From: Bryan O'Sullivan Date: Thu, 28 Sep 2006 16:00:13 +0000 (-0700) Subject: IB/ipath: Improved support for PowerPC X-Git-Tag: firefly_0821_release~33026^2~10 X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=1fd3b40fde3bfacdf742cadfe99cfd47ffd05219;p=firefly-linux-kernel-4.4.55.git IB/ipath: Improved support for PowerPC Signed-off-by: Bryan O'Sullivan Signed-off-by: Roland Dreier --- diff --git a/drivers/infiniband/hw/ipath/ipath_driver.c b/drivers/infiniband/hw/ipath/ipath_driver.c index 467816043d10..68fc9b5a4ad8 100644 --- a/drivers/infiniband/hw/ipath/ipath_driver.c +++ b/drivers/infiniband/hw/ipath/ipath_driver.c @@ -755,8 +755,8 @@ static void get_rhf_errstring(u32 err, char *msg, size_t len) static inline void *ipath_get_egrbuf(struct ipath_devdata *dd, u32 bufnum, int err) { - return dd->ipath_port0_skbs ? - (void *)dd->ipath_port0_skbs[bufnum]->data : NULL; + return dd->ipath_port0_skbinfo ? + (void *) dd->ipath_port0_skbinfo[bufnum].skb->data : NULL; } /** @@ -778,31 +778,34 @@ struct sk_buff *ipath_alloc_skb(struct ipath_devdata *dd, */ /* - * We need 4 extra bytes for unaligned transfer copying + * We need 2 extra bytes for ipath_ether data sent in the + * key header. In order to keep everything dword aligned, + * we'll reserve 4 bytes. */ + len = dd->ipath_ibmaxlen + 4; + if (dd->ipath_flags & IPATH_4BYTE_TID) { - /* we need a 4KB multiple alignment, and there is no way + /* We need a 2KB multiple alignment, and there is no way * to do it except to allocate extra and then skb_reserve * enough to bring it up to the right alignment. */ - len = dd->ipath_ibmaxlen + 4 + (1 << 11) - 1; + len += 2047; } - else - len = dd->ipath_ibmaxlen + 4; + skb = __dev_alloc_skb(len, gfp_mask); if (!skb) { ipath_dev_err(dd, "Failed to allocate skbuff, length %u\n", len); goto bail; } + + skb_reserve(skb, 4); + if (dd->ipath_flags & IPATH_4BYTE_TID) { - u32 una = ((1 << 11) - 1) & (unsigned long)(skb->data + 4); + u32 una = (unsigned long)skb->data & 2047; if (una) - skb_reserve(skb, 4 + (1 << 11) - una); - else - skb_reserve(skb, 4); - } else - skb_reserve(skb, 4); + skb_reserve(skb, 2048 - una); + } bail: return skb; @@ -1345,8 +1348,9 @@ int ipath_create_rcvhdrq(struct ipath_devdata *dd, ipath_cdbg(VERBOSE, "reuse port %d rcvhdrq @%p %llx phys; " "hdrtailaddr@%p %llx physical\n", pd->port_port, pd->port_rcvhdrq, - pd->port_rcvhdrq_phys, pd->port_rcvhdrtail_kvaddr, - (unsigned long long)pd->port_rcvhdrqtailaddr_phys); + (unsigned long long) pd->port_rcvhdrq_phys, + pd->port_rcvhdrtail_kvaddr, (unsigned long long) + pd->port_rcvhdrqtailaddr_phys); /* clear for security and sanity on each use */ memset(pd->port_rcvhdrq, 0, pd->port_rcvhdrq_size); @@ -1827,17 +1831,22 @@ void ipath_free_pddata(struct ipath_devdata *dd, struct ipath_portdata *pd) kfree(pd->port_rcvegrbuf_phys); pd->port_rcvegrbuf_phys = NULL; pd->port_rcvegrbuf_chunks = 0; - } else if (pd->port_port == 0 && dd->ipath_port0_skbs) { + } else if (pd->port_port == 0 && dd->ipath_port0_skbinfo) { unsigned e; - struct sk_buff **skbs = dd->ipath_port0_skbs; + struct ipath_skbinfo *skbinfo = dd->ipath_port0_skbinfo; - dd->ipath_port0_skbs = NULL; - ipath_cdbg(VERBOSE, "free closed port %d ipath_port0_skbs " - "@ %p\n", pd->port_port, skbs); + dd->ipath_port0_skbinfo = NULL; + ipath_cdbg(VERBOSE, "free closed port %d " + "ipath_port0_skbinfo @ %p\n", pd->port_port, + skbinfo); for (e = 0; e < dd->ipath_rcvegrcnt; e++) - if (skbs[e]) - dev_kfree_skb(skbs[e]); - vfree(skbs); + if (skbinfo[e].skb) { + pci_unmap_single(dd->pcidev, skbinfo[e].phys, + dd->ipath_ibmaxlen, + PCI_DMA_FROMDEVICE); + dev_kfree_skb(skbinfo[e].skb); + } + vfree(skbinfo); } kfree(pd->port_tid_pg_list); vfree(pd->subport_uregbase); @@ -1934,7 +1943,7 @@ static void cleanup_device(struct ipath_devdata *dd) if (dd->ipath_pioavailregs_dma) { dma_free_coherent(&dd->pcidev->dev, PAGE_SIZE, - dd->ipath_pioavailregs_dma, + (void *) dd->ipath_pioavailregs_dma, dd->ipath_pioavailregs_phys); dd->ipath_pioavailregs_dma = NULL; } @@ -1947,6 +1956,7 @@ static void cleanup_device(struct ipath_devdata *dd) if (dd->ipath_pageshadow) { struct page **tmpp = dd->ipath_pageshadow; + dma_addr_t *tmpd = dd->ipath_physshadow; int i, cnt = 0; ipath_cdbg(VERBOSE, "Unlocking any expTID pages still " @@ -1957,6 +1967,8 @@ static void cleanup_device(struct ipath_devdata *dd) for (i = port_tidbase; i < maxtid; i++) { if (!tmpp[i]) continue; + pci_unmap_page(dd->pcidev, tmpd[i], + PAGE_SIZE, PCI_DMA_FROMDEVICE); ipath_release_user_pages(&tmpp[i], 1); tmpp[i] = NULL; cnt++; diff --git a/drivers/infiniband/hw/ipath/ipath_file_ops.c b/drivers/infiniband/hw/ipath/ipath_file_ops.c index d4fc4118ddd5..64221b937762 100644 --- a/drivers/infiniband/hw/ipath/ipath_file_ops.c +++ b/drivers/infiniband/hw/ipath/ipath_file_ops.c @@ -364,11 +364,14 @@ static int ipath_tid_update(struct ipath_portdata *pd, struct file *fp, "vaddr %lx\n", i, tid + tidoff, vaddr); /* we "know" system pages and TID pages are same size */ dd->ipath_pageshadow[porttid + tid] = pagep[i]; + dd->ipath_physshadow[porttid + tid] = ipath_map_page( + dd->pcidev, pagep[i], 0, PAGE_SIZE, + PCI_DMA_FROMDEVICE); /* * don't need atomic or it's overhead */ __set_bit(tid, tidmap); - physaddr = page_to_phys(pagep[i]); + physaddr = dd->ipath_physshadow[porttid + tid]; ipath_stats.sps_pagelocks++; ipath_cdbg(VERBOSE, "TID %u, vaddr %lx, physaddr %llx pgp %p\n", @@ -402,6 +405,9 @@ static int ipath_tid_update(struct ipath_portdata *pd, struct file *fp, tid); dd->ipath_f_put_tid(dd, &tidbase[tid], 1, dd->ipath_tidinvalid); + pci_unmap_page(dd->pcidev, + dd->ipath_physshadow[porttid + tid], + PAGE_SIZE, PCI_DMA_FROMDEVICE); dd->ipath_pageshadow[porttid + tid] = NULL; ipath_stats.sps_pageunlocks++; } @@ -515,6 +521,9 @@ static int ipath_tid_free(struct ipath_portdata *pd, unsigned subport, pd->port_pid, tid); dd->ipath_f_put_tid(dd, &tidbase[tid], 1, dd->ipath_tidinvalid); + pci_unmap_page(dd->pcidev, + dd->ipath_physshadow[porttid + tid], + PAGE_SIZE, PCI_DMA_FROMDEVICE); ipath_release_user_pages( &dd->ipath_pageshadow[porttid + tid], 1); dd->ipath_pageshadow[porttid + tid] = NULL; @@ -711,7 +720,7 @@ static int ipath_manage_rcvq(struct ipath_portdata *pd, unsigned subport, * updated and correct itself, even in the face of software * bugs. */ - *pd->port_rcvhdrtail_kvaddr = 0; + *(volatile u64 *)pd->port_rcvhdrtail_kvaddr = 0; set_bit(INFINIPATH_R_PORTENABLE_SHIFT + pd->port_port, &dd->ipath_rcvctrl); } else @@ -923,11 +932,11 @@ bail: /* common code for the mappings on dma_alloc_coherent mem */ static int ipath_mmap_mem(struct vm_area_struct *vma, - struct ipath_portdata *pd, unsigned len, - int write_ok, dma_addr_t addr, char *what) + struct ipath_portdata *pd, unsigned len, int write_ok, + void *kvaddr, char *what) { struct ipath_devdata *dd = pd->port_dd; - unsigned pfn = (unsigned long)addr >> PAGE_SHIFT; + unsigned long pfn; int ret; if ((vma->vm_end - vma->vm_start) > len) { @@ -950,17 +959,17 @@ static int ipath_mmap_mem(struct vm_area_struct *vma, vma->vm_flags &= ~VM_MAYWRITE; } + pfn = virt_to_phys(kvaddr) >> PAGE_SHIFT; ret = remap_pfn_range(vma, vma->vm_start, pfn, len, vma->vm_page_prot); if (ret) - dev_info(&dd->pcidev->dev, - "%s port%u mmap of %lx, %x bytes r%c failed: %d\n", - what, pd->port_port, (unsigned long)addr, len, - write_ok?'w':'o', ret); + dev_info(&dd->pcidev->dev, "%s port%u mmap of %lx, %x " + "bytes r%c failed: %d\n", what, pd->port_port, + pfn, len, write_ok?'w':'o', ret); else - ipath_cdbg(VERBOSE, "%s port%u mmaped %lx, %x bytes r%c\n", - what, pd->port_port, (unsigned long)addr, len, - write_ok?'w':'o'); + ipath_cdbg(VERBOSE, "%s port%u mmaped %lx, %x bytes " + "r%c\n", what, pd->port_port, pfn, len, + write_ok?'w':'o'); bail: return ret; } @@ -1049,7 +1058,7 @@ static int mmap_rcvegrbufs(struct vm_area_struct *vma, struct ipath_devdata *dd = pd->port_dd; unsigned long start, size; size_t total_size, i; - dma_addr_t *phys; + unsigned long pfn; int ret; size = pd->port_rcvegrbuf_size; @@ -1073,11 +1082,11 @@ static int mmap_rcvegrbufs(struct vm_area_struct *vma, vma->vm_flags &= ~VM_MAYWRITE; start = vma->vm_start; - phys = pd->port_rcvegrbuf_phys; for (i = 0; i < pd->port_rcvegrbuf_chunks; i++, start += size) { - ret = remap_pfn_range(vma, start, phys[i] >> PAGE_SHIFT, - size, vma->vm_page_prot); + pfn = virt_to_phys(pd->port_rcvegrbuf[i]) >> PAGE_SHIFT; + ret = remap_pfn_range(vma, start, pfn, size, + vma->vm_page_prot); if (ret < 0) goto bail; } @@ -1290,7 +1299,7 @@ static int ipath_mmap(struct file *fp, struct vm_area_struct *vma) else if (pgaddr == dd->ipath_pioavailregs_phys) /* in-memory copy of pioavail registers */ ret = ipath_mmap_mem(vma, pd, PAGE_SIZE, 0, - dd->ipath_pioavailregs_phys, + (void *) dd->ipath_pioavailregs_dma, "pioavail registers"); else if (subport_fp(fp)) /* Subports don't mmap the physical receive buffers */ @@ -1304,12 +1313,12 @@ static int ipath_mmap(struct file *fp, struct vm_area_struct *vma) * from an i/o perspective. */ ret = ipath_mmap_mem(vma, pd, pd->port_rcvhdrq_size, 1, - pd->port_rcvhdrq_phys, + pd->port_rcvhdrq, "rcvhdrq"); else if (pgaddr == (u64) pd->port_rcvhdrqtailaddr_phys) /* in-memory copy of rcvhdrq tail register */ ret = ipath_mmap_mem(vma, pd, PAGE_SIZE, 0, - pd->port_rcvhdrqtailaddr_phys, + pd->port_rcvhdrtail_kvaddr, "rcvhdrq tail"); else ret = -EINVAL; @@ -1802,7 +1811,7 @@ static int ipath_do_user_init(struct file *fp, * We explictly set the in-memory copy to 0 beforehand, so we don't * have to wait to be sure the DMA update has happened. */ - *pd->port_rcvhdrtail_kvaddr = 0ULL; + *(volatile u64 *)pd->port_rcvhdrtail_kvaddr = 0ULL; set_bit(INFINIPATH_R_PORTENABLE_SHIFT + pd->port_port, &dd->ipath_rcvctrl); ipath_write_kreg(dd, dd->ipath_kregs->kr_rcvctrl, @@ -1832,6 +1841,8 @@ static void unlock_expected_tids(struct ipath_portdata *pd) if (!dd->ipath_pageshadow[i]) continue; + pci_unmap_page(dd->pcidev, dd->ipath_physshadow[i], + PAGE_SIZE, PCI_DMA_FROMDEVICE); ipath_release_user_pages_on_close(&dd->ipath_pageshadow[i], 1); dd->ipath_pageshadow[i] = NULL; @@ -1936,14 +1947,14 @@ static int ipath_close(struct inode *in, struct file *fp) i = dd->ipath_pbufsport * (port - 1); ipath_disarm_piobufs(dd, i, dd->ipath_pbufsport); + dd->ipath_f_clear_tids(dd, pd->port_port); + if (dd->ipath_pageshadow) unlock_expected_tids(pd); ipath_stats.sps_ports--; ipath_cdbg(PROC, "%s[%u] closed port %u:%u\n", pd->port_comm, pd->port_pid, dd->ipath_unit, port); - - dd->ipath_f_clear_tids(dd, pd->port_port); } pd->port_pid = 0; diff --git a/drivers/infiniband/hw/ipath/ipath_iba6120.c b/drivers/infiniband/hw/ipath/ipath_iba6120.c index ac5cbe27c068..08a44dd9ed6f 100644 --- a/drivers/infiniband/hw/ipath/ipath_iba6120.c +++ b/drivers/infiniband/hw/ipath/ipath_iba6120.c @@ -1113,7 +1113,7 @@ static void ipath_pe_put_tid_2(struct ipath_devdata *dd, u64 __iomem *tidptr, if (pa != dd->ipath_tidinvalid) { if (pa & ((1U << 11) - 1)) { dev_info(&dd->pcidev->dev, "BUG: physaddr %lx " - "not 4KB aligned!\n", pa); + "not 2KB aligned!\n", pa); return; } pa >>= 11; diff --git a/drivers/infiniband/hw/ipath/ipath_init_chip.c b/drivers/infiniband/hw/ipath/ipath_init_chip.c index 44669dc2e22d..d819cca524cd 100644 --- a/drivers/infiniband/hw/ipath/ipath_init_chip.c +++ b/drivers/infiniband/hw/ipath/ipath_init_chip.c @@ -88,13 +88,13 @@ MODULE_PARM_DESC(kpiobufs, "Set number of PIO buffers for driver"); static int create_port0_egr(struct ipath_devdata *dd) { unsigned e, egrcnt; - struct sk_buff **skbs; + struct ipath_skbinfo *skbinfo; int ret; egrcnt = dd->ipath_rcvegrcnt; - skbs = vmalloc(sizeof(*dd->ipath_port0_skbs) * egrcnt); - if (skbs == NULL) { + skbinfo = vmalloc(sizeof(*dd->ipath_port0_skbinfo) * egrcnt); + if (skbinfo == NULL) { ipath_dev_err(dd, "allocation error for eager TID " "skb array\n"); ret = -ENOMEM; @@ -109,13 +109,13 @@ static int create_port0_egr(struct ipath_devdata *dd) * 4 bytes so that the data buffer stays word aligned. * See ipath_kreceive() for more details. */ - skbs[e] = ipath_alloc_skb(dd, GFP_KERNEL); - if (!skbs[e]) { + skbinfo[e].skb = ipath_alloc_skb(dd, GFP_KERNEL); + if (!skbinfo[e].skb) { ipath_dev_err(dd, "SKB allocation error for " "eager TID %u\n", e); while (e != 0) - dev_kfree_skb(skbs[--e]); - vfree(skbs); + dev_kfree_skb(skbinfo[--e].skb); + vfree(skbinfo); ret = -ENOMEM; goto bail; } @@ -124,14 +124,17 @@ static int create_port0_egr(struct ipath_devdata *dd) * After loop above, so we can test non-NULL to see if ready * to use at receive, etc. */ - dd->ipath_port0_skbs = skbs; + dd->ipath_port0_skbinfo = skbinfo; for (e = 0; e < egrcnt; e++) { - unsigned long phys = - virt_to_phys(dd->ipath_port0_skbs[e]->data); + dd->ipath_port0_skbinfo[e].phys = + ipath_map_single(dd->pcidev, + dd->ipath_port0_skbinfo[e].skb->data, + dd->ipath_ibmaxlen, PCI_DMA_FROMDEVICE); dd->ipath_f_put_tid(dd, e + (u64 __iomem *) ((char __iomem *) dd->ipath_kregbase + - dd->ipath_rcvegrbase), 0, phys); + dd->ipath_rcvegrbase), 0, + dd->ipath_port0_skbinfo[e].phys); } ret = 0; @@ -432,16 +435,33 @@ done: */ static void init_shadow_tids(struct ipath_devdata *dd) { - dd->ipath_pageshadow = (struct page **) - vmalloc(dd->ipath_cfgports * dd->ipath_rcvtidcnt * + struct page **pages; + dma_addr_t *addrs; + + pages = vmalloc(dd->ipath_cfgports * dd->ipath_rcvtidcnt * sizeof(struct page *)); - if (!dd->ipath_pageshadow) + if (!pages) { ipath_dev_err(dd, "failed to allocate shadow page * " "array, no expected sends!\n"); - else - memset(dd->ipath_pageshadow, 0, - dd->ipath_cfgports * dd->ipath_rcvtidcnt * - sizeof(struct page *)); + dd->ipath_pageshadow = NULL; + return; + } + + addrs = vmalloc(dd->ipath_cfgports * dd->ipath_rcvtidcnt * + sizeof(dma_addr_t)); + if (!addrs) { + ipath_dev_err(dd, "failed to allocate shadow dma handle " + "array, no expected sends!\n"); + vfree(dd->ipath_pageshadow); + dd->ipath_pageshadow = NULL; + return; + } + + memset(pages, 0, dd->ipath_cfgports * dd->ipath_rcvtidcnt * + sizeof(struct page *)); + + dd->ipath_pageshadow = pages; + dd->ipath_physshadow = addrs; } static void enable_chip(struct ipath_devdata *dd, diff --git a/drivers/infiniband/hw/ipath/ipath_intr.c b/drivers/infiniband/hw/ipath/ipath_intr.c index 54b3dbc8195a..f4d8aafc6306 100644 --- a/drivers/infiniband/hw/ipath/ipath_intr.c +++ b/drivers/infiniband/hw/ipath/ipath_intr.c @@ -605,7 +605,7 @@ static int handle_errors(struct ipath_devdata *dd, ipath_err_t errs) * don't report same point multiple times, * except kernel */ - tl = (u32) * pd->port_rcvhdrtail_kvaddr; + tl = *(u64 *) pd->port_rcvhdrtail_kvaddr; if (tl == dd->ipath_lastrcvhdrqtails[i]) continue; hd = ipath_read_ureg32(dd, ur_rcvhdrhead, diff --git a/drivers/infiniband/hw/ipath/ipath_kernel.h b/drivers/infiniband/hw/ipath/ipath_kernel.h index 96e2bd8fb5f8..2a0e9a430634 100644 --- a/drivers/infiniband/hw/ipath/ipath_kernel.h +++ b/drivers/infiniband/hw/ipath/ipath_kernel.h @@ -39,6 +39,8 @@ */ #include +#include +#include #include #include "ipath_common.h" @@ -62,7 +64,7 @@ struct ipath_portdata { /* rcvhdrq base, needs mmap before useful */ void *port_rcvhdrq; /* kernel virtual address where hdrqtail is updated */ - volatile __le64 *port_rcvhdrtail_kvaddr; + void *port_rcvhdrtail_kvaddr; /* * temp buffer for expected send setup, allocated at open, instead * of each setup call @@ -146,6 +148,11 @@ struct _ipath_layer { void *l_arg; }; +struct ipath_skbinfo { + struct sk_buff *skb; + dma_addr_t phys; +}; + struct ipath_devdata { struct list_head ipath_list; @@ -168,7 +175,7 @@ struct ipath_devdata { /* ipath_cfgports pointers */ struct ipath_portdata **ipath_pd; /* sk_buffs used by port 0 eager receive queue */ - struct sk_buff **ipath_port0_skbs; + struct ipath_skbinfo *ipath_port0_skbinfo; /* kvirt address of 1st 2k pio buffer */ void __iomem *ipath_pio2kbase; /* kvirt address of 1st 4k pio buffer */ @@ -335,6 +342,8 @@ struct ipath_devdata { u64 *ipath_tidsimshadow; /* shadow copy of struct page *'s for exp tid pages */ struct page **ipath_pageshadow; + /* shadow copy of dma handles for exp tid pages */ + dma_addr_t *ipath_physshadow; /* lock to workaround chip bug 9437 */ spinlock_t ipath_tid_lock; @@ -864,6 +873,13 @@ void ipath_exit_ipathfs(void); int ipathfs_add_device(struct ipath_devdata *); int ipathfs_remove_device(struct ipath_devdata *); +/* + * dma_addr wrappers - all 0's invalid for hw + */ +dma_addr_t ipath_map_page(struct pci_dev *, struct page *, unsigned long, + size_t, int); +dma_addr_t ipath_map_single(struct pci_dev *, void *, size_t, int); + /* * Flush write combining store buffers (if present) and perform a write * barrier. diff --git a/drivers/infiniband/hw/ipath/ipath_user_pages.c b/drivers/infiniband/hw/ipath/ipath_user_pages.c index e32fca9faf80..413754b1d8a2 100644 --- a/drivers/infiniband/hw/ipath/ipath_user_pages.c +++ b/drivers/infiniband/hw/ipath/ipath_user_pages.c @@ -89,6 +89,62 @@ bail: return ret; } +/** + * ipath_map_page - a safety wrapper around pci_map_page() + * + * A dma_addr of all 0's is interpreted by the chip as "disabled". + * Unfortunately, it can also be a valid dma_addr returned on some + * architectures. + * + * The powerpc iommu assigns dma_addrs in ascending order, so we don't + * have to bother with retries or mapping a dummy page to insure we + * don't just get the same mapping again. + * + * I'm sure we won't be so lucky with other iommu's, so FIXME. + */ +dma_addr_t ipath_map_page(struct pci_dev *hwdev, struct page *page, + unsigned long offset, size_t size, int direction) +{ + dma_addr_t phys; + + phys = pci_map_page(hwdev, page, offset, size, direction); + + if (phys == 0) { + pci_unmap_page(hwdev, phys, size, direction); + phys = pci_map_page(hwdev, page, offset, size, direction); + /* + * FIXME: If we get 0 again, we should keep this page, + * map another, then free the 0 page. + */ + } + + return phys; +} + +/** + * ipath_map_single - a safety wrapper around pci_map_single() + * + * Same idea as ipath_map_page(). + */ +dma_addr_t ipath_map_single(struct pci_dev *hwdev, void *ptr, size_t size, + int direction) +{ + dma_addr_t phys; + + phys = pci_map_single(hwdev, ptr, size, direction); + + if (phys == 0) { + pci_unmap_single(hwdev, phys, size, direction); + phys = pci_map_single(hwdev, ptr, size, direction); + /* + * FIXME: If we get 0 again, we should keep this page, + * map another, then free the 0 page. + */ + } + + return phys; +} + /** * ipath_get_user_pages - lock user pages into memory * @start_page: the start page diff --git a/drivers/infiniband/hw/ipath/ipath_wc_ppc64.c b/drivers/infiniband/hw/ipath/ipath_wc_ppc64.c index 036fde662aa9..0095bb70f34e 100644 --- a/drivers/infiniband/hw/ipath/ipath_wc_ppc64.c +++ b/drivers/infiniband/hw/ipath/ipath_wc_ppc64.c @@ -38,13 +38,23 @@ #include "ipath_kernel.h" /** - * ipath_unordered_wc - indicate whether write combining is ordered + * ipath_enable_wc - enable write combining for MMIO writes to the device + * @dd: infinipath device * - * PowerPC systems (at least those in the 970 processor family) - * write partially filled store buffers in address order, but will write - * completely filled store buffers in "random" order, and therefore must - * have serialization for correctness with current InfiniPath chips. + * Nothing to do on PowerPC, so just return without error. + */ +int ipath_enable_wc(struct ipath_devdata *dd) +{ + return 0; +} + +/** + * ipath_unordered_wc - indicate whether write combining is unordered * + * Because our performance depends on our ability to do write + * combining mmio writes in the most efficient way, we need to + * know if we are on a processor that may reorder stores when + * write combining. */ int ipath_unordered_wc(void) {