Subject: [PATCH 1/5] net: Add davicom wemac ethernet driver found on Allwinner A10 SoC's

From: [email-masked] (Florian Fainelli)
Date: Sat, 16 Mar 2013 15:41:36 +0100

Hello Maxime, Stefan,

Please find below some comments regarding your PHY implementation in the driver 
as well as the transmit and transmit completion routines.

Le vendredi 15 mars 2013 21:50:00, Maxime Ripard a ?crit :
> From: Stefan Roese <[email-masked]>
> 
> The Allwinner A10 has an ethernet controller that is advertised as
> coming from Davicom.
> 
> The exact feature set of this controller is unknown, since there is no
> public documentation for this IP, and this driver is mostly the one
> published by Allwinner that has been heavily cleaned up.
> 
> Signed-off-by: Stefan Roese <[email-masked]>
> Signed-off-by: Maxime Ripard <[email-masked]>

[snip]

> +
> +wemac: ethernet at 01c0b000 {
> +       compatible = "davicom,wemac";
> +       reg = <0x01c0b000 0x1000>;
> +       interrupts = <55>;
> +       allwinner,power-gpios = <&pio 7 19 0>;
> +};

You do not define any handle for the PHY chip, but I think you should make this 
configurable and use the standard Device Tree helpers for finding and connecting 
a PHY driver to your EMAC adapter driver.
[snip]

> +#define WEMAC_PHY		0x100	/* PHY address 0x01 */

This should be made configurable if possible.

[snip]

> + */
> +
> +struct wemac_board_info {
> +	struct clk		*clk;
> +	struct device		*dev;
> +	spinlock_t		lock;
> +	void __iomem		*membase;
> +	struct mii_if_info	mii;
> +	u32			msg_enable;
> +	struct net_device	*ndev;
> +	struct mutex		phy_lock;
> +	struct delayed_work	phy_poll;

Consider using phylib which should allow you to remove struct mii_if_info and 
the mutex and poll delayed workqueue.

> +	unsigned		power_gpio;

you could make this an int, so that you use gpio_is_valid() on this one.

> +	struct sk_buff		*skb_last;
> +	u16			tx_fifo_stat;
> +};
> +
> +static inline struct wemac_board_info *to_wemac_board(struct net_device
> *dev) +{
> +	return netdev_priv(dev);
> +}
> +
> +static int wemac_phy_read(struct net_device *dev, int phyaddr, int reg)
> +{
> +	struct wemac_board_info *db = netdev_priv(dev);
> +	unsigned long flags;
> +	int ret;
> +
> +	mutex_lock(&db->phy_lock);
> +
> +	spin_lock_irqsave(&db->lock, flags);
> +	/* issue the phy address and reg */
> +	writel(phyaddr | reg, db->membase + EMAC_MAC_MADR_REG);
> +	/* pull up the phy io line */
> +	writel(0x1, db->membase + EMAC_MAC_MCMD_REG);
> +	spin_unlock_irqrestore(&db->lock, flags);
> +
> +	/* Wait read complete */
> +	mdelay(1);
> +
> +	/* push down the phy io line and read data */
> +	spin_lock_irqsave(&db->lock, flags);
> +	/* push down the phy io line */
> +	writel(0x0, db->membase + EMAC_MAC_MCMD_REG);
> +	/* and read data */
> +	ret = readl(db->membase + EMAC_MAC_MRDD_REG);
> +	spin_unlock_irqrestore(&db->lock, flags);
> +
> +	mutex_unlock(&db->phy_lock);

This sounds pretty complicated as a locking scheme, using phylib should make 
this simpler anyway.

> +
> +	return ret;
> +}
> +
> +/* Write a word to phyxcer */
> +static void wemac_phy_write(struct net_device *dev,
> +			    int phyaddr, int reg, int value)
> +{
> +	struct wemac_board_info *db = netdev_priv(dev);
> +	unsigned long flags;
> +
> +	mutex_lock(&db->phy_lock);
> +
> +	spin_lock_irqsave(&db->lock, flags);
> +	/* issue the phy address and reg */
> +	writel(phyaddr | reg, db->membase + EMAC_MAC_MADR_REG);
> +	/* pull up the phy io line */
> +	writel(0x1, db->membase + EMAC_MAC_MCMD_REG);
> +	spin_unlock_irqrestore(&db->lock, flags);
> +
> +	/* Wait write complete */
> +	mdelay(1);
> +
> +	spin_lock_irqsave(&db->lock, flags);
> +	/* push down the phy io line */
> +	writel(0x0, db->membase + EMAC_MAC_MCMD_REG);
> +	/* and write data */
> +	writel(value, db->membase + EMAC_MAC_MWTD_REG);
> +	spin_unlock_irqrestore(&db->lock, flags);
> +
> +	mutex_unlock(&db->phy_lock);

Ditto

> +}
> +
> +static int emacrx_completed_flag = 1;

This should be moved to your interface specific private structure, as it won't 
work when there are two instances of the same driver.

[snip]

> +
> +static void wemac_dumpblk_32bit(void __iomem *reg, int count)
> +{
> +	int i;
> +	int tmp;
> +
> +	for (i = 0; i < (round_up(count, 4) / 4); i++)
> +		tmp = readl(reg);
> +}

This could probably be removed, tmp is a write only location, did you remove 
the variable printing that came along this?

> +
> +static void wemac_schedule_poll(struct wemac_board_info *db)
> +{
> +	schedule_delayed_work(&db->phy_poll, HZ * 2);
> +}

phylib takes care of the polling for you.

> +
> +static int wemac_ioctl(struct net_device *dev, struct ifreq *req, int cmd)
> +{
> +	struct wemac_board_info *dm = to_wemac_board(dev);
> +
> +	if (!netif_running(dev))
> +		return -EINVAL;
> +
> +	return generic_mii_ioctl(&dm->mii, if_mii(req), cmd, NULL);
> +}
> +
> +/* ethtool ops */
> +static void wemac_get_drvinfo(struct net_device *dev,
> +			      struct ethtool_drvinfo *info)
> +{
> +	strcpy(info->driver, DRV_NAME);
> +	strcpy(info->version, DRV_VERSION);

You should use strlcpy() here to ensure null-termination, and you should also 
fill in the bus_info member of struct ethtool_drvinfo.

> +}
> +

[snip]

> +unsigned int phy_link_check(struct net_device *dev)
> +{
> +	unsigned int reg_val;
> +
> +	reg_val = wemac_phy_read(dev, WEMAC_PHY, 1);
> +
> +	if (reg_val & 0x4) {
> +		netdev_info(dev, "EMAC PHY Linked...\n");
> +		return 1;
> +	} else {
> +		netdev_info(dev, "EMAC PHY Link waiting......\n");
> +		return 0;
> +	}
> +}

Please remove this and migrate to phylib.

> +
> +unsigned int emac_setup(struct net_device *ndev)
> +{
> +	unsigned int reg_val;
> +	unsigned int phy_val;
> +	unsigned int duplex_flag;
> +	struct wemac_board_info *db = netdev_priv(ndev);
> +
> +	/* set up TX */
> +	reg_val = readl(db->membase + EMAC_TX_MODE_REG);
> +
> +	writel(reg_val | EMAC_TX_MODE_ABORTED_FRAME_EN,
> +		db->membase + EMAC_TX_MODE_REG);
> +
> +	/* set up RX */
> +	reg_val = readl(db->membase + EMAC_RX_CTL_REG);
> +
> +	writel(reg_val | EMAC_RX_CTL_PASS_LEN_OOR_EN |
> +		EMAC_RX_CTL_ACCEPT_UNICAST_EN | EMAC_RX_CTL_DA_FILTER_EN |
> +		EMAC_RX_CTL_ACCEPT_MULTICAST_EN |
> +		EMAC_RX_CTL_ACCEPT_BROADCAST_EN,
> +		db->membase + EMAC_RX_CTL_REG);
> +
> +	/* set MAC */
> +	/* set MAC CTL0 */
> +	reg_val = readl(db->membase + EMAC_MAC_CTL0_REG);
> +	writel(reg_val | EMAC_MAC_CTL0_RX_FLOW_CTL_EN |
> +		EMAC_MAC_CTL0_TX_FLOW_CTL_EN,
> +		db->membase + EMAC_MAC_CTL0_REG);
> +
> +	/* set MAC CTL1 */
> +	reg_val = readl(db->membase + EMAC_MAC_CTL1_REG);
> +	phy_val = wemac_phy_read(ndev, WEMAC_PHY, 0);
> +	dev_dbg(db->dev, "PHY SETUP, reg 0 value: %x\n", phy_val);
> +	duplex_flag = !!(phy_val & EMAC_PHY_DUPLEX);
> +
> +	if (duplex_flag)
> +		reg_val |= EMAC_MAC_CTL1_DUPLEX_EN;
> +
> +	reg_val |= EMAC_MAC_CTL1_LEN_CHECK_EN;
> +	reg_val |= EMAC_MAC_CTL1_CRC_EN;
> +	reg_val |= EMAC_MAC_CTL1_PAD_EN;
> +	writel(reg_val, db->membase + EMAC_MAC_CTL1_REG);
> +
> +	/* set up IPGT */
> +	writel(EMAC_MAC_IPGT_FULL_DUPLEX, db->membase + EMAC_MAC_IPGT_REG);
> +
> +	/* set up IPGR */
> +	writel((EMAC_MAC_IPGR_IPG1 << 8) | EMAC_MAC_IPGR_IPG2,
> +		db->membase + EMAC_MAC_IPGR_REG);
> +
> +	/* set up Collison window */
> +	writel((EMAC_MAC_CLRT_COLLISION_WINDOW << 8) | EMAC_MAC_CLRT_RM,
> +		db->membase + EMAC_MAC_CLRT_REG);
> +
> +	/* set up Max Frame Length */
> +	writel(WEMAC_MAX_FRAME_LEN,
> +		db->membase + EMAC_MAC_MAXF_REG);
> +
> +	return 0;
> +}
> +
> +unsigned int wemac_powerup(struct net_device *ndev)
> +{
> +	struct wemac_board_info *db = netdev_priv(ndev);
> +	unsigned int reg_val;
> +
> +	/* initial EMAC */
> +	/* flush RX FIFO */
> +	reg_val = readl(db->membase + EMAC_RX_CTL_REG);
> +	reg_val |= 0x8;
> +	writel(reg_val, db->membase + EMAC_RX_CTL_REG);
> +	udelay(1);
> +
> +	/* initial MAC */
> +	/* soft reset MAC */
> +	reg_val = readl(db->membase + EMAC_MAC_CTL0_REG);
> +	reg_val &= ~EMAC_MAC_CTL0_SOFT_RESET;
> +	writel(reg_val, db->membase + EMAC_MAC_CTL0_REG);
> +
> +	/* set MII clock */
> +	reg_val = readl(db->membase + EMAC_MAC_MCFG_REG);
> +	reg_val &= (~(0xf << 2));
> +	reg_val |= (0xD << 2);
> +	writel(reg_val, db->membase + EMAC_MAC_MCFG_REG);
> +
> +	/* clear RX counter */
> +	writel(0x0, db->membase + EMAC_RX_FBC_REG);
> +
> +	/* disable all interrupt and clear interrupt status */
> +	writel(0, db->membase + EMAC_INT_CTL_REG);
> +	reg_val = readl(db->membase + EMAC_INT_STA_REG);
> +	writel(reg_val, db->membase + EMAC_INT_STA_REG);
> +
> +	udelay(1);
> +
> +	/* set up EMAC */
> +	emac_setup(ndev);
> +
> +	/* set mac_address to chip */
> +	writel(ndev->dev_addr[0] << 16 | ndev->dev_addr[1] << 8 | ndev->
> +	       dev_addr[2], db->membase + EMAC_MAC_A1_REG);
> +	writel(ndev->dev_addr[3] << 16 | ndev->dev_addr[4] << 8 | ndev->
> +	       dev_addr[5], db->membase + EMAC_MAC_A0_REG);
> +
> +	mdelay(1);
> +
> +	return 1;
> +}
> +
> +static void wemac_poll_work(struct work_struct *w)
> +{
> +	struct delayed_work *dw = container_of(w, struct delayed_work, work);
> +	struct wemac_board_info *db = container_of(dw,
> +						struct wemac_board_info,
> +						phy_poll);
> +	struct net_device *ndev = db->ndev;
> +
> +	mii_check_media(&db->mii, netif_msg_link(db), 0);
> +
> +	if (netif_running(ndev))
> +		wemac_schedule_poll(db);
> +}
> +
> +static int wemac_set_mac_address(struct net_device *dev, void *p)
> +{
> +	struct sockaddr *addr = p;
> +	struct wemac_board_info *db = netdev_priv(dev);
> +
> +	if (netif_running(dev))
> +		return -EBUSY;
> +
> +	memcpy(dev->dev_addr, addr->sa_data, ETH_ALEN);
> +
> +	writel(dev->dev_addr[0] << 16 | dev->dev_addr[1] << 8 | dev->
> +	       dev_addr[2], db->membase + EMAC_MAC_A1_REG);
> +	writel(dev->dev_addr[3] << 16 | dev->dev_addr[4] << 8 | dev->
> +	       dev_addr[5], db->membase + EMAC_MAC_A0_REG);
> +
> +	return 0;
> +}
> +
> +/* Initialize wemac board */
> +static void wemac_init_wemac(struct net_device *dev)
> +{
> +	struct wemac_board_info *db = netdev_priv(dev);
> +	unsigned int phy_reg;
> +	unsigned int reg_val;
> +
> +	if (gpio_is_valid(db->power_gpio))
> +		gpio_set_value(db->power_gpio, 1);
> +
> +	/* PHY POWER UP */
> +	phy_reg = wemac_phy_read(dev, WEMAC_PHY, 0);
> +	wemac_phy_write(dev, WEMAC_PHY, 0, phy_reg & (~(1 << 11)));
> +	mdelay(1);
> +
> +	phy_reg = wemac_phy_read(dev, WEMAC_PHY, 0);
> +
> +	/* set EMAC SPEED, depend on PHY  */
> +	reg_val = readl(db->membase + EMAC_MAC_SUPP_REG);
> +	reg_val &= (~(0x1 << 8));
> +	reg_val |= (((phy_reg & (1 << 13)) >> 13) << 8);
> +	writel(reg_val, db->membase + EMAC_MAC_SUPP_REG);
> +
> +	/* set duplex depend on phy */
> +	reg_val = readl(db->membase + EMAC_MAC_CTL1_REG);
> +	reg_val &= (~(0x1 << 0));
> +	reg_val |= (((phy_reg & (1 << 8)) >> 8) << 0);
> +	writel(reg_val, db->membase + EMAC_MAC_CTL1_REG);
> +
> +	/* enable RX/TX */
> +	reg_val = readl(db->membase + EMAC_CTL_REG);
> +	writel(reg_val | EMAC_CTL_RESET | EMAC_CTL_TX_EN | EMAC_CTL_RX_EN,
> +		db->membase + EMAC_CTL_REG);
> +
> +	/* enable RX/TX0/RX Hlevel interrup */
> +	reg_val = readl(db->membase + EMAC_INT_CTL_REG);
> +	reg_val |= (0xf << 0) | (0x01 << 8);
> +	writel(reg_val, db->membase + EMAC_INT_CTL_REG);
> +
> +	/* Init Driver variable */
> +	db->tx_fifo_stat = 0;
> +	dev->trans_start = 0;

I do not think this is required you are supposed to update this field only in 
the receive path.

> +}
> +
> +/* Our watchdog timed out. Called by the networking layer */
> +static void wemac_timeout(struct net_device *dev)
> +{
> +	struct wemac_board_info *db = netdev_priv(dev);
> +	unsigned long flags;
> +
> +	if (netif_msg_timer(db))
> +		dev_err(db->dev, "tx time out.\n");
> +
> +	/* Save previous register address */
> +	spin_lock_irqsave(&db->lock, flags);
> +
> +	netif_stop_queue(dev);
> +	wemac_reset(db);
> +	wemac_init_wemac(dev);
> +	/* We can accept TX packets again */
> +	dev->trans_start = jiffies;
> +	netif_wake_queue(dev);
> +
> +	/* Restore previous register address */
> +	spin_unlock_irqrestore(&db->lock, flags);
> +}
> +
> +/* Hardware start transmission.
> + * Send a packet to media from the upper layer.
> + */
> +static int wemac_start_xmit(struct sk_buff *skb, struct net_device *dev)
> +{
> +	struct wemac_board_info *db = netdev_priv(dev);
> +	unsigned long channel;
> +	unsigned long flags;
> +
> +	channel = db->tx_fifo_stat & 3;
> +	if (channel == 3)
> +		return 1;

start_xmit expects standardized return values such as NETDEV_TX_BUSY and 
NETDEV_TX_COMPLETE, please use them.

> +
> +	channel = (channel == 1 ? 1 : 0);
> +
> +	spin_lock_irqsave(&db->lock, flags);
> +
> +	writel(channel, db->membase + EMAC_TX_INS_REG);
> +
> +	wemac_outblk_32bit(db->membase + EMAC_TX_IO_DATA_REG,
> +			skb->data, skb->len);
> +	dev->stats.tx_bytes += skb->len;
> +
> +	db->tx_fifo_stat |= 1 << channel;
> +	/* TX control: First packet immediately send, second packet queue */
> +	if (channel == 0) {
> +		/* set TX len */
> +		writel(skb->len, db->membase + EMAC_TX_PL0_REG);
> +		/* start translate from fifo to phy */
> +		writel(readl(db->membase + EMAC_TX_CTL0_REG) | 1,
> +		       db->membase + EMAC_TX_CTL0_REG);

Do not you need some write barrier here to ensure your descriptor address and 
control are properly written before the EMAC will see these?

> +
> +		/* save the time stamp */
> +		dev->trans_start = jiffies;
> +	} else if (channel == 1) {
> +		/* set TX len */
> +		writel(skb->len, db->membase + EMAC_TX_PL1_REG);
> +		/* start translate from fifo to phy */
> +		writel(readl(db->membase + EMAC_TX_CTL1_REG) | 1,
> +		       db->membase + EMAC_TX_CTL1_REG);
> +
> +		/* save the time stamp */
> +		dev->trans_start = jiffies;
> +	}
> +
> +	if ((db->tx_fifo_stat & 3) == 3) {
> +		/* Second packet */
> +		netif_stop_queue(dev);

Why is that required? Does that mean that your EMAC can only transmit one 
packet at a time?

> +	}
> +
> +	spin_unlock_irqrestore(&db->lock, flags);
> +
> +	/* free this SKB */
> +	dev_kfree_skb(skb);
> +
> +	return 0;
> +}
> +
> +/* WEMAC interrupt handler
> + * receive the packet to upper layer, free the transmitted packet
> + */
> +static void wemac_tx_done(struct net_device *dev, struct wemac_board_info
> *db, +			  unsigned int tx_status)
> +{
> +	/* One packet sent complete */
> +	db->tx_fifo_stat &= ~(tx_status & 3);
> +	if (3 == (tx_status & 3))
> +		dev->stats.tx_packets += 2;
> +	else
> +		dev->stats.tx_packets++;
> +
> +	if (netif_msg_tx_done(db))
> +		dev_dbg(db->dev, "tx done, NSR %02x\n", tx_status);
> +
> +	netif_wake_queue(dev);

Why is that also required? According to your start_xmit function you should do 
this only when you have transmitted 2 packets no?

[snip]

> +
> +		reg_val = readl(db->membase + EMAC_RX_IO_DATA_REG);
> +		if (netif_msg_rx_status(db))
> +			dev_dbg(db->dev, "receive header: %x\n", reg_val);
> +		if (reg_val != 0x0143414d) {

Where is that magic value coming from?
-- 
Florian