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Commit f2dd0afe authored by Wei Yang's avatar Wei Yang Committed by Michael Ellerman
Browse files

powerpc/powernv: replace the hard coded boundary with gate 



At the moment 64bit-prefetchable window can be maximum 64GB, which is
currently got from device tree. This means that in shared mode the maximum
supported VF BAR size is 64GB/256=256MB. While this size could exhaust the
whole 64bit-prefetchable window. This is a design decision to set a
boundary to 64MB of the VF BAR size. Since VF BAR size with 64MB would
occupy a quarter of the 64bit-prefetchable window, this is affordable.

This patch replaces magic limit of 64MB with "gate", which is 1/4 of the
M64 Segment Size(m64_segsize >> 2) and adds comment to explain the reason
for it.

Signed-off-by: default avatarWei Yang <weiyang@linux.vnet.ibm.com>
Reviewed-by: default avatarGavin Shan <gwshan@linux.vent.ibm.com>
Acked-by: default avatarAlexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
parent ee8222fe

arch/powerpc/platforms/powernv/pci-ioda.c

+19 −9
Original line number Original line Diff line number Diff line
@@ -2798,8 +2798,9 @@ static void pnv_pci_init_ioda_msis(struct pnv_phb *phb) { } 
#ifdef CONFIG_PCI_IOV

#ifdef CONFIG_PCI_IOV

static void pnv_pci_ioda_fixup_iov_resources(struct pci_dev *pdev)

static void pnv_pci_ioda_fixup_iov_resources(struct pci_dev *pdev)

{

{

	struct pci_controller *hose;

	struct pci_controller *hose = pci_bus_to_host(pdev->bus);

	struct pnv_phb *phb;

	struct pnv_phb *phb = hose->private_data;

	const resource_size_t gate = phb->ioda.m64_segsize >> 2;

	struct resource *res;

	struct resource *res;

	int i;

	int i;

	resource_size_t size;

	resource_size_t size;
@@ -2809,9 +2810,6 @@ static void pnv_pci_ioda_fixup_iov_resources(struct pci_dev *pdev) 
	if (!pdev->is_physfn || pdev->is_added)

	if (!pdev->is_physfn || pdev->is_added)

		return;

		return;





	hose = pci_bus_to_host(pdev->bus);

	phb = hose->private_data;



	pdn = pci_get_pdn(pdev);

	pdn = pci_get_pdn(pdev);

	pdn->vfs_expanded = 0;

	pdn->vfs_expanded = 0;

	pdn->m64_single_mode = false;

	pdn->m64_single_mode = false;
@@ -2832,10 +2830,22 @@ static void pnv_pci_ioda_fixup_iov_resources(struct pci_dev *pdev) 




		size = pci_iov_resource_size(pdev, i + PCI_IOV_RESOURCES);

		size = pci_iov_resource_size(pdev, i + PCI_IOV_RESOURCES);





		/* bigger than 64M */

		/*

		if (size > (1 << 26)) {

		 * If bigger than quarter of M64 segment size, just round up

			dev_info(&pdev->dev, "PowerNV: VF BAR%d: %pR IOV size is bigger than 64M, roundup power2\n",

		 * power of two.

				 i, res);

		 *

		 * Generally, one M64 BAR maps one IOV BAR. To avoid conflict

		 * with other devices, IOV BAR size is expanded to be

		 * (total_pe * VF_BAR_size).  When VF_BAR_size is half of M64

		 * segment size , the expanded size would equal to half of the

		 * whole M64 space size, which will exhaust the M64 Space and

		 * limit the system flexibility.  This is a design decision to

		 * set the boundary to quarter of the M64 segment size.

		 */

		if (size > gate) {

			dev_info(&pdev->dev, "PowerNV: VF BAR%d: %pR IOV size "

				"is bigger than %lld, roundup power2\n",

				 i, res, gate);

			mul = roundup_pow_of_two(total_vfs);

			mul = roundup_pow_of_two(total_vfs);

			pdn->m64_single_mode = true;

			pdn->m64_single_mode = true;

			break;

			break;