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authorChaithrika U S <chaithrika@ti.com>2009-01-19 14:13:05 +0530
committerKevin Hilman <khilman@deeprootsystems.com>2009-05-26 07:18:14 -0700
commit17eb15704142dc1b302a3f0cd632c426ee326b6d (patch)
tree48c563fa921c858d4648d485309125beed436395
parentdc75602628472d7fbc4cb43f010bf0257e95ab71 (diff)
davinci: use 32-bit accesses for low-level debug macros
This patch defines debug macros for low-level debugging for Davinci based platforms Tested on : - DM644x DaVinci EVM - DM646X DaVinciHD EVM - DM355 EVM This patch attempts to solve the low-level debug issue in DM646x. The UART on DM646x SoC allows only 32-bit access. The existing debug-macro.S uses the macros from debug-8250.S file. This led to garbage serial out in the case of DM646x. The inclusion of debug-8250.S does not allow for run time fix for this issue. There are compile time errors due to multiple definitions of the macros. Also when building a single image for multiple DaVinci Platforms, the ifdefs cannot be relied upon. The solution below does not include the debug-8250.S file and defines the necessary macros. This solution was arrived at after observing that word access does not affect the low-level debug messages on DM644x/DM355. The other approach to this issue is to use the UART module information available in the peripheral registers to decide the access mechanism. But this will have to be done for every access of UART specifically for DM646x. Also this calls for a modification of the debug-8250.S file. Signed-off-by: Chaithrika U S <chaithrika@ti.com> Signed-off-by: Kevin Hilman <khilman@deeprootsystems.com>
-rw-r--r--arch/arm/mach-davinci/include/mach/debug-macro.S31
1 files changed, 29 insertions, 2 deletions
diff --git a/arch/arm/mach-davinci/include/mach/debug-macro.S b/arch/arm/mach-davinci/include/mach/debug-macro.S
index e6c0f0d5d06..de3fc2182b4 100644
--- a/arch/arm/mach-davinci/include/mach/debug-macro.S
+++ b/arch/arm/mach-davinci/include/mach/debug-macro.S
@@ -9,6 +9,16 @@
* or implied.
*/
+/* Modifications
+ * Jan 2009 Chaithrika U S Added senduart, busyuart, waituart
+ * macros, based on debug-8250.S file
+ * but using 32-bit accesses required for
+ * some davinci devices.
+ */
+
+#include <linux/serial_reg.h>
+#define UART_SHIFT 2
+
.macro addruart, rx
mrc p15, 0, \rx, c1, c0
tst \rx, #1 @ MMU enabled?
@@ -17,5 +27,22 @@
orr \rx, \rx, #0x00c20000 @ UART 0
.endm
-#define UART_SHIFT 2
-#include <asm/hardware/debug-8250.S>
+ .macro senduart,rd,rx
+ str \rd, [\rx, #UART_TX << UART_SHIFT]
+ .endm
+
+ .macro busyuart,rd,rx
+1002: ldr \rd, [\rx, #UART_LSR << UART_SHIFT]
+ and \rd, \rd, #UART_LSR_TEMT | UART_LSR_THRE
+ teq \rd, #UART_LSR_TEMT | UART_LSR_THRE
+ bne 1002b
+ .endm
+
+ .macro waituart,rd,rx
+#ifdef FLOW_CONTROL
+1001: ldr \rd, [\rx, #UART_MSR << UART_SHIFT]
+ tst \rd, #UART_MSR_CTS
+ beq 1001b
+#endif
+ .endm
+