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From 1cacd0f7b0d35f8e3d3f8a69ecb3b5e436d6b9e8 Mon Sep 17 00:00:00 2001
From: Jonas Gorski <jogo@openwrt.org>
Date: Sun, 22 Dec 2013 13:25:25 +0100
Subject: [PATCH 52/56] MIPS: BCM63XX: fixup mapped SPI flash access on boot

Some bootloaders leave the flash access in an invalid state with dual
read enabled; fix it by disabling it and falling back to simple fast
reads.

Signed-off-by: Jonas Gorski <jogo@openwrt.org>
---
 arch/mips/bcm63xx/dev-flash.c | 51 ++++++++++++++++++++++++++++++++++++
 1 file changed, 51 insertions(+)

--- a/arch/mips/bcm63xx/dev-flash.c
+++ b/arch/mips/bcm63xx/dev-flash.c
@@ -16,6 +16,7 @@
 #include <linux/mtd/mtd.h>
 #include <linux/mtd/partitions.h>
 #include <linux/mtd/physmap.h>
+#include <linux/mtd/spi-nor.h>
 
 #include <bcm63xx_cpu.h>
 #include <bcm63xx_dev_flash.h>
@@ -110,9 +111,59 @@ static int __init bcm63xx_detect_flash_t
        }
 }
 
+#define HSSPI_FLASH_CTRL_REG           0x14
+#define FLASH_CTRL_READ_OPCODE_MASK    0xff
+#define FLASH_CTRL_ADDR_BYTES_MASK     (0x3 << 8)
+#define FLASH_CTRL_ADDR_BYTES_2                (0 << 8)
+#define FLASH_CTRL_ADDR_BYTES_3                (1 << 8)
+#define FLASH_CTRL_ADDR_BYTES_4                (2 << 8)
+#define FLASH_CTRL_DUMMY_BYTES_SHIFT   10
+#define FLASH_CTRL_DUMMY_BYTES_MASK    (0x3 << FLASH_CTRL_DUMMY_BYTES_SHIFT)
+#define FLASH_CTRL_MB_EN               (1 << 23)
+
 void __init bcm63xx_flash_detect(void)
 {
        flash_type = bcm63xx_detect_flash_type();
+
+       /* ensure flash mapping has sane values */
+       if (flash_type == BCM63XX_FLASH_TYPE_SERIAL &&
+           (BCMCPU_IS_6318() || BCMCPU_IS_6328() || BCMCPU_IS_6362() ||
+            BCMCPU_IS_63268())) {
+               u32 val = bcm_rset_readl(RSET_HSSPI, HSSPI_FLASH_CTRL_REG);
+
+               if (val & FLASH_CTRL_MB_EN) {
+                       /* cfe might configure non working dual-io mode */
+                       val &= ~FLASH_CTRL_MB_EN;
+                       val &= ~FLASH_CTRL_READ_OPCODE_MASK;
+                       val &= ~FLASH_CTRL_DUMMY_BYTES_MASK;
+                       val |= 1 << FLASH_CTRL_DUMMY_BYTES_SHIFT;
+
+                       switch (val & FLASH_CTRL_ADDR_BYTES_MASK) {
+                       case FLASH_CTRL_ADDR_BYTES_3:
+                               val |= SPINOR_OP_READ_FAST;
+                               break;
+                       case FLASH_CTRL_ADDR_BYTES_4:
+                               val |= SPINOR_OP_READ_FAST_4B;
+                               break;
+                       case FLASH_CTRL_ADDR_BYTES_2:
+                       default:
+                               pr_warn("unsupported address byte mode (%x), not fixing up\n",
+                                       val & FLASH_CTRL_ADDR_BYTES_MASK);
+                               return;
+                       }
+               } else {
+                       /* ensure dummy bytes is set to 1 for _FAST reads */
+                       u8 cmd = val & FLASH_CTRL_READ_OPCODE_MASK;
+
+                       if (cmd != SPINOR_OP_READ_FAST && cmd != SPINOR_OP_READ_FAST_4B)
+                               return;
+
+                       val &= ~FLASH_CTRL_DUMMY_BYTES_MASK;
+                       val |= 1 << FLASH_CTRL_DUMMY_BYTES_SHIFT;
+               }
+
+               bcm_rset_writel(RSET_HSSPI, val, HSSPI_FLASH_CTRL_REG);
+       }
 }
 
 int __init bcm63xx_flash_register(void)