On Sat, May 09, 2015 at 08:24:14PM +1000, Alexey Kardashevskiy wrote:
>On 05/01/2015 04:02 PM, Gavin Shan wrote:
>>We're having the hardware or enforced (on P7IOC) limitation: M64
>
>I would think if it is enforced, then it is enforced by hardware but you say
>"hardware OR enforced" :)
>
PHB3 doesn't have M64DT from hardware. P7IOC supports that, but I
don't utilize the capability. So I called it's enforced. Maybe it
may be more clear to have "software enforced" ? :-)
>
>>segment#x can only be assigned to PE#x. IO and M32 segment can be
>>mapped to arbitrary PE# via IODT and M32DT. It means the PE number
>>should be x if M64 segment#x has been assigned to the PE. Also, each
>>PE own one M64 segment at most. Currently, we are reserving PE#
>>according to root port's M64 window. It won't be reliable once we
>>extend M64 windows of root port, or the upstream port of the PCIE
>>switch behind root port to PHB's M64 window, in order to support
>>PCI hotplug in future.
>>
>>The patch reserves PE# for M64 segments according to the M64 resources
>>of the PCI devices (not bridges) contained in the PE. Besides, it's
>>always worthy to trace the M64 segments consumed by the PE, which can
>>be released at PCI unplugging time.
>>
>>Signed-off-by: Gavin Shan <gwshan@xxxxxxxxxxxxxxxxxx>
>>---
>> arch/powerpc/platforms/powernv/pci-ioda.c | 190 ++++++++++++++++++------------
>> arch/powerpc/platforms/powernv/pci.h | 10 +-
>> 2 files changed, 122 insertions(+), 78 deletions(-)
>>
>>diff --git a/arch/powerpc/platforms/powernv/pci-ioda.c b/arch/powerpc/platforms/powernv/pci-ioda.c
>>index 646962f..a994882 100644
>>--- a/arch/powerpc/platforms/powernv/pci-ioda.c
>>+++ b/arch/powerpc/platforms/powernv/pci-ioda.c
>>@@ -283,28 +283,78 @@ fail:
>> return -EIO;
>> }
>>
>>-static void pnv_ioda_reserve_m64_pe(struct pnv_phb *phb)
>>+/* We extend the M64 window of root port, or the upstream bridge port
>>+ * of the PCIE switch behind root port. So we shouldn't reserve PEs
>>+ * for M64 resources because there are no (normal) PCI devices consuming
>
>"PCI devices"? Not "root ports or PCI bridges"?
>
I have "no (normal) PCI devices" here, which means root port and PCI bridges
are excluded.
>>+ * M64 resources on the PCI buses leading from root port, or the upstream
>>+ * bridge port.The function returns true if the indicated PCI bus needs
>>+ * reserved PEs because of M64 resources in advance. Otherwise, the
>>+ * function returns false.
>>+ */
>>+static bool pnv_ioda_need_m64_pe(struct pnv_phb *phb,
>>+ struct pci_bus *bus)
>> {
>>- resource_size_t sgsz = phb->ioda.m64_segsize;
>>+ /* Root bus */
>
>The comment is too obvious as the call below is called "pci_is_root_bus" :)
>
Indeed, it will be dropped in next revision.
>>+ if (!bus || pci_is_root_bus(bus))
>>+ return false;
>>+
>>+ /* Bus leading from root port. We need check what types of PCI
>>+ * devices on the bus. If it's connecting PCI bridge, we don't
>>+ * need reserve M64 PEs for it. Otherwise, we still need to do
>>+ * that.
>>+ */
>>+ if (pci_is_root_bus(bus->self->bus)) {
>>+ struct pci_dev *pdev;
>>+
>>+ list_for_each_entry(pdev, &bus->devices, bus_list) {
>>+ if (pdev->hdr_type == PCI_HEADER_TYPE_NORMAL)
>>+ return true;
>>+ }
>>+
>>+ return false;
>>+ }
>>+
>>+ /* Bus leading from the upstream bridge port on top level */
>>+ if (pci_is_root_bus(bus->self->bus->self->bus))
>
>
>Is it for second level bridges? Like root->bridge->bridge? And for 3 levels
>you will need a PE?
>
It's for upstream port of PCIe switch behind root port (a bit complicated).
Yes, the bus leaded from the downstream port will need a PE as you said.
>>+ return false;
>>+
>>+ return true;
>>+}
>>+
>>+static void pnv_ioda_reserve_m64_pe(struct pnv_phb *phb,
>>+ struct pci_bus *bus)
>>+{
>>+ resource_size_t segsz = phb->ioda.m64_segsize;
>> struct pci_dev *pdev;
>> struct resource *r;
>>- int base, step, i;
>>+ unsigned long pe_no, limit;
>>+ int i;
>>
>>- /*
>>- * Root bus always has full M64 range and root port has
>>- * M64 range used in reality. So we're checking root port
>>- * instead of root bus.
>>+ if (!pnv_ioda_need_m64_pe(phb, bus))
>>+ return;
>>+
>>+ /* The bridge's M64 window might have been extended to the
>>+ * PHB's M64 window in order to support PCI hotplug. So the
>>+ * bridge's M64 window isn't reliable to be used for picking
>>+ * PE# for its leading PCI bus. We have to check the M64
>>+ * resources consumed by the PCI devices, which seat on the
>>+ * PCI bus.
>> */
>>- list_for_each_entry(pdev, &phb->hose->bus->devices, bus_list) {
>>- for (i = 0; i < PCI_BRIDGE_RESOURCE_NUM; i++) {
>>- r = &pdev->resource[PCI_BRIDGE_RESOURCES + i];
>>- if (!r->parent ||
>>- !pnv_pci_is_mem_pref_64(r->flags))
>>+ list_for_each_entry(pdev, &bus->devices, bus_list) {
>>+ for (i = 0; i < PCI_NUM_RESOURCES; i++) {
>>+#ifdef CONFIG_PCI_IOV
>>+ if (i >= PCI_IOV_RESOURCES && i <= PCI_IOV_RESOURCE_END)
>>+ continue;
>>+#endif
>>+ r = &pdev->resource[i];
>>+ if (!r->flags || r->start >= r->end ||
>>+ !r->parent || !pnv_pci_is_mem_pref_64(r->flags))
>> continue;
>>
>>- base = (r->start - phb->ioda.m64_base) / sgsz;
>>- for (step = 0; step < resource_size(r) / sgsz; step++)
>>- pnv_ioda_reserve_pe(phb, base + step);
>>+ pe_no = (r->start - phb->ioda.m64_base) / segsz;
>>+ limit = ALIGN(r->end - phb->ioda.m64_base, segsz) / segsz;
>>+ for (; pe_no < limit; pe_no++)
>>+ pnv_ioda_reserve_pe(phb, pe_no);
>> }
>> }
>> }
>>@@ -316,85 +366,64 @@ static int pnv_ioda_pick_m64_pe(struct pnv_phb *phb,
>> struct pci_dev *pdev;
>> struct resource *r;
>> struct pnv_ioda_pe *master_pe, *pe;
>>- unsigned long size, *pe_alloc;
>>- bool found;
>>- int start, i, j;
>>-
>>- /* Root bus shouldn't use M64 */
>>- if (pci_is_root_bus(bus))
>>- return IODA_INVALID_PE;
>>-
>>- /* We support only one M64 window on each bus */
>>- found = false;
>>- pci_bus_for_each_resource(bus, r, i) {
>>- if (r && r->parent &&
>>- pnv_pci_is_mem_pref_64(r->flags)) {
>>- found = true;
>>- break;
>>- }
>>- }
>>+ unsigned long size, *pe_bitsmap;
>
>s/pe_bitsmap/pe_bitmap/
>
Yeah, will fix it up. Thanks!
>>+ unsigned long pe_no, limit;
>>+ int i;
>>
>>- /* No M64 window found ? */
>>- if (!found)
>>+ if (!pnv_ioda_need_m64_pe(phb, bus))
>> return IODA_INVALID_PE;
>>
>>- /* Allocate bitmap */
>>+ /* Allocate bitmap */
>> size = _ALIGN_UP(phb->ioda.total_pe / 8, sizeof(unsigned long));
>>- pe_alloc = kzalloc(size, GFP_KERNEL);
>>- if (!pe_alloc) {
>>- pr_warn("%s: Out of memory !\n",
>>- __func__);
>>+ pe_bitsmap = kzalloc(size, GFP_KERNEL);
>>+ if (!pe_bitsmap) {
>>+ pr_warn("%s: Out of memory !\n", __func__);
>> return IODA_INVALID_PE;
>> }
>>
>>- /*
>>- * Figure out reserved PE numbers by the PE
>>- * the its child PEs.
>>- */
>>- start = (r->start - phb->ioda.m64_base) / segsz;
>>- for (i = 0; i < resource_size(r) / segsz; i++)
>>- set_bit(start + i, pe_alloc);
>>-
>>- if (all)
>>- goto done;
>>-
>>- /*
>>- * If the PE doesn't cover all subordinate buses,
>>- * we need subtract from reserved PEs for children.
>>+ /* The bridge's M64 window might be extended to PHB's M64
>>+ * window by intention to support PCI hotplug. So we have
>>+ * to check the M64 resources consumed by the PCI devices
>>+ * on the PCI bus.
>> */
>> list_for_each_entry(pdev, &bus->devices, bus_list) {
>>- if (!pdev->subordinate)
>>- continue;
>>+ for (i = 0; i < PCI_NUM_RESOURCES; i++) {
>>+#ifdef CONFIG_PCI_IOV
>>+ if (i >= PCI_IOV_RESOURCES &&
>>+ i <= PCI_IOV_RESOURCE_END)
>>+ continue;
>>+#endif
>>+ /* Don't scan bridge's window if the PE
>>+ * doesn't contain its subordinate bus.
>>+ */
>>+ if (!all && i >= PCI_BRIDGE_RESOURCES &&
>>+ i <= PCI_BRIDGE_RESOURCE_END)
>>+ continue;
>>
>>- pci_bus_for_each_resource(pdev->subordinate, r, i) {
>>- if (!r || !r->parent ||
>>- !pnv_pci_is_mem_pref_64(r->flags))
>>+ r = &pdev->resource[i];
>>+ if (!r->flags || r->start >= r->end ||
>>+ !r->parent || !pnv_pci_is_mem_pref_64(r->flags))
>> continue;
>>
>>- start = (r->start - phb->ioda.m64_base) / segsz;
>>- for (j = 0; j < resource_size(r) / segsz ; j++)
>>- clear_bit(start + j, pe_alloc);
>>- }
>>- }
>>+ pe_no = (r->start - phb->ioda.m64_base) / segsz;
>>+ limit = ALIGN(r->end - phb->ioda.m64_base, segsz) / segsz;
>>+ for (; pe_no < limit; pe_no++)
>>+ set_bit(pe_no, pe_bitsmap);
>>+ }
>>+ }
>>
>>- /*
>>- * the current bus might not own M64 window and that's all
>>- * contributed by its child buses. For the case, we needn't
>>- * pick M64 dependent PE#.
>>- */
>>- if (bitmap_empty(pe_alloc, phb->ioda.total_pe)) {
>>- kfree(pe_alloc);
>>+ /* No M64 window found ? */
>>+ if (bitmap_empty(pe_bitsmap, phb->ioda.total_pe)) {
>>+ kfree(pe_bitsmap);
>> return IODA_INVALID_PE;
>> }
>>
>>- /*
>>- * Figure out the master PE and put all slave PEs to master
>>- * PE's list to form compound PE.
>>+ /* Figure out the master PE and put all slave PEs
>>+ * to master PE's list to form compound PE.
>> */
>>-done:
>> master_pe = NULL;
>> i = -1;
>>- while ((i = find_next_bit(pe_alloc, phb->ioda.total_pe, i + 1)) <
>>+ while ((i = find_next_bit(pe_bitsmap, phb->ioda.total_pe, i + 1)) <
>> phb->ioda.total_pe) {
>> pe = &phb->ioda.pe_array[i];
>>
>>@@ -408,6 +437,13 @@ done:
>> list_add_tail(&pe->list, &master_pe->slaves);
>> }
>>
>>+ /* Pick the M64 segment, which should be available. Also,
>
>test_and_set_bit() does not pick or choose, it just marks PE#pe_number used.
>
It's true. I will replace "Pick" with "Reserve" M64 segment in next revision.
If that's still not what you're suggesting, please let me know :-)
>>+ * those M64 segments consumed by slave PEs are contributed
>>+ * to the master PE.
>>+ */
>>+ BUG_ON(test_and_set_bit(pe->pe_number, phb->ioda.m64_segmap));
>>+ BUG_ON(test_and_set_bit(pe->pe_number, master_pe->m64_segmap));
>>+
>> /* P7IOC supports M64DT, which helps mapping M64 segment
>> * to one particular PE#. Unfortunately, PHB3 has fixed
>> * mapping between M64 segment and PE#. In order for same
>>@@ -431,7 +467,7 @@ done:
>> }
>> }
>>
>>- kfree(pe_alloc);
>>+ kfree(pe_bitsmap);
>> return master_pe->pe_number;
>> }
>>
>>@@ -1233,7 +1269,7 @@ static void pnv_pci_ioda_setup_PEs(void)
>>
>> /* M64 layout might affect PE allocation */
>> if (phb->reserve_m64_pe)
>>- phb->reserve_m64_pe(phb);
>>+ phb->reserve_m64_pe(phb, phb->hose->bus);
>>
>> pnv_ioda_setup_PEs(hose->bus);
>> }
>>diff --git a/arch/powerpc/platforms/powernv/pci.h b/arch/powerpc/platforms/powernv/pci.h
>>index 070ee88..19022cf 100644
>>--- a/arch/powerpc/platforms/powernv/pci.h
>>+++ b/arch/powerpc/platforms/powernv/pci.h
>>@@ -49,6 +49,13 @@ struct pnv_ioda_pe {
>> /* PE number */
>> unsigned int pe_number;
>>
>>+ /* IO/M32/M64 segments consumed by the PE. Each PE can
>>+ * have one M64 segment at most, but M64 segments consumed
>>+ * by slave PEs will be contributed to the master PE. One
>>+ * PE can own multiple IO and M32 segments.
>>+ */
>>+ unsigned long m64_segmap[8];
>
>
>Why 8? 64*8 = 512 segments? s'8'512/sizeof(unsigned long)' may be?
>
There are 128 M64 segments for P7IOC, but 256 M64 segments for PHB3.
512 is number bigger than 128 and 256. I still prefer m64_segmap[8] :-)
>
>>+
>> /* "Weight" assigned to the PE for the sake of DMA resource
>> * allocations
>> */
>>@@ -114,7 +121,7 @@ struct pnv_phb {
>> u32 (*bdfn_to_pe)(struct pnv_phb *phb, struct pci_bus *bus, u32 devfn);
>> void (*shutdown)(struct pnv_phb *phb);
>> int (*init_m64)(struct pnv_phb *phb);
>>- void (*reserve_m64_pe)(struct pnv_phb *phb);
>>+ void (*reserve_m64_pe)(struct pnv_phb *phb, struct pci_bus *bus);
>> int (*pick_m64_pe)(struct pnv_phb *phb, struct pci_bus *bus, int all);
>> int (*get_pe_state)(struct pnv_phb *phb, int pe_no);
>> void (*freeze_pe)(struct pnv_phb *phb, int pe_no);
>>@@ -153,6 +160,7 @@ struct pnv_phb {
>> struct mutex pe_alloc_mutex;
>>
>> /* M32 & IO segment maps */
>>+ unsigned long m64_segmap[8];
>> unsigned int *m32_segmap;
>> unsigned int *io_segmap;
>> struct pnv_ioda_pe *pe_array;
>>
Thanks,
Gavin
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