hollalinux
/
linux-sg2042
mirror of https://github.com/sophgo/linux-riscv.git
1
0
Fork 0
Code Issues Packages Projects Releases Wiki Activity

powerpc/vas: poll for return of window credits 

Normally, the NX driver waits for the CRBs to be processed before closing
the window. But it is better to ensure that the credits are returned before
the window gets reassigned later.

Signed-off-by: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
This commit is contained in:
Sukadev Bhattiprolu 2017-11-07 18:23:48 -08:00 committed by Michael Ellerman
parent 62f659e08c
commit 6fccac16c5
1 changed files with 45 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

45
arch/powerpc/platforms/powernv/vas-window.c
View File

@ -1062,6 +1062,49 @@ int vas_paste_crb(struct vas_window *txwin, int offset, bool re)
}
EXPORT_SYMBOL_GPL(vas_paste_crb);
/*
* If credit checking is enabled for this window, poll for the return
* of window credits (i.e for NX engines to process any outstanding CRBs).
* Since NX-842 waits for the CRBs to be processed before closing the
* window, we should not have to wait for too long.
*
* TODO: We retry in 10ms intervals now. We could/should probably peek at
* the VAS_LRFIFO_PUSH_OFFSET register to get an estimate of pending
* CRBs on the FIFO and compute the delay dynamically on each retry.
* But that is not really needed until we support NX-GZIP access from
* user space. (NX-842 driver waits for CSB and Fast thread-wakeup
* doesn't use credit checking).
*/
static void poll_window_credits(struct vas_window *window)
{
u64 val;
int creds, mode;
val = read_hvwc_reg(window, VREG(WINCTL));
if (window->tx_win)
mode = GET_FIELD(VAS_WINCTL_TX_WCRED_MODE, val);
else
mode = GET_FIELD(VAS_WINCTL_RX_WCRED_MODE, val);
if (!mode)
return;
retry:
if (window->tx_win) {
val = read_hvwc_reg(window, VREG(TX_WCRED));
creds = GET_FIELD(VAS_TX_WCRED, val);
} else {
val = read_hvwc_reg(window, VREG(LRX_WCRED));
creds = GET_FIELD(VAS_LRX_WCRED, val);
}
if (creds < window->wcreds_max) {
val = 0;
set_current_state(TASK_UNINTERRUPTIBLE);
schedule_timeout(msecs_to_jiffies(10));
goto retry;
}
}
/*
* Wait for the window to go to "not-busy" state. It should only take a
* short time to queue a CRB, so window should not be busy for too long.
@ -1149,6 +1192,8 @@ int vas_win_close(struct vas_window *window)
unpin_close_window(window);
poll_window_credits(window);
poll_window_castout(window);
/* if send window, drop reference to matching receive window */