[PATCH v2 2/2] macb: Add support for SiFive FU540-C000

[Yash Shah]

The management IP block is tightly coupled with the Cadence MACB IP
block on the FU540, and manages many of the boundary signals from the
MACB IP. This patch only controls the tx_clk input signal to the MACB
IP. Future patches may add support for monitoring or controlling other
IP boundary signals.

Signed-off-by: Yash Shah <yash.shah@xxxxxxxxxx>
---
 drivers/net/ethernet/cadence/Kconfig     |   6 ++
 drivers/net/ethernet/cadence/macb_main.c | 129 +++++++++++++++++++++++++++++++
 2 files changed, 135 insertions(+)

diff --git a/drivers/net/ethernet/cadence/Kconfig b/drivers/net/ethernet/cadence/Kconfig
index b998401..d478fae 100644
--- a/drivers/net/ethernet/cadence/Kconfig
+++ b/drivers/net/ethernet/cadence/Kconfig
@@ -48,4 +48,10 @@ config MACB_PCI
 	  To compile this driver as a module, choose M here: the module
 	  will be called macb_pci.
 
+config MACB_SIFIVE_FU540
+	bool "Cadence MACB/GEM support for SiFive FU540 SoC"
+	depends on MACB && GPIO_SIFIVE
+	help
+	  Enable the Cadence MACB/GEM support for SiFive FU540 SoC.
+
 endif # NET_VENDOR_CADENCE
diff --git a/drivers/net/ethernet/cadence/macb_main.c b/drivers/net/ethernet/cadence/macb_main.c
index c049410..275b5e8 100644
--- a/drivers/net/ethernet/cadence/macb_main.c
+++ b/drivers/net/ethernet/cadence/macb_main.c
@@ -10,6 +10,7 @@
 
 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
 #include <linux/clk.h>
+#include <linux/clk-provider.h>
 #include <linux/crc32.h>
 #include <linux/module.h>
 #include <linux/moduleparam.h>
@@ -40,6 +41,15 @@
 #include <linux/pm_runtime.h>
 #include "macb.h"
 
+/* This structure is only used for MACB on SiFive FU540 devices */
+struct sifive_fu540_macb_mgmt {
+	void __iomem *reg;
+	unsigned long rate;
+	struct clk_hw hw;
+};
+
+static struct sifive_fu540_macb_mgmt *mgmt;
+
 #define MACB_RX_BUFFER_SIZE	128
 #define RX_BUFFER_MULTIPLE	64  /* bytes */
 
@@ -3903,6 +3913,116 @@ static int at91ether_init(struct platform_device *pdev)
 	return 0;
 }
 
+static unsigned long fu540_macb_tx_recalc_rate(struct clk_hw *hw,
+					       unsigned long parent_rate)
+{
+	return mgmt->rate;
+}
+
+static long fu540_macb_tx_round_rate(struct clk_hw *hw, unsigned long rate,
+				     unsigned long *parent_rate)
+{
+	if (WARN_ON(rate < 2500000))
+		return 2500000;
+	else if (rate == 2500000)
+		return 2500000;
+	else if (WARN_ON(rate < 13750000))
+		return 2500000;
+	else if (WARN_ON(rate < 25000000))
+		return 25000000;
+	else if (rate == 25000000)
+		return 25000000;
+	else if (WARN_ON(rate < 75000000))
+		return 25000000;
+	else if (WARN_ON(rate < 125000000))
+		return 125000000;
+	else if (rate == 125000000)
+		return 125000000;
+
+	WARN_ON(rate > 125000000);
+
+	return 125000000;
+}
+
+static int fu540_macb_tx_set_rate(struct clk_hw *hw, unsigned long rate,
+				  unsigned long parent_rate)
+{
+	rate = fu540_macb_tx_round_rate(hw, rate, &parent_rate);
+	if (rate != 125000000)
+		iowrite32(1, mgmt->reg);
+	else
+		iowrite32(0, mgmt->reg);
+	mgmt->rate = rate;
+
+	return 0;
+}
+
+static const struct clk_ops fu540_c000_ops = {
+	.recalc_rate = fu540_macb_tx_recalc_rate,
+	.round_rate = fu540_macb_tx_round_rate,
+	.set_rate = fu540_macb_tx_set_rate,
+};
+
+static int fu540_c000_clk_init(struct platform_device *pdev, struct clk **pclk,
+			       struct clk **hclk, struct clk **tx_clk,
+			       struct clk **rx_clk, struct clk **tsu_clk)
+{
+	struct clk_init_data init;
+	int err = 0;
+
+	err = macb_clk_init(pdev, pclk, hclk, tx_clk, rx_clk, tsu_clk);
+	if (err)
+		return err;
+
+	mgmt = devm_kzalloc(&pdev->dev, sizeof(*mgmt), GFP_KERNEL);
+	if (!mgmt)
+		return -ENOMEM;
+
+	init.name = "sifive-gemgxl-mgmt";
+	init.ops = &fu540_c000_ops;
+	init.flags = 0;
+	init.num_parents = 0;
+
+	mgmt->rate = 0;
+	mgmt->hw.init = &init;
+
+	*tx_clk = clk_register(NULL, &mgmt->hw);
+	if (IS_ERR(*tx_clk))
+		return PTR_ERR(*tx_clk);
+
+	err = clk_prepare_enable(*tx_clk);
+	if (err)
+		dev_err(&pdev->dev, "failed to enable tx_clk (%u)\n", err);
+	else
+		dev_info(&pdev->dev, "Registered clk switch '%s'\n", init.name);
+
+	return 0;
+}
+
+static int fu540_c000_init(struct platform_device *pdev)
+{
+	struct resource *res;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 1);
+	if (!res)
+		return -ENODEV;
+
+	mgmt->reg = ioremap(res->start, resource_size(res));
+	if (!mgmt->reg)
+		return -ENOMEM;
+
+	return macb_init(pdev);
+}
+
+static const struct macb_config fu540_c000_config = {
+	.caps = MACB_CAPS_GIGABIT_MODE_AVAILABLE | MACB_CAPS_JUMBO |
+		MACB_CAPS_GEM_HAS_PTP,
+	.dma_burst_length = 16,
+	.clk_init = fu540_c000_clk_init,
+	.init = fu540_c000_init,
+	.jumbo_max_len = 10240,
+};
+
 static const struct macb_config at91sam9260_config = {
 	.caps = MACB_CAPS_USRIO_HAS_CLKEN | MACB_CAPS_USRIO_DEFAULT_IS_MII_GMII,
 	.clk_init = macb_clk_init,
@@ -3992,6 +4112,9 @@ static int at91ether_init(struct platform_device *pdev)
 	{ .compatible = "cdns,emac", .data = &emac_config },
 	{ .compatible = "cdns,zynqmp-gem", .data = &zynqmp_config},
 	{ .compatible = "cdns,zynq-gem", .data = &zynq_config },
+#ifdef CONFIG_MACB_SIFIVE_FU540
+	{ .compatible = "sifive,fu540-macb", .data = &fu540_c000_config },
+#endif
 	{ /* sentinel */ }
 };
 MODULE_DEVICE_TABLE(of, macb_dt_ids);
@@ -4199,6 +4322,9 @@ static int macb_probe(struct platform_device *pdev)
 
 err_disable_clocks:
 	clk_disable_unprepare(tx_clk);
+#ifdef CONFIG_MACB_SIFIVE_FU540
+	clk_unregister(tx_clk);
+#endif
 	clk_disable_unprepare(hclk);
 	clk_disable_unprepare(pclk);
 	clk_disable_unprepare(rx_clk);
@@ -4233,6 +4359,9 @@ static int macb_remove(struct platform_device *pdev)
 		pm_runtime_dont_use_autosuspend(&pdev->dev);
 		if (!pm_runtime_suspended(&pdev->dev)) {
 			clk_disable_unprepare(bp->tx_clk);
+#ifdef CONFIG_MACB_SIFIVE_FU540
+			clk_unregister(bp->tx_clk);
+#endif
 			clk_disable_unprepare(bp->hclk);
 			clk_disable_unprepare(bp->pclk);
 			clk_disable_unprepare(bp->rx_clk);
-- 
1.9.1