ppc4xx: Add Sequoia RAM-booting target

This patch adds another build target for the AMCC Sequoia PPC440EPx
eval board. This RAM-booting version is targeted for boards without
NOR FLASH (NAND booting) which need a possibility to initially
program their NAND FLASH. Using a JTAG debugger (e.g. BDI2000/3000)
configured to setup the SDRAM, this debugger can load this RAM-
booting image to the target address in SDRAM (in this case 0x1000000)
and start it there. Then U-Boot's standard NAND commands can be
used to program the NAND FLASH (e.g. "nand write ...").

Here the commands to load and start this image from the BDI2000:

440EPX>reset halt
440EPX>load 0x1000000 /tftpboot/sequoia/u-boot.bin
440EPX>go 0x1000000

Please note that this image automatically scans for an already
initialized SDRAM TLB (detected by EPN=0). This TLB will not be
cleared. This TLB doesn't need to be TLB #0, this RAM-booting
version will detect it and preserve it. So booting via BDI2000
will work and booting with a complete different TLB init via
U-Boot works as well.

Signed-off-by: Stefan Roese <sr@denx.de>

8 files changed, 215 insertions, 16 deletions

diff --git a/Makefile b/Makefile
index 4983c0e..10f6b1f 100644
--- a/Makefile
+++ b/Makefile
@@ -1533,6 +1533,17 @@ rainier_nand_config: unconfig
 	@echo "TEXT_BASE = 0x01000000" > $(obj)board/amcc/sequoia/config.tmp
 	@echo "CONFIG_NAND_U_BOOT = y" >> $(obj)include/config.mk
 
+sequoia_ramboot_config \
+rainier_ramboot_config: unconfig
+	@mkdir -p $(obj)include $(obj)board/amcc/sequoia
+	@echo "#define CONFIG_SYS_RAMBOOT" > $(obj)include/config.h
+	@echo "#define CONFIG_$$(echo $(subst ,,$(@:_config=)) | \
+		tr '[:lower:]' '[:upper:]')" >> $(obj)include/config.h
+	@$(MKCONFIG) -n $@ -a sequoia ppc ppc4xx sequoia amcc
+	@echo "TEXT_BASE = 0x01000000" > $(obj)board/amcc/sequoia/config.tmp
+	@echo "LDSCRIPT = board/amcc/sequoia/u-boot-ram.lds" >> \
+		$(obj)board/amcc/sequoia/config.tmp
+
 taihu_config:	unconfig
 	@$(MKCONFIG) $(@:_config=) ppc ppc4xx taihu amcc
 
diff --git a/board/amcc/sequoia/init.S b/board/amcc/sequoia/init.S
index 4452d26..3c0e400 100644
--- a/board/amcc/sequoia/init.S
+++ b/board/amcc/sequoia/init.S
@@ -43,12 +43,19 @@ tlbtab:
 	/* vxWorks needs this as first entry for the Machine Check interrupt */
 	tlbentry( 0x40000000, SZ_256M, 0, 0, AC_R|AC_W|AC_X|SA_G|SA_I )
 
+	/*
+	 * The RAM-boot version skips the SDRAM TLB (identified by EPN=0). This
+	 * entry is already configured for SDRAM via the JTAG debugger and mustn't
+	 * be re-initialized by this RAM-booting U-Boot version.
+	 */
+#ifndef CONFIG_SYS_RAMBOOT
 	/* TLB-entry for DDR SDRAM (Up to 2GB) */
 #ifdef CONFIG_4xx_DCACHE
 	tlbentry( CONFIG_SYS_SDRAM_BASE, SZ_256M, CONFIG_SYS_SDRAM_BASE, 0, AC_R|AC_W|AC_X|SA_G)
 #else
 	tlbentry( CONFIG_SYS_SDRAM_BASE, SZ_256M, CONFIG_SYS_SDRAM_BASE, 0, AC_R|AC_W|AC_X|SA_G|SA_I )
 #endif
+#endif /* CONFIG_SYS_RAMBOOT */
 
 	/* TLB-entry for EBC */
 	tlbentry( CONFIG_SYS_BCSR_BASE, SZ_256M, CONFIG_SYS_BCSR_BASE, 1, AC_R|AC_W|AC_X|SA_G|SA_I )
diff --git a/board/amcc/sequoia/sdram.c b/board/amcc/sequoia/sdram.c
index 6df4c6d..bde471c 100644
--- a/board/amcc/sequoia/sdram.c
+++ b/board/amcc/sequoia/sdram.c
@@ -54,7 +54,8 @@ extern void denali_core_search_data_eye(void);
  ************************************************************************/
 phys_size_t initdram (int board_type)
 {
-#if !defined(CONFIG_NAND_U_BOOT) || defined(CONFIG_NAND_SPL)
+#if !(defined(CONFIG_NAND_U_BOOT) || defined(CONFIG_SYS_RAMBOOT)) || \
+    defined(CONFIG_NAND_SPL)
 	ulong speed = get_bus_freq(0);
 
 	mtsdram(DDR0_02, 0x00000000);
diff --git a/board/amcc/sequoia/sequoia.c b/board/amcc/sequoia/sequoia.c
index e824b8f..246ad94 100644
--- a/board/amcc/sequoia/sequoia.c
+++ b/board/amcc/sequoia/sequoia.c
@@ -33,7 +33,9 @@
 
 DECLARE_GLOBAL_DATA_PTR;
 
+#if !defined(CONFIG_SYS_NO_FLASH)
 extern flash_info_t flash_info[CONFIG_SYS_MAX_FLASH_BANKS]; /* info for FLASH chips */
+#endif
 
 extern void __ft_board_setup(void *blob, bd_t *bd);
 ulong flash_get_size(ulong base, int banknum);
@@ -122,16 +124,19 @@ int board_early_init_f(void)
 
 int misc_init_r(void)
 {
+#if !defined(CONFIG_SYS_NO_FLASH)
 	uint pbcr;
 	int size_val = 0;
-	u32 reg;
+#endif
 #ifdef CONFIG_440EPX
 	unsigned long usb2d0cr = 0;
 	unsigned long usb2phy0cr, usb2h0cr = 0;
 	unsigned long sdr0_pfc1;
 	char *act = getenv("usbact");
 #endif
+	u32 reg;
 
+#if !defined(CONFIG_SYS_NO_FLASH)
 	/* Re-do flash sizing to get full correct info */
 
 	/* adjust flash start and offset */
@@ -171,6 +176,7 @@ int misc_init_r(void)
 			    CONFIG_ENV_ADDR_REDUND + 2*CONFIG_ENV_SECT_SIZE - 1,
 			    &flash_info[0]);
 #endif
+#endif /* CONFIG_SYS_NO_FLASH */
 
 	/*
 	 * USB suff...
@@ -515,7 +521,7 @@ int post_hotkeys_pressed(void)
 }
 #endif /* CONFIG_POST */
 
-#if defined(CONFIG_NAND_U_BOOT)
+#if defined(CONFIG_NAND_U_BOOT) || defined(CONFIG_SYS_RAMBOOT)
 /*
  * On NAND-booting sequoia, we need to patch the chips select numbers
  * in the dtb (CS0 - NAND, CS3 - NOR)
diff --git a/board/amcc/sequoia/u-boot-ram.lds b/board/amcc/sequoia/u-boot-ram.lds
new file mode 100644
index 0000000..9393b65
--- /dev/null
+++ b/board/amcc/sequoia/u-boot-ram.lds
@@ -0,0 +1,126 @@
+/*
+ * (C) Copyright 2009
+ * Stefan Roese, DENX Software Engineering, sr@denx.de.
+ *
+ * See file CREDITS for list of people who contributed to this
+ * project.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of
+ * the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
+ * MA 02111-1307 USA
+ */
+
+OUTPUT_ARCH(powerpc)
+SECTIONS
+{
+  /* Read-only sections, merged into text segment: */
+  . = + SIZEOF_HEADERS;
+  .interp : { *(.interp) }
+  .hash          : { *(.hash)		}
+  .dynsym        : { *(.dynsym)		}
+  .dynstr        : { *(.dynstr)		}
+  .rel.text      : { *(.rel.text)		}
+  .rela.text     : { *(.rela.text)	}
+  .rel.data      : { *(.rel.data)		}
+  .rela.data     : { *(.rela.data)	}
+  .rel.rodata    : { *(.rel.rodata)	}
+  .rela.rodata   : { *(.rela.rodata)	}
+  .rel.got       : { *(.rel.got)		}
+  .rela.got      : { *(.rela.got)		}
+  .rel.ctors     : { *(.rel.ctors)	}
+  .rela.ctors    : { *(.rela.ctors)	}
+  .rel.dtors     : { *(.rel.dtors)	}
+  .rela.dtors    : { *(.rela.dtors)	}
+  .rel.bss       : { *(.rel.bss)		}
+  .rela.bss      : { *(.rela.bss)		}
+  .rel.plt       : { *(.rel.plt)		}
+  .rela.plt      : { *(.rela.plt)		}
+  .init          : { *(.init)	}
+  .plt : { *(.plt) }
+  .text      :
+  {
+    cpu/ppc4xx/start.o	(.text)
+
+    *(.text)
+    *(.fixup)
+    *(.got1)
+  }
+  _etext = .;
+  PROVIDE (etext = .);
+  .rodata    :
+  {
+    *(SORT_BY_ALIGNMENT(SORT_BY_NAME(.rodata*)))
+  }
+  .fini      : { *(.fini)    } =0
+  .ctors     : { *(.ctors)   }
+  .dtors     : { *(.dtors)   }
+
+  /* Read-write section, merged into data segment: */
+  . = (. + 0x00FF) & 0xFFFFFF00;
+  _erotext = .;
+  PROVIDE (erotext = .);
+  .reloc   :
+  {
+    *(.got)
+    _GOT2_TABLE_ = .;
+    *(.got2)
+    _FIXUP_TABLE_ = .;
+    *(.fixup)
+  }
+  __got2_entries = (_FIXUP_TABLE_ - _GOT2_TABLE_) >>2;
+  __fixup_entries = (. - _FIXUP_TABLE_)>>2;
+
+  .data    :
+  {
+    *(.data)
+    *(.data1)
+    *(.sdata)
+    *(.sdata2)
+    *(.dynamic)
+    CONSTRUCTORS
+  }
+  _edata  =  .;
+  PROVIDE (edata = .);
+
+  . = .;
+  __u_boot_cmd_start = .;
+  .u_boot_cmd : { *(.u_boot_cmd) }
+  __u_boot_cmd_end = .;
+
+
+  . = .;
+  __start___ex_table = .;
+  __ex_table : { *(__ex_table) }
+  __stop___ex_table = .;
+
+  . = ALIGN(256);
+  __init_begin = .;
+  .text.init : { *(.text.init) }
+  .data.init : { *(.data.init) }
+  . = ALIGN(256);
+  __init_end = .;
+
+  __bss_start = .;
+  .bss (NOLOAD)       :
+  {
+   *(.sbss) *(.scommon)
+   *(.dynbss)
+   *(.bss)
+   *(COMMON)
+   . = ALIGN(4);
+  }
+
+  _end = . ;
+  PROVIDE (end = .);
+}
diff --git a/cpu/ppc4xx/start.S b/cpu/ppc4xx/start.S
index f2b8908..ac96fc2 100644
--- a/cpu/ppc4xx/start.S
+++ b/cpu/ppc4xx/start.S
@@ -257,6 +257,14 @@
 	bl	board_init_f
 #endif
 
+#if defined(CONFIG_SYS_RAMBOOT)
+	/*
+	 * 4xx RAM-booting U-Boot image is started from offset 0
+	 */
+	.text
+	bl	_start_440
+#endif
+
 /*
  * 440 Startup -- on reset only the top 4k of the effective
  * address space is mapped in by an entry in the instruction
@@ -444,10 +452,17 @@ skip_debug_init:
 	addis	r0,0,0x0000
 	li	r1,0x003f	/* 64 TLB entries */
 	mtctr	r1
-rsttlb:	tlbwe	r0,r1,0x0000	/* Invalidate all entries (V=0)*/
-	tlbwe	r0,r1,0x0001
-	tlbwe	r0,r1,0x0002
-	subi	r1,r1,0x0001
+	li	r4,0		/* Start with TLB #0 */
+rsttlb:
+#ifdef CONFIG_SYS_RAMBOOT
+	tlbre	r3,r4,0		/* Read contents from TLB word #0 to get EPN */
+	rlwinm.	r3,r3,0,0xfffffc00	/* Mask EPN */
+	beq	tlbnxt		/* Skip EPN=0 TLB, this is the SDRAM TLB */
+#endif
+	tlbwe	r0,r4,0		/* Invalidate all entries (V=0)*/
+	tlbwe	r0,r4,1
+	tlbwe	r0,r4,2
+tlbnxt:	addi	r4,r4,1		/* Next TLB */
 	bdnz	rsttlb
 
 	/*----------------------------------------------------------------*/
@@ -476,7 +491,13 @@ rsttlb:	tlbwe	r0,r1,0x0000	/* Invalidate all entries (V=0)*/
 	li	r4,0		/* TLB # */
 
 	addi	r5,r5,-4
-1:	lwzu	r0,4(r5)
+1:
+#ifdef CONFIG_SYS_RAMBOOT
+	tlbre	r3,r4,0		/* Read contents from TLB word #0 */
+	rlwinm.	r3,r3,0,0x00000200	/* Mask V (valid) bit */
+	bne	tlbnx2		/* Skip V=1 TLB, this is the SDRAM TLB */
+#endif
+	lwzu	r0,4(r5)
 	cmpwi	r0,0
 	beq	2f		/* 0 marks end */
 	lwzu	r1,4(r5)
@@ -484,7 +505,7 @@ rsttlb:	tlbwe	r0,r1,0x0000	/* Invalidate all entries (V=0)*/
 	tlbwe	r0,r4,0		/* TLB Word 0 */
 	tlbwe	r1,r4,1		/* TLB Word 1 */
 	tlbwe	r2,r4,2		/* TLB Word 2 */
-	addi	r4,r4,1		/* Next TLB */
+tlbnx2:	addi	r4,r4,1		/* Next TLB */
 	bdnz	1b
 
 	/*----------------------------------------------------------------*/
diff --git a/include/configs/amcc-common.h b/include/configs/amcc-common.h
index d3dc3e5..3b733c0 100644
--- a/include/configs/amcc-common.h
+++ b/include/configs/amcc-common.h
@@ -76,6 +76,17 @@
 #define CONFIG_CMD_PING
 #define CONFIG_CMD_REGINFO
 
+#if defined(CONFIG_SYS_RAMBOOT)
+/*
+ * Disable NOR FLASH commands on RAM-booting version. One main reason for this
+ * RAM-booting version is boards with NAND and without NOR. This image can
+ * be used for initial NAND programming.
+ */
+#define CONFIG_SYS_NO_FLASH
+#undef CONFIG_CMD_FLASH
+#undef CONFIG_CMD_IMLS
+#endif
+
 /*
  * Miscellaneous configurable options
  */
diff --git a/include/configs/sequoia.h b/include/configs/sequoia.h
index fa226b2..89acacc 100644
--- a/include/configs/sequoia.h
+++ b/include/configs/sequoia.h
@@ -112,13 +112,26 @@
 /*
  * Environment
  */
-#if !defined(CONFIG_NAND_U_BOOT) && !defined(CONFIG_NAND_SPL)
-#define CONFIG_ENV_IS_IN_FLASH	1	/* use FLASH for environ vars	*/
+#if defined(CONFIG_NAND_U_BOOT) || defined(CONFIG_NAND_SPL)
+#define CONFIG_ENV_IS_IN_NAND		/* use NAND for environ vars	*/
+#define CONFIG_ENV_IS_EMBEDDED		/* use embedded environment	*/
+#elif defined(CONFIG_SYS_RAMBOOT)
+#define CONFIG_ENV_IS_NOWHERE		/* Store env in memory only	*/
+#define CONFIG_ENV_SIZE		(8 << 10)
+/*
+ * In RAM-booting version, we have no environment storage. So we need to
+ * provide at least preliminary MAC addresses for the 4xx EMAC driver to
+ * register the interfaces. Those two addresses are generated via the
+ * tools/gen_eth_addr tool and should only be used in a closed laboratory
+ * environment.
+ */
+#define	CONFIG_ETHADDR		4a:56:49:22:3e:43
+#define	CONFIG_ETH1ADDR		02:93:53:d5:06:98
 #else
-#define CONFIG_ENV_IS_IN_NAND	1	/* use NAND for environ vars	*/
-#define CONFIG_ENV_IS_EMBEDDED	1	/* use embedded environment	*/
+#define CONFIG_ENV_IS_IN_FLASH		/* use FLASH for environ vars	*/
 #endif
 
+#if defined(CONFIG_CMD_FLASH)
 /*
  * FLASH related
  */
@@ -148,6 +161,7 @@
 #define CONFIG_ENV_ADDR_REDUND	(CONFIG_ENV_ADDR-CONFIG_ENV_SECT_SIZE)
 #define CONFIG_ENV_SIZE_REDUND	(CONFIG_ENV_SIZE)
 #endif
+#endif /* CONFIG_CMD_FLASH */
 
 /*
  * IPL (Initial Program Loader, integrated inside CPU)
@@ -211,7 +225,8 @@
  * DDR SDRAM
  */
 #define CONFIG_SYS_MBYTES_SDRAM        (256)	/* 256MB			*/
-#if !defined(CONFIG_NAND_U_BOOT) && !defined(CONFIG_NAND_SPL)
+#if !defined(CONFIG_NAND_U_BOOT) && !defined(CONFIG_NAND_SPL) && \
+    !defined(CONFIG_SYS_RAMBOOT)
 #define CONFIG_DDR_DATA_EYE		/* use DDR2 optimization	*/
 #endif
 #define CONFIG_SYS_MEM_TOP_HIDE	(4 << 10) /* don't use last 4kbytes	*/
@@ -306,7 +321,7 @@
  * overwrite part of the U-Boot image which is already loaded from NAND
  * to SDRAM.
  */
-#if defined(CONFIG_NAND_U_BOOT)
+#if defined(CONFIG_NAND_U_BOOT) || defined(CONFIG_SYS_RAMBOOT)
 #define CONFIG_SYS_POST_MEMORY_ON	0
 #else
 #define CONFIG_SYS_POST_MEMORY_ON	CONFIG_SYS_POST_MEMORY
@@ -354,7 +369,8 @@
 /*
  * On Sequoia CS0 and CS3 are switched when configuring for NAND booting
  */
-#if !defined(CONFIG_NAND_U_BOOT) && !defined(CONFIG_NAND_SPL)
+#if !defined(CONFIG_NAND_U_BOOT) && !defined(CONFIG_NAND_SPL) && \
+    !defined(CONFIG_SYS_RAMBOOT)
 #define CONFIG_SYS_NAND_CS		3	/* NAND chip connected to CSx	*/
 /* Memory Bank 0 (NOR-FLASH) initialization				*/
 #define CONFIG_SYS_EBC_PB0AP		0x03017200