net: dsa: mv88e6xxx: move ATU ageing time setter

Move the ATU ageing time setter code in a new global1_atu.c file, which
will be extended in future patches to contains all consequent Global (1)
ATU support code.

Signed-off-by: Vivien Didelot <vivien.didelot@savoirfairelinux.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 43 insertions, 0 deletions

diff --git a/drivers/net/dsa/mv88e6xxx/global1_atu.c b/drivers/net/dsa/mv88e6xxx/global1_atu.c
new file mode 100644
index 000000000000..4d0ada9efc6d
--- /dev/null
+++ b/drivers/net/dsa/mv88e6xxx/global1_atu.c
@@ -0,0 +1,43 @@
+/*
+ * Marvell 88E6xxx Address Translation Unit (ATU) support
+ *
+ * Copyright (c) 2008 Marvell Semiconductor
+ * Copyright (c) 2017 Savoir-faire Linux, Inc.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ */
+
+#include "mv88e6xxx.h"
+#include "global1.h"
+
+/* Offset 0x0A: ATU Control Register */
+
+int mv88e6xxx_g1_atu_set_age_time(struct mv88e6xxx_chip *chip,
+				  unsigned int msecs)
+{
+	const unsigned int coeff = chip->info->age_time_coeff;
+	const unsigned int min = 0x01 * coeff;
+	const unsigned int max = 0xff * coeff;
+	u8 age_time;
+	u16 val;
+	int err;
+
+	if (msecs < min || msecs > max)
+		return -ERANGE;
+
+	/* Round to nearest multiple of coeff */
+	age_time = (msecs + coeff / 2) / coeff;
+
+	err = mv88e6xxx_g1_read(chip, GLOBAL_ATU_CONTROL, &val);
+	if (err)
+		return err;
+
+	/* AgeTime is 11:4 bits */
+	val &= ~0xff0;
+	val |= age_time << 4;
+
+	return mv88e6xxx_g1_write(chip, GLOBAL_ATU_CONTROL, val);
+}