[Skiboot] [PATCH 2/2] npu2: Implement FLR

[Reza Arbab]

Add basic handling of FLR (function level reset) by porting the changes
from commit b74841db759d ("npu: Implement FLR") to npu2.

The only difference for npu2 is that we track the reset state explicitly
with a link flag instead of inferring it from
dev->procedure_{status,number,step,data}.

Signed-off-by: Reza Arbab <arbab at linux.vnet.ibm.com>
Cc: Alexey Kardashevskiy <aik at ozlabs.ru>
---
 hw/npu2-hw-procedures.c |  5 +++++
 hw/npu2.c               | 29 ++++++++++++++++++++++++++++-
 include/npu2.h          |  1 +
 3 files changed, 34 insertions(+), 1 deletion(-)

diff --git a/hw/npu2-hw-procedures.c b/hw/npu2-hw-procedures.c
index 71af3e7..1a990f2 100644
--- a/hw/npu2-hw-procedures.c
+++ b/hw/npu2-hw-procedures.c
@@ -719,3 +719,8 @@ int64_t npu2_dev_procedure(void *dev, struct pci_cfg_reg_filter *pcrf,
 
 	return npu_dev_procedure_read(ndev, offset - pcrf->start, len, data);
 }
+
+void npu2_dev_procedure_reset(struct npu2_dev *dev)
+{
+	npu2_clear_link_flag(dev, NPU2_DEV_DL_RESET);
+}
diff --git a/hw/npu2.c b/hw/npu2.c
index 807c78d..87f52e2 100644
--- a/hw/npu2.c
+++ b/hw/npu2.c
@@ -405,6 +405,29 @@ static int64_t npu2_dev_cfg_bar(void *dev, struct pci_cfg_reg_filter *pcrf,
 	return npu2_cfg_read_bar(ndev, pcrf, offset, len, data);
 }
 
+static int64_t npu2_dev_cfg_exp_devcap(void *dev,
+		struct pci_cfg_reg_filter *pcrf __unused,
+		uint32_t offset, uint32_t size,
+		uint32_t *data, bool write)
+{
+	struct pci_virt_device *pvd = dev;
+	struct npu2_dev *ndev = pvd->data;
+
+	assert(write);
+
+	if ((size != 2) || (offset & 1)) {
+		/* Short config writes are not supported */
+		prlog(PR_ERR, "NPU%d: Unsupported write to pcie control register\n",
+		      ndev->phb->opal_id);
+		return OPAL_PARAMETER;
+	}
+
+	if (*data & PCICAP_EXP_DEVCTL_FUNC_RESET)
+		npu2_dev_procedure_reset(ndev);
+
+	return OPAL_PARTIAL;
+}
+
 #define NPU2_CFG_READ(size, type)					\
 static int64_t npu2_cfg_read##size(struct phb *phb, uint32_t bdfn,	\
 				   uint32_t offset, type *data)		\
@@ -1336,7 +1359,7 @@ static uint32_t npu2_populate_pcie_cap(struct npu2_dev *dev,
 
 	/* 0x04 - Device capability
 	 *
-	 * We should support FLR. Oterwhsie, it might have
+	 * We should support FLR. Otherwise, it might have
 	 * problem passing it through to userland via Linux
 	 * VFIO infrastructure
 	 */
@@ -1347,6 +1370,10 @@ static uint32_t npu2_populate_pcie_cap(struct npu2_dev *dev,
 	       (PCICAP_EXP_DEVCAP_FUNC_RESET));
 	PCI_VIRT_CFG_INIT_RO(pvd, start + PCICAP_EXP_DEVCAP, 4, val);
 
+	pci_virt_add_filter(pvd, start + PCICAP_EXP_DEVCTL, 2,
+			    PCI_REG_FLAG_WRITE,
+			    npu2_dev_cfg_exp_devcap, NULL);
+
 	/* 0x08 - Device control and status */
 	PCI_VIRT_CFG_INIT(pvd, start + PCICAP_EXP_DEVCTL, 4, 0x00002810,
 			  0xffff0000, 0x000f0000);
diff --git a/include/npu2.h b/include/npu2.h
index ef05f46..f11a13a 100644
--- a/include/npu2.h
+++ b/include/npu2.h
@@ -155,6 +155,7 @@ void npu2_write_mask(struct npu2 *p, uint64_t reg, uint64_t val, uint64_t mask);
 int64_t npu2_dev_procedure(void *dev, struct pci_cfg_reg_filter *pcrf,
 			   uint32_t offset, uint32_t len, uint32_t *data,
 			   bool write);
+void npu2_dev_procedure_reset(struct npu2_dev *dev);
 void npu2_set_link_flag(struct npu2_dev *ndev, uint8_t flag);
 void npu2_clear_link_flag(struct npu2_dev *ndev, uint8_t flag);
 extern int nv_zcal_nominal;
-- 
1.8.3.1