[U-Boot] [PATCH V2] ppc4xx: Initialize magnetic couplers in PLU405

[Matthias Fuchs]

This patch fixes an ugly behavior of the IL712 magnetic couplers
as used on PLU405. These parts will remember their last state
over a power cycle which might cause unwanted behavior.

Signed-off-by: Matthias Fuchs <matthias.fuchs at esd.eu>
---
V2 changes: 
 - use C struct to access CAN controller registes

 board/esd/plu405/plu405.c |   56 +++++++++++++++++++++++++++++++++++++++++++++
 include/configs/PLU405.h  |    3 +-
 2 files changed, 58 insertions(+), 1 deletions(-)

diff --git a/board/esd/plu405/plu405.c b/board/esd/plu405/plu405.c
index 1841cda..7fd24c1 100644
--- a/board/esd/plu405/plu405.c
+++ b/board/esd/plu405/plu405.c
@@ -45,6 +45,55 @@ const unsigned char fpgadata[] =
  */
 #include "../common/fpga.c"
 
+/*
+ * SJA1000 register layout in basic can mode
+ */
+struct sja1000_basic_s {
+	u8 cr;
+	u8 cmr;
+	u8 sr;
+	u8 ir;
+	u8 ac;
+	u8 am;
+	u8 btr0;
+	u8 btr1;
+	u8 oc;
+	u8 txb[10];
+	u8 rxb[10];
+	u8 unused;
+	u8 cdr;
+};
+
+#define SJA1000_CR_RR 0x01
+#define SJA1000_OC_MODE0 0x01
+
+/*
+ * generate a short spike on the CAN tx line
+ * to bring the couplers in sync
+ */
+void init_coupler(u32 addr)
+{
+	struct sja1000_basic_s *ctrl = (struct sja1000_basic_s *)addr;
+
+	/* reset */
+	out_8(&ctrl->cr, 0x20 | SJA1000_CR_RR);
+
+	/* dominant */
+	out_8(&ctrl->btr0, 0x00); /* btr setup is required */
+	out_8(&ctrl->btr1, 0x14); /* we use 1Mbit/s */
+	out_8(&ctrl->oc, ~SJA1000_OC_MODE0);
+	out_8(&ctrl->cr, 0x20);
+
+	/* delay */
+	in_8(&ctrl->cr);
+	in_8(&ctrl->cr);
+	in_8(&ctrl->cr);
+	in_8(&ctrl->cr);
+
+	/* reset */
+	out_8(&ctrl->cr, 0x20 | SJA1000_CR_RR);
+}
+
 /* Prototypes */
 int gunzip(void *, int, unsigned char *, unsigned long *);
 
@@ -198,6 +247,13 @@ int misc_init_r(void)
 	out_8((void *)DUART1_BA + 1, fctr); /* write FCTR */
 	out_8((void *)DUART1_BA + 3, 0);    /* write LCR */
 
+	/*
+	 * Init magnetic couplers
+	 */
+	if (!getenv("noinitcoupler")) {
+		init_coupler(CAN0_BA);
+		init_coupler(CAN1_BA);
+	}
 	return 0;
 }
 
diff --git a/include/configs/PLU405.h b/include/configs/PLU405.h
index 07fc715..b6740de 100644
--- a/include/configs/PLU405.h
+++ b/include/configs/PLU405.h
@@ -298,7 +298,8 @@
 /*
  * External Bus Controller (EBC) Setup
  */
-#define CAN_BA		0xF0000000	    /* CAN Base Address	        */
+#define CAN0_BA		0xF0000000	    /* CAN0 Base Address	*/
+#define CAN1_BA		0xF0000100	    /* CAN1 Base Address	*/
 #define DUART0_BA	0xF0000400	    /* DUART Base Address       */
 #define DUART1_BA	0xF0000408	    /* DUART Base Address       */
 #define RTC_BA		0xF0000500	    /* RTC Base Address         */
-- 
1.6.1