[PATCH] powerpc: fixup QE_General4 errata

Subsystems: linux for powerpc (32-bit and 64-bit), the rest

STALE5402d

3 messages, 3 authors, 2011-11-24 · open the first message on its own page

[PATCH] powerpc: fixup QE_General4 errata

From: Joakim Tjernlund <hidden>
Date: 2011-08-23 12:38:18

QE_General4 should only round up the divisor iff divisor is > 3.
Rounding up lower divisors makes the error too big, causing USB
on MPC832x to fail.

Signed-off-by: Joakim Tjernlund <redacted>
---
 arch/powerpc/sysdev/qe_lib/qe.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
diff --git a/arch/powerpc/sysdev/qe_lib/qe.c b/arch/powerpc/sysdev/qe_lib/qe.c
index 093e0ae..5399316 100644
--- a/arch/powerpc/sysdev/qe_lib/qe.c
+++ b/arch/powerpc/sysdev/qe_lib/qe.c
@@ -216,7 +216,7 @@ int qe_setbrg(enum qe_clock brg, unsigned int rate, unsigned int multiplier)
 	/* Errata QE_General4, which affects some MPC832x and MPC836x SOCs, says
 	   that the BRG divisor must be even if you're not using divide-by-16
 	   mode. */
-	if (!div16 && (divisor & 1))
+	if (!div16 && (divisor & 1) && (divisor > 3))
 		divisor++;
 
 	tempval = ((divisor - 1) << QE_BRGC_DIVISOR_SHIFT) |
-- 
1.7.3.4

Re: [PATCH] powerpc: fixup QE_General4 errata

From: Timur Tabi <hidden>
Date: 2011-08-23 17:49:53

Joakim Tjernlund wrote:
QE_General4 should only round up the divisor iff divisor is > 3.
Rounding up lower divisors makes the error too big, causing USB
on MPC832x to fail.

Signed-off-by: Joakim Tjernlund <redacted>
Acked-by: Timur Tabi <redacted>

-- 
Timur Tabi
Linux kernel developer at Freescale

Re: [PATCH] powerpc: fixup QE_General4 errata

From: Kumar Gala <hidden>
Date: 2011-11-24 07:45:23


On Aug 23, 2011, at 7:30 AM, Joakim Tjernlund wrote:
QE_General4 should only round up the divisor iff divisor is > 3.
Rounding up lower divisors makes the error too big, causing USB
on MPC832x to fail.

Signed-off-by: Joakim Tjernlund <redacted>
---
arch/powerpc/sysdev/qe_lib/qe.c |    2 +-
1 files changed, 1 insertions(+), 1 deletions(-)
applied to merge

- k
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