diff options
Diffstat (limited to 'drivers/net/wimax/i2400m/tx.c')
| -rw-r--r-- | drivers/net/wimax/i2400m/tx.c | 1013 |
1 files changed, 1013 insertions, 0 deletions
diff --git a/drivers/net/wimax/i2400m/tx.c b/drivers/net/wimax/i2400m/tx.c new file mode 100644 index 000000000..f20886ade --- /dev/null +++ b/drivers/net/wimax/i2400m/tx.c @@ -0,0 +1,1013 @@ +/* + * 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 + * incomplete 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 <linux/slab.h> +#include <linux/export.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. + * 32KiB is insufficient for 1400 MTU, hence increasing + * tx buffer size to 64KiB. + */ + I2400M_TX_BUF_SIZE = 65536, + /** + * 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. + */ + /* + * According to Intel Wimax i3200, i5x50 and i6x50 specification + * documents, the maximum number of payloads per message can be + * up to 60. Increasing the number of payloads to 60 per message + * helps to accommodate smaller payloads in a single transaction. + */ + I2400M_TX_PLD_MAX = 60, + I2400M_TX_PLD_SIZE = sizeof(struct i2400m_msg_hdr) + + I2400M_TX_PLD_MAX * sizeof(struct i2400m_pld), + I2400M_TX_SKIP = 0x80000000, + /* + * According to Intel Wimax i3200, i5x50 and i6x50 specification + * documents, the maximum size of each message can be up to 16KiB. + */ + I2400M_TX_MSG_SIZE = 16384, +}; + +#define TAIL_FULL ((void *)~(unsigned long)NULL) + +/* + * Calculate how much tail room is available + * + * Note the trick here. This path is ONLY caleed for Case A (see + * i2400m_tx_fifo_push() below), where we have: + * + * Case A + * N ___________ + * | tail room | + * | | + * |<- IN ->| + * | | + * | data | + * | | + * |<- OUT ->| + * | | + * | head room | + * 0 ----------- + * + * When calculating the tail_room, tx_in might get to be zero if + * i2400m->tx_in is right at the end of the buffer (really full + * buffer) if there is no head room. In this case, tail_room would be + * I2400M_TX_BUF_SIZE, although it is actually zero. Hence the final + * mod (%) operation. However, when doing this kind of optimization, + * i2400m->tx_in being zero would fail, so we treat is an a special + * case. + */ +static inline +size_t __i2400m_tx_tail_room(struct i2400m *i2400m) +{ + size_t tail_room; + size_t tx_in; + + if (unlikely(i2400m->tx_in == 0)) + return I2400M_TX_BUF_SIZE; + tx_in = i2400m->tx_in % I2400M_TX_BUF_SIZE; + tail_room = I2400M_TX_BUF_SIZE - tx_in; + tail_room %= I2400M_TX_BUF_SIZE; + return tail_room; +} + + +/* + * 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. + * @try_head: specify either to allocate head room or tail room space + * in the TX FIFO. This boolean is required to avoids a system hang + * due to an infinite loop caused by i2400m_tx_fifo_push(). + * The caller must always try to allocate tail room space first by + * calling this routine with try_head = 0. In case if there + * is not enough tail room space but there is enough head room space, + * (i2400m_tx_fifo_push() returns TAIL_FULL) try to allocate head + * room space, by calling this routine again with try_head = 1. + * + * 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. + * + * There is a corner case, wherein i2400m_tx_new() can get into + * an infinite loop calling i2400m_tx_fifo_push(). + * In certain situations, tx_in would have reached on the top of TX FIFO + * and i2400m_tx_tail_room() returns 0, as described below: + * + * N ___________ tail room is zero + * |<- IN ->| + * | | + * | | + * | | + * | data | + * |<- OUT ->| + * | | + * | | + * | head room | + * 0 ----------- + * During such a time, where tail room is zero in the TX FIFO and if there + * is a request to add a payload to TX FIFO, which calls: + * i2400m_tx() + * ->calls i2400m_tx_close() + * ->calls i2400m_tx_skip_tail() + * goto try_new; + * ->calls i2400m_tx_new() + * |----> [try_head:] + * infinite loop | ->calls i2400m_tx_fifo_push() + * | if (tail_room < needed) + * | if (head_room => needed) + * | return TAIL_FULL; + * |<---- goto try_head; + * + * i2400m_tx() calls i2400m_tx_close() to close the message, since there + * is no tail room to accommodate the payload and calls + * i2400m_tx_skip_tail() to skip the tail space. Now i2400m_tx() calls + * i2400m_tx_new() to allocate space for new message header calling + * i2400m_tx_fifo_push() that returns TAIL_FULL, since there is no tail space + * to accommodate the message header, but there is enough head space. + * The i2400m_tx_new() keeps re-retrying by calling i2400m_tx_fifo_push() + * ending up in a loop causing system freeze. + * + * This corner case is avoided by using a try_head boolean, + * as an argument to i2400m_tx_fifo_push(). + * + * 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, bool try_head) +{ + 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_tail_room(i2400m); + if (!try_head && tail_room < needed_size) { + /* + * If the tail room space is not enough to push the message + * in the TX FIFO, then there are two possibilities: + * 1. There is enough head room space to accommodate + * this message in the TX FIFO. + * 2. There is not enough space in the head room and + * in tail room of the TX FIFO to accommodate the message. + * In the case (1), return TAIL_FULL so that the caller + * can figure out, if the caller wants to push the message + * into the head room space. + * In the case (2), return NULL, indicating that the TX FIFO + * cannot accommodate the message. + */ + if (room - tail_room >= needed_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). + * + * Tail room can get to be zero if a message was opened when there was + * space only for a header. _tx_close() will mark it as to-skip (as it + * will have no payloads) and there will be no more space to flush, so + * nothing has to be done here. This is probably cheaper than ensuring + * in _tx_new() that there is some space for payloads...as we could + * always possibly hit the same problem if the payload wouldn't fit. + * + * Note: + * + * Assumes i2400m->tx_lock is taken, and we use that as a barrier + * + * This path is only taken for Case A FIFO situations [see + * i2400m_tx_fifo_push()] + */ +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_tail_room(i2400m); + struct i2400m_msg_hdr *msg = i2400m->tx_buf + tx_in; + if (unlikely(tail_room == 0)) + return; + 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; + bool try_head = false; + BUG_ON(i2400m->tx_msg != NULL); + /* + * In certain situations, TX queue might have enough space to + * accommodate the new message header I2400M_TX_PLD_SIZE, but + * might not have enough space to accommodate the payloads. + * Adding bus_tx_room_min padding while allocating a new TX message + * increases the possibilities of including at least one payload of the + * size <= bus_tx_room_min. + */ +try_head: + tx_msg = i2400m_tx_fifo_push(i2400m, I2400M_TX_PLD_SIZE, + i2400m->bus_tx_room_min, try_head); + 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"); + try_head = true; + 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; + unsigned num_pls; + + if (tx_msg->size & I2400M_TX_SKIP) /* a skipper? nothing to do */ + goto out; + num_pls = le16_to_cpu(tx_msg->num_pls); + /* We can get this situation when a new message was started + * and there was no space to add payloads before hitting the + tail (and taking padding into consideration). */ + if (num_pls == 0) { + tx_msg->size |= I2400M_TX_SKIP; + 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_ALIGN); + 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, 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; + bool try_head = false; + 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_ALIGN); + 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); + /* If tx_buf is NULL, device is shutdown */ + if (i2400m->tx_buf == NULL) { + result = -ESHUTDOWN; + goto error_tx_new; + } +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 == NULL) + goto error_tx_new; + /* + * Check if this skb will fit in the TX queue's current active + * TX message. The total message size must not exceed the maximum + * size of each message I2400M_TX_MSG_SIZE. If it exceeds, + * close the current message and push this skb into the new message. + */ + if (i2400m->tx_msg->size + padded_len > I2400M_TX_MSG_SIZE) { + 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, try_head); + 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); + try_head = true; + 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); + /* kick in most cases, except when the TX subsys is down, as + * it might free space */ + if (likely(result != -ESHUTDOWN)) + i2400m->bus_tx_kick(i2400m); + 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 + * transferring 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); + tx_msg_moved = NULL; + if (i2400m->tx_buf == NULL) + goto out_unlock; +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); + if (i2400m->tx_buf == NULL) + goto out_unlock; + 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; +out_unlock: + 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. Same rational + * for tx_in, tx_out, tx_msg_size and tx_msg. We reset them since + * the memory for TX queue is reallocated. + */ +int i2400m_tx_setup(struct i2400m *i2400m) +{ + int result = 0; + void *tx_buf; + unsigned long flags; + + /* 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); + + tx_buf = kmalloc(I2400M_TX_BUF_SIZE, GFP_ATOMIC); + if (tx_buf == NULL) { + result = -ENOMEM; + goto error_kmalloc; + } + + /* + * Fail the build if we can't fit at least two maximum size messages + * on the TX FIFO [one being delivered while one is constructed]. + */ + BUILD_BUG_ON(2 * I2400M_TX_MSG_SIZE > I2400M_TX_BUF_SIZE); + spin_lock_irqsave(&i2400m->tx_lock, flags); + i2400m->tx_sequence = 0; + i2400m->tx_in = 0; + i2400m->tx_out = 0; + i2400m->tx_msg_size = 0; + i2400m->tx_msg = NULL; + i2400m->tx_buf = tx_buf; + spin_unlock_irqrestore(&i2400m->tx_lock, flags); + /* Huh? the bus layer has to define this... */ + BUG_ON(i2400m->bus_tx_block_size == 0); +error_kmalloc: + return result; + +} + + +/** + * i2400m_tx_release - Tear down the TX queue and infrastructure + */ +void i2400m_tx_release(struct i2400m *i2400m) +{ + unsigned long flags; + spin_lock_irqsave(&i2400m->tx_lock, flags); + kfree(i2400m->tx_buf); + i2400m->tx_buf = NULL; + spin_unlock_irqrestore(&i2400m->tx_lock, flags); +} |