From 501ea76687ef16a88a96cc9848e5d760f1c68e4e Mon Sep 17 00:00:00 2001 From: Christophe Leroy Date: Thu, 4 Feb 2016 11:07:48 +0100 Subject: [PATCH] powerpc/885: set SDCR to 0x40 The MPC885 reference manual says that SDCR shall have value 0x40, but most exemples set SDCR to 0x1 With 0x1 in SDCR, we observe TX underruns on SCC when using it in QMC mode. According the NXP technical support, this is a copy/paste error from MPC860 reference manual, 0x40 being the only value supported by the MPC885 HW. Signed-off-by: Christophe Leroy Signed-off-by: Scott Wood --- arch/powerpc/sysdev/cpm1.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/arch/powerpc/sysdev/cpm1.c b/arch/powerpc/sysdev/cpm1.c index 5e6ff38ea69f..8ed65365be50 100644 --- a/arch/powerpc/sysdev/cpm1.c +++ b/arch/powerpc/sysdev/cpm1.c @@ -228,7 +228,10 @@ void __init cpm_reset(void) * Bit 25, FAM can also be set to use FEC aggressive mode (860T). */ siu_conf = immr_map(im_siu_conf); - out_be32(&siu_conf->sc_sdcr, 1); + if ((mfspr(SPRN_IMMR) & 0xffff) == 0x0900) /* MPC885 */ + out_be32(&siu_conf->sc_sdcr, 0x40); + else + out_be32(&siu_conf->sc_sdcr, 1); immr_unmap(siu_conf); cpm_muram_init(); -- 2.20.1