P9 supports PCI tunneled operations (atomics and as_notify). This
patch adds support for tunneled operations on powernv, with a new
API, to be called by device drivers:

pnv_pci_get_tunnel_ind()
   Tell driver the 16-bit ASN indication used by kernel.

pnv_pci_set_tunnel_bar()
   Tell kernel the Tunnel BAR Response address used by driver.

The latter uses two new OPAL calls, as the PBCQ Tunnel BAR register
is configured by skiboot.

Signed-off-by: Philippe Bergheaud <fe...@linux.vnet.ibm.com>
---
Changelog:

v2: Do not set the ASN indication. Get it from the device tree.

v3: Make pnv_pci_get_phb_node() available when compiling without cxl.

This patch depends on the following skiboot prerequisites:

    https://patchwork.ozlabs.org/patch/843474/
    https://patchwork.ozlabs.org/patch/843473/
---

 arch/powerpc/include/asm/opal-api.h            |  4 +-
 arch/powerpc/include/asm/opal.h                |  2 +
 arch/powerpc/include/asm/pnv-pci.h             |  4 +-
 arch/powerpc/platforms/powernv/opal-wrappers.S |  2 +
 arch/powerpc/platforms/powernv/pci-cxl.c       |  8 ---
 arch/powerpc/platforms/powernv/pci.c           | 77 ++++++++++++++++++++++++++
 6 files changed, 87 insertions(+), 10 deletions(-)

diff --git a/arch/powerpc/include/asm/opal-api.h 
b/arch/powerpc/include/asm/opal-api.h
index 233c7504b1f2..1aa069cc2d61 100644
--- a/arch/powerpc/include/asm/opal-api.h
+++ b/arch/powerpc/include/asm/opal-api.h
@@ -201,7 +201,9 @@
 #define OPAL_SET_POWER_SHIFT_RATIO             155
 #define OPAL_SENSOR_GROUP_CLEAR                        156
 #define OPAL_PCI_SET_P2P                       157
-#define OPAL_LAST                              157
+#define OPAL_PCI_GET_PBCQ_TUNNEL_BAR           158
+#define OPAL_PCI_SET_PBCQ_TUNNEL_BAR           159
+#define OPAL_LAST                              159
 
 /* Device tree flags */
 
diff --git a/arch/powerpc/include/asm/opal.h b/arch/powerpc/include/asm/opal.h
index 0c545f7fc77b..8705e422b893 100644
--- a/arch/powerpc/include/asm/opal.h
+++ b/arch/powerpc/include/asm/opal.h
@@ -198,6 +198,8 @@ int64_t opal_unregister_dump_region(uint32_t id);
 int64_t opal_slw_set_reg(uint64_t cpu_pir, uint64_t sprn, uint64_t val);
 int64_t opal_config_cpu_idle_state(uint64_t state, uint64_t flag);
 int64_t opal_pci_set_phb_cxl_mode(uint64_t phb_id, uint64_t mode, uint64_t 
pe_number);
+int64_t opal_pci_get_pbcq_tunnel_bar(uint64_t phb_id, uint64_t *addr);
+int64_t opal_pci_set_pbcq_tunnel_bar(uint64_t phb_id, uint64_t addr);
 int64_t opal_ipmi_send(uint64_t interface, struct opal_ipmi_msg *msg,
                uint64_t msg_len);
 int64_t opal_ipmi_recv(uint64_t interface, struct opal_ipmi_msg *msg,
diff --git a/arch/powerpc/include/asm/pnv-pci.h 
b/arch/powerpc/include/asm/pnv-pci.h
index 3e5cf251ad9a..f064e93495ac 100644
--- a/arch/powerpc/include/asm/pnv-pci.h
+++ b/arch/powerpc/include/asm/pnv-pci.h
@@ -28,7 +28,9 @@ extern int pnv_pci_set_power_state(uint64_t id, uint8_t state,
                                   struct opal_msg *msg);
 extern int pnv_pci_set_p2p(struct pci_dev *initiator, struct pci_dev *target,
                           u64 desc);
-
+extern int pnv_pci_get_tunnel_ind(struct pci_dev *dev, uint64_t *ind);
+extern int pnv_pci_set_tunnel_bar(struct pci_dev *dev, uint64_t addr,
+                                 int enable);
 int pnv_phb_to_cxl_mode(struct pci_dev *dev, uint64_t mode);
 int pnv_cxl_ioda_msi_setup(struct pci_dev *dev, unsigned int hwirq,
                           unsigned int virq);
diff --git a/arch/powerpc/platforms/powernv/opal-wrappers.S 
b/arch/powerpc/platforms/powernv/opal-wrappers.S
index 6f4b00a2ac46..5da790fb7fef 100644
--- a/arch/powerpc/platforms/powernv/opal-wrappers.S
+++ b/arch/powerpc/platforms/powernv/opal-wrappers.S
@@ -320,3 +320,5 @@ OPAL_CALL(opal_set_powercap,                        
OPAL_SET_POWERCAP);
 OPAL_CALL(opal_get_power_shift_ratio,          OPAL_GET_POWER_SHIFT_RATIO);
 OPAL_CALL(opal_set_power_shift_ratio,          OPAL_SET_POWER_SHIFT_RATIO);
 OPAL_CALL(opal_sensor_group_clear,             OPAL_SENSOR_GROUP_CLEAR);
+OPAL_CALL(opal_pci_get_pbcq_tunnel_bar,                
OPAL_PCI_GET_PBCQ_TUNNEL_BAR);
+OPAL_CALL(opal_pci_set_pbcq_tunnel_bar,                
OPAL_PCI_SET_PBCQ_TUNNEL_BAR);
diff --git a/arch/powerpc/platforms/powernv/pci-cxl.c 
b/arch/powerpc/platforms/powernv/pci-cxl.c
index 94498a04558b..cee003de63af 100644
--- a/arch/powerpc/platforms/powernv/pci-cxl.c
+++ b/arch/powerpc/platforms/powernv/pci-cxl.c
@@ -16,14 +16,6 @@
 
 #include "pci.h"
 
-struct device_node *pnv_pci_get_phb_node(struct pci_dev *dev)
-{
-       struct pci_controller *hose = pci_bus_to_host(dev->bus);
-
-       return of_node_get(hose->dn);
-}
-EXPORT_SYMBOL(pnv_pci_get_phb_node);
-
 int pnv_phb_to_cxl_mode(struct pci_dev *dev, uint64_t mode)
 {
        struct pci_controller *hose = pci_bus_to_host(dev->bus);
diff --git a/arch/powerpc/platforms/powernv/pci.c 
b/arch/powerpc/platforms/powernv/pci.c
index 5422f4a6317c..5c0de7e08091 100644
--- a/arch/powerpc/platforms/powernv/pci.c
+++ b/arch/powerpc/platforms/powernv/pci.c
@@ -38,6 +38,7 @@
 #include "pci.h"
 
 static DEFINE_MUTEX(p2p_mutex);
+static DEFINE_MUTEX(tunnel_mutex);
 
 int pnv_pci_get_slot_id(struct device_node *np, uint64_t *id)
 {
@@ -1092,6 +1093,82 @@ int pnv_pci_set_p2p(struct pci_dev *initiator, struct 
pci_dev *target, u64 desc)
 }
 EXPORT_SYMBOL_GPL(pnv_pci_set_p2p);
 
+struct device_node *pnv_pci_get_phb_node(struct pci_dev *dev)
+{
+       struct pci_controller *hose = pci_bus_to_host(dev->bus);
+
+       return of_node_get(hose->dn);
+}
+EXPORT_SYMBOL(pnv_pci_get_phb_node);
+
+int pnv_pci_get_tunnel_ind(struct pci_dev *dev, u64 *asnind)
+{
+       struct device_node *np;
+       const __be32 *prop;
+
+       if (!(np = pnv_pci_get_phb_node(dev)))
+               return -ENXIO;
+
+       prop = of_get_property(np, "ibm,phb-indications", NULL);
+       if (!prop || !prop[1])
+               return -ENXIO;
+
+       *asnind = (u64)be32_to_cpu(prop[1]);
+       return 0;
+}
+EXPORT_SYMBOL_GPL(pnv_pci_get_tunnel_ind);
+
+int pnv_pci_set_tunnel_bar(struct pci_dev *dev, u64 addr, int enable)
+{
+       __be64 val;
+       struct pci_controller *hose;
+       struct pnv_phb *phb;
+       u64 tunnel_bar;
+       int rc;
+
+       if (!opal_check_token(OPAL_PCI_GET_PBCQ_TUNNEL_BAR))
+               return -ENXIO;
+       if (!opal_check_token(OPAL_PCI_SET_PBCQ_TUNNEL_BAR))
+               return -ENXIO;
+
+       hose = pci_bus_to_host(dev->bus);
+       phb = hose->private_data;
+
+       mutex_lock(&tunnel_mutex);
+       rc = opal_pci_get_pbcq_tunnel_bar(phb->opal_id, &val);
+       if (rc != OPAL_SUCCESS) {
+               rc = -EIO;
+               goto out;
+       }
+       tunnel_bar = be64_to_cpu(val);
+       if (enable) {
+               /*
+               * Only one device per PHB can use atomics.
+               * Our policy is first-come, first-served.
+               */
+               if (tunnel_bar) {
+                       rc = -EBUSY;
+                       goto out;
+               }
+       } else {
+               /*
+               * The device that owns atomics and wants to release
+               * them must pass the same address with enable == 0.
+               */
+               if (tunnel_bar != addr) {
+                       rc = -EPERM;
+                       goto out;
+               }
+               addr = 0x0ULL;
+       }
+       rc = opal_pci_set_pbcq_tunnel_bar(phb->opal_id, addr);
+       rc = opal_error_code(rc);
+out:
+       mutex_unlock(&tunnel_mutex);
+       return rc;
+}
+EXPORT_SYMBOL_GPL(pnv_pci_set_tunnel_bar);
+
 void pnv_pci_shutdown(void)
 {
        struct pci_controller *hose;
-- 
2.15.0

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