powerpc/powernv/pci: Refactor pnv_ioda_alloc_pe()

Rework the PE allocation logic to allow allocating blocks of PEs rather
than individually. We'll use this to allocate contigious blocks of PEs for
the SR-IOVs.

This patch also adds code to pnv_ioda_alloc_pe() and pnv_ioda_reserve_pe() to
use the existing, but unused, phb->pe_alloc_mutex. Currently these functions
use atomic bit ops to release a currently allocated PE number. However,
the pnv_ioda_alloc_pe() wants to have exclusive access to the bit map while
scanning for hole large enough to accomodate the allocation size.

Signed-off-by: Oliver O'Halloran <oohall@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200722065715.1432738-10-oohall@gmail.com

diff --git a/arch/powerpc/platforms/powernv/pci-ioda.c b/arch/powerpc/platforms/powernv/pci-ioda.c
index 2d36a9e..c9c25fb 100644 (file)
--- a/arch/powerpc/platforms/powernv/pci-ioda.c
+++ b/arch/powerpc/platforms/powernv/pci-ioda.c
@@ -145,23 +145,45 @@ static void pnv_ioda_reserve_pe(struct pnv_phb *phb, int pe_no)
                return;
        }
 
+       mutex_lock(&phb->ioda.pe_alloc_mutex);
        if (test_and_set_bit(pe_no, phb->ioda.pe_alloc))
                pr_debug("%s: PE %x was reserved on PHB#%x\n",
                         __func__, pe_no, phb->hose->global_number);
+       mutex_unlock(&phb->ioda.pe_alloc_mutex);
 
        pnv_ioda_init_pe(phb, pe_no);
 }
 
-struct pnv_ioda_pe *pnv_ioda_alloc_pe(struct pnv_phb *phb)
+struct pnv_ioda_pe *pnv_ioda_alloc_pe(struct pnv_phb *phb, int count)
 {
-       long pe;
+       struct pnv_ioda_pe *ret = NULL;
+       int run = 0, pe, i;
 
+       mutex_lock(&phb->ioda.pe_alloc_mutex);
+
+       /* scan backwards for a run of @count cleared bits */
        for (pe = phb->ioda.total_pe_num - 1; pe >= 0; pe--) {
-               if (!test_and_set_bit(pe, phb->ioda.pe_alloc))
-                       return pnv_ioda_init_pe(phb, pe);
+               if (test_bit(pe, phb->ioda.pe_alloc)) {
+                       run = 0;
+                       continue;
+               }
+
+               run++;
+               if (run == count)
+                       break;
        }
+       if (run != count)
+               goto out;
 
-       return NULL;
+       for (i = pe; i < pe + count; i++) {
+               set_bit(i, phb->ioda.pe_alloc);
+               pnv_ioda_init_pe(phb, i);
+       }
+       ret = &phb->ioda.pe_array[pe];
+
+out:
+       mutex_unlock(&phb->ioda.pe_alloc_mutex);
+       return ret;
 }
 
 void pnv_ioda_free_pe(struct pnv_ioda_pe *pe)
@@ -173,7 +195,10 @@ void pnv_ioda_free_pe(struct pnv_ioda_pe *pe)
        WARN_ON(pe->npucomp); /* NPUs for nvlink are not supposed to be freed */
        kfree(pe->npucomp);
        memset(pe, 0, sizeof(struct pnv_ioda_pe));
+
+       mutex_lock(&phb->ioda.pe_alloc_mutex);
        clear_bit(pe_num, phb->ioda.pe_alloc);
+       mutex_unlock(&phb->ioda.pe_alloc_mutex);
 }
 
 /* The default M64 BAR is shared by all PEs */
@@ -976,7 +1001,7 @@ static struct pnv_ioda_pe *pnv_ioda_setup_dev_PE(struct pci_dev *dev)
        if (pdn->pe_number != IODA_INVALID_PE)
                return NULL;
 
-       pe = pnv_ioda_alloc_pe(phb);
+       pe = pnv_ioda_alloc_pe(phb, 1);
        if (!pe) {
                pr_warn("%s: Not enough PE# available, disabling device\n",
                        pci_name(dev));
@@ -1047,7 +1072,7 @@ static struct pnv_ioda_pe *pnv_ioda_setup_bus_PE(struct pci_bus *bus, bool all)
 
        /* The PE number isn't pinned by M64 */
        if (!pe)
-               pe = pnv_ioda_alloc_pe(phb);
+               pe = pnv_ioda_alloc_pe(phb, 1);
 
        if (!pe) {
                pr_warn("%s: Not enough PE# available for PCI bus %04x:%02x\n",
@@ -3065,7 +3090,7 @@ static void __init pnv_pci_init_ioda_phb(struct device_node *np,
                pnv_ioda_reserve_pe(phb, phb->ioda.root_pe_idx);
        } else {
                /* otherwise just allocate one */
-               root_pe = pnv_ioda_alloc_pe(phb);
+               root_pe = pnv_ioda_alloc_pe(phb, 1);
                phb->ioda.root_pe_idx = root_pe->pe_number;
        }
 

diff --git a/arch/powerpc/platforms/powernv/pci.h b/arch/powerpc/platforms/powernv/pci.h
index 23fc5e3..06431a4 100644 (file)
--- a/arch/powerpc/platforms/powernv/pci.h
+++ b/arch/powerpc/platforms/powernv/pci.h
@@ -224,7 +224,7 @@ int pnv_ioda_deconfigure_pe(struct pnv_phb *phb, struct pnv_ioda_pe *pe);
 void pnv_pci_ioda2_setup_dma_pe(struct pnv_phb *phb, struct pnv_ioda_pe *pe);
 void pnv_pci_ioda2_release_pe_dma(struct pnv_ioda_pe *pe);
 
-struct pnv_ioda_pe *pnv_ioda_alloc_pe(struct pnv_phb *phb);
+struct pnv_ioda_pe *pnv_ioda_alloc_pe(struct pnv_phb *phb, int count);
 void pnv_ioda_free_pe(struct pnv_ioda_pe *pe);
 
 #ifdef CONFIG_PCI_IOV