[PATCH v1 14/47] IB/ipath: use __arch_phys_wc_add()

Luis R. Rodriguez
2015-03-20T23:51:49Z

From: "Luis R. Rodriguez" <mcgrof@suse.com>

This driver sadly does not have the MMIO registers and WC
desired areas (PIO buffers in this case) properly split up
and addressing a split is considerable work, as such this
such requires using the __arch_phys_wc_add() call to
ensure write combining is enforced using MTRR on x86
even when PAT is available.

Cc: Rickard Strandqvist <rickard_strandqvist@spectrumdigital.se>
Cc: Mike Marciniszyn <mike.marciniszyn@intel.com>
Cc: Roland Dreier <roland@purestorage.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Suresh Siddha <suresh.b.siddha@intel.com>
Cc: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Juergen Gross <jgross@suse.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Dave Airlie <airlied@redhat.com>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Antonino Daplas <adaplas@gmail.com>
Cc: Jean-Christophe Plagniol-Villard <plagnioj@jcrosoft.com>
Cc: Tomi Valkeinen <tomi.valkeinen@ti.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Michael S. Tsirkin <mst@redhat.com>
Cc: venkatesh.pallipadi@intel.com
Cc: Stefan Bader <stefan.bader@canonical.com>
Cc: konrad.wilk@oracle.com
Cc: ville.syrjala@linux.intel.com
Cc: david.vrabel@citrix.com
Cc: jbeulich@suse.com
Cc: toshi.kani@hp.com
Cc: Roger Pau Monné <roger.pau@citrix.com>
Cc: linux-fbdev@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Cc: xen-devel@lists.xensource.com
Signed-off-by: Luis R. Rodriguez <mcgrof@suse.com>
---
drivers/infiniband/hw/ipath/ipath_driver.c | 7 ++--
drivers/infiniband/hw/ipath/ipath_kernel.h | 4 +--
drivers/infiniband/hw/ipath/ipath_wc_x86_64.c | 47 ++++++++++-----------------
3 files changed, 20 insertions(+), 38 deletions(-)

diff --git a/drivers/infiniband/hw/ipath/ipath_driver.c b/drivers/infiniband/hw/ipath/ipath_driver.c
index bd0caed..464f39c 100644
--- a/drivers/infiniband/hw/ipath/ipath_driver.c
+++ b/drivers/infiniband/hw/ipath/ipath_driver.c
@@ -542,6 +542,7 @@ static int ipath_init_one(struct pci_dev *pdev, const struct pci_device_id *ent)
dd->ipath_kregbase = __ioremap(addr, len,
(_PAGE_NO_CACHE|_PAGE_WRITETHRU));
#else
+ /* XXX: split pio on a separate ioremap_wc() */
dd->ipath_kregbase = ioremap_nocache(addr, len);
#endif

@@ -587,12 +588,8 @@ static int ipath_init_one(struct pci_dev *pdev, const struct pci_device_id *ent)

ret = ipath_enable_wc(dd);

- if (ret) {
- ipath_dev_err(dd, "Write combining not enabled "
- "(err %d): performance may be poor\n",
- -ret);
+ if (ret)
ret = 0;
- }

ipath_verify_pioperf(dd);

diff --git a/drivers/infiniband/hw/ipath/ipath_kernel.h b/drivers/infiniband/hw/ipath/ipath_kernel.h
index e08db70..f0f9471 100644
--- a/drivers/infiniband/hw/ipath/ipath_kernel.h
+++ b/drivers/infiniband/hw/ipath/ipath_kernel.h
@@ -463,9 +463,7 @@ struct ipath_devdata {
/* offset in HT config space of slave/primary interface block */
u8 ipath_ht_slave_off;
/* for write combining settings */
- unsigned long ipath_wc_cookie;
- unsigned long ipath_wc_base;
- unsigned long ipath_wc_len;
+ int wc_cookie;
/* ref count for each pkey */
atomic_t ipath_pkeyrefs[4];
/* shadow copy of struct page *'s for exp tid pages */
diff --git a/drivers/infiniband/hw/ipath/ipath_wc_x86_64.c b/drivers/infiniband/hw/ipath/ipath_wc_x86_64.c
index 70c1f3a..88709c1 100644
--- a/drivers/infiniband/hw/ipath/ipath_wc_x86_64.c
+++ b/drivers/infiniband/hw/ipath/ipath_wc_x86_64.c
@@ -37,7 +37,6 @@
*/

#include <linux/pci.h>
-#include <asm/mtrr.h>
#include <asm/processor.h>

#include "ipath_kernel.h"
@@ -122,27 +121,26 @@ int ipath_enable_wc(struct ipath_devdata *dd)
}

if (!ret) {
- int cookie;
ipath_cdbg(VERBOSE, "Setting mtrr for chip to WC "
"(addr %llx, len=0x%llx)\n",
(unsigned long long) pioaddr,
(unsigned long long) piolen);
- cookie = mtrr_add(pioaddr, piolen, MTRR_TYPE_WRCOMB, 1);
- if (cookie < 0) {
- {
- dev_info(&dd->pcidev->dev,
- "mtrr_add() WC for PIO bufs "
- "failed (%d)\n",
- cookie);
- ret = -EINVAL;
- }
- } else {
- ipath_cdbg(VERBOSE, "Set mtrr for chip to WC, "
- "cookie is %d\n", cookie);
- dd->ipath_wc_cookie = cookie;
- dd->ipath_wc_base = (unsigned long) pioaddr;
- dd->ipath_wc_len = (unsigned long) piolen;
- }
+ dd->wc_cookie = __arch_phys_wc_add(pioaddr, piolen);
+ if (dd->wc_cookie <= 0) {
+ /*
+ * If MTRR is not available on an architecture
+ * or if it could not be enabled at run time
+ * folks who care should work towards the
+ * ioremap_wc() split.
+ */
+ if (!dd->wc_cookie)
+ ipath_dev_err(dd, "System does not support MTRR\n");
+ else {
+ ipath_dev_err(dd, "Seting mtrr failed on PIO buffers\n");
+ ret = -EINVAL;
+ }
+ } else
+ ipath_cdbg(VERBOSE, "Set mtrr for chip to WC\n");
}

return ret;
@@ -154,16 +152,5 @@ int ipath_enable_wc(struct ipath_devdata *dd)
*/
void ipath_disable_wc(struct ipath_devdata *dd)
{
- if (dd->ipath_wc_cookie) {
- int r;
- ipath_cdbg(VERBOSE, "undoing WCCOMB on pio buffers\n");
- r = mtrr_del(dd->ipath_wc_cookie, dd->ipath_wc_base,
- dd->ipath_wc_len);
- if (r < 0)
- dev_info(&dd->pcidev->dev,
- "mtrr_del(%lx, %lx, %lx) failed: %d\n",
- dd->ipath_wc_cookie, dd->ipath_wc_base,
- dd->ipath_wc_len, r);
- dd->ipath_wc_cookie = 0; /* even on failure */
- }
+ arch_phys_wc_del(dd->wc_cookie);
}
--
2.3.2.209.gd67f9d5.dirty