Re: [PATCH] cxl: Don't fail initialization if PSL timebase can't be synced
From: Michael Neuling <hidden>
Date: 2016-03-17 22:13:43
[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 <redacted>
Signed-off-by: Frederic Barrat <redacted> --- =20 Patch will need a small update for next, due to the powerVM patchset.
Will send that as soon as this one is agreed upon.
quoted hunk ↗ jump to hunk
=20 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(-) =20diff --git a/Documentation/ABI/testing/sysfs-class-cxl
b/Documentation/ABI/testing/sysfs-class-cxl
quoted hunk ↗ jump to hunk
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 =3D don't trust, the image may be different
(default)
1 =3D 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.
quoted hunk ↗ jump to hunk
+Users: https://github.com/ibm-capi/libcxl \ No newline at end of filediff --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; };=20 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 =20 -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 =3D 0;
struct device_node *np;
=20
+ adapter->psl_timebase_synced =3D false;
+
if (!(np =3D pnv_pci_get_phb_node(dev)))
- return -ENODEV;
+ return;
=20
/* Do not fail when CAPP timebase sync is not supportedby 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 supportmissing\n");
- return 0; + dev_info(&dev->dev, "PSL timebase inactive:
OPAL support missing\n");
quoted hunk ↗ jump to hunk
+ return; } of_node_put(np); =20@@ -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: givingup!\n");
- return -EIO; + dev_info(&dev->dev, "PSL timebase
can't synchronize\n");
+ return; } psl_tb =3D cxl_p1_read(adapter,
CXL_PSL_Timebase);
quoted hunk ↗ jump to hunk
delta =3D mftb() - psl_tb;@@ -417,7 +419,8 @@ static int cxl_setup_psl_timebase(struct cxl
*adapter, struct pci_dev *dev)
quoted hunk ↗ jump to hunk
delta =3D -delta; } while (tb_to_ns(delta) > 16000); =20 - return 0; + adapter->psl_timebase_synced =3D true; + return; } =20 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 =3D pnv_phb_to_cxl_mode(dev,
OPAL_PHB_CAPI_MODE_SNOOP_ON)))
goto err; =20 - if ((rc =3D 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 */
quoted hunk ↗ jump to hunk
+ cxl_setup_psl_timebase(adapter, dev); =20 if ((rc =3D 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"); } =20 +static ssize_t psl_timebase_synced_show(struct device *device, + struct
device_attribute *attr,
+ char *buf)
+{
+ struct cxl *adapter =3D 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)
quoted hunk ↗ jump to hunk
@@ -142,6 +151,7 @@ static struct device_attribute adapter_attrs[] =3D
{__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),