Re: [PATCH v4 02/21] powerpc/powernv: Enable M64 on P7IOC

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On 05/01/2015 04:02 PM, Gavin Shan wrote:
The patch enables M64 window on P7IOC, which has been enabled on
PHB3. Comparing to PHB3, there are 16 M64 BARs and each of them
are divided to 8 segments.

"compared to something" means you will tell about PHB3 too :)

Do I understand correctly that IODA==IODA1==P7IOC and P7IOC != IODA2? The code does not use "PHB3" or "P7IOC" acronym so it is a bit confusing.


So each PHB can support 128 M64 segments.
Also, P7IOC has M64DT, which helps mapping one particular M64
segment# to arbitrary PE#. However, we just provide 128 M64 (16 BARs)
segments and fixed mapping between PE# and M64 segment# in order
to keep same logic to support M64 for PHB3 and P7IOC. In turn, we
just need different phb->init_m64() hooks for P7IOC and PHB3.

Signed-off-by: Gavin Shan <gwshan@xxxxxxxxxxxxxxxxxx>
---
  arch/powerpc/platforms/powernv/pci-ioda.c | 115 ++++++++++++++++++++++++++----
  1 file changed, 103 insertions(+), 12 deletions(-)

diff --git a/arch/powerpc/platforms/powernv/pci-ioda.c b/arch/powerpc/platforms/powernv/pci-ioda.c
index f8bc950..646962f 100644
--- a/arch/powerpc/platforms/powernv/pci-ioda.c
+++ b/arch/powerpc/platforms/powernv/pci-ioda.c
@@ -165,6 +165,67 @@ static void pnv_ioda_free_pe(struct pnv_phb *phb, int pe)
  	clear_bit(pe, phb->ioda.pe_alloc);
  }

+static int pnv_ioda1_init_m64(struct pnv_phb *phb)
+{
+	struct resource *r;
+	int seg;
+	s64 rc;

Here @rc is of the "s64" type.

+
+	/* Each PHB supports 16 separate M64 BARs, each of which are
+	 * divided into 8 segments. So there are number of M64 segments
+	 * as total PE#, which is 128.
+	 */

"there are as many M64 segments as a maximum number of PEs which is 128"?


+	for (seg = 0; seg < phb->ioda.total_pe; seg += 8) {
+		unsigned long base;
+
+		base = phb->ioda.m64_base + seg * phb->ioda.m64_segsize;
+		rc = opal_pci_set_phb_mem_window(phb->opal_id,
+						 OPAL_M64_WINDOW_TYPE,
+						 seg / 8,
+						 base,
+						 0, /* unused */
+						 8 * phb->ioda.m64_segsize);
+		if (rc != OPAL_SUCCESS) {
+			pr_warn("  Failure %lld configuring M64 BAR#%d on PHB#%d\n",
+				rc, seg / 8, phb->hose->global_number);
+			goto fail;
+		}
+
+		rc = opal_pci_phb_mmio_enable(phb->opal_id,
+					      OPAL_M64_WINDOW_TYPE,
+					      seg / 8,
+					      OPAL_ENABLE_M64_SPLIT);
+		if (rc != OPAL_SUCCESS) {
+			pr_warn("  Failure %lld enabling M64 BAR#%d on PHB#%d\n",
+				rc, seg / 8, phb->hose->global_number);
+			goto fail;
+		}
+	}
+
+	/* Strip of the segment used by the reserved PE, which
+	 * is expected to be 0 or last supported PE#
+	 */
+	r = &phb->hose->mem_resources[1];

mem_resources[0] is IO, mem_resources[1] is MMIO, mem_resources[2] is for what? Would be nice to have this commented somewhere.


+	if (phb->ioda.reserved_pe == 0)
+		r->start += phb->ioda.m64_segsize;
+	else if (phb->ioda.reserved_pe == (phb->ioda.total_pe - 1))
+		r->end -= phb->ioda.m64_segsize;
+	else
+		pr_warn("  Cannot strip M64 segment for reserved PE#%d\n",
+			phb->ioda.reserved_pe);
+
+	return 0;
+
+fail:
+	for ( ; seg >= 0; seg -= 8)
+		opal_pci_phb_mmio_enable(phb->opal_id,
+					 OPAL_M64_WINDOW_TYPE,
+					 seg / 8,
+					 OPAL_DISABLE_M64);

Out of curiosity - is not there a counterpart for opal_pci_set_phb_mem_window() for cleanup?


+
+	return -EIO;
+}
+
  /* The default M64 BAR is shared by all PEs */
  static int pnv_ioda2_init_m64(struct pnv_phb *phb)
  {
@@ -222,7 +283,7 @@ fail:
  	return -EIO;
  }

-static void pnv_ioda2_reserve_m64_pe(struct pnv_phb *phb)
+static void pnv_ioda_reserve_m64_pe(struct pnv_phb *phb)
  {
  	resource_size_t sgsz = phb->ioda.m64_segsize;
  	struct pci_dev *pdev;
@@ -248,8 +309,8 @@ static void pnv_ioda2_reserve_m64_pe(struct pnv_phb *phb)
  	}
  }

-static int pnv_ioda2_pick_m64_pe(struct pnv_phb *phb,
-				 struct pci_bus *bus, int all)
+static int pnv_ioda_pick_m64_pe(struct pnv_phb *phb,
+				struct pci_bus *bus, int all)
  {
  	resource_size_t segsz = phb->ioda.m64_segsize;
  	struct pci_dev *pdev;
@@ -346,6 +407,28 @@ done:
  			pe->master = master_pe;
  			list_add_tail(&pe->list, &master_pe->slaves);
  		}
+
+		/* P7IOC supports M64DT, which helps mapping M64 segment
+		 * to one particular PE#. Unfortunately, PHB3 has fixed

Why is it "Unfortunately"? This is just the way it is :)


+		 * mapping between M64 segment and PE#. In order for same
+		 * logic for P7IOC and PHB3, we enforce fixed mapping
+		 * between M64 segment and PE# on P7IOC.
+		 */
+		if (phb->type == PNV_PHB_IODA1) {
+			int64_t rc;

Here @rc is of the "int64_t" type. And this one and the one above are used for return code from OPAL API. Make them the same (int64_t or long, up to you).


+
+			rc = opal_pci_map_pe_mmio_window(phb->opal_id,
+							 pe->pe_number,
+							 OPAL_M64_WINDOW_TYPE,
+							 pe->pe_number / 8,
+							 pe->pe_number % 8);
+			if (rc != OPAL_SUCCESS)
+				pr_warn("%s: Failure %lld mapping "
+					"M64 for PHB#%d-PE#%d\n",
+					__func__, rc,
+					phb->hose->global_number,
+					pe->pe_number);
+		}
  	}

  	kfree(pe_alloc);
@@ -360,12 +443,6 @@ static void __init pnv_ioda_parse_m64_window(struct pnv_phb *phb)
  	const u32 *r;
  	u64 pci_addr;

-	/* FIXME: Support M64 for P7IOC */
-	if (phb->type != PNV_PHB_IODA2) {
-		pr_info("  Not support M64 window\n");
-		return;
-	}
-
  	if (!firmware_has_feature(FW_FEATURE_OPALv3)) {
  		pr_info("  Firmware too old to support M64 window\n");
  		return;
@@ -394,9 +471,23 @@ static void __init pnv_ioda_parse_m64_window(struct pnv_phb *phb)

  	/* Use last M64 BAR to cover M64 window */
  	phb->ioda.m64_bar_idx = 15;
-	phb->init_m64 = pnv_ioda2_init_m64;
-	phb->reserve_m64_pe = pnv_ioda2_reserve_m64_pe;
-	phb->pick_m64_pe = pnv_ioda2_pick_m64_pe;
+	phb->reserve_m64_pe = pnv_ioda_reserve_m64_pe;


reserve_m64_pe() is called once from pnv_pci_ioda_setup_PEs() so it is IODA-only and in this case reserve_m64_pe != NULL and pnv_ioda_reserve_m64_pe() will be called always.

In general, it feels like pnv_phb has too many callbacks while they could be just direct calls.



+	phb->pick_m64_pe = pnv_ioda_pick_m64_pe;
+	switch (phb->type) {
+	case PNV_PHB_IODA1:
+		phb->init_m64 = pnv_ioda1_init_m64;
+		break;
+	case PNV_PHB_IODA2:
+		phb->init_m64 = pnv_ioda2_init_m64;
+		break;
+	default:
+		phb->init_m64 = NULL;
+		phb->reserve_m64_pe = NULL;
+		phb->pick_m64_pe = NULL;
+		phb->ioda.m64_size = 0;
+		phb->ioda.m64_segsize = 0;
+		phb->ioda.m64_base = 0;

There are just 2 PHB types - IODA1 and IODA2, right? And the fields you reset after "default" - they have to be zeroes already, no? And on what hardware would the default branch actuall work? None?


+	}
  }

  static void pnv_ioda_freeze_pe(struct pnv_phb *phb, int pe_no)



--
Alexey
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