[PATCH] intel ixp2000 network driver

The way the hardware and firmware work is that there is one shared RX
queue and IRQ for a number of different network interfaces.  Due to this,
we would like to process received packets for every interface in the same
NAPI poll handler, so we need a pseudo-device to schedule polling on.

What the driver currently does is that it always schedules polling for
the first network interface in the list, and processes packets for every
interface in the poll handler for that first interface -- however, this
scheme breaks down if the first network interface happens to not be up,
since netif_rx_schedule_prep() checks netif_running().

sky2 apparently has the same issue, and Stephen Hemminger suggested a
way to work around this: create a variant of netif_rx_schedule_prep()
that does not check netif_running().  I implemented this locally and
called it netif_rx_schedule_prep_notup(), and it seems to work well,
but it's something that probably not everyone would be happy with.

The ixp2000 is an ARM CPU with a high-speed network interface in the
CPU itself (full duplex 4Gb/s or 10Gb/s depending on the IXP model.)
The CPU package also contains 8 or 16 (again depending on the IXP
model) 'microengines', which are somewhat primitive but very fast
and efficient processor cores which can be used to offload various
things from the main CPU.

This driver makes the high-speed network interface in the CPU visible
and usable as a regular linux network device.  Currently, it only
supports the Radisys ENP2611 IXP board, but adding support for other
board types should be fairly easy.

Signed-off-by: Lennert Buytenhek <buytenh@wantstofly.org>
Signed-off-by: Jeff Garzik <jgarzik@pobox.com>

1 files changed, 213 insertions, 0 deletions

diff --git a/drivers/net/ixp2000/ixp2400-msf.c b/drivers/net/ixp2000/ixp2400-msf.c
new file mode 100644
index 000000000000..48a3a891d3a4
--- /dev/null
+++ b/drivers/net/ixp2000/ixp2400-msf.c
@@ -0,0 +1,213 @@
+/*
+ * Generic library functions for the MSF (Media and Switch Fabric) unit
+ * found on the Intel IXP2400 network processor.
+ *
+ * Copyright (C) 2004, 2005 Lennert Buytenhek <buytenh@wantstofly.org>
+ * Dedicated to Marija Kulikova.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as
+ * published by the Free Software Foundation; either version 2.1 of the
+ * License, or (at your option) any later version.
+ */
+
+#include <linux/config.h>
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <asm/hardware.h>
+#include <asm/arch/ixp2000-regs.h>
+#include <asm/delay.h>
+#include <asm/io.h>
+#include "ixp2400-msf.h"
+
+/*
+ * This is the Intel recommended PLL init procedure as described on
+ * page 340 of the IXP2400/IXP2800 Programmer's Reference Manual.
+ */
+static void ixp2400_pll_init(struct ixp2400_msf_parameters *mp)
+{
+        int rx_dual_clock;
+        int tx_dual_clock;
+        u32 value;
+
+        /*
+         * If the RX mode is not 1x32, we have to enable both RX PLLs
+         * (#0 and #1.)  The same thing for the TX direction.
+         */
+        rx_dual_clock = !!(mp->rx_mode & IXP2400_RX_MODE_WIDTH_MASK);
+        tx_dual_clock = !!(mp->tx_mode & IXP2400_TX_MODE_WIDTH_MASK);
+
+        /*
+         * Read initial value.
+         */
+        value = ixp2000_reg_read(IXP2000_MSF_CLK_CNTRL);
+
+        /*
+         * Put PLLs in powerdown and bypass mode.
+         */
+        value |= 0x0000f0f0;
+        ixp2000_reg_write(IXP2000_MSF_CLK_CNTRL, value);
+
+        /*
+         * Set single or dual clock mode bits.
+         */
+        value &= ~0x03000000;
+        value |= (rx_dual_clock << 24) | (tx_dual_clock << 25);
+
+        /*
+         * Set multipliers.
+         */
+        value &= ~0x00ff0000;
+        value |= mp->rxclk01_multiplier << 16;
+        value |= mp->rxclk23_multiplier << 18;
+        value |= mp->txclk01_multiplier << 20;
+        value |= mp->txclk23_multiplier << 22;
+
+        /*
+         * And write value.
+         */
+        ixp2000_reg_write(IXP2000_MSF_CLK_CNTRL, value);
+
+        /*
+         * Disable PLL bypass mode.
+         */
+        value &= ~(0x00005000 | rx_dual_clock << 13 | tx_dual_clock << 15);
+        ixp2000_reg_write(IXP2000_MSF_CLK_CNTRL, value);
+
+        /*
+         * Turn on PLLs.
+         */
+        value &= ~(0x00000050 | rx_dual_clock << 5 | tx_dual_clock << 7);
+        ixp2000_reg_write(IXP2000_MSF_CLK_CNTRL, value);
+
+        /*
+         * Wait for PLLs to lock.  There are lock status bits, but IXP2400
+         * erratum #65 says that these lock bits should not be relied upon
+         * as they might not accurately reflect the true state of the PLLs.
+         */
+        udelay(100);
+}
+
+/*
+ * Needed according to p480 of Programmer's Reference Manual.
+ */
+static void ixp2400_msf_free_rbuf_entries(struct ixp2400_msf_parameters *mp)
+{
+        int size_bits;
+        int i;
+
+        /*
+         * Work around IXP2400 erratum #69 (silent RBUF-to-DRAM transfer
+         * corruption) in the Intel-recommended way: do not add the RBUF
+         * elements susceptible to corruption to the freelist.
+         */
+        size_bits = mp->rx_mode & IXP2400_RX_MODE_RBUF_SIZE_MASK;
+        if (size_bits == IXP2400_RX_MODE_RBUF_SIZE_64) {
+                for (i = 1; i < 128; i++) {
+                        if (i == 9 || i == 18 || i == 27)
+                                continue;
+                        ixp2000_reg_write(IXP2000_MSF_RBUF_ELEMENT_DONE, i);
+                }
+        } else if (size_bits == IXP2400_RX_MODE_RBUF_SIZE_128) {
+                for (i = 1; i < 64; i++) {
+                        if (i == 4 || i == 9 || i == 13)
+                                continue;
+                        ixp2000_reg_write(IXP2000_MSF_RBUF_ELEMENT_DONE, i);
+                }
+        } else if (size_bits == IXP2400_RX_MODE_RBUF_SIZE_256) {
+                for (i = 1; i < 32; i++) {
+                        if (i == 2 || i == 4 || i == 6)
+                                continue;
+                        ixp2000_reg_write(IXP2000_MSF_RBUF_ELEMENT_DONE, i);
+                }
+        }
+}
+
+static u32 ixp2400_msf_valid_channels(u32 reg)
+{
+        u32 channels;
+
+        channels = 0;
+        switch (reg & IXP2400_RX_MODE_WIDTH_MASK) {
+        case IXP2400_RX_MODE_1x32:
+                channels = 0x1;
+                if (reg & IXP2400_RX_MODE_MPHY &&
+                    !(reg & IXP2400_RX_MODE_MPHY_32))
+                        channels = 0xf;
+                break;
+
+        case IXP2400_RX_MODE_2x16:
+                channels = 0x5;
+                break;
+
+        case IXP2400_RX_MODE_4x8:
+                channels = 0xf;
+                break;
+
+        case IXP2400_RX_MODE_1x16_2x8:
+                channels = 0xd;
+                break;
+        }
+
+        return channels;
+}
+
+static void ixp2400_msf_enable_rx(struct ixp2400_msf_parameters *mp)
+{
+        u32 value;
+
+        value = ixp2000_reg_read(IXP2000_MSF_RX_CONTROL) & 0x0fffffff;
+        value |= ixp2400_msf_valid_channels(mp->rx_mode) << 28;
+        ixp2000_reg_write(IXP2000_MSF_RX_CONTROL, value);
+}
+
+static void ixp2400_msf_enable_tx(struct ixp2400_msf_parameters *mp)
+{
+        u32 value;
+
+        value = ixp2000_reg_read(IXP2000_MSF_TX_CONTROL) & 0x0fffffff;
+        value |= ixp2400_msf_valid_channels(mp->tx_mode) << 28;
+        ixp2000_reg_write(IXP2000_MSF_TX_CONTROL, value);
+}
+
+
+void ixp2400_msf_init(struct ixp2400_msf_parameters *mp)
+{
+        u32 value;
+        int i;
+
+        /*
+         * Init the RX/TX PLLs based on the passed parameter block.
+         */
+        ixp2400_pll_init(mp);
+
+        /*
+         * Reset MSF.  Bit 7 in IXP_RESET_0 resets the MSF.
+         */
+        value = ixp2000_reg_read(IXP2000_RESET0);
+        ixp2000_reg_write(IXP2000_RESET0, value | 0x80);
+        ixp2000_reg_write(IXP2000_RESET0, value & ~0x80);
+
+        /*
+         * Initialise the RX section.
+         */
+        ixp2000_reg_write(IXP2000_MSF_RX_MPHY_POLL_LIMIT, mp->rx_poll_ports - 1);
+        ixp2000_reg_write(IXP2000_MSF_RX_CONTROL, mp->rx_mode);
+        for (i = 0; i < 4; i++) {
+                ixp2000_reg_write(IXP2000_MSF_RX_UP_CONTROL_0 + i,
+                                                mp->rx_channel_mode[i]);
+        }
+        ixp2400_msf_free_rbuf_entries(mp);
+        ixp2400_msf_enable_rx(mp);
+
+        /*
+         * Initialise the TX section.
+         */
+        ixp2000_reg_write(IXP2000_MSF_TX_MPHY_POLL_LIMIT, mp->tx_poll_ports - 1);
+        ixp2000_reg_write(IXP2000_MSF_TX_CONTROL, mp->tx_mode);
+        for (i = 0; i < 4; i++) {
+                ixp2000_reg_write(IXP2000_MSF_TX_UP_CONTROL_0 + i,
+                                                mp->tx_channel_mode[i]);
+        }
+        ixp2400_msf_enable_tx(mp);
+}