[PATCH rtems-libbsd 2/3] freebsd/cgem: Read clock frequency from device tree

[Padmarao Begari]

Read the clock frequency from the device tree and use it to
calculate the mdc clock divider for the MII bus if not found
then use default clock divider.
---
 freebsd/sys/dev/cadence/if_cgem.c | 39 ++++++++++++++++++++++++++++---
 1 file changed, 36 insertions(+), 3 deletions(-)

diff --git a/freebsd/sys/dev/cadence/if_cgem.c b/freebsd/sys/dev/cadence/if_cgem.c
index 2888a085..363a9717 100644
--- a/freebsd/sys/dev/cadence/if_cgem.c
+++ b/freebsd/sys/dev/cadence/if_cgem.c
@@ -135,6 +135,7 @@ struct cgem_softc {
 	uint32_t		net_cfg_shadow;
 	int			neednullqs;
 	int			phy_contype;
+	uint32_t		pclk_rate;
 #endif /* __rtems__ */
 	int			ref_clk_num;
 #ifndef __rtems__
@@ -1238,6 +1239,27 @@ cgem_get_phyaddr(phandle_t node, int *phy_addr)
 	return (0);
 }
 
+static uint32_t cgem_mdc_clk_div(struct cgem_softc *sc)
+{
+	uint32_t config;
+	uint32_t pclk_hz = sc->pclk_rate;
+
+	if (pclk_hz <= 20000000)
+		config = CGEM_NET_CFG_MDC_CLK_DIV_8;
+	else if (pclk_hz <= 40000000)
+		config = CGEM_NET_CFG_MDC_CLK_DIV_16;
+	else if (pclk_hz <= 80000000)
+		config = CGEM_NET_CFG_MDC_CLK_DIV_32;
+	else if (pclk_hz <= 120000000)
+		config = CGEM_NET_CFG_MDC_CLK_DIV_48;
+	else if (pclk_hz <= 160000000)
+		config = CGEM_NET_CFG_MDC_CLK_DIV_64;
+	else
+		config = CGEM_NET_CFG_MDC_CLK_DIV_96;
+
+	return config;
+}
+
 /* Reset hardware. */
 static void
 cgem_reset(struct cgem_softc *sc)
@@ -1279,12 +1301,16 @@ cgem_reset(struct cgem_softc *sc)
 		sc->net_cfg_shadow = CGEM_NET_CFG_DBUS_WIDTH_32;
 	}
 
+	if (sc->pclk_rate != 0) {
+		sc->net_cfg_shadow |= cgem_mdc_clk_div(sc);
+	} else {
 #ifdef CGEM64
-	sc->net_cfg_shadow |= CGEM_NET_CFG_MDC_CLK_DIV_48;
+		sc->net_cfg_shadow |= CGEM_NET_CFG_MDC_CLK_DIV_48;
 #else
-	sc->net_cfg_shadow |= CGEM_NET_CFG_MDC_CLK_DIV_64;
+		sc->net_cfg_shadow |= CGEM_NET_CFG_MDC_CLK_DIV_64;
 #endif
-	WR4(sc, CGEM_NET_CFG, sc->net_cfg_shadow);
+		WR4(sc, CGEM_NET_CFG, sc->net_cfg_shadow);
+	}
 #endif /* __rtems__ */
 
 	sc->net_ctl_shadow = CGEM_NET_CTRL_MGMT_PORT_EN;
@@ -2038,6 +2064,13 @@ cgem_attach(device_t dev)
 #endif /* __rtems__ */
 	/* Get reference clock number and base divider from fdt. */
 	node = ofw_bus_get_node(dev);
+#ifdef __rtems__
+	if (OF_getencprop(node, "clock-frequency", &cell, sizeof(cell)) > 0)
+		sc->pclk_rate = cell;
+	else
+		sc->pclk_rate = 0;
+#endif /* __rtems__ */
+
 	sc->ref_clk_num = 0;
 	if (OF_getprop(node, "ref-clock-num", &cell, sizeof(cell)) > 0)
 		sc->ref_clk_num = fdt32_to_cpu(cell);
-- 
2.25.1