projects / thirdparty / kernel / stable-queue.git / blame
| Commit | Line | Data |
|---|---|---|
| a65d4bac GKH |
1 | From foo@baz Sat Jul 28 10:25:26 CEST 2018 |
| 2 | From: Stewart Smith <stewart@linux.ibm.com> | |
| 3 | Date: Thu, 29 Mar 2018 17:02:46 +1100 | |
| 4 | Subject: hvc_opal: don't set tb_ticks_per_usec in udbg_init_opal_common() | |
| 5 | ||
| 6 | From: Stewart Smith <stewart@linux.ibm.com> | |
| 7 | ||
| 8 | [ Upstream commit 447808bf500a7cc92173266a59f8a494e132b122 ] | |
| 9 | ||
| 10 | time_init() will set up tb_ticks_per_usec based on reality. | |
| 11 | time_init() is called *after* udbg_init_opal_common() during boot. | |
| 12 | ||
| 13 | from arch/powerpc/kernel/time.c: | |
| 14 | unsigned long tb_ticks_per_usec = 100; /* sane default */ | |
| 15 | ||
| 16 | Currently, all powernv systems have a timebase frequency of 512mhz | |
| 17 | (512000000/1000000 == 0x200) - although there's nothing written | |
| 18 | down anywhere that I can find saying that we couldn't make that | |
| 19 | different based on the requirements in the ISA. | |
| 20 | ||
| 21 | So, we've been (accidentally) thwacking the (currently) correct | |
| 22 | (for powernv at least) value for tb_ticks_per_usec earlier than | |
| 23 | we otherwise would have. | |
| 24 | ||
| 25 | The "sane default" seems to be adequate for our purposes between | |
| 26 | udbg_init_opal_common() and time_init() being called, and if it isn't, | |
| 27 | then we should probably be setting it somewhere that isn't hvc_opal.c! | |
| 28 | ||
| 29 | Signed-off-by: Stewart Smith <stewart@linux.ibm.com> | |
| 30 | Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> | |
| 31 | Signed-off-by: Sasha Levin <alexander.levin@microsoft.com> | |
| 32 | Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> | |
| 33 | --- | |
| 34 | drivers/tty/hvc/hvc_opal.c | 1 - | |
| 35 | 1 file changed, 1 deletion(-) | |
| 36 | ||
| 37 | --- a/drivers/tty/hvc/hvc_opal.c | |
| 38 | +++ b/drivers/tty/hvc/hvc_opal.c | |
| 39 | @@ -332,7 +332,6 @@ static void udbg_init_opal_common(void) | |
| 40 | udbg_putc = udbg_opal_putc; | |
| 41 | udbg_getc = udbg_opal_getc; | |
| 42 | udbg_getc_poll = udbg_opal_getc_poll; | |
| 43 | - tb_ticks_per_usec = 0x200; /* Make udelay not suck */ | |
| 44 | } | |
| 45 | ||
| 46 | void __init hvc_opal_init_early(void) |