ARM: brcmstb: Add earlyprintk support using run-time checks
The SUN_TOP_CTRL_FAMILY_ID register is at a fixed absolute address for
all of our supported chips, so utilize its value to determine what the
UARTA base address should be based on the value we read.
Since the code is called both during decompressor when the MMU is off,
and after the MMU has been turned on in the kernel, and we want to do
the lookup only once, we use the same technique as tegra.S and have a
shared storage location between the decompressor and the kernel.
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
diff --git a/arch/arm/include/debug/brcmstb.S b/arch/arm/include/debug/brcmstb.S
new file mode 100644
index 0000000..9113d7b
--- /dev/null
+++ b/arch/arm/include/debug/brcmstb.S
@@ -0,0 +1,145 @@
+/*
+ * Copyright (C) 2016 Broadcom
+ *
+ * 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 version 2.
+ *
+ * This program is distributed "as is" WITHOUT ANY WARRANTY of any
+ * kind, whether express or implied; without even the implied warranty
+ * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ */
+#include <linux/serial_reg.h>
+
+/* Physical register offset and virtual register offset */
+#define REG_PHYS_BASE 0xf0000000
+#define REG_VIRT_BASE 0xfc000000
+#define REG_PHYS_ADDR(x) ((x) + REG_PHYS_BASE)
+
+/* Product id can be read from here */
+#define SUN_TOP_CTRL_BASE REG_PHYS_ADDR(0x404000)
+
+#define UARTA_3390 REG_PHYS_ADDR(0x40a900)
+#define UARTA_7250 REG_PHYS_ADDR(0x40b400)
+#define UARTA_7268 REG_PHYS_ADDR(0x40c000)
+#define UARTA_7271 UARTA_7268
+#define UARTA_7364 REG_PHYS_ADDR(0x40b000)
+#define UARTA_7366 UARTA_7364
+#define UARTA_74371 REG_PHYS_ADDR(0x406b00)
+#define UARTA_7439 REG_PHYS_ADDR(0x40a900)
+#define UARTA_7445 REG_PHYS_ADDR(0x40ab00)
+
+#define UART_SHIFT 2
+
+#define checkuart(rp, rv, family_id, family) \
+ /* Load family id */ \
+ ldr rp, =family_id ; \
+ /* Compare SUN_TOP_CTRL value against it */ \
+ cmp rp, rv ; \
+ /* Passed test, load address */ \
+ ldreq rp, =UARTA_##family ; \
+ /* Jump to save UART address */ \
+ beq 91f
+
+ .macro addruart, rp, rv, tmp
+ adr \rp, 99f @ actual addr of 99f
+ ldr \rv, [\rp] @ linked addr is stored there
+ sub \rv, \rv, \rp @ offset between the two
+ ldr \rp, [\rp, #4] @ linked brcmstb_uart_config
+ sub \tmp, \rp, \rv @ actual brcmstb_uart_config
+ ldr \rp, [\tmp] @ Load brcmstb_uart_config
+ cmp \rp, #1 @ needs initialization?
+ bne 100f @ no; go load the addresses
+ mov \rv, #0 @ yes; record init is done
+ str \rv, [\tmp]
+
+ /* Check SUN_TOP_CTRL base */
+ ldr \rp, =SUN_TOP_CTRL_BASE @ load SUN_TOP_CTRL PA
+ ldr \rv, [\rp, #0] @ get register contents
+ and \rv, \rv, #0xffffff00 @ strip revision bits [7:0]
+
+ /* Chip specific detection starts here */
+20: checkuart(\rp, \rv, 0x33900000, 3390)
+21: checkuart(\rp, \rv, 0x72500000, 7250)
+22: checkuart(\rp, \rv, 0x72680000, 7268)
+23: checkuart(\rp, \rv, 0x72710000, 7271)
+24: checkuart(\rp, \rv, 0x73640000, 7364)
+25: checkuart(\rp, \rv, 0x73660000, 7366)
+26: checkuart(\rp, \rv, 0x07437100, 74371)
+27: checkuart(\rp, \rv, 0x74390000, 7439)
+28: checkuart(\rp, \rv, 0x74450000, 7445)
+
+ /* No valid UART found */
+90: mov \rp, #0
+ /* fall through */
+
+ /* Record whichever UART we chose */
+91: str \rp, [\tmp, #4] @ Store in brcmstb_uart_phys
+ cmp \rp, #0 @ Valid UART address?
+ bne 92f @ Yes, go process it
+ str \rp, [\tmp, #8] @ Store 0 in brcmstb_uart_virt
+ b 100f @ Done
+92: and \rv, \rp, #0xffffff @ offset within 16MB section
+ add \rv, \rv, #REG_VIRT_BASE
+ str \rv, [\tmp, #8] @ Store in brcmstb_uart_virt
+ b 100f
+
+ .align
+99: .word .
+ .word brcmstb_uart_config
+ .ltorg
+
+ /* Load previously selected UART address */
+100: ldr \rp, [\tmp, #4] @ Load brcmstb_uart_phys
+ ldr \rv, [\tmp, #8] @ Load brcmstb_uart_virt
+ .endm
+
+ .macro store, rd, rx:vararg
+ str \rd, \rx
+ .endm
+
+ .macro load, rd, rx:vararg
+ ldr \rd, \rx
+ .endm
+
+ .macro senduart,rd,rx
+ store \rd, [\rx, #UART_TX << UART_SHIFT]
+ .endm
+
+ .macro busyuart,rd,rx
+1002: load \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
+ .endm
+
+/*
+ * Storage for the state maintained by the macros above.
+ *
+ * In the kernel proper, this data is located in arch/arm/mach-bcm/brcmstb.c.
+ * That's because this header is included from multiple files, and we only
+ * want a single copy of the data. In particular, the UART probing code above
+ * assumes it's running using physical addresses. This is true when this file
+ * is included from head.o, but not when included from debug.o. So we need
+ * to share the probe results between the two copies, rather than having
+ * to re-run the probing again later.
+ *
+ * In the decompressor, we put the symbol/storage right here, since common.c
+ * isn't included in the decompressor build. This symbol gets put in .text
+ * even though it's really data, since .data is discarded from the
+ * decompressor. Luckily, .text is writeable in the decompressor, unless
+ * CONFIG_ZBOOT_ROM. That dependency is handled in arch/arm/Kconfig.debug.
+ */
+#if defined(ZIMAGE)
+brcmstb_uart_config:
+ /* Debug UART initialization required */
+ .word 1
+ /* Debug UART physical address */
+ .word 0
+ /* Debug UART virtual address */
+ .word 0
+#endif