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authorjuhosg <juhosg@3c298f89-4303-0410-b956-a3cf2f4a3e73>2012-12-29 13:52:38 +0000
committerjuhosg <juhosg@3c298f89-4303-0410-b956-a3cf2f4a3e73>2012-12-29 13:52:38 +0000
commita57b8e3d45b416f10bb2bb6ada96b2d69c938542 (patch)
treef6a58c904c9aca882569ecb122f2780928e7406a /target/linux
parent1565cab1a6768fb773972fea9836e58821d0d64a (diff)
ar71xx: use a backported patch to fix AR933x UART baud rate calculation
Signed-off-by: Gabor Juhos <juhosg@openwrt.org> git-svn-id: svn://svn.openwrt.org/openwrt/trunk@34915 3c298f89-4303-0410-b956-a3cf2f4a3e73
Diffstat (limited to 'target/linux')
-rw-r--r--target/linux/ar71xx/patches-3.6/004-tty-serial-ar933x_uart-fix-baud-rate-calculation.patch (renamed from target/linux/ar71xx/patches-3.6/211-ar933x_uart-improve-serial-clock-calculation.patch)62
1 files changed, 60 insertions, 2 deletions
diff --git a/target/linux/ar71xx/patches-3.6/211-ar933x_uart-improve-serial-clock-calculation.patch b/target/linux/ar71xx/patches-3.6/004-tty-serial-ar933x_uart-fix-baud-rate-calculation.patch
index 510b75ed0f..44eebabb18 100644
--- a/target/linux/ar71xx/patches-3.6/211-ar933x_uart-improve-serial-clock-calculation.patch
+++ b/target/linux/ar71xx/patches-3.6/004-tty-serial-ar933x_uart-fix-baud-rate-calculation.patch
@@ -1,3 +1,61 @@
+From 2dff8ad92661b6c99e9ba8b5918e43b522551556 Mon Sep 17 00:00:00 2001
+From: Gabor Juhos <juhosg@openwrt.org>
+Date: Wed, 14 Nov 2012 10:38:13 +0100
+Subject: [PATCH] tty/serial/ar933x_uart: fix baud rate calculation
+
+commit 2dff8ad92661b6c99e9ba8b5918e43b522551556 upstream.
+
+The UART of the AR933x SoC implements a fractional divisor
+for generating the desired baud rate.
+
+The current code uses a fixed value for the fractional
+part of the divisor, and this leads to improperly
+calculated baud rates:
+
+ baud scale step real baud diff
+ 300 5207* 8192 17756 17456 5818.66%
+ 600 2603* 8192 35511 34911 5818.50%
+ 1200 1301* 8192 71023 69823 5818.58%
+ 2400 650* 8192 11241 8841 368.37%
+ 4800 324* 8192 22645 17845 371.77%
+ 9600 161 8192 9645 45 0.46%
+ 14400 107 8192 14468 68 0.47%
+ 19200 80 8192 19290 90 0.46%
+ 28800 53 8192 28935 135 0.46%
+ 38400 39 8192 39063 663 1.72%
+ 57600 26 8192 57870 270 0.46%
+ 115200 12 8192 120192 4992 4.33%
+ 230400 5 8192 260417 30017 13.02%
+ 460800 2 8192 520833 60033 13.02%
+ 921600 0 8192 1562500 640900 69.93%
+
+After the patch, the integer and fractional parts of the
+divisor will be calculated dynamically. This ensures that
+the UART will use correct baud rates:
+
+ baud scale step real baud diff
+ 300 6 11 300 0 0.00%
+ 600 54 173 600 0 0.00%
+ 1200 30 195 1200 0 0.00%
+ 2400 30 390 2400 0 0.00%
+ 4800 48 1233 4800 0 0.00%
+ 9600 78 3976 9600 0 0.00%
+ 14400 98 7474 14400 0 0.00%
+ 19200 55 5637 19200 0 0.00%
+ 28800 130 19780 28800 0 0.00%
+ 38400 36 7449 38400 0 0.00%
+ 57600 78 23857 57600 0 0.00%
+ 115200 43 26575 115200 0 0.00%
+ 230400 23 28991 230400 0 0.00%
+ 460800 11 28991 460800 0 0.00%
+ 921600 5 28991 921599 -1 0.00%
+
+Signed-off-by: Gabor Juhos <juhosg@openwrt.org>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+---
+ drivers/tty/serial/ar933x_uart.c | 90 +++++++++++++++++++++++++++++++++++---
+ 1 file changed, 85 insertions(+), 5 deletions(-)
+
--- a/drivers/tty/serial/ar933x_uart.c
+++ b/drivers/tty/serial/ar933x_uart.c
@@ -25,11 +25,19 @@
@@ -133,8 +191,8 @@
+ /* reenable the UART */
+ ar933x_uart_rmw(up, AR933X_UART_CS_REG,
-+ AR933X_UART_CS_IF_MODE_M << AR933X_UART_CS_IF_MODE_S,
-+ AR933X_UART_CS_IF_MODE_DCE << AR933X_UART_CS_IF_MODE_S);
++ AR933X_UART_CS_IF_MODE_M << AR933X_UART_CS_IF_MODE_S,
++ AR933X_UART_CS_IF_MODE_DCE << AR933X_UART_CS_IF_MODE_S);
+
spin_unlock_irqrestore(&up->port.lock, flags);