[U-Boot] [PATCH v2 3/4] macb: support DMA bus widths > 32 bits

[Dave Aldridge]

Some GEM implementations may support DMA bus widths up to 128 bits.
We can get the maximum supported DMA bus width from the design
configuration register so use that to program the device up.

Signed-off-by: Dave Aldridge <fovsoft at gmail.com>
---
 drivers/net/macb.c |   25 +++++++++++++++++++++++++
 drivers/net/macb.h |   18 ++++++++++++++++++
 2 files changed, 43 insertions(+), 0 deletions(-)

diff --git a/drivers/net/macb.c b/drivers/net/macb.c
index 07d1ba8..36f0a0f 100644
--- a/drivers/net/macb.c
+++ b/drivers/net/macb.c
@@ -574,6 +574,27 @@ static u32 macb_mdc_clk_div(struct macb_device *macb, int id)
 	return ncfgr;
 }
 
+/*
+ * Get the DMA bus width field of the network configuration register that we
+ * should program.  We find the width from decoding the design configuration
+ * register to find the maximum supported data bus width.
+ */
+static u32 macb_dbw(struct macb_device *macb)
+{
+	if (!macb->is_gem)
+		return 0;
+
+	switch (GEM_BFEXT(DBWDEF, gem_readl(macb, DCFG1))) {
+	case 4:
+		return GEM_BF(DBW, GEM_DBW128);
+	case 2:
+		return GEM_BF(DBW, GEM_DBW64);
+	case 1:
+	default:
+		return GEM_BF(DBW, GEM_DBW32);
+	}
+}
+
 int macb_eth_initialize(int id, void *regs, unsigned int phy_addr)
 {
 	struct macb_device *macb;
@@ -614,6 +635,10 @@ int macb_eth_initialize(int id, void *regs, unsigned int phy_addr)
 
 	/* Set MII management clock divider */
 	ncfgr = macb_mdc_clk_div(macb, id);
+
+	/* Set up the DMA bus width */
+	ncfgr |= macb_dbw(macb);
+
 	macb_writel(macb, NCFGR, ncfgr);
 
 	eth_register(netdev);
diff --git a/drivers/net/macb.h b/drivers/net/macb.h
index b08a057..c0759cf 100644
--- a/drivers/net/macb.h
+++ b/drivers/net/macb.h
@@ -80,6 +80,13 @@
 #define GEM_HRT					0x0084
 #define GEM_SA1B				0x0088
 #define GEM_SA1T				0x008C
+#define GEM_DCFG1				0x0280
+#define GEM_DCFG2				0x0284
+#define GEM_DCFG3				0x0288
+#define GEM_DCFG4				0x028c
+#define GEM_DCFG5				0x0290
+#define GEM_DCFG6				0x0294
+#define GEM_DCFG7				0x0298
 
 /* Bitfields in NCR */
 #define MACB_LB_OFFSET				0
@@ -150,6 +157,13 @@
 /* GEM specific NCFGR bitfields. */
 #define GEM_CLK_OFFSET				18
 #define GEM_CLK_SIZE				3
+#define GEM_DBW_OFFSET				21
+#define GEM_DBW_SIZE				2
+
+/* Constants for data bus width. */
+#define GEM_DBW32				0
+#define GEM_DBW64				1
+#define GEM_DBW128				2
 
 /* Bitfields in NSR */
 #define MACB_NSR_LINK_OFFSET			0
@@ -259,6 +273,10 @@
 #define MACB_REV_OFFSET				0
 #define MACB_REV_SIZE				16
 
+/* Bitfields in DCFG1. */
+#define GEM_DBWDEF_OFFSET			25
+#define GEM_DBWDEF_SIZE				3
+
 /* Constants for CLK */
 #define MACB_CLK_DIV8				0
 #define MACB_CLK_DIV16				1
-- 
1.7.3.4