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Diffstat (limited to 'drivers/net/dsa/mv88e6xxx/smi.c')
-rw-r--r--drivers/net/dsa/mv88e6xxx/smi.c190
1 files changed, 190 insertions, 0 deletions
diff --git a/drivers/net/dsa/mv88e6xxx/smi.c b/drivers/net/dsa/mv88e6xxx/smi.c
new file mode 100644
index 000000000..a990271b7
--- /dev/null
+++ b/drivers/net/dsa/mv88e6xxx/smi.c
@@ -0,0 +1,190 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Marvell 88E6xxx System Management Interface (SMI) support
+ *
+ * Copyright (c) 2008 Marvell Semiconductor
+ *
+ * Copyright (c) 2019 Vivien Didelot <vivien.didelot@gmail.com>
+ */
+
+#include "chip.h"
+#include "smi.h"
+
+/* The switch ADDR[4:1] configuration pins define the chip SMI device address
+ * (ADDR[0] is always zero, thus only even SMI addresses can be strapped).
+ *
+ * When ADDR is all zero, the chip uses Single-chip Addressing Mode, assuming it
+ * is the only device connected to the SMI master. In this mode it responds to
+ * all 32 possible SMI addresses, and thus maps directly the internal devices.
+ *
+ * When ADDR is non-zero, the chip uses Multi-chip Addressing Mode, allowing
+ * multiple devices to share the SMI interface. In this mode it responds to only
+ * 2 registers, used to indirectly access the internal SMI devices.
+ *
+ * Some chips use a different scheme: Only the ADDR4 pin is used for
+ * configuration, and the device responds to 16 of the 32 SMI
+ * addresses, allowing two to coexist on the same SMI interface.
+ */
+
+static int mv88e6xxx_smi_direct_read(struct mv88e6xxx_chip *chip,
+ int dev, int reg, u16 *data)
+{
+ int ret;
+
+ ret = mdiobus_read_nested(chip->bus, dev, reg);
+ if (ret < 0)
+ return ret;
+
+ *data = ret & 0xffff;
+
+ return 0;
+}
+
+static int mv88e6xxx_smi_direct_write(struct mv88e6xxx_chip *chip,
+ int dev, int reg, u16 data)
+{
+ int ret;
+
+ ret = mdiobus_write_nested(chip->bus, dev, reg, data);
+ if (ret < 0)
+ return ret;
+
+ return 0;
+}
+
+static int mv88e6xxx_smi_direct_wait(struct mv88e6xxx_chip *chip,
+ int dev, int reg, int bit, int val)
+{
+ const unsigned long timeout = jiffies + msecs_to_jiffies(50);
+ u16 data;
+ int err;
+ int i;
+
+ /* Even if the initial poll takes longer than 50ms, always do
+ * at least one more attempt.
+ */
+ for (i = 0; time_before(jiffies, timeout) || (i < 2); i++) {
+ err = mv88e6xxx_smi_direct_read(chip, dev, reg, &data);
+ if (err)
+ return err;
+
+ if (!!(data & BIT(bit)) == !!val)
+ return 0;
+
+ if (i < 2)
+ cpu_relax();
+ else
+ usleep_range(1000, 2000);
+ }
+
+ return -ETIMEDOUT;
+}
+
+static const struct mv88e6xxx_bus_ops mv88e6xxx_smi_direct_ops = {
+ .read = mv88e6xxx_smi_direct_read,
+ .write = mv88e6xxx_smi_direct_write,
+};
+
+static int mv88e6xxx_smi_dual_direct_read(struct mv88e6xxx_chip *chip,
+ int dev, int reg, u16 *data)
+{
+ return mv88e6xxx_smi_direct_read(chip, chip->sw_addr + dev, reg, data);
+}
+
+static int mv88e6xxx_smi_dual_direct_write(struct mv88e6xxx_chip *chip,
+ int dev, int reg, u16 data)
+{
+ return mv88e6xxx_smi_direct_write(chip, chip->sw_addr + dev, reg, data);
+}
+
+static const struct mv88e6xxx_bus_ops mv88e6xxx_smi_dual_direct_ops = {
+ .read = mv88e6xxx_smi_dual_direct_read,
+ .write = mv88e6xxx_smi_dual_direct_write,
+};
+
+/* Offset 0x00: SMI Command Register
+ * Offset 0x01: SMI Data Register
+ */
+
+static int mv88e6xxx_smi_indirect_read(struct mv88e6xxx_chip *chip,
+ int dev, int reg, u16 *data)
+{
+ int err;
+
+ err = mv88e6xxx_smi_direct_write(chip, chip->sw_addr,
+ MV88E6XXX_SMI_CMD,
+ MV88E6XXX_SMI_CMD_BUSY |
+ MV88E6XXX_SMI_CMD_MODE_22 |
+ MV88E6XXX_SMI_CMD_OP_22_READ |
+ (dev << 5) | reg);
+ if (err)
+ return err;
+
+ err = mv88e6xxx_smi_direct_wait(chip, chip->sw_addr,
+ MV88E6XXX_SMI_CMD, 15, 0);
+ if (err)
+ return err;
+
+ return mv88e6xxx_smi_direct_read(chip, chip->sw_addr,
+ MV88E6XXX_SMI_DATA, data);
+}
+
+static int mv88e6xxx_smi_indirect_write(struct mv88e6xxx_chip *chip,
+ int dev, int reg, u16 data)
+{
+ int err;
+
+ err = mv88e6xxx_smi_direct_write(chip, chip->sw_addr,
+ MV88E6XXX_SMI_DATA, data);
+ if (err)
+ return err;
+
+ err = mv88e6xxx_smi_direct_write(chip, chip->sw_addr,
+ MV88E6XXX_SMI_CMD,
+ MV88E6XXX_SMI_CMD_BUSY |
+ MV88E6XXX_SMI_CMD_MODE_22 |
+ MV88E6XXX_SMI_CMD_OP_22_WRITE |
+ (dev << 5) | reg);
+ if (err)
+ return err;
+
+ return mv88e6xxx_smi_direct_wait(chip, chip->sw_addr,
+ MV88E6XXX_SMI_CMD, 15, 0);
+}
+
+static int mv88e6xxx_smi_indirect_init(struct mv88e6xxx_chip *chip)
+{
+ /* Ensure that the chip starts out in the ready state. As both
+ * reads and writes always ensure this on return, they can
+ * safely depend on the chip not being busy on entry.
+ */
+ return mv88e6xxx_smi_direct_wait(chip, chip->sw_addr,
+ MV88E6XXX_SMI_CMD, 15, 0);
+}
+
+static const struct mv88e6xxx_bus_ops mv88e6xxx_smi_indirect_ops = {
+ .read = mv88e6xxx_smi_indirect_read,
+ .write = mv88e6xxx_smi_indirect_write,
+ .init = mv88e6xxx_smi_indirect_init,
+};
+
+int mv88e6xxx_smi_init(struct mv88e6xxx_chip *chip,
+ struct mii_bus *bus, int sw_addr)
+{
+ if (chip->info->dual_chip)
+ chip->smi_ops = &mv88e6xxx_smi_dual_direct_ops;
+ else if (sw_addr == 0)
+ chip->smi_ops = &mv88e6xxx_smi_direct_ops;
+ else if (chip->info->multi_chip)
+ chip->smi_ops = &mv88e6xxx_smi_indirect_ops;
+ else
+ return -EINVAL;
+
+ chip->bus = bus;
+ chip->sw_addr = sw_addr;
+
+ if (chip->smi_ops->init)
+ return chip->smi_ops->init(chip);
+
+ return 0;
+}