> [PATCH] cxl: Don't fail initialization if PSL timebase can't be synced
Nice double negative.. How about: cxl: Allow initialization on timebase sync failures > Failure to synchronize the PSL timebase currently prevents the > initialization of the cxl card, thus rendering the card useless. This > is too extreme for a feature which is rarely used, if at all. I'd probably mention that no hardware AFUs or software currently use timebase at all. > This patch still tries to synchronize the PSL timebase when the card > is initialized, but doesn't fail if it can't. Instead, it reports a > status via /sys. "...doesn't fail if it can't".. triple negative, awesome! :-P Other than these minor nits.. Acked-by: Michael Neuling <mi...@neuling.org> > Signed-off-by: Frederic Barrat <fbar...@linux.vnet.ibm.com> > --- > > Patch will need a small update for next, due to the powerVM patchset. Will send that as soon as this one is agreed upon. > > Documentation/ABI/testing/sysfs-class-cxl | 8 ++++++++ > drivers/misc/cxl/cxl.h | 1 + > drivers/misc/cxl/pci.c | 21 ++++++++++++--------- > drivers/misc/cxl/sysfs.c | 10 ++++++++++ > 4 files changed, 31 insertions(+), 9 deletions(-) > > diff --git a/Documentation/ABI/testing/sysfs-class-cxl b/Documentation/ABI/testing/sysfs-class-cxl > index b07e86d..ba33cdf 100644 > --- a/Documentation/ABI/testing/sysfs-class-cxl > +++ b/Documentation/ABI/testing/sysfs-class-cxl > @@ -233,3 +233,11 @@ Description:> read/write > 0 = don't trust, the image may be different (default) > 1 = trust that the image will not change. > Users:> https://github.com/ibm-capi/libcxl > + > +What: /sys/class/cxl/<card>/psl_timebase_synced > +Date: March 2016 > +Contact: linuxppc-dev@lists.ozlabs.org > +Description: read only > + Returns 1 if the psl timebase register is synchronized > + with the core timebase register, 0 otherwise. Thinking forward, for libcxl we'll want a cxl_tb_synced() call which will need to return true, false and unknown. "unknown" is when this file doesn't exists, when a new libcxl is run on an older kernel. Do we want to same interface here? Probably not, but something to consider. > +Users: https://github.com/ibm-capi/libcxl > \ No newline at end of file > diff --git a/drivers/misc/cxl/cxl.h b/drivers/misc/cxl/cxl.h > index a521bc7..baa5052 100644 > --- a/drivers/misc/cxl/cxl.h > +++ b/drivers/misc/cxl/cxl.h > @@ -517,6 +517,7 @@ struct cxl { > bool perst_loads_image; > bool perst_select_user; > bool perst_same_image; > + bool psl_timebase_synced; > }; > > int cxl_alloc_one_irq(struct cxl *adapter); > diff --git a/drivers/misc/cxl/pci.c b/drivers/misc/cxl/pci.c > index 0c6c17a1..625df03 100644 > --- a/drivers/misc/cxl/pci.c > +++ b/drivers/misc/cxl/pci.c > @@ -374,22 +374,24 @@ static int init_implementation_adapter_regs(struct cxl *adapter, struct pci_dev > #define TBSYNC_CNT(n) (((u64)n & 0x7) << (63-6)) > #define _2048_250MHZ_CYCLES 1 > > -static int cxl_setup_psl_timebase(struct cxl *adapter, struct pci_dev *dev) > +static void cxl_setup_psl_timebase(struct cxl *adapter, struct pci_dev *dev) > { > u64 psl_tb; > int delta; > unsigned int retry = 0; > struct device_node *np; > > + adapter->psl_timebase_synced = false; > + > if (!(np = pnv_pci_get_phb_node(dev))) > - return -ENODEV; > + return; > > /* Do not fail when CAPP timebase sync is not supported by OPAL */ > of_node_get(np); > if (! of_get_property(np, "ibm,capp-timebase-sync", NULL)) { > of_node_put(np); > - pr_err("PSL: Timebase sync: OPAL support missing\n"); > - return 0; > + dev_info(&dev->dev, "PSL timebase inactive: OPAL support missing\n"); > + return; > } > of_node_put(np); > > @@ -408,8 +410,8 @@ static int cxl_setup_psl_timebase(struct cxl *adapter, struct pci_dev *dev) > do { > msleep(1); > if (retry++ > 5) { > - pr_err("PSL: Timebase sync: giving up!\n"); > - return -EIO; > + dev_info(&dev->dev, "PSL timebase can't synchronize\n"); > + return; > } > psl_tb = cxl_p1_read(adapter, CXL_PSL_Timebase); > delta = mftb() - psl_tb; > @@ -417,7 +419,8 @@ static int cxl_setup_psl_timebase(struct cxl *adapter, struct pci_dev *dev) > delta = -delta; > } while (tb_to_ns(delta) > 16000); > > - return 0; > + adapter->psl_timebase_synced = true; > + return; > } > > static int init_implementation_afu_regs(struct cxl_afu *afu) > @@ -1189,8 +1192,8 @@ static int cxl_configure_adapter(struct cxl *adapter, struct pci_dev *dev) > if ((rc = pnv_phb_to_cxl_mode(dev, OPAL_PHB_CAPI_MODE_SNOOP_ON))) > goto err; > > - if ((rc = cxl_setup_psl_timebase(adapter, dev))) > - goto err; > + /* psl timebase not syncing shouldn't prevent device init */ /* Adapter init is not dependant on timebase sync */ > + cxl_setup_psl_timebase(adapter, dev); > > if ((rc = cxl_register_psl_err_irq(adapter))) > goto err; > diff --git a/drivers/misc/cxl/sysfs.c b/drivers/misc/cxl/sysfs.c > index 02006f71..b4bb9b2 100644 > --- a/drivers/misc/cxl/sysfs.c > +++ b/drivers/misc/cxl/sysfs.c > @@ -57,6 +57,15 @@ static ssize_t image_loaded_show(struct device *device, > return scnprintf(buf, PAGE_SIZE, "factory\n"); > } > > +static ssize_t psl_timebase_synced_show(struct device *device, > + struct device_attribute *attr, > + char *buf) > +{ > + struct cxl *adapter = to_cxl_adapter(device); > + > + return scnprintf(buf, PAGE_SIZE, "%i\n", adapter ->psl_timebase_synced); > +} > + > static ssize_t reset_adapter_store(struct device *device, > struct device_attribute *attr, > const char *buf, size_t count) > @@ -142,6 +151,7 @@ static struct device_attribute adapter_attrs[] = { > __ATTR_RO(psl_revision), > __ATTR_RO(base_image), > __ATTR_RO(image_loaded), > + __ATTR_RO(psl_timebase_synced), > __ATTR_RW(load_image_on_perst), > __ATTR_RW(perst_reloads_same_image), > __ATTR(reset, S_IWUSR, NULL, reset_adapter_store), _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev
