net: macb: Extend MACB driver for SiFive Unleashed board

The SiFive MACB ethernet has a custom TX_CLK_SEL register to select
different TX clock for 1000mbps vs 10/100mbps.

This patch adds SiFive MACB compatible string and extends the MACB
ethernet driver to change TX clock using TX_CLK_SEL register for
SiFive MACB.

Signed-off-by: Anup Patel <anup.patel@wdc.com>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: Ramon Fried <rfried.dev@gmail.com>
Acked-by: Joe Hershberger <joe.hershberger@ni.com>

drivers/net/macb.c

@@ -90,7 +90,8 @@ struct macb_dma_desc {
 
 struct macb_device {
 	void			*regs;
-	unsigned int		dma_burst_length;
+
+	const struct macb_config *config;
 
 	unsigned int		rx_tail;
 	unsigned int		tx_head;
@@ -131,6 +132,8 @@ struct macb_device {
 
 struct macb_config {
 	unsigned int		dma_burst_length;
+
+	int			(*clk_init)(struct udevice *dev, ulong rate);
 };
 
 #ifndef CONFIG_DM_ETH
@@ -492,21 +495,38 @@ static int macb_phy_find(struct macb_device *macb, const char *name)
  * when operation failed.
  */
 #ifdef CONFIG_DM_ETH
+static int macb_sifive_clk_init(struct udevice *dev, ulong rate)
+{
+	fdt_addr_t addr;
+	void *gemgxl_regs;
+
+	addr = dev_read_addr_index(dev, 1);
+	if (addr == FDT_ADDR_T_NONE)
+		return -ENODEV;
+
+	gemgxl_regs = (void __iomem *)addr;
+	if (!gemgxl_regs)
+		return -ENODEV;
+
+	/*
+	 * SiFive GEMGXL TX clock operation mode:
+	 *
+	 * 0 = GMII mode. Use 125 MHz gemgxlclk from PRCI in TX logic
+	 *     and output clock on GMII output signal GTX_CLK
+	 * 1 = MII mode. Use MII input signal TX_CLK in TX logic
+	 */
+	writel(rate != 125000000, gemgxl_regs);
+	return 0;
+}
+
 int __weak macb_linkspd_cb(struct udevice *dev, unsigned int speed)
 {
 #ifdef CONFIG_CLK
+	struct macb_device *macb = dev_get_priv(dev);
 	struct clk tx_clk;
 	ulong rate;
 	int ret;
 
-	/*
-	 * "tx_clk" is an optional clock source for MACB.
-	 * Ignore if it does not exist in DT.
-	 */
-	ret = clk_get_by_name(dev, "tx_clk", &tx_clk);
-	if (ret)
-		return 0;
-
 	switch (speed) {
 	case _10BASET:
 		rate = 2500000;		/* 2.5 MHz */
@@ -522,6 +542,17 @@ int __weak macb_linkspd_cb(struct udevice *dev, unsigned int speed)
 		return 0;
 	}
 
+	if (macb->config->clk_init)
+		return macb->config->clk_init(dev, rate);
+
+	/*
+	 * "tx_clk" is an optional clock source for MACB.
+	 * Ignore if it does not exist in DT.
+	 */
+	ret = clk_get_by_name(dev, "tx_clk", &tx_clk);
+	if (ret)
+		return 0;
+
 	if (tx_clk.dev) {
 		ret = clk_set_rate(&tx_clk, rate);
 		if (ret)
@@ -716,8 +747,9 @@ static void gmac_configure_dma(struct macb_device *macb)
 	dmacfg = gem_readl(macb, DMACFG) & ~GEM_BF(RXBS, -1L);
 	dmacfg |= GEM_BF(RXBS, buffer_size);
 
-	if (macb->dma_burst_length)
+	if (macb->config->dma_burst_length)
-		dmacfg = GEM_BFINS(FBLDO, macb->dma_burst_length, dmacfg);
+		dmacfg = GEM_BFINS(FBLDO,
+				   macb->config->dma_burst_length, dmacfg);
 
 	dmacfg |= GEM_BIT(TXPBMS) | GEM_BF(RXBMS, -1L);
 	dmacfg &= ~GEM_BIT(ENDIA_PKT);
@@ -1186,15 +1218,15 @@ static int macb_enable_clk(struct udevice *dev)
 
 static const struct macb_config default_gem_config = {
 	.dma_burst_length = 16,
+	.clk_init = NULL,
 };
 
 static int macb_eth_probe(struct udevice *dev)
 {
-	const struct macb_config *macb_config;
 	struct eth_pdata *pdata = dev_get_platdata(dev);
 	struct macb_device *macb = dev_get_priv(dev);
 	const char *phy_mode;
-	__maybe_unused int ret;
+	int ret;
 
 	phy_mode = fdt_getprop(gd->fdt_blob, dev_of_offset(dev), "phy-mode",
 			       NULL);
@@ -1207,11 +1239,10 @@ static int macb_eth_probe(struct udevice *dev)
 
 	macb->regs = (void *)pdata->iobase;
 
-	macb_config = (struct macb_config *)dev_get_driver_data(dev);
+	macb->config = (struct macb_config *)dev_get_driver_data(dev);
-	if (!macb_config)
+	if (!macb->config)
-		macb_config = &default_gem_config;
+		macb->config = &default_gem_config;
 
-	macb->dma_burst_length = macb_config->dma_burst_length;
 #ifdef CONFIG_CLK
 	ret = macb_enable_clk(dev);
 	if (ret)
@@ -1274,6 +1305,12 @@ static int macb_eth_ofdata_to_platdata(struct udevice *dev)
 
 static const struct macb_config sama5d4_config = {
 	.dma_burst_length = 4,
+	.clk_init = NULL,
+};
+
+static const struct macb_config sifive_config = {
+	.dma_burst_length = 16,
+	.clk_init = macb_sifive_clk_init,
 };
 
 static const struct udevice_id macb_eth_ids[] = {
@@ -1283,6 +1320,8 @@ static const struct udevice_id macb_eth_ids[] = {
 	{ .compatible = "atmel,sama5d3-gem" },
 	{ .compatible = "atmel,sama5d4-gem", .data = (ulong)&sama5d4_config },
 	{ .compatible = "cdns,zynq-gem" },
+	{ .compatible = "sifive,fu540-c000-gem",
+	  .data = (ulong)&sifive_config },
 	{ }
 };