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cxl: Fix timebase synchronization status on P9

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The PSL Timebase register is updated by the PSL to maintain the
timebase.

On P9, the Timebase value is only provided by the CAPP as received the
last time a timebase request was performed.

The timebase requests are initiated through the adapter configuration
or application registers.

The specific sysfs entry "/sys/class/cxl/cardxx/psl_timebase_synced"
is now dynamically updated according the content of the PSL Timebase
register.

Fixes: f24be42aab ("cxl: Add psl9 specific code")
Signed-off-by: Christophe Lombard <clombard@linux.vnet.ibm.com>
Reviewed-by: Vaibhav Jain <vaibhav@linux.vnet.ibm.com>
Acked-by: Andrew Donnellan <andrew.donnellan@au1.ibm.com>
Acked-by: Frederic Barrat <fbarrat@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
This commit is contained in:
Christophe Lombard 2018-02-20 14:48:56 +01:00 committed by Michael Ellerman
parent 014a32b30e
commit c2be663d53
2 changed files with 12 additions and 17 deletions
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17
drivers/misc/cxl/pci.c
View File

@ -659,9 +659,6 @@ static u64 timebase_read_xsl(struct cxl *adapter)
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;
@ -689,20 +686,6 @@ static void cxl_setup_psl_timebase(struct cxl *adapter, struct pci_dev *dev)
cxl_p1_write(adapter, CXL_PSL_Control, 0x0000000000000000);
cxl_p1_write(adapter, CXL_PSL_Control, CXL_PSL_Control_tb);
/* Wait until CORE TB and PSL TB difference <= 16usecs */
do {
msleep(1);
if (retry++ > 5) {
dev_info(&dev->dev, "PSL timebase can't synchronize\n");
return;
}
psl_tb = adapter->native->sl_ops->timebase_read(adapter);
delta = mftb() - psl_tb;
if (delta < 0)
delta = -delta;
} while (tb_to_ns(delta) > 16000);
adapter->psl_timebase_synced = true;
return;
}

12
drivers/misc/cxl/sysfs.c
View File

@ -62,7 +62,19 @@ static ssize_t psl_timebase_synced_show(struct device *device,
char *buf)
{
struct cxl *adapter = to_cxl_adapter(device);
u64 psl_tb, delta;
/* Recompute the status only in native mode */
if (cpu_has_feature(CPU_FTR_HVMODE)) {
psl_tb = adapter->native->sl_ops->timebase_read(adapter);
delta = abs(mftb() - psl_tb);
/* CORE TB and PSL TB difference <= 16usecs ? */
adapter->psl_timebase_synced = (tb_to_ns(delta) < 16000) ? true : false;
pr_devel("PSL timebase %s - delta: 0x%016llx\n",
(tb_to_ns(delta) < 16000) ? "synchronized" :
"not synchronized", tb_to_ns(delta));
}
return scnprintf(buf, PAGE_SIZE, "%i\n", adapter->psl_timebase_synced);
}