From patchwork Mon Sep 24 06:20:18 2012
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Subject: Powerpc 8xx CPM_UART maxidl should not depend on fifo size
From: LEROY Christophe <christophe.leroy@c-s.fr>
X-Patchwork-Id: 186299
Message-Id: <201209240620.q8O6KINT029454@localhost.localdomain>
To: Alan Cox <alan@linux.intel.com>, Vitaly Bordug <vitb@kernel.crashing.org>, 
 Marcelo Tosatti <marcelo@kvack.org>
Cc: linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org,
 linux-serial@vger.kernel.org
Date: Mon, 24 Sep 2012 08:20:18 +0200

maxidl register was set to fifo size. There is no reason to set this
register to same value as fifo size. Setting it now to 0x10 by default
as in the UCC UART driver.

Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>


--- linux-3.5-vanilla/drivers/tty/serial/cpm_uart/cpm_uart_core.c	2012-07-21 22:58:29.000000000 +0200
+++ linux-3.5/drivers/tty/serial/cpm_uart/cpm_uart_core.c	2012-08-09 17:38:37.000000000 +0200
@@ -799,7 +799,7 @@
 	cpm_set_scc_fcr(sup);
 
 	out_be16(&sup->scc_genscc.scc_mrblr, pinfo->rx_fifosize);
-	out_be16(&sup->scc_maxidl, pinfo->rx_fifosize);
+	out_be16(&sup->scc_maxidl, 0x10);
 	out_be16(&sup->scc_brkcr, 1);
 	out_be16(&sup->scc_parec, 0);
 	out_be16(&sup->scc_frmec, 0);
@@ -873,7 +873,7 @@
 
 	/* Using idle character time requires some additional tuning.  */
 	out_be16(&up->smc_mrblr, pinfo->rx_fifosize);
-	out_be16(&up->smc_maxidl, pinfo->rx_fifosize);
+	out_be16(&up->smc_maxidl, 0x10);
 	out_be16(&up->smc_brklen, 0);
 	out_be16(&up->smc_brkec, 0);
 	out_be16(&up->smc_brkcr, 1);