[PATCH v3] powerpc/powernv: Enable PCI peer-to-peer
Frederic Barrat
fbarrat at linux.vnet.ibm.com
Tue Jul 18 09:50:48 AEST 2017
P9 has support for PCI peer-to-peer, enabling a device to write in the
mmio space of another device directly, without interrupting the CPU.
This patch adds support for it on powernv, by adding a new API to be
called by drivers. The pnv_pci_set_p2p(...) call configures an
'initiator', i.e the device which will issue the mmio operation, and a
'target', i.e. the device on the receiving side.
P9 really only supports mmio stores for the time being but that's
expected to change in the future, so the API allows to define both
load and store operations.
/* PCI p2p descriptor */
#define OPAL_PCI_P2P_ENABLE 0x1
#define OPAL_PCI_P2P_LOAD 0x2
#define OPAL_PCI_P2P_STORE 0x4
int pnv_pci_set_p2p(struct pci_dev *initiator, struct pci_dev *target,
uint64_t desc)
It uses a new OPAL call, as the configuration magic is done on the
PHBs by skiboot.
Signed-off-by: Frederic Barrat <fbarrat at linux.vnet.ibm.com>
---
Changelog:
Requires skiboot patch:
http://patchwork.ozlabs.org/patch/789763/
Changelog:
v3:
- move target reference count from skiboot to linux
v2:
- change of API
- allow disabling of p2p setting
arch/powerpc/include/asm/opal-api.h | 8 ++-
arch/powerpc/include/asm/opal.h | 2 +
arch/powerpc/include/asm/pnv-pci.h | 2 +
arch/powerpc/platforms/powernv/opal-wrappers.S | 1 +
arch/powerpc/platforms/powernv/pci-ioda.c | 3 +-
arch/powerpc/platforms/powernv/pci.c | 71 ++++++++++++++++++++++++++
arch/powerpc/platforms/powernv/pci.h | 5 ++
7 files changed, 89 insertions(+), 3 deletions(-)
diff --git a/arch/powerpc/include/asm/opal-api.h b/arch/powerpc/include/asm/opal-api.h
index 3130a73652c7..d7ae1bb1cabd 100644
--- a/arch/powerpc/include/asm/opal-api.h
+++ b/arch/powerpc/include/asm/opal-api.h
@@ -190,7 +190,8 @@
#define OPAL_NPU_INIT_CONTEXT 146
#define OPAL_NPU_DESTROY_CONTEXT 147
#define OPAL_NPU_MAP_LPAR 148
-#define OPAL_LAST 148
+#define OPAL_PCI_SET_P2P 152
+#define OPAL_LAST 152
/* Device tree flags */
@@ -1084,6 +1085,11 @@ enum {
XIVE_DUMP_EMU_STATE = 5,
};
+/* PCI p2p descriptor */
+#define OPAL_PCI_P2P_ENABLE 0x1
+#define OPAL_PCI_P2P_LOAD 0x2
+#define OPAL_PCI_P2P_STORE 0x4
+
#endif /* __ASSEMBLY__ */
#endif /* __OPAL_API_H */
diff --git a/arch/powerpc/include/asm/opal.h b/arch/powerpc/include/asm/opal.h
index 588fb1c23af9..bd9674f4c4ae 100644
--- a/arch/powerpc/include/asm/opal.h
+++ b/arch/powerpc/include/asm/opal.h
@@ -267,6 +267,8 @@ int64_t opal_xive_allocate_irq(uint32_t chip_id);
int64_t opal_xive_free_irq(uint32_t girq);
int64_t opal_xive_sync(uint32_t type, uint32_t id);
int64_t opal_xive_dump(uint32_t type, uint32_t id);
+int64_t opal_pci_set_p2p(uint64_t phb_init, uint64_t phb_target,
+ uint64_t desc, uint16_t pe_number);
/* Internal functions */
extern int early_init_dt_scan_opal(unsigned long node, const char *uname,
diff --git a/arch/powerpc/include/asm/pnv-pci.h b/arch/powerpc/include/asm/pnv-pci.h
index de9681034353..59a548909d0b 100644
--- a/arch/powerpc/include/asm/pnv-pci.h
+++ b/arch/powerpc/include/asm/pnv-pci.h
@@ -26,6 +26,8 @@ extern int pnv_pci_get_presence_state(uint64_t id, uint8_t *state);
extern int pnv_pci_get_power_state(uint64_t id, uint8_t *state);
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,
+ uint64_t desc);
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,
diff --git a/arch/powerpc/platforms/powernv/opal-wrappers.S b/arch/powerpc/platforms/powernv/opal-wrappers.S
index 4ca6c26a56d5..8cc0a6266111 100644
--- a/arch/powerpc/platforms/powernv/opal-wrappers.S
+++ b/arch/powerpc/platforms/powernv/opal-wrappers.S
@@ -310,3 +310,4 @@ OPAL_CALL(opal_xive_dump, OPAL_XIVE_DUMP);
OPAL_CALL(opal_npu_init_context, OPAL_NPU_INIT_CONTEXT);
OPAL_CALL(opal_npu_destroy_context, OPAL_NPU_DESTROY_CONTEXT);
OPAL_CALL(opal_npu_map_lpar, OPAL_NPU_MAP_LPAR);
+OPAL_CALL(opal_pci_set_p2p, OPAL_PCI_SET_P2P);
diff --git a/arch/powerpc/platforms/powernv/pci-ioda.c b/arch/powerpc/platforms/powernv/pci-ioda.c
index 437613588df1..026a06c51458 100644
--- a/arch/powerpc/platforms/powernv/pci-ioda.c
+++ b/arch/powerpc/platforms/powernv/pci-ioda.c
@@ -1408,7 +1408,6 @@ static int pnv_pci_vf_assign_m64(struct pci_dev *pdev, u16 num_vfs)
static long pnv_pci_ioda2_unset_window(struct iommu_table_group *table_group,
int num);
-static void pnv_pci_ioda2_set_bypass(struct pnv_ioda_pe *pe, bool enable);
static void pnv_pci_ioda2_release_dma_pe(struct pci_dev *dev, struct pnv_ioda_pe *pe)
{
@@ -2394,7 +2393,7 @@ static long pnv_pci_ioda2_set_window(struct iommu_table_group *table_group,
return 0;
}
-static void pnv_pci_ioda2_set_bypass(struct pnv_ioda_pe *pe, bool enable)
+void pnv_pci_ioda2_set_bypass(struct pnv_ioda_pe *pe, bool enable)
{
uint16_t window_id = (pe->pe_number << 1 ) + 1;
int64_t rc;
diff --git a/arch/powerpc/platforms/powernv/pci.c b/arch/powerpc/platforms/powernv/pci.c
index 7905d179d036..d53d4f3d7671 100644
--- a/arch/powerpc/platforms/powernv/pci.c
+++ b/arch/powerpc/platforms/powernv/pci.c
@@ -37,6 +37,8 @@
#include "powernv.h"
#include "pci.h"
+static DEFINE_MUTEX(p2p_mutex);
+
int pnv_pci_get_slot_id(struct device_node *np, uint64_t *id)
{
struct device_node *parent = np;
@@ -1017,6 +1019,75 @@ void pnv_pci_dma_bus_setup(struct pci_bus *bus)
}
}
+int pnv_pci_set_p2p(struct pci_dev *initiator, struct pci_dev *target,
+ uint64_t desc)
+{
+ struct pci_controller *hose;
+ struct pnv_phb *phb_init, *phb_target;
+ struct pnv_ioda_pe *pe_init;
+ int rc;
+
+ if (!opal_check_token(OPAL_PCI_SET_P2P))
+ return -ENXIO;
+
+ hose = pci_bus_to_host(initiator->bus);
+ phb_init = hose->private_data;
+
+ hose = pci_bus_to_host(target->bus);
+ phb_target = hose->private_data;
+
+ pe_init = pnv_ioda_get_pe(initiator);
+ if (!pe_init)
+ return -ENODEV;
+ /*
+ * Configuring the initiator's PHB requires to adjust its
+ * TVE#1 setting. Since the same device can be an initiator
+ * several times for different target devices, we need to keep
+ * a reference count to know when we can restore the default
+ * bypass setting on its TVE#1 when disabling. Opal is not
+ * tracking PE states, so we add a reference count on the PE
+ * in linux.
+ *
+ * For the target, the configuration is per PHB, so we keep a
+ * target reference count on the PHB.
+ */
+ mutex_lock(&p2p_mutex);
+
+ if (desc & OPAL_PCI_P2P_ENABLE) {
+ /* always go to opal to validate the configuration */
+ rc = opal_pci_set_p2p(phb_init->opal_id, phb_target->opal_id,
+ desc, pe_init->pe_number);
+ if (rc != OPAL_SUCCESS) {
+ rc = -EIO;
+ goto out;
+ }
+ pe_init->p2p_initiator_count++;
+ phb_target->p2p_target_count++;
+ } else {
+ if (!pe_init->p2p_initiator_count ||
+ !phb_target->p2p_target_count) {
+ rc = -EINVAL;
+ goto out;
+ }
+ if (--pe_init->p2p_initiator_count == 0)
+ pnv_pci_ioda2_set_bypass(pe_init, true);
+ if (--phb_target->p2p_target_count == 0) {
+ rc = opal_pci_set_p2p(phb_init->opal_id,
+ phb_target->opal_id,
+ desc, pe_init->pe_number);
+ if (rc != OPAL_SUCCESS) {
+ rc = -EIO;
+ goto out;
+ }
+ }
+ }
+ rc = 0;
+out:
+ mutex_unlock(&p2p_mutex);
+ return rc;
+}
+EXPORT_SYMBOL_GPL(pnv_pci_set_p2p);
+
void pnv_pci_shutdown(void)
{
struct pci_controller *hose;
diff --git a/arch/powerpc/platforms/powernv/pci.h b/arch/powerpc/platforms/powernv/pci.h
index f16bc403ec03..a95273c524f6 100644
--- a/arch/powerpc/platforms/powernv/pci.h
+++ b/arch/powerpc/platforms/powernv/pci.h
@@ -78,6 +78,9 @@ struct pnv_ioda_pe {
struct pnv_ioda_pe *master;
struct list_head slaves;
+ /* PCI peer-to-peer*/
+ int p2p_initiator_count;
+
/* Link in list of PE#s */
struct list_head list;
};
@@ -189,6 +192,7 @@ struct pnv_phb {
#ifdef CONFIG_CXL_BASE
struct cxl_afu *cxl_afu;
#endif
+ int p2p_target_count;
};
extern struct pci_ops pnv_pci_ops;
@@ -229,6 +233,7 @@ extern void pnv_teardown_msi_irqs(struct pci_dev *pdev);
extern struct pnv_ioda_pe *pnv_ioda_get_pe(struct pci_dev *dev);
extern void pnv_set_msi_irq_chip(struct pnv_phb *phb, unsigned int virq);
extern bool pnv_pci_enable_device_hook(struct pci_dev *dev);
+extern void pnv_pci_ioda2_set_bypass(struct pnv_ioda_pe *pe, bool enable);
extern void pe_level_printk(const struct pnv_ioda_pe *pe, const char *level,
const char *fmt, ...);
--
2.11.0
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