f5a105..f5c817a51c 100644
--- a/xen/arch/arm/include/asm/vpci.h
+++ b/xen/arch/arm/include/asm/vpci.h
@@ -16,6 +16,10 @@ struct vpci_arch_msix_entry {
 
 int domain_vpci_init(struct domain *d);
 unsigned int domain_vpci_get_num_mmio_handlers(struct domain *d);
+
+void platform_pci_fixup_bar(const struct pci_dev *pdev, unsigned int bar_num,
+                            paddr_t *addr);
+
 #else
 static inline int domain_vpci_init(struct domain *d)
 {
@@ -26,6 +30,11 @@ static inline unsigned int 
domain_vpci_get_num_mmio_handlers(struct domain *d)
 {
     return 0;
 }
+
+static inline void platform_pci_fixup_bar(const struct pci_dev *pdev,
+                                          unsigned int bar_num,
+                                          paddr_t *addr)
+{}
 #endif /* CONFIG_HAS_VPCI */
 
 #endif /* ARM_VPCI_H */
diff --git a/xen/arch/arm/vpci.c b/xen/arch/arm/vpci.c
index d41aa383a8..ec6efec22e 100644
--- a/xen/arch/arm/vpci.c
+++ b/xen/arch/arm/vpci.c
@@ -189,6 +189,18 @@ unsigned int domain_vpci_get_num_mmio_handlers(struct 
domain *d)
     return 1;
 }
 
+void platform_pci_fixup_bar(const struct pci_dev *pdev,
+                                          unsigned int bar_num,
+                                          paddr_t *addr)
+{
+    struct pci_host_bridge *bridge = pci_find_host_bridge(pdev->sbdf.seg, 
pdev->sbdf.bus);
+
+    if ( bridge->ops->fixup_bar )
+    {
+        bridge->ops->fixup_bar(bridge, bar_num, addr);
+    }
+}
+
 /*
  * Local variables:
  * mode: C
diff --git a/xen/arch/x86/include/asm/vpci.h b/xen/arch/x86/include/asm/vpci.h
index c501ff1709..a05b70abbf 100644
--- a/xen/arch/x86/include/asm/vpci.h
+++ b/xen/arch/x86/include/asm/vpci.h
@@ -16,6 +16,12 @@ struct vpci_arch_msix_entry {
     int pirq;
 };
 
+/* X86 does not require PCI BAR modifications */
+static inline void platform_pci_fixup_bar(const struct pci_dev *pdev,
+                                          unsigned int bar_num,
+                                          paddr_t *addr)
+{}
+
 #endif /* X86_VPCI_H */
 
 /*
diff --git a/xen/drivers/vpci/header.c b/xen/drivers/vpci/header.c
index a760d8c32f..d89e43354c 100644
--- a/xen/drivers/vpci/header.c
+++ b/xen/drivers/vpci/header.c
@@ -882,6 +882,8 @@ int vpci_init_header(struct pci_dev *pdev)
         bars[i].size = size;
         bars[i].prefetchable = val & PCI_BASE_ADDRESS_MEM_PREFETCH;
 
+        platform_pci_fixup_bar(pdev, i, &bars[i].addr);
+
         rc = vpci_add_register(pdev->vpci,
                                is_hwdom ? vpci_hw_read32 : guest_mem_bar_read,
                                is_hwdom ? bar_write : guest_mem_bar_write,
-- 
2.51.2