On Fri, Aug 14, 2015 at 1:43 PM, Ross Zwisler <ross.zwisler@xxxxxxxxxxxxxxx> wrote: > Add support for the "read flush" _DSM flag, as outlined in the DSM spec: > > http://pmem.io/documents/NVDIMM_DSM_Interface_Example.pdf > > This flag tells the ND BLK driver that it needs to flush the cache lines > associated with the aperture after the aperture is moved but before any > new data is read. This ensures that any stale cache lines from the > previous contents of the aperture will be discarded from the processor > cache, and the new data will be read properly from the DIMM. We know > that the cache lines are clean and will be discarded without any > writeback because either a) the previous aperture operation was a read, > and we never modified the contents of the aperture, or b) the previous > aperture operation was a write and we must have written back the dirtied > contents of the aperture to the DIMM before the I/O was completed. > > By supporting the "read flush" flag we can also change the ND BLK > aperture mapping from write-combining to write-back via memremap(). > > In order to add support for the "read flush" flag I needed to add a > generic routine to invalidate cache lines, mmio_flush_range(). This is > protected by the ARCH_HAS_MMIO_FLUSH Kconfig variable, and is currently > only supported on x86. > > Signed-off-by: Ross Zwisler <ross.zwisler@xxxxxxxxxxxxxxx> > --- > arch/x86/Kconfig | 1 + > arch/x86/include/asm/cacheflush.h | 2 ++ > drivers/acpi/Kconfig | 1 + > drivers/acpi/nfit.c | 55 ++++++++++++++++++++++----------------- > drivers/acpi/nfit.h | 16 ++++++++---- > lib/Kconfig | 3 +++ > 6 files changed, 49 insertions(+), 29 deletions(-) > [..] > diff --git a/drivers/acpi/nfit.c b/drivers/acpi/nfit.c > index 628a42c..816c778 100644 > --- a/drivers/acpi/nfit.c > +++ b/drivers/acpi/nfit.c [..] > @@ -1206,20 +1214,19 @@ static void __iomem *__nfit_spa_map(struct acpi_nfit_desc *acpi_desc, > if (!res) > goto err_mem; > > - if (type == SPA_MAP_APERTURE) { > - /* > - * TODO: memremap_pmem() support, but that requires cache > - * flushing when the aperture is moved. > - */ > - spa_map->iomem = ioremap_wc(start, n); > - } else > - spa_map->iomem = ioremap_nocache(start, n); > + spa_map->type = type; > + if (type == SPA_MAP_APERTURE) > + spa_map->addr.aperture = (void __pmem *)memremap(start, n, > + MEMREMAP_WB); This should be s/MEMREMAP_WB/ARCH_MEMREMAP_PMEM/, but other than that looks good to me. I also should go move ARCH_MEMREMAP_PMEM over to arch/x86/include/asm/pmem.h and fold it in to your other pending pmem-api cleanups. -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
