Patch "xtensa: xtfpga: fix hardware lockup caused by LCD driver" has been added to the 3.19-stable tree

This is a note to let you know that I've just added the patch titled

xtensa: xtfpga: fix hardware lockup caused by LCD driver

to the 3.19-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
xtensa-xtfpga-fix-hardware-lockup-caused-by-lcd-driver.patch
and it can be found in the queue-3.19 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Max Filippov <[email protected]>
Date: Fri, 27 Feb 2015 06:28:00 +0300
Subject: xtensa: xtfpga: fix hardware lockup caused by LCD driver

From: Max Filippov <[email protected]>

commit 4949009eb8d40a441dcddcd96e101e77d31cf1b2 upstream.

LCD driver is always built for the XTFPGA platform, but its base address is not configurable, and is wrong for ML605/KC705. Its initialization locks up KC705 board hardware.

Make the whole driver optional, and its base address and bus width configurable. Implement 4-bit bus access method.

---
 arch/xtensa/Kconfig                                      |   30 ++++++++
 arch/xtensa/platforms/xtfpga/Makefile                    |    3 
 arch/xtensa/platforms/xtfpga/include/platform/hardware.h |    3 
 arch/xtensa/platforms/xtfpga/include/platform/lcd.h      |   15 ++++
 arch/xtensa/platforms/xtfpga/lcd.c                       |   55 +++++++++------
 5 files changed, 81 insertions(+), 25 deletions(-)

@@ -428,6 +428,36 @@ config DEFAULT_MEM_SIZE
 
 	  If unsure, leave the default value here.
 
+config XTFPGA_LCD
+	bool "Enable XTFPGA LCD driver"
+	depends on XTENSA_PLATFORM_XTFPGA
+	default n
+	help
+	  There's a 2x16 LCD on most of XTFPGA boards, kernel may output
+	  progress messages there during bootup/shutdown. It may be useful
+	  during board bringup.
+
+	  If unsure, say N.
+
+config XTFPGA_LCD_BASE_ADDR
+	hex "XTFPGA LCD base address"
+	depends on XTFPGA_LCD
+	default "0x0d0c0000"
+	help
+	  Base address of the LCD controller inside KIO region.
+	  Different boards from XTFPGA family have LCD controller at different
+	  addresses. Please consult prototyping user guide for your board for
+	  the correct address. Wrong address here may lead to hardware lockup.
+
+config XTFPGA_LCD_8BIT_ACCESS
+	bool "Use 8-bit access to XTFPGA LCD"
+	depends on XTFPGA_LCD
+	default n
+	help
+	  LCD may be connected with 4- or 8-bit interface, 8-bit access may
+	  only be used with 8-bit interface. Please consult prototyping user
+	  guide for your board for the correct interface width.
+
 endmenu
 
 menu "Executable file formats"

@@ -6,4 +6,5 @@
 #
 # Note 2! The CFLAGS definitions are in the main makefile...
 
-obj-y			= setup.o lcd.o
+obj-y			+= setup.o
+obj-$(CONFIG_XTFPGA_LCD) += lcd.o

@@ -40,9 +40,6 @@
 
 /* UART */
 #define DUART16552_PADDR	(XCHAL_KIO_PADDR + 0x0D050020)
-/* LCD instruction and data addresses. */
-#define LCD_INSTR_ADDR		((char *)IOADDR(0x0D040000))
-#define LCD_DATA_ADDR		((char *)IOADDR(0x0D040004))
 
 /* Misc. */
 #define XTFPGA_FPGAREGS_VADDR	IOADDR(0x0D020000)

@@ -11,10 +11,25 @@
 #ifndef __XTENSA_XTAVNET_LCD_H
 #define __XTENSA_XTAVNET_LCD_H
 
+#ifdef CONFIG_XTFPGA_LCD
 /* Display string STR at position POS on the LCD. */
 void lcd_disp_at_pos(char *str, unsigned char pos);
 
 /* Shift the contents of the LCD display left or right. */
 void lcd_shiftleft(void);
 void lcd_shiftright(void);
+#else
+static inline void lcd_disp_at_pos(char *str, unsigned char pos)
+{
+}
+
+static inline void lcd_shiftleft(void)
+{
+}
+
+static inline void lcd_shiftright(void)
+{
+}
+#endif
+
 #endif

Patches currently in stable-queue which might be from [email protected] are

queue-3.19/xtensa-iss-fix-locking-in-tap-network-adapter.patch queue-3.19/xtensa-xtfpga-fix-hardware-lockup-caused-by-lcd-driver.patch queue-3.19/xtensa-provide-__nr_sync_file_range2-instead-of-__nr_sync_file_range.patch