Re: [PATCH 2/9] cpm2: Fix off-by-one error in setbrg().
On Tue, 28 Aug 2007 15:19:21 -0500 Scott Wood wrote: The hardware adds one to the BRG value to get the divider, so it must be subtracted by software. Prolly a note why it used to work, or what exactly this is resulting in the code. IIRC this was just fw-ported so arch/ppc should have this as well. Signed-off-by: Scott Wood [EMAIL PROTECTED] --- arch/powerpc/sysdev/cpm2_common.c |2 +- 1 files changed, 1 insertions(+), 1 deletions(-) diff --git a/arch/powerpc/sysdev/cpm2_common.c b/arch/powerpc/sysdev/cpm2_common.c index dbef50c..99ad1ed 100644 --- a/arch/powerpc/sysdev/cpm2_common.c +++ b/arch/powerpc/sysdev/cpm2_common.c @@ -102,7 +102,7 @@ cpm_setbrg(uint brg, uint rate) brg -= 4; } bp += brg; - out_be32(bp, ((BRG_UART_CLK / rate) 1) | CPM_BRG_EN); + out_be32(bp, (((BRG_UART_CLK / rate) - 1) 1) | CPM_BRG_EN); cpm2_unmap(bp); } -- Sincerely, Vitaly ___ Linuxppc-dev mailing list Linuxppc-dev@ozlabs.org https://ozlabs.org/mailman/listinfo/linuxppc-dev
Re: [PATCH 2/9] cpm2: Fix off-by-one error in setbrg().
On Thu, 30 Aug 2007 15:13:12 -0500 Scott Wood wrote: On Thu, Aug 30, 2007 at 02:09:07AM +0400, Vitaly Bordug wrote: On Tue, 28 Aug 2007 15:19:21 -0500 Scott Wood wrote: The hardware adds one to the BRG value to get the divider, so it must be subtracted by software. Prolly a note why it used to work, or what exactly this is resulting in the code. IIRC this was just fw-ported so arch/ppc should have this as well. It *didn't* work before -- hence the fix. It used to work at least at the time I did initial port, but I am not going to argue. The failure mode from being off by just one isn't total nonfunctionality, but rather a corrupted character now and then, which could explain why it wasn't fixed before. Can this be added to description please? Someone may be grepping for such a weirdness in some custom code forked off some kernel.org revision, and will be happy to know it is addressed. As for arch/ppc, I'm just trying to not break it more than it already is. I mean, when powerpc/ was nearly empty, same issue in ppc/ went unnoticed for years... -- Sincerely, Vitaly ___ Linuxppc-dev mailing list Linuxppc-dev@ozlabs.org https://ozlabs.org/mailman/listinfo/linuxppc-dev
[PATCH 2/9] cpm2: Fix off-by-one error in setbrg().
The hardware adds one to the BRG value to get the divider, so it must be subtracted by software. Signed-off-by: Scott Wood [EMAIL PROTECTED] --- arch/powerpc/sysdev/cpm2_common.c |2 +- 1 files changed, 1 insertions(+), 1 deletions(-) diff --git a/arch/powerpc/sysdev/cpm2_common.c b/arch/powerpc/sysdev/cpm2_common.c index dbef50c..99ad1ed 100644 --- a/arch/powerpc/sysdev/cpm2_common.c +++ b/arch/powerpc/sysdev/cpm2_common.c @@ -102,7 +102,7 @@ cpm_setbrg(uint brg, uint rate) brg -= 4; } bp += brg; - out_be32(bp, ((BRG_UART_CLK / rate) 1) | CPM_BRG_EN); + out_be32(bp, (((BRG_UART_CLK / rate) - 1) 1) | CPM_BRG_EN); cpm2_unmap(bp); } -- 1.5.0.3 ___ Linuxppc-dev mailing list Linuxppc-dev@ozlabs.org https://ozlabs.org/mailman/listinfo/linuxppc-dev
