[PATCH v1 08/14] xen:arm: Implement pci access functions

[Rahul Singh <rahul.singh@xxxxxxx>]

Implement generic pci access functions to read/write the configuration
space.

Signed-off-by: Rahul Singh <rahul.singh@xxxxxxx>
---
 xen/arch/arm/pci/pci-access.c      | 31 +++++++++++++++++++++++++++++-
 xen/arch/arm/pci/pci-host-common.c | 19 ++++++++++++++++++
 xen/include/asm-arm/pci.h          |  2 ++
 3 files changed, 51 insertions(+), 1 deletion(-)

diff --git a/xen/arch/arm/pci/pci-access.c b/xen/arch/arm/pci/pci-access.c
index f39f6a3a38..b94de3c3ac 100644
--- a/xen/arch/arm/pci/pci-access.c
+++ b/xen/arch/arm/pci/pci-access.c
@@ -72,12 +72,41 @@ int pci_generic_config_write(struct pci_host_bridge 
*bridge, uint32_t sbdf,
 static uint32_t pci_config_read(pci_sbdf_t sbdf, unsigned int reg,
                                 unsigned int len)
 {
-    return ~0U;
+    uint32_t val = GENMASK(0, len * 8);
+
+    struct pci_host_bridge *bridge = pci_find_host_bridge(sbdf.seg, sbdf.bus);
+
+    if ( unlikely(!bridge) )
+    {
+        printk(XENLOG_ERR "Unable to find bridge for "PRI_pci"\n",
+                sbdf.seg, sbdf.bus, sbdf.dev, sbdf.fn);
+        return val;
+    }
+
+    if ( unlikely(!bridge->ops->read) )
+        return val;
+
+    bridge->ops->read(bridge, (uint32_t) sbdf.sbdf, reg, len, &val);
+
+    return val;
 }
 
 static void pci_config_write(pci_sbdf_t sbdf, unsigned int reg,
                              unsigned int len, uint32_t val)
 {
+    struct pci_host_bridge *bridge = pci_find_host_bridge(sbdf.seg, sbdf.bus);
+
+    if ( unlikely(!bridge) )
+    {
+        printk(XENLOG_ERR "Unable to find bridge for "PRI_pci"\n",
+                sbdf.seg, sbdf.bus, sbdf.dev, sbdf.fn);
+        return;
+    }
+
+    if ( unlikely(!bridge->ops->write) )
+        return;
+
+    bridge->ops->write(bridge, (uint32_t) sbdf.sbdf, reg, len, val);
 }
 
 /*
diff --git a/xen/arch/arm/pci/pci-host-common.c 
b/xen/arch/arm/pci/pci-host-common.c
index c582527e92..62715b4676 100644
--- a/xen/arch/arm/pci/pci-host-common.c
+++ b/xen/arch/arm/pci/pci-host-common.c
@@ -261,6 +261,25 @@ err_exit:
     return err;
 }
 
+/*
+ * This function will lookup an hostbridge based on the segment and bus
+ * number.
+ */
+struct pci_host_bridge *pci_find_host_bridge(uint16_t segment, uint8_t bus)
+{
+    struct pci_host_bridge *bridge;
+
+    list_for_each_entry( bridge, &pci_host_bridges, node )
+    {
+        if ( bridge->segment != segment )
+            continue;
+        if ( (bus < bridge->bus_start) || (bus > bridge->bus_end) )
+            continue;
+        return bridge;
+    }
+
+    return NULL;
+}
 /*
  * Local variables:
  * mode: C
diff --git a/xen/include/asm-arm/pci.h b/xen/include/asm-arm/pci.h
index 22866244d2..756f8637ab 100644
--- a/xen/include/asm-arm/pci.h
+++ b/xen/include/asm-arm/pci.h
@@ -20,6 +20,7 @@
 #ifdef CONFIG_HAS_PCI
 
 #define pci_to_dev(pcidev) (&(pcidev)->arch.dev)
+#define PRI_pci "%04x:%02x:%02x.%u"
 
 /* Arch pci dev struct */
 struct arch_pci_dev {
@@ -86,6 +87,7 @@ int pci_generic_config_write(struct pci_host_bridge *bridge, 
uint32_t sbdf,
 void __iomem *pci_ecam_map_bus(struct pci_host_bridge *bridge,
                                uint32_t sbdf, uint32_t where);
 
+struct pci_host_bridge *pci_find_host_bridge(uint16_t segment, uint8_t bus);
 #else   /*!CONFIG_HAS_PCI*/
 
 struct arch_pci_dev { };
-- 
2.17.1