-----Original Message-----
From: Ben Hutchings [mailto:bhutchings@solarflare.com]
Sent: Friday, May 27, 2011 1:56 AM
To: GuanXuetao
Cc: arnd@arndb.de; linux-kernel@vger.kernel.org; linux-arch@vger.kernel.org; greg@kroah.com; netdev@vger.kernel.org
Subject: Re: [PATCH 2/6] unicore32: add pkunity-v3 mac/net driver (umal)

On Thu, 2011-05-26 at 11:36 +0000, GuanXuetao wrote:
[...]

quoted

--- /dev/null
+++ b/drivers/net/mac-puv3.c

[...]

quoted

+/**********************************************************************
+ *  Simple types
+ ********************************************************************* */
+enum umal_speed {
+	umal_speed_none = 0,
+	umal_speed_10 = SPEED_10,
+	umal_speed_100 = SPEED_100,
+	umal_speed_1000 = SPEED_1000,
+};

Just use the numbers directly: 0, 10, 100, 1000.

Applied.

[...]

quoted

+#define ETHER_ADDR_LEN		6

This is already called ETH_ALEN.

Applied.

[...]

quoted

+/**********************************************************************
+ *  DMA Descriptor structure
+ ********************************************************************* */
+struct umaldmadscr {
+	dma_addr_t   PacketStartAddr;
+	int          PacketSize;
+	dma_addr_t   NextDescriptor;
+	struct umaldmadscr *NextDescriptor_Virt;
+};

Linux naming convention for structure fields is words_with_underscores
not TitleCase.

Ok, thanks.

[...]

quoted

+/**********************************************************************
+ *  UMAL_MII_RESET(bus)
+ *
+ *  Reset MII bus.
+ *
+ *  Input parameters:
+ *	   bus     - MDIO bus handle
+ *
+ *  Return value:
+ *	   0 if ok
+ ********************************************************************* */

Function documentation comments must follow the kernel-doc format.

Ok, thanks.

[...]

quoted

+static int umaldma_add_rcvbuffer(struct umal_softc *sc, struct umaldma *d,
+		struct sk_buff *sb)
+{

[...]

quoted

+	/*
+	 * Allocate a sk_buff if we don't already have one.
+	 * If we do have an sk_buff, reset it so that it's empty.
+	 *
+	 * Note: sk_buffs don't seem to be guaranteed to have any sort
+	 * of alignment when they are allocated.  Therefore, allocate enough
+	 * extra space to make sure that:
+	 *
+	 *    1. the data does not start in the middle of a cache line.
+	 *    2. The data does not end in the middle of a cache line
+	 *    3. The buffer can be aligned such that the IP addresses are
+	 *       naturally aligned.
+	 *
+	 *  Remember, the SOCs MAC writes whole cache lines at a time,
+	 *  without reading the old contents first.  So, if the sk_buff's
+	 *  data portion starts in the middle of a cache line, the SOC
+	 *  DMA will trash the beginning (and ending) portions.
+	 */
+	if (sb == NULL) {
+		sb_new = netdev_alloc_skb(dev, ENET_PACKET_SIZE +
+		       SMP_CACHE_BYTES * 2 + NET_IP_ALIGN);
+		if (sb_new == NULL) {
+			pr_info("%s: sk_buff allocation failed\n",
+			       d->umaldma_eth->umal_dev->name);
+			return -ENOBUFS;

Surely -ENOMEM.

Applied.

quoted

+		}
+		skb_reserve(sb_new, 2);

This presumably needs to be:

		skb_reserve(sb_new, SMP_CACHE_BYTES + NET_IP_ALIGN);

unless you assume that the skb allocator will always ensure cache line
alignment (in which case, why use padding of SMP_CACHE_BYTES * 2?).

Applied, thanks.
Each packet address needs to be added by NET_IP_ALIGN.
And I think that SMP_CACHE_BYTES is also necessary to guarantee correctness
when invalidate dma cache lines.

[...]

quoted

+static void umaldma_tx_process(struct umal_softc *sc, struct umaldma *d,
+		int poll)
+{
+	struct net_device *dev = sc->umal_dev;
+	int curidx;
+	int hwidx;
+	struct umaldmadscr *dsc;
+	struct sk_buff *sb;
+	unsigned long flags;
+	int packets_handled = 0;
+	unsigned int int_status;
+
+	spin_lock_irqsave(&(sc->umal_lock), flags);
+
+	if (!netif_device_present(dev))
+		return;

[...]

This returns with the lock held!

Applied, thanks.

(This is not by any means a thorough review.)

Ben.

--
Ben Hutchings, Senior Software Engineer, Solarflare
Not speaking for my employer; that's the marketing department's job.
They asked us to note that Solarflare product names are trademarked.

Thanks Ben.
I will submit next version after correcting the coding-style.

Guan Xuetao