[PATCH RFC 4/9] net: stmmac: qcom-ethqos: add per-platform NOC clock voting

[Mohd Ayaan Anwar]

Some SoCs gate the EMAC's path to the System NOC behind dedicated clocks
that must be enabled before the DMA can reach memory.  Add
ethqos_noc_clk_cfg and the corresponding fields in the driver-data and
runtime structs so each compatible can declare its own set with per-clock
rates.  The clocks are acquired during probe and enabled/disabled
alongside the existing link clock in ethqos_clks_config().

No functional change for existing compatibles. This will help us when
we add support for Shikra.

Signed-off-by: Mohd Ayaan Anwar <mohd.anwar at oss.qualcomm.com>
---
 .../ethernet/stmicro/stmmac/dwmac-qcom-ethqos.c    | 63 ++++++++++++++++++++++
 1 file changed, 63 insertions(+)

diff --git a/drivers/net/ethernet/stmicro/stmmac/dwmac-qcom-ethqos.c b/drivers/net/ethernet/stmicro/stmmac/dwmac-qcom-ethqos.c
index bec08f1eb8cb41484ba3c91c77393e163e7fd071..f4d4b419a76277cc6c56f03bb10d883cd4dff424 100644
--- a/drivers/net/ethernet/stmicro/stmmac/dwmac-qcom-ethqos.c
+++ b/drivers/net/ethernet/stmicro/stmmac/dwmac-qcom-ethqos.c
@@ -84,11 +84,18 @@
 
 #define SGMII_10M_RX_CLK_DVDR			0x31
 
+#define ETHQOS_MAX_NOC_CLKS			3
+
 struct ethqos_emac_por {
 	unsigned int offset;
 	unsigned int value;
 };
 
+struct ethqos_noc_clk_cfg {
+	const char *id;
+	unsigned long rate;
+};
+
 struct ethqos_emac_driver_data {
 	const struct ethqos_emac_por *rgmii_por;
 	unsigned int num_rgmii_por;
@@ -98,6 +105,8 @@ struct ethqos_emac_driver_data {
 	const char *link_clk_name;
 	struct dwmac4_addrs dwmac4_addrs;
 	bool needs_sgmii_loopback;
+	const struct ethqos_noc_clk_cfg *noc_clk_cfg;
+	unsigned int num_noc_clks;
 };
 
 struct qcom_ethqos {
@@ -112,6 +121,9 @@ struct qcom_ethqos {
 	bool rgmii_config_loopback_en;
 	bool has_emac_ge_3;
 	bool needs_sgmii_loopback;
+
+	struct clk_bulk_data noc_clks[ETHQOS_MAX_NOC_CLKS];
+	int num_noc_clks;
 };
 
 static u32 rgmii_readl(struct qcom_ethqos *ethqos, unsigned int offset)
@@ -696,6 +708,17 @@ static int ethqos_clks_config(void *priv, bool enabled)
 			return ret;
 		}
 
+		if (ethqos->num_noc_clks) {
+			ret = clk_bulk_prepare_enable(ethqos->num_noc_clks,
+						      ethqos->noc_clks);
+			if (ret) {
+				dev_err(&ethqos->pdev->dev,
+					"NOC clocks enable failed: %d\n", ret);
+				clk_disable_unprepare(ethqos->link_clk);
+				return ret;
+			}
+		}
+
 		/* Enable functional clock to prevent DMA reset to timeout due
 		 * to lacking PHY clock after the hardware block has been power
 		 * cycled. The actual configuration will be adjusted once
@@ -704,6 +727,9 @@ static int ethqos_clks_config(void *priv, bool enabled)
 		qcom_ethqos_set_sgmii_loopback(ethqos, true);
 		ethqos_set_func_clk_en(ethqos);
 	} else {
+		if (ethqos->num_noc_clks)
+			clk_bulk_disable_unprepare(ethqos->num_noc_clks,
+						   ethqos->noc_clks);
 		clk_disable_unprepare(ethqos->link_clk);
 	}
 
@@ -732,6 +758,37 @@ static void ethqos_ptp_clk_freq_config(struct stmmac_priv *priv)
 	netdev_dbg(priv->dev, "PTP rate %lu\n", plat_dat->clk_ptp_rate);
 }
 
+/*
+ * Some SoCs gate interconnect access to the System NOC behind dedicated
+ * clocks.  Acquire them, set their required rates, and store the result in
+ * ethqos so ethqos_clks_config() can enable/disable them at runtime.
+ */
+static int qcom_ethqos_init_noc_clks(struct qcom_ethqos *ethqos,
+				     const struct ethqos_emac_driver_data *data)
+{
+	struct device *dev = &ethqos->pdev->dev;
+	unsigned int i;
+	int ret;
+
+	for (i = 0; i < data->num_noc_clks; i++)
+		ethqos->noc_clks[i].id = data->noc_clk_cfg[i].id;
+	ethqos->num_noc_clks = data->num_noc_clks;
+
+	ret = devm_clk_bulk_get(dev, ethqos->num_noc_clks, ethqos->noc_clks);
+	if (ret)
+		return dev_err_probe(dev, ret, "Failed to get NOC clocks\n");
+
+	for (i = 0; i < data->num_noc_clks; i++) {
+		ret = clk_set_rate(ethqos->noc_clks[i].clk,
+				   data->noc_clk_cfg[i].rate);
+		if (ret)
+			dev_warn(dev, "Failed to set %s rate: %d\n",
+				 data->noc_clk_cfg[i].id, ret);
+	}
+
+	return 0;
+}
+
 static int qcom_ethqos_probe(struct platform_device *pdev)
 {
 	struct device_node *np = pdev->dev.of_node;
@@ -791,6 +848,12 @@ static int qcom_ethqos_probe(struct platform_device *pdev)
 	ethqos->has_emac_ge_3 = data->has_emac_ge_3;
 	ethqos->needs_sgmii_loopback = data->needs_sgmii_loopback;
 
+	if (data->num_noc_clks) {
+		ret = qcom_ethqos_init_noc_clks(ethqos, data);
+		if (ret)
+			return ret;
+	}
+
 	ethqos->link_clk = devm_clk_get(dev, data->link_clk_name ?: "rgmii");
 	if (IS_ERR(ethqos->link_clk))
 		return dev_err_probe(dev, PTR_ERR(ethqos->link_clk),

-- 
2.34.1