net: macb: Update tsu clk usage in runtime suspend/resume for Versal

On Versal TSU clock cannot be disabled irrespective of whether PTP is
used. Hence introduce a new Versal config structure with a "need tsu"
caps flag and check the same in runtime_suspend/resume before cutting
off clocks.

More information on this for future reference:
This is an IP limitation on versions 1p11 and 1p12 when Qbv is enabled
(See designcfg1, bit 3). However it is better to rely on an SoC specific
check rather than the IP version because tsu clk property itself may not
represent actual HW tsu clock on some chip designs.
Signed-off-by: Harini Katakam <harini.katakam@xilinx.com>
Signed-off-by: Radhey Shyam Pandey <radhey.shyam.pandey@xilinx.com>
Reviewed-by: Claudiu Beznea <claudiu.beznea@microchip.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/cadence/macb.h

@@ -717,6 +717,7 @@
 #define MACB_CAPS_BD_RD_PREFETCH		0x00000080
 #define MACB_CAPS_NEEDS_RSTONUBR		0x00000100
 #define MACB_CAPS_MIIONRGMII			0x00000200
+#define MACB_CAPS_NEED_TSUCLK			0x00000400
 #define MACB_CAPS_PCS				0x01000000
 #define MACB_CAPS_HIGH_SPEED			0x02000000
 #define MACB_CAPS_CLK_HW_CHG			0x04000000

drivers/net/ethernet/cadence/macb_main.c

@@ -4773,6 +4773,16 @@ static const struct macb_config sama7g5_emac_config = {
 	.usrio = &sama7g5_usrio,
 };
 
+static const struct macb_config versal_config = {
+	.caps = MACB_CAPS_GIGABIT_MODE_AVAILABLE | MACB_CAPS_JUMBO |
+		MACB_CAPS_GEM_HAS_PTP | MACB_CAPS_BD_RD_PREFETCH | MACB_CAPS_NEED_TSUCLK,
+	.dma_burst_length = 16,
+	.clk_init = macb_clk_init,
+	.init = init_reset_optional,
+	.jumbo_max_len = 10240,
+	.usrio = &macb_default_usrio,
+};
+
 static const struct of_device_id macb_dt_ids[] = {
 	{ .compatible = "cdns,at32ap7000-macb" },
 	{ .compatible = "cdns,at91sam9260-macb", .data = &at91sam9260_config },
@@ -4794,6 +4804,7 @@ static const struct of_device_id macb_dt_ids[] = {
 	{ .compatible = "microchip,mpfs-macb", .data = &mpfs_config },
 	{ .compatible = "microchip,sama7g5-gem", .data = &sama7g5_gem_config },
 	{ .compatible = "microchip,sama7g5-emac", .data = &sama7g5_emac_config },
+	{ .compatible = "cdns,versal-gem", .data = &versal_config},
 	{ /* sentinel */ }
 };
 MODULE_DEVICE_TABLE(of, macb_dt_ids);
@@ -5203,7 +5214,7 @@ static int __maybe_unused macb_runtime_suspend(struct device *dev)
 
 	if (!(device_may_wakeup(dev)))
 		macb_clks_disable(bp->pclk, bp->hclk, bp->tx_clk, bp->rx_clk, bp->tsu_clk);
-	else
+	else if (!(bp->caps & MACB_CAPS_NEED_TSUCLK))
 		macb_clks_disable(NULL, NULL, NULL, NULL, bp->tsu_clk);
 
 	return 0;
@@ -5219,8 +5230,10 @@ static int __maybe_unused macb_runtime_resume(struct device *dev)
 		clk_prepare_enable(bp->hclk);
 		clk_prepare_enable(bp->tx_clk);
 		clk_prepare_enable(bp->rx_clk);
+		clk_prepare_enable(bp->tsu_clk);
+	} else if (!(bp->caps & MACB_CAPS_NEED_TSUCLK)) {
+		clk_prepare_enable(bp->tsu_clk);
 	}
-	clk_prepare_enable(bp->tsu_clk);
 
 	return 0;
 }