i2400m/SDIO: TX and RX path backends

Implements the backend so that the generic driver can TX/RX to/from
the SDIO device.

For RX, when data is ready the SDIO IRQ is fired and that will
allocate an skb, put all the data there and then pass it to the
generic driver RX code for processing and delivery.

TX, when kicked by the generic driver, will schedule work on a
driver-specific workqueue that pulls data from the TX FIFO and sends
it to the device until it drains it.

Thread contexts are needed as SDIO functions are blocking.

Signed-off-by: Inaky Perez-Gonzalez <inaky@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 153 insertions, 0 deletions

diff --git a/drivers/net/wimax/i2400m/sdio-tx.c b/drivers/net/wimax/i2400m/sdio-tx.c
new file mode 100644
index 000000000000..5105a5ebc44f
--- /dev/null
+++ b/drivers/net/wimax/i2400m/sdio-tx.c
@@ -0,0 +1,153 @@
+/*
+ * Intel Wireless WiMAX Connection 2400m
+ * SDIO TX transaction backends
+ *
+ *
+ * Copyright (C) 2007-2008 Intel Corporation. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ *   * Redistributions of source code must retain the above copyright
+ *     notice, this list of conditions and the following disclaimer.
+ *   * Redistributions in binary form must reproduce the above copyright
+ *     notice, this list of conditions and the following disclaimer in
+ *     the documentation and/or other materials provided with the
+ *     distribution.
+ *   * Neither the name of Intel Corporation nor the names of its
+ *     contributors may be used to endorse or promote products derived
+ *     from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ *
+ * Intel Corporation <linux-wimax@intel.com>
+ * Dirk Brandewie <dirk.j.brandewie@intel.com>
+ *  - Initial implementation
+ *
+ *
+ * Takes the TX messages in the i2400m's driver TX FIFO and sends them
+ * to the device until there are no more.
+ *
+ * If we fail sending the message, we just drop it. There isn't much
+ * we can do at this point. Most of the traffic is network, which has
+ * recovery methods for dropped packets.
+ *
+ * The SDIO functions are not atomic, so we can't run from the context
+ * where i2400m->bus_tx_kick() [i2400ms_bus_tx_kick()] is being called
+ * (some times atomic). Thus, the actual TX work is deferred to a
+ * workqueue.
+ *
+ * ROADMAP
+ *
+ * i2400ms_bus_tx_kick()
+ *   i2400ms_tx_submit()     [through workqueue]
+ *
+ * i2400m_tx_setup()
+ *
+ * i2400m_tx_release()
+ */
+#include <linux/mmc/sdio_func.h>
+#include "i2400m-sdio.h"
+
+#define D_SUBMODULE tx
+#include "sdio-debug-levels.h"
+
+
+/*
+ * Pull TX transations from the TX FIFO and send them to the device
+ * until there are no more.
+ */
+static
+void i2400ms_tx_submit(struct work_struct *ws)
+{
+        int result;
+        struct i2400ms *i2400ms = container_of(ws, struct i2400ms, tx_worker);
+        struct i2400m *i2400m = &i2400ms->i2400m;
+        struct sdio_func *func = i2400ms->func;
+        struct device *dev = &func->dev;
+        struct i2400m_msg_hdr *tx_msg;
+        size_t tx_msg_size;
+
+        d_fnstart(4, dev, "(i2400ms %p, i2400m %p)\n", i2400ms, i2400ms);
+
+        while (NULL != (tx_msg = i2400m_tx_msg_get(i2400m, &tx_msg_size))) {
+                d_printf(2, dev, "TX: submitting %zu bytes\n", tx_msg_size);
+                d_dump(5, dev, tx_msg, tx_msg_size);
+
+                sdio_claim_host(func);
+                result = sdio_memcpy_toio(func, 0, tx_msg, tx_msg_size);
+                sdio_release_host(func);
+
+                i2400m_tx_msg_sent(i2400m);
+
+                if (result < 0) {
+                        dev_err(dev, "TX: cannot submit TX; tx_msg @%zu %zu B:"
+                                " %d\n", (void *) tx_msg - i2400m->tx_buf,
+                                tx_msg_size, result);
+                }
+
+                d_printf(2, dev, "TX: %zub submitted\n", tx_msg_size);
+        }
+
+        d_fnend(4, dev, "(i2400ms %p) = void\n", i2400ms);
+}
+
+
+/*
+ * The generic driver notifies us that there is data ready for TX
+ *
+ * Schedule a run of i2400ms_tx_submit() to handle it.
+ */
+void i2400ms_bus_tx_kick(struct i2400m *i2400m)
+{
+        struct i2400ms *i2400ms = container_of(i2400m, struct i2400ms, i2400m);
+        struct device *dev = &i2400ms->func->dev;
+
+        d_fnstart(3, dev, "(i2400m %p) = void\n", i2400m);
+
+        /* schedule tx work, this is because tx may block, therefore
+         * it has to run in a thread context.
+         */
+        queue_work(i2400ms->tx_workqueue, &i2400ms->tx_worker);
+
+        d_fnend(3, dev, "(i2400m %p) = void\n", i2400m);
+}
+
+int i2400ms_tx_setup(struct i2400ms *i2400ms)
+{
+        int result;
+        struct device *dev = &i2400ms->func->dev;
+        struct i2400m *i2400m = &i2400ms->i2400m;
+
+        d_fnstart(5, dev, "(i2400ms %p)\n", i2400ms);
+
+        INIT_WORK(&i2400ms->tx_worker, i2400ms_tx_submit);
+        snprintf(i2400ms->tx_wq_name, sizeof(i2400ms->tx_wq_name),
+                 "%s-tx", i2400m->wimax_dev.name);
+        i2400ms->tx_workqueue =
+                create_singlethread_workqueue(i2400ms->tx_wq_name);
+        if (NULL == i2400ms->tx_workqueue) {
+                dev_err(dev, "TX: failed to create workqueue\n");
+                result = -ENOMEM;
+        } else
+                result = 0;
+        d_fnend(5, dev, "(i2400ms %p) = %d\n", i2400ms, result);
+        return result;
+}
+
+void i2400ms_tx_release(struct i2400ms *i2400ms)
+{
+        destroy_workqueue(i2400ms->tx_workqueue);
+}