| /* |
| * 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 <linux/slab.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 = 0; |
| 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 = 1; |
| 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 = 0; |
| 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 = 1; |
| 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 |
| * 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); |
| 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); |
| } |
