diff options
Diffstat (limited to 'hw')
| -rw-r--r-- | hw/phb4.c | 53 |
1 files changed, 29 insertions, 24 deletions
@@ -809,6 +809,33 @@ static int64_t phb4_pcicfg_no_dstate(void *dev __unused, return OPAL_PARTIAL; } +void phb4_pec2_dma_engine_realloc(struct phb4 *p) +{ + uint64_t reg; + + /* + * Allocate 16 extra dma read engines to stack 0, to boost dma + * performance for devices on stack 0 of PEC2, i.e PHB3. + * It comes at a price of reduced read engine allocation for + * devices on stack 1 and 2. The engine allocation becomes + * 48/8/8 instead of the default 32/16/16. + * + * The reallocation magic value should be 0xffff0000ff008000, + * but per the PCI designers, dma engine 32 (bit 0) has a + * quirk, and 0x7fff80007F008000 has the same effect (engine + * 32 goes to PHB4). + */ + if (p->index != 3) /* shared slot on PEC2 */ + return; + + PHBINF(p, "Allocating an extra 16 dma read engines on PEC2 stack0\n"); + reg = 0x7fff80007F008000ULL; + xscom_write(p->chip_id, + p->pci_xscom + XPEC_PCI_PRDSTKOVR, reg); + xscom_write(p->chip_id, + p->pe_xscom + XPEC_NEST_READ_STACK_OVERRIDE, reg); +} + static void phb4_check_device_quirks(struct pci_device *dev) { /* Some special adapter tweaks for devices directly under the PHB */ @@ -4415,30 +4442,8 @@ static int64_t enable_capi_mode(struct phb4 *p, uint64_t pe_number, * dma-read engines allocations to maximize the DMA read performance */ if ((p->index == CAPP1_PHB_INDEX) && - (capp_eng & CAPP_MAX_DMA_READ_ENGINES)) { - - /* - * Allocate Additional 16/8 dma read engines to stack0/stack1 - * respectively. Read engines 0:31 are anyways always assigned - * to stack0. Also skip allocating DMA Read Engine-32 by - * enabling Bit[0] in XPEC_NEST_READ_STACK_OVERRIDE register. - * Enabling this bit seems cause a parity error reported in - * NFIR[1]-nonbar_pe. - */ - reg = 0x7fff80007F008000ULL; - - xscom_write(p->chip_id, p->pci_xscom + XPEC_PCI_PRDSTKOVR, reg); - xscom_write(p->chip_id, p->pe_xscom + - XPEC_NEST_READ_STACK_OVERRIDE, reg); - - /* Log this reallocation as it may impact dma performance of - * other slots connected to PEC2 - */ - PHBINF(p, "CAPP: Set %d dma-read engines for PEC2/stack-0\n", - 32 + __builtin_popcountll(reg & PPC_BITMASK(0, 31))); - PHBDBG(p, "CAPP: XPEC_NEST_READ_STACK_OVERRIDE: %016llx\n", - reg); - } + (capp_eng & CAPP_MAX_DMA_READ_ENGINES)) + phb4_pec2_dma_engine_realloc(p); /* PCI to PB data movement ignores the PB init signal. */ xscom_write_mask(p->chip_id, p->pe_xscom + XPEC_NEST_PBCQ_HW_CONFIG, |