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+/*
+ * Intel Wireless WiMAX Connection 2400m
+ * Generic (non-bus specific) TX handling
+ *
+ *
+ * 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>
+ * Yanir Lubetkin <yanirx.lubetkin@intel.com>
+ * - Initial implementation
+ *
+ * Intel Corporation <linux-wimax@intel.com>
+ * Inaky Perez-Gonzalez <inaky.perez-gonzalez@intel.com>
+ * - Rewritten to use a single FIFO to lower the memory allocation
+ * pressure and optimize cache hits when copying to the queue, as
+ * well as splitting out bus-specific code.
+ *
+ *
+ * Implements data transmission to the device; this is done through a
+ * software FIFO, as data/control frames can be coalesced (while the
+ * device is reading the previous tx transaction, others accumulate).
+ *
+ * A FIFO is used because at the end it is resource-cheaper that trying
+ * to implement scatter/gather over USB. As well, most traffic is going
+ * to be download (vs upload).
+ *
+ * The format for sending/receiving data to/from the i2400m is
+ * described in detail in rx.c:PROTOCOL FORMAT. In here we implement
+ * the transmission of that. This is split between a bus-independent
+ * part that just prepares everything and a bus-specific part that
+ * does the actual transmission over the bus to the device (in the
+ * bus-specific driver).
+ *
+ *
+ * The general format of a device-host transaction is MSG-HDR, PLD1,
+ * PLD2...PLDN, PL1, PL2,...PLN, PADDING.
+ *
+ * Because we need the send payload descriptors and then payloads and
+ * because it is kind of expensive to do scatterlists in USB (one URB
+ * per node), it becomes cheaper to append all the data to a FIFO
+ * (copying to a FIFO potentially in cache is cheaper).
+ *
+ * Then the bus-specific code takes the parts of that FIFO that are
+ * written and passes them to the device.
+ *
+ * So the concepts to keep in mind there are:
+ *
+ * We use a FIFO to queue the data in a linear buffer. We first append
+ * a MSG-HDR, space for I2400M_TX_PLD_MAX payload descriptors and then
+ * go appending payloads until we run out of space or of payload
+ * descriptors. Then we append padding to make the whole transaction a
+ * multiple of i2400m->bus_tx_block_size (as defined by the bus layer).
+ *
+ * - A TX message: a combination of a message header, payload
+ * descriptors and payloads.
+ *
+ * Open: it is marked as active (i2400m->tx_msg is valid) and we
+ * can keep adding payloads to it.
+ *
+ * Closed: we are not appending more payloads to this TX message
+ * (exahusted space in the queue, too many payloads or
+ * whichever). We have appended padding so the whole message
+ * length is aligned to i2400m->bus_tx_block_size (as set by the
+ * bus/transport layer).
+ *
+ * - Most of the time we keep a TX message open to which we append
+ * payloads.
+ *
+ * - If we are going to append and there is no more space (we are at
+ * the end of the FIFO), we close the message, mark the rest of the
+ * FIFO space unusable (skip_tail), create a new message at the
+ * beginning of the FIFO (if there is space) and append the message
+ * there.
+ *
+ * This is because we need to give linear TX messages to the bus
+ * engine. So we don't write a message to the remaining FIFO space
+ * until the tail and continue at the head of it.
+ *
+ * - We overload one of the fields in the message header to use it as
+ * 'size' of the TX message, so we can iterate over them. It also
+ * contains a flag that indicates if we have to skip it or not.
+ * When we send the buffer, we update that to its real on-the-wire
+ * value.
+ *
+ * - The MSG-HDR PLD1...PLD2 stuff has to be a size multiple of 16.
+ *
+ * It follows that if MSG-HDR says we have N messages, the whole
+ * header + descriptors is 16 + 4*N; for those to be a multiple of
+ * 16, it follows that N can be 4, 8, 12, ... (32, 48, 64, 80...
+ * bytes).
+ *
+ * So if we have only 1 payload, we have to submit a header that in
+ * all truth has space for 4.
+ *
+ * The implication is that we reserve space for 12 (64 bytes); but
+ * if we fill up only (eg) 2, our header becomes 32 bytes only. So
+ * the TX engine has to shift those 32 bytes of msg header and 2
+ * payloads and padding so that right after it the payloads start
+ * and the TX engine has to know about that.
+ *
+ * It is cheaper to move the header up than the whole payloads down.
+ *
+ * We do this in i2400m_tx_close(). See 'i2400m_msg_hdr->offset'.
+ *
+ * - Each payload has to be size-padded to 16 bytes; before appending
+ * it, we just do it.
+ *
+ * - The whole message has to be padded to i2400m->bus_tx_block_size;
+ * we do this at close time. Thus, when reserving space for the
+ * payload, we always make sure there is also free space for this
+ * padding that sooner or later will happen.
+ *
+ * When we append a message, we tell the bus specific code to kick in
+ * TXs. It will TX (in parallel) until the buffer is exhausted--hence
+ * the lockin we do. The TX code will only send a TX message at the
+ * time (which remember, might contain more than one payload). Of
+ * course, when the bus-specific driver attempts to TX a message that
+ * is still open, it gets closed first.
+ *
+ * Gee, this is messy; well a picture. In the example below we have a
+ * partially full FIFO, with a closed message ready to be delivered
+ * (with a moved message header to make sure it is size-aligned to
+ * 16), TAIL room that was unusable (and thus is marked with a message
+ * header that says 'skip this') and at the head of the buffer, an
+ * imcomplete message with a couple of payloads.
+ *
+ * N ___________________________________________________
+ * | |
+ * | TAIL room |
+ * | |
+ * | msg_hdr to skip (size |= 0x80000) |
+ * |---------------------------------------------------|-------
+ * | | /|\
+ * | | |
+ * | TX message padding | |
+ * | | |
+ * | | |
+ * |- - - - - - - - - - - - - - - - - - - - - - - - - -| |
+ * | | |
+ * | payload 1 | |
+ * | | N * tx_block_size
+ * | | |
+ * |- - - - - - - - - - - - - - - - - - - - - - - - - -| |
+ * | | |
+ * | payload 1 | |
+ * | | |
+ * | | |
+ * |- - - - - - - - - - - - - - - - - - - - - - - - - -|- -|- - - -
+ * | padding 3 /|\ | | /|\
+ * | padding 2 | | | |
+ * | pld 1 32 bytes (2 * 16) | | |
+ * | pld 0 | | | |
+ * | moved msg_hdr \|/ | \|/ |
+ * |- - - - - - - - - - - - - - - - - - - - - - - - - -|- - - |
+ * | | _PLD_SIZE
+ * | unused | |
+ * | | |
+ * |- - - - - - - - - - - - - - - - - - - - - - - - - -| |
+ * | msg_hdr (size X) [this message is closed] | \|/
+ * |===================================================|========== <=== OUT
+ * | |
+ * | |
+ * | |
+ * | Free rooom |
+ * | |
+ * | |
+ * | |
+ * | |
+ * | |
+ * | |
+ * | |
+ * | |
+ * | |
+ * |===================================================|========== <=== IN
+ * | |
+ * | |
+ * | |
+ * | |
+ * | payload 1 |
+ * | |
+ * | |
+ * |- - - - - - - - - - - - - - - - - - - - - - - - - -|
+ * | |
+ * | payload 0 |
+ * | |
+ * | |
+ * |- - - - - - - - - - - - - - - - - - - - - - - - - -|
+ * | pld 11 /|\ |
+ * | ... | |
+ * | pld 1 64 bytes (2 * 16) |
+ * | pld 0 | |
+ * | msg_hdr (size X) \|/ [message is open] |
+ * 0 ---------------------------------------------------
+ *
+ *
+ * ROADMAP
+ *
+ * i2400m_tx_setup() Called by i2400m_setup
+ * i2400m_tx_release() Called by i2400m_release()
+ *
+ * i2400m_tx() Called to send data or control frames
+ * i2400m_tx_fifo_push() Allocates append-space in the FIFO
+ * i2400m_tx_new() Opens a new message in the FIFO
+ * i2400m_tx_fits() Checks if a new payload fits in the message
+ * i2400m_tx_close() Closes an open message in the FIFO
+ * i2400m_tx_skip_tail() Marks unusable FIFO tail space
+ * i2400m->bus_tx_kick()
+ *
+ * Now i2400m->bus_tx_kick() is the the bus-specific driver backend
+ * implementation; that would do:
+ *
+ * i2400m->bus_tx_kick()
+ * i2400m_tx_msg_get() Gets first message ready to go
+ * ...sends it...
+ * i2400m_tx_msg_sent() Ack the message is sent; repeat from
+ * _tx_msg_get() until it returns NULL
+ * (FIFO empty).
+ */
+#include <linux/netdevice.h>
+#include "i2400m.h"
+
+
+#define D_SUBMODULE tx
+#include "debug-levels.h"
+
+enum {
+ /**
+ * TX Buffer size
+ *
+ * Doc says maximum transaction is 16KiB. If we had 16KiB en
+ * route and 16KiB being queued, it boils down to needing
+ * 32KiB.
+ */
+ I2400M_TX_BUF_SIZE = 32768,
+ /**
+ * Message header and payload descriptors have to be 16
+ * aligned (16 + 4 * N = 16 * M). If we take that average sent
+ * packets are MTU size (~1400-~1500) it follows that we could
+ * fit at most 10-11 payloads in one transaction. To meet the
+ * alignment requirement, that means we need to leave space
+ * for 12 (64 bytes). To simplify, we leave space for that. If
+ * at the end there are less, we pad up to the nearest
+ * multiple of 16.
+ */
+ I2400M_TX_PLD_MAX = 12,
+ I2400M_TX_PLD_SIZE = sizeof(struct i2400m_msg_hdr)
+ + I2400M_TX_PLD_MAX * sizeof(struct i2400m_pld),
+ I2400M_TX_SKIP = 0x80000000,
+};
+
+#define TAIL_FULL ((void *)~(unsigned long)NULL)
+
+/*
+ * Allocate @size bytes in the TX fifo, return a pointer to it
+ *
+ * @i2400m: device descriptor
+ * @size: size of the buffer we need to allocate
+ * @padding: ensure that there is at least this many bytes of free
+ * contiguous space in the fifo. This is needed because later on
+ * we might need to add padding.
+ *
+ * Returns:
+ *
+ * Pointer to the allocated space. NULL if there is no
+ * space. TAIL_FULL if there is no space at the tail but there is at
+ * the head (Case B below).
+ *
+ * These are the two basic cases we need to keep an eye for -- it is
+ * much better explained in linux/kernel/kfifo.c, but this code
+ * basically does the same. No rocket science here.
+ *
+ * Case A Case B
+ * N ___________ ___________
+ * | tail room | | data |
+ * | | | |
+ * |<- IN ->| |<- OUT ->|
+ * | | | |
+ * | data | | room |
+ * | | | |
+ * |<- OUT ->| |<- IN ->|
+ * | | | |
+ * | head room | | data |
+ * 0 ----------- -----------
+ *
+ * We allocate only *contiguous* space.
+ *
+ * We can allocate only from 'room'. In Case B, it is simple; in case
+ * A, we only try from the tail room; if it is not enough, we just
+ * fail and return TAIL_FULL and let the caller figure out if we wants to
+ * skip the tail room and try to allocate from the head.
+ *
+ * Note:
+ *
+ * Assumes i2400m->tx_lock is taken, and we use that as a barrier
+ *
+ * The indexes keep increasing and we reset them to zero when we
+ * pop data off the queue
+ */
+static
+void *i2400m_tx_fifo_push(struct i2400m *i2400m, size_t size, size_t padding)
+{
+ struct device *dev = i2400m_dev(i2400m);
+ size_t room, tail_room, needed_size;
+ void *ptr;
+
+ needed_size = size + padding;
+ room = I2400M_TX_BUF_SIZE - (i2400m->tx_in - i2400m->tx_out);
+ if (room < needed_size) { /* this takes care of Case B */
+ d_printf(2, dev, "fifo push %zu/%zu: no space\n",
+ size, padding);
+ return NULL;
+ }
+ /* Is there space at the tail? */
+ tail_room = I2400M_TX_BUF_SIZE - i2400m->tx_in % I2400M_TX_BUF_SIZE;
+ if (tail_room < needed_size) {
+ if (i2400m->tx_out % I2400M_TX_BUF_SIZE
+ < i2400m->tx_in % I2400M_TX_BUF_SIZE) {
+ d_printf(2, dev, "fifo push %zu/%zu: tail full\n",
+ size, padding);
+ return TAIL_FULL; /* There might be head space */
+ } else {
+ d_printf(2, dev, "fifo push %zu/%zu: no head space\n",
+ size, padding);
+ return NULL; /* There is no space */
+ }
+ }
+ ptr = i2400m->tx_buf + i2400m->tx_in % I2400M_TX_BUF_SIZE;
+ d_printf(2, dev, "fifo push %zu/%zu: at @%zu\n", size, padding,
+ i2400m->tx_in % I2400M_TX_BUF_SIZE);
+ i2400m->tx_in += size;
+ return ptr;
+}
+
+
+/*
+ * Mark the tail of the FIFO buffer as 'to-skip'
+ *
+ * We should never hit the BUG_ON() because all the sizes we push to
+ * the FIFO are padded to be a multiple of 16 -- the size of *msg
+ * (I2400M_PL_PAD for the payloads, I2400M_TX_PLD_SIZE for the
+ * header).
+ *
+ * Note:
+ *
+ * Assumes i2400m->tx_lock is taken, and we use that as a barrier
+ */
+static
+void i2400m_tx_skip_tail(struct i2400m *i2400m)
+{
+ struct device *dev = i2400m_dev(i2400m);
+ size_t tx_in = i2400m->tx_in % I2400M_TX_BUF_SIZE;
+ size_t tail_room = I2400M_TX_BUF_SIZE - tx_in;
+ struct i2400m_msg_hdr *msg = i2400m->tx_buf + tx_in;
+ BUG_ON(tail_room < sizeof(*msg));
+ msg->size = tail_room | I2400M_TX_SKIP;
+ d_printf(2, dev, "skip tail: skipping %zu bytes @%zu\n",
+ tail_room, tx_in);
+ i2400m->tx_in += tail_room;
+}
+
+
+/*
+ * Check if a skb will fit in the TX queue's current active TX
+ * message (if there are still descriptors left unused).
+ *
+ * Returns:
+ * 0 if the message won't fit, 1 if it will.
+ *
+ * Note:
+ *
+ * Assumes a TX message is active (i2400m->tx_msg).
+ *
+ * Assumes i2400m->tx_lock is taken, and we use that as a barrier
+ */
+static
+unsigned i2400m_tx_fits(struct i2400m *i2400m)
+{
+ struct i2400m_msg_hdr *msg_hdr = i2400m->tx_msg;
+ return le16_to_cpu(msg_hdr->num_pls) < I2400M_TX_PLD_MAX;
+
+}
+
+
+/*
+ * Start a new TX message header in the queue.
+ *
+ * Reserve memory from the base FIFO engine and then just initialize
+ * the message header.
+ *
+ * We allocate the biggest TX message header we might need (one that'd
+ * fit I2400M_TX_PLD_MAX payloads) -- when it is closed it will be
+ * 'ironed it out' and the unneeded parts removed.
+ *
+ * NOTE:
+ *
+ * Assumes that the previous message is CLOSED (eg: either
+ * there was none or 'i2400m_tx_close()' was called on it).
+ *
+ * Assumes i2400m->tx_lock is taken, and we use that as a barrier
+ */
+static
+void i2400m_tx_new(struct i2400m *i2400m)
+{
+ struct device *dev = i2400m_dev(i2400m);
+ struct i2400m_msg_hdr *tx_msg;
+ BUG_ON(i2400m->tx_msg != NULL);
+try_head:
+ tx_msg = i2400m_tx_fifo_push(i2400m, I2400M_TX_PLD_SIZE, 0);
+ if (tx_msg == NULL)
+ goto out;
+ else if (tx_msg == TAIL_FULL) {
+ i2400m_tx_skip_tail(i2400m);
+ d_printf(2, dev, "new TX message: tail full, trying head\n");
+ goto try_head;
+ }
+ memset(tx_msg, 0, I2400M_TX_PLD_SIZE);
+ tx_msg->size = I2400M_TX_PLD_SIZE;
+out:
+ i2400m->tx_msg = tx_msg;
+ d_printf(2, dev, "new TX message: %p @%zu\n",
+ tx_msg, (void *) tx_msg - i2400m->tx_buf);
+}
+
+
+/*
+ * Finalize the current TX message header
+ *
+ * Sets the message header to be at the proper location depending on
+ * how many descriptors we have (check documentation at the file's
+ * header for more info on that).
+ *
+ * Appends padding bytes to make sure the whole TX message (counting
+ * from the 'relocated' message header) is aligned to
+ * tx_block_size. We assume the _append() code has left enough space
+ * in the FIFO for that. If there are no payloads, just pass, as it
+ * won't be transferred.
+ *
+ * The amount of padding bytes depends on how many payloads are in the
+ * TX message, as the "msg header and payload descriptors" will be
+ * shifted up in the buffer.
+ */
+static
+void i2400m_tx_close(struct i2400m *i2400m)
+{
+ struct device *dev = i2400m_dev(i2400m);
+ struct i2400m_msg_hdr *tx_msg = i2400m->tx_msg;
+ struct i2400m_msg_hdr *tx_msg_moved;
+ size_t aligned_size, padding, hdr_size;
+ void *pad_buf;
+
+ if (tx_msg->size & I2400M_TX_SKIP) /* a skipper? nothing to do */
+ goto out;
+
+ /* Relocate the message header
+ *
+ * Find the current header size, align it to 16 and if we need
+ * to move it so the tail is next to the payloads, move it and
+ * set the offset.
+ *
+ * If it moved, this header is good only for transmission; the
+ * original one (it is kept if we moved) is still used to
+ * figure out where the next TX message starts (and where the
+ * offset to the moved header is).
+ */
+ hdr_size = sizeof(*tx_msg)
+ + le16_to_cpu(tx_msg->num_pls) * sizeof(tx_msg->pld[0]);
+ hdr_size = ALIGN(hdr_size, I2400M_PL_PAD);
+ tx_msg->offset = I2400M_TX_PLD_SIZE - hdr_size;
+ tx_msg_moved = (void *) tx_msg + tx_msg->offset;
+ memmove(tx_msg_moved, tx_msg, hdr_size);
+ tx_msg_moved->size -= tx_msg->offset;
+ /*
+ * Now figure out how much we have to add to the (moved!)
+ * message so the size is a multiple of i2400m->bus_tx_block_size.
+ */
+ aligned_size = ALIGN(tx_msg_moved->size, i2400m->bus_tx_block_size);
+ padding = aligned_size - tx_msg_moved->size;
+ if (padding > 0) {
+ pad_buf = i2400m_tx_fifo_push(i2400m, padding, 0);
+ if (unlikely(WARN_ON(pad_buf == NULL
+ || pad_buf == TAIL_FULL))) {
+ /* This should not happen -- append should verify
+ * there is always space left at least to append
+ * tx_block_size */
+ dev_err(dev,
+ "SW BUG! Possible data leakage from memory the "
+ "device should not read for padding - "
+ "size %lu aligned_size %zu tx_buf %p in "
+ "%zu out %zu\n",
+ (unsigned long) tx_msg_moved->size,
+ aligned_size, i2400m->tx_buf, i2400m->tx_in,
+ i2400m->tx_out);
+ } else
+ memset(pad_buf, 0xad, padding);
+ }
+ tx_msg_moved->padding = cpu_to_le16(padding);
+ tx_msg_moved->size += padding;
+ if (tx_msg != tx_msg_moved)
+ tx_msg->size += padding;
+out:
+ i2400m->tx_msg = NULL;
+}
+
+
+/**
+ * i2400m_tx - send the data in a buffer to the device
+ *
+ * @buf: pointer to the buffer to transmit
+ *
+ * @buf_len: buffer size
+ *
+ * @pl_type: type of the payload we are sending.
+ *
+ * Returns:
+ * 0 if ok, < 0 errno code on error (-ENOSPC, if there is no more
+ * room for the message in the queue).
+ *
+ * Appends the buffer to the TX FIFO and notifies the bus-specific
+ * part of the driver that there is new data ready to transmit.
+ * Once this function returns, the buffer has been copied, so it can
+ * be reused.
+ *
+ * The steps followed to append are explained in detail in the file
+ * header.
+ *
+ * Whenever we write to a message, we increase msg->size, so it
+ * reflects exactly how big the message is. This is needed so that if
+ * we concatenate two messages before they can be sent, the code that
+ * sends the messages can find the boundaries (and it will replace the
+ * size with the real barker before sending).
+ *
+ * Note:
+ *
+ * Cold and warm reset payloads need to be sent as a single
+ * payload, so we handle that.
+ */
+int i2400m_tx(struct i2400m *i2400m, const void *buf, size_t buf_len,
+ enum i2400m_pt pl_type)
+{
+ int result = -ENOSPC;
+ struct device *dev = i2400m_dev(i2400m);
+ unsigned long flags;
+ size_t padded_len;
+ void *ptr;
+ unsigned is_singleton = pl_type == I2400M_PT_RESET_WARM
+ || pl_type == I2400M_PT_RESET_COLD;
+
+ d_fnstart(3, dev, "(i2400m %p skb %p [%zu bytes] pt %u)\n",
+ i2400m, buf, buf_len, pl_type);
+ padded_len = ALIGN(buf_len, I2400M_PL_PAD);
+ d_printf(5, dev, "padded_len %zd buf_len %zd\n", padded_len, buf_len);
+ /* If there is no current TX message, create one; if the
+ * current one is out of payload slots or we have a singleton,
+ * close it and start a new one */
+ spin_lock_irqsave(&i2400m->tx_lock, flags);
+try_new:
+ if (unlikely(i2400m->tx_msg == NULL))
+ i2400m_tx_new(i2400m);
+ else if (unlikely(!i2400m_tx_fits(i2400m)
+ || (is_singleton && i2400m->tx_msg->num_pls != 0))) {
+ d_printf(2, dev, "closing TX message (fits %u singleton "
+ "%u num_pls %u)\n", i2400m_tx_fits(i2400m),
+ is_singleton, i2400m->tx_msg->num_pls);
+ i2400m_tx_close(i2400m);
+ i2400m_tx_new(i2400m);
+ }
+ if (i2400m->tx_msg->size + padded_len > I2400M_TX_BUF_SIZE / 2) {
+ d_printf(2, dev, "TX: message too big, going new\n");
+ i2400m_tx_close(i2400m);
+ i2400m_tx_new(i2400m);
+ }
+ if (i2400m->tx_msg == NULL)
+ goto error_tx_new;
+ /* So we have a current message header; now append space for
+ * the message -- if there is not enough, try the head */
+ ptr = i2400m_tx_fifo_push(i2400m, padded_len,
+ i2400m->bus_tx_block_size);
+ if (ptr == TAIL_FULL) { /* Tail is full, try head */
+ d_printf(2, dev, "pl append: tail full\n");
+ i2400m_tx_close(i2400m);
+ i2400m_tx_skip_tail(i2400m);
+ goto try_new;
+ } else if (ptr == NULL) { /* All full */
+ result = -ENOSPC;
+ d_printf(2, dev, "pl append: all full\n");
+ } else { /* Got space, copy it, set padding */
+ struct i2400m_msg_hdr *tx_msg = i2400m->tx_msg;
+ unsigned num_pls = le16_to_cpu(tx_msg->num_pls);
+ memcpy(ptr, buf, buf_len);
+ memset(ptr + buf_len, 0xad, padded_len - buf_len);
+ i2400m_pld_set(&tx_msg->pld[num_pls], buf_len, pl_type);
+ d_printf(3, dev, "pld 0x%08x (type 0x%1x len 0x%04zx\n",
+ le32_to_cpu(tx_msg->pld[num_pls].val),
+ pl_type, buf_len);
+ tx_msg->num_pls = le16_to_cpu(num_pls+1);
+ tx_msg->size += padded_len;
+ d_printf(2, dev, "TX: appended %zu b (up to %u b) pl #%u \n",
+ padded_len, tx_msg->size, num_pls+1);
+ d_printf(2, dev,
+ "TX: appended hdr @%zu %zu b pl #%u @%zu %zu/%zu b\n",
+ (void *)tx_msg - i2400m->tx_buf, (size_t)tx_msg->size,
+ num_pls+1, ptr - i2400m->tx_buf, buf_len, padded_len);
+ result = 0;
+ if (is_singleton)
+ i2400m_tx_close(i2400m);
+ }
+error_tx_new:
+ spin_unlock_irqrestore(&i2400m->tx_lock, flags);
+ i2400m->bus_tx_kick(i2400m); /* always kick, might free up space */
+ d_fnend(3, dev, "(i2400m %p skb %p [%zu bytes] pt %u) = %d\n",
+ i2400m, buf, buf_len, pl_type, result);
+ return result;
+}
+EXPORT_SYMBOL_GPL(i2400m_tx);
+
+
+/**
+ * i2400m_tx_msg_get - Get the first TX message in the FIFO to start sending it
+ *
+ * @i2400m: device descriptors
+ * @bus_size: where to place the size of the TX message
+ *
+ * Called by the bus-specific driver to get the first TX message at
+ * the FIF that is ready for transmission.
+ *
+ * It sets the state in @i2400m to indicate the bus-specific driver is
+ * transfering that message (i2400m->tx_msg_size).
+ *
+ * Once the transfer is completed, call i2400m_tx_msg_sent().
+ *
+ * Notes:
+ *
+ * The size of the TX message to be transmitted might be smaller than
+ * that of the TX message in the FIFO (in case the header was
+ * shorter). Hence, we copy it in @bus_size, for the bus layer to
+ * use. We keep the message's size in i2400m->tx_msg_size so that
+ * when the bus later is done transferring we know how much to
+ * advance the fifo.
+ *
+ * We collect statistics here as all the data is available and we
+ * assume it is going to work [see i2400m_tx_msg_sent()].
+ */
+struct i2400m_msg_hdr *i2400m_tx_msg_get(struct i2400m *i2400m,
+ size_t *bus_size)
+{
+ struct device *dev = i2400m_dev(i2400m);
+ struct i2400m_msg_hdr *tx_msg, *tx_msg_moved;
+ unsigned long flags, pls;
+
+ d_fnstart(3, dev, "(i2400m %p bus_size %p)\n", i2400m, bus_size);
+ spin_lock_irqsave(&i2400m->tx_lock, flags);
+skip:
+ tx_msg_moved = NULL;
+ if (i2400m->tx_in == i2400m->tx_out) { /* Empty FIFO? */
+ i2400m->tx_in = 0;
+ i2400m->tx_out = 0;
+ d_printf(2, dev, "TX: FIFO empty: resetting\n");
+ goto out_unlock;
+ }
+ tx_msg = i2400m->tx_buf + i2400m->tx_out % I2400M_TX_BUF_SIZE;
+ if (tx_msg->size & I2400M_TX_SKIP) { /* skip? */
+ d_printf(2, dev, "TX: skip: msg @%zu (%zu b)\n",
+ i2400m->tx_out % I2400M_TX_BUF_SIZE,
+ (size_t) tx_msg->size & ~I2400M_TX_SKIP);
+ i2400m->tx_out += tx_msg->size & ~I2400M_TX_SKIP;
+ goto skip;
+ }
+
+ if (tx_msg->num_pls == 0) { /* No payloads? */
+ if (tx_msg == i2400m->tx_msg) { /* open, we are done */
+ d_printf(2, dev,
+ "TX: FIFO empty: open msg w/o payloads @%zu\n",
+ (void *) tx_msg - i2400m->tx_buf);
+ tx_msg = NULL;
+ goto out_unlock;
+ } else { /* closed, skip it */
+ d_printf(2, dev,
+ "TX: skip msg w/o payloads @%zu (%zu b)\n",
+ (void *) tx_msg - i2400m->tx_buf,
+ (size_t) tx_msg->size);
+ i2400m->tx_out += tx_msg->size & ~I2400M_TX_SKIP;
+ goto skip;
+ }
+ }
+ if (tx_msg == i2400m->tx_msg) /* open msg? */
+ i2400m_tx_close(i2400m);
+
+ /* Now we have a valid TX message (with payloads) to TX */
+ tx_msg_moved = (void *) tx_msg + tx_msg->offset;
+ i2400m->tx_msg_size = tx_msg->size;
+ *bus_size = tx_msg_moved->size;
+ d_printf(2, dev, "TX: pid %d msg hdr at @%zu offset +@%zu "
+ "size %zu bus_size %zu\n",
+ current->pid, (void *) tx_msg - i2400m->tx_buf,
+ (size_t) tx_msg->offset, (size_t) tx_msg->size,
+ (size_t) tx_msg_moved->size);
+ tx_msg_moved->barker = le32_to_cpu(I2400M_H2D_PREVIEW_BARKER);
+ tx_msg_moved->sequence = le32_to_cpu(i2400m->tx_sequence++);
+
+ pls = le32_to_cpu(tx_msg_moved->num_pls);
+ i2400m->tx_pl_num += pls; /* Update stats */
+ if (pls > i2400m->tx_pl_max)
+ i2400m->tx_pl_max = pls;
+ if (pls < i2400m->tx_pl_min)
+ i2400m->tx_pl_min = pls;
+ i2400m->tx_num++;
+ i2400m->tx_size_acc += *bus_size;
+ if (*bus_size < i2400m->tx_size_min)
+ i2400m->tx_size_min = *bus_size;
+ if (*bus_size > i2400m->tx_size_max)
+ i2400m->tx_size_max = *bus_size;
+out_unlock:
+ spin_unlock_irqrestore(&i2400m->tx_lock, flags);
+ d_fnstart(3, dev, "(i2400m %p bus_size %p [%zu]) = %p\n",
+ i2400m, bus_size, *bus_size, tx_msg_moved);
+ return tx_msg_moved;
+}
+EXPORT_SYMBOL_GPL(i2400m_tx_msg_get);
+
+
+/**
+ * i2400m_tx_msg_sent - indicate the transmission of a TX message
+ *
+ * @i2400m: device descriptor
+ *
+ * Called by the bus-specific driver when a message has been sent;
+ * this pops it from the FIFO; and as there is space, start the queue
+ * in case it was stopped.
+ *
+ * Should be called even if the message send failed and we are
+ * dropping this TX message.
+ */
+void i2400m_tx_msg_sent(struct i2400m *i2400m)
+{
+ unsigned n;
+ unsigned long flags;
+ struct device *dev = i2400m_dev(i2400m);
+
+ d_fnstart(3, dev, "(i2400m %p)\n", i2400m);
+ spin_lock_irqsave(&i2400m->tx_lock, flags);
+ i2400m->tx_out += i2400m->tx_msg_size;
+ d_printf(2, dev, "TX: sent %zu b\n", (size_t) i2400m->tx_msg_size);
+ i2400m->tx_msg_size = 0;
+ BUG_ON(i2400m->tx_out > i2400m->tx_in);
+ /* level them FIFO markers off */
+ n = i2400m->tx_out / I2400M_TX_BUF_SIZE;
+ i2400m->tx_out %= I2400M_TX_BUF_SIZE;
+ i2400m->tx_in -= n * I2400M_TX_BUF_SIZE;
+ netif_start_queue(i2400m->wimax_dev.net_dev);
+ spin_unlock_irqrestore(&i2400m->tx_lock, flags);
+ d_fnend(3, dev, "(i2400m %p) = void\n", i2400m);
+}
+EXPORT_SYMBOL_GPL(i2400m_tx_msg_sent);
+
+
+/**
+ * i2400m_tx_setup - Initialize the TX queue and infrastructure
+ *
+ * Make sure we reset the TX sequence to zero, as when this function
+ * is called, the firmware has been just restarted.
+ */
+int i2400m_tx_setup(struct i2400m *i2400m)
+{
+ int result;
+
+ /* Do this here only once -- can't do on
+ * i2400m_hard_start_xmit() as we'll cause race conditions if
+ * the WS was scheduled on another CPU */
+ INIT_WORK(&i2400m->wake_tx_ws, i2400m_wake_tx_work);
+
+ i2400m->tx_sequence = 0;
+ i2400m->tx_buf = kmalloc(I2400M_TX_BUF_SIZE, GFP_KERNEL);
+ if (i2400m->tx_buf == NULL)
+ result = -ENOMEM;
+ else
+ result = 0;
+ /* Huh? the bus layer has to define this... */
+ BUG_ON(i2400m->bus_tx_block_size == 0);
+ return result;
+
+}
+
+
+/**
+ * i2400m_tx_release - Tear down the TX queue and infrastructure
+ */
+void i2400m_tx_release(struct i2400m *i2400m)
+{
+ kfree(i2400m->tx_buf);
+}
Implements data transmission to the device; this is done through a software FIFO, as data/control frames can be coalesced (while the device is reading the previous tx transaction, others accumulate). A FIFO is used because at the end it is resource-cheaper that trying to implement scatter/gather over USB. As well, most traffic is going to be download (vs upload). Signed-off-by: Inaky Perez-Gonzalez <inaky@linux.intel.com> --- drivers/net/wimax/i2400m/tx.c | 817 +++++++++++++++++++++++++++++++++++++++++ 1 files changed, 817 insertions(+), 0 deletions(-) create mode 100644 drivers/net/wimax/i2400m/tx.c