Re: [PATCH try#2] Blackfin ethernet driver: on chip ethernet MAC controller driver

Bryan Wu wrote:

On Sun, 2007-07-15 at 14:17 +0200, Michael Buesch wrote:

quoted

On Sunday 15 July 2007 14:07:44 Bryan Wu wrote:

quoted

@@ -483,9 +487,12 @@
 
 void setup_mac_addr(u8 * mac_addr)
 {
+	u32 addr_low = le32_to_cpu(*(u32 *) & mac_addr[0]);
+	u16 addr_hi = le16_to_cpu(*(u16 *) & mac_addr[4]);
+
 	/* this depends on a little-endian machine */
-	bfin_write_EMAC_ADDRLO(*(u32 *) & mac_addr[0]);
-	bfin_write_EMAC_ADDRHI(*(u16 *) & mac_addr[4]);
+	bfin_write_EMAC_ADDRLO(addr_low);
+	bfin_write_EMAC_ADDRHI(addr_hi);
 }
 
 static void adjust_tx_list(void)

@@ -866,10 +873,10 @@
 	int retval;
 
 	/* Grab the MAC address in the MAC */
-	*(u32 *) (&(dev->dev_addr[0])) = bfin_read_EMAC_ADDRLO();
-	*(u16 *) (&(dev->dev_addr[4])) = (u16) bfin_read_EMAC_ADDRHI();
+	*(u32 *) (&(dev->dev_addr[0])) = cpu_to_le32(bfin_read_EMAC_ADDRLO());
+	*(u16 *) (&(dev->dev_addr[4])) = cpu_to_le16((u16) bfin_read_EMAC_ADDRHI());

Try something like this:

@@ -483,9 +487,12 @@
 
 void setup_mac_addr(u8 * mac_addr)
 {
+       u32 addr_low = le32_to_cpu(*(__le32 *) & mac_addr[0]);
+       u16 addr_hi = le16_to_cpu(*(__le16 *) & mac_addr[4]);
+
-       /* this depends on a little-endian machine */
-       bfin_write_EMAC_ADDRLO(*(u32 *) & mac_addr[0]);
-       bfin_write_EMAC_ADDRHI(*(u16 *) & mac_addr[4]);
+       bfin_write_EMAC_ADDRLO(addr_low);
+       bfin_write_EMAC_ADDRHI(addr_hi);
 }
 
 static void adjust_tx_list(void)

@@ -866,10 +873,10 @@
        int retval;
 
        /* Grab the MAC address in the MAC */
-       *(u32 *) (&(dev->dev_addr[0])) = bfin_read_EMAC_ADDRLO();
-       *(u16 *) (&(dev->dev_addr[4])) = (u16) bfin_read_EMAC_ADDRHI();
+       *(__le32 *) (&(dev->dev_addr[0])) = cpu_to_le32(bfin_read_EMAC_ADDRLO());
+       *(__le16 *) (&(dev->dev_addr[4])) = cpu_to_le16((u16) bfin_read_EMAC_ADDRHI());

Thanks a lot, Michael. 

I got a generic question about this endianess check. When should use it
in a driver or something else? I grep it in the driver/net/

---
drivers/net/e100.c:             ns->tx_window_errors += le32_to_cpu(s->tx_late_collisions);
drivers/net/e100.c:             ns->tx_carrier_errors += le32_to_cpu(s->tx_lost_crs);
drivers/net/e100.c:             ns->tx_fifo_errors += le32_to_cpu(s->tx_underruns);
drivers/net/e100.c:             ns->tx_errors += le32_to_cpu(s->tx_max_collisions) +
drivers/net/e100.c:                     le32_to_cpu(s->tx_lost_crs);
drivers/net/e100.c:             ns->rx_length_errors += le32_to_cpu(s->rx_short_frame_errors) +
drivers/net/e100.c:             ns->rx_crc_errors += le32_to_cpu(s->rx_crc_errors);
drivers/net/e100.c:             ns->rx_frame_errors += le32_to_cpu(s->rx_alignment_errors);
drivers/net/e100.c:             ns->rx_over_errors += le32_to_cpu(s->rx_overrun_errors);
drivers/net/e100.c:             ns->rx_fifo_errors += le32_to_cpu(s->rx_overrun_errors);
drivers/net/e100.c:             ns->rx_missed_errors += le32_to_cpu(s->rx_resource_errors);
drivers/net/e100.c:             ns->rx_errors += le32_to_cpu(s->rx_crc_errors) +
drivers/net/e100.c:                     le32_to_cpu(s->rx_alignment_errors) +
drivers/net/e100.c:                     le32_to_cpu(s->rx_short_frame_errors) +
drivers/net/e100.c:                     le32_to_cpu(s->rx_cdt_errors);
drivers/net/e100.c:             nic->tx_deferred += le32_to_cpu(s->tx_deferred);
drivers/net/e100.c:                     le32_to_cpu(s->tx_single_collisions);
drivers/net/e100.c:                     le32_to_cpu(s->tx_multiple_collisions);
drivers/net/e100.c:                     nic->tx_fc_pause += le32_to_cpu(s->fc_xmt_pause);
drivers/net/e100.c:                     nic->rx_fc_pause += le32_to_cpu(s->fc_rcv_pause);
drivers/net/e100.c:                             le32_to_cpu(s->fc_rcv_unsupported);
drivers/net/e100.c:                             le32_to_cpu(cb->u.tcb.tbd.buf_addr),
drivers/net/e100.c:                                     le32_to_cpu(cb->u.tcb.tbd.buf_addr),
---

Normally, it is used to protect some rx/tx status flags or dma buf addr.

Any guide line for this leXX_to_cpu usage?

It has to be used when accessing any data structure stored in RAM that 
the device will access and where byte order is significant. cpu_to_le32 
when writing to the RAM, le32_to_cpu when reading it. (or le16, etc. if 
needed).

-- 
Robert Hancock      Saskatoon, SK, Canada
To email, remove "nospam" from hancockr@nospamshaw.ca
Home Page: http://www.roberthancock.com/