brcmfmac: use pre-allocated scatter-gather table for txglomming

Instead of allocating a scatter-gather table for every transmit
reuse a pre-allocated table. The transmit path will be faster by
taking out this allocation.

Reviewed-by: Daniel (Deognyoun) Kim <dekim@broadcom.com>
Reviewed-by: Hante Meuleman <meuleman@broadcom.com>
Reviewed-by: Franky (Zhenhui) Lin <frankyl@broadcom.com>
Reviewed-by: Pieter-Paul Giesberts <pieterpg@broadcom.com>
Signed-off-by: Arend van Spriel <arend@broadcom.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

3 files changed, 41 insertions, 16 deletions

diff --git a/drivers/net/wireless/brcm80211/brcmfmac/bcmsdh.c b/drivers/net/wireless/brcm80211/brcmfmac/bcmsdh.c
index 07e7d2520257..9eea7d4dd501 100644
--- a/drivers/net/wireless/brcm80211/brcmfmac/bcmsdh.c
+++ b/drivers/net/wireless/brcm80211/brcmfmac/bcmsdh.c
@@ -53,6 +53,12 @@
 /* Maximum milliseconds to wait for F2 to come up */
 #define SDIO_WAIT_F2RDY 3000
 
+#define BRCMF_DEFAULT_TXGLOM_SIZE       32  /* max tx frames in glom chain */
+#define BRCMF_DEFAULT_RXGLOM_SIZE       32  /* max rx frames in glom chain */
+
+static int brcmf_sdiod_txglomsz = BRCMF_DEFAULT_TXGLOM_SIZE;
+module_param_named(txglomsz, brcmf_sdiod_txglomsz, int, 0);
+MODULE_PARM_DESC(txglomsz, "maximum tx packet chain size [SDIO]");
 
 static irqreturn_t brcmf_sdiod_oob_irqhandler(int irq, void *dev_id)
 {
@@ -487,7 +493,6 @@ static int brcmf_sdiod_sglist_rw(struct brcmf_sdio_dev *sdiodev, uint fn,
         struct mmc_request mmc_req;
         struct mmc_command mmc_cmd;
         struct mmc_data mmc_dat;
-        struct sg_table st;
         struct scatterlist *sgl;
         int ret = 0;
 
@@ -532,16 +537,11 @@ static int brcmf_sdiod_sglist_rw(struct brcmf_sdio_dev *sdiodev, uint fn,
         pkt_offset = 0;
         pkt_next = target_list->next;
 
-        if (sg_alloc_table(&st, max_seg_cnt, GFP_KERNEL)) {
-                ret = -ENOMEM;
-                goto exit;
-        }
-
         memset(&mmc_req, 0, sizeof(struct mmc_request));
         memset(&mmc_cmd, 0, sizeof(struct mmc_command));
         memset(&mmc_dat, 0, sizeof(struct mmc_data));
 
-        mmc_dat.sg = st.sgl;
+        mmc_dat.sg = sdiodev->sgtable.sgl;
         mmc_dat.blksz = func_blk_sz;
         mmc_dat.flags = write ? MMC_DATA_WRITE : MMC_DATA_READ;
         mmc_cmd.opcode = SD_IO_RW_EXTENDED;
@@ -557,7 +557,7 @@ static int brcmf_sdiod_sglist_rw(struct brcmf_sdio_dev *sdiodev, uint fn,
         while (seg_sz) {
                 req_sz = 0;
                 sg_cnt = 0;
-                sgl = st.sgl;
+                sgl = sdiodev->sgtable.sgl;
                 /* prep sg table */
                 while (pkt_next != (struct sk_buff *)target_list) {
                         pkt_data = pkt_next->data + pkt_offset;
@@ -639,7 +639,7 @@ static int brcmf_sdiod_sglist_rw(struct brcmf_sdio_dev *sdiodev, uint fn,
         }
 
 exit:
-        sg_free_table(&st);
+        sg_init_table(sdiodev->sgtable.sgl, sdiodev->sgtable.orig_nents);
         while ((pkt_next = __skb_dequeue(&local_list)) != NULL)
                 brcmu_pkt_buf_free_skb(pkt_next);
 
@@ -863,6 +863,29 @@ int brcmf_sdiod_abort(struct brcmf_sdio_dev *sdiodev, uint fn)
         return 0;
 }
 
+static void brcmf_sdiod_sgtable_alloc(struct brcmf_sdio_dev *sdiodev)
+{
+        uint nents;
+        int err;
+
+        if (!sdiodev->sg_support)
+                return;
+
+        nents = max_t(uint, BRCMF_DEFAULT_RXGLOM_SIZE, brcmf_sdiod_txglomsz);
+        nents += (nents >> 4) + 1;
+
+        WARN_ON(nents > sdiodev->max_segment_count);
+
+        brcmf_dbg(TRACE, "nents=%d\n", nents);
+        err = sg_alloc_table(&sdiodev->sgtable, nents, GFP_KERNEL);
+        if (err < 0) {
+                brcmf_err("allocation failed: disable scatter-gather");
+                sdiodev->sg_support = false;
+        }
+
+        sdiodev->txglomsz = brcmf_sdiod_txglomsz;
+}
+
 static int brcmf_sdiod_remove(struct brcmf_sdio_dev *sdiodev)
 {
         if (sdiodev->bus) {
@@ -880,6 +903,7 @@ static int brcmf_sdiod_remove(struct brcmf_sdio_dev *sdiodev)
         sdio_disable_func(sdiodev->func[1]);
         sdio_release_host(sdiodev->func[1]);
 
+        sg_free_table(&sdiodev->sgtable);
         sdiodev->sbwad = 0;
 
         return 0;
@@ -935,6 +959,11 @@ static int brcmf_sdiod_probe(struct brcmf_sdio_dev *sdiodev)
                                            SG_MAX_SINGLE_ALLOC);
         sdiodev->max_segment_size = host->max_seg_size;
 
+        /* allocate scatter-gather table. sg support
+         * will be disabled upon allocation failure.
+         */
+        brcmf_sdiod_sgtable_alloc(sdiodev);
+
         /* try to attach to the target device */
         sdiodev->bus = brcmf_sdio_probe(sdiodev);
         if (!sdiodev->bus) {
diff --git a/drivers/net/wireless/brcm80211/brcmfmac/dhd_sdio.c b/drivers/net/wireless/brcm80211/brcmfmac/dhd_sdio.c
index c894ee358153..b5ded8a57cb0 100644
--- a/drivers/net/wireless/brcm80211/brcmfmac/dhd_sdio.c
+++ b/drivers/net/wireless/brcm80211/brcmfmac/dhd_sdio.c
@@ -113,8 +113,6 @@ struct rte_console {
 #define BRCMF_TXBOUND   20      /* Default for max tx frames in
                                  one scheduling */
 
-#define BRCMF_DEFAULT_TXGLOM_SIZE       32  /* max tx frames in glom chain */
-
 #define BRCMF_TXMINMAX  1       /* Max tx frames if rx still pending */
 
 #define MEMBLOCK        2048    /* Block size used for downloading
@@ -511,10 +509,6 @@ static const uint max_roundup = 512;
 
 #define ALIGNMENT  4
 
-static int brcmf_sdio_txglomsz = BRCMF_DEFAULT_TXGLOM_SIZE;
-module_param_named(txglomsz, brcmf_sdio_txglomsz, int, 0);
-MODULE_PARM_DESC(txglomsz, "maximum tx packet chain size [SDIO]");
-
 enum brcmf_sdio_frmtype {
         BRCMF_SDIO_FT_NORMAL,
         BRCMF_SDIO_FT_SUPER,
@@ -2321,7 +2315,7 @@ static uint brcmf_sdio_sendfromq(struct brcmf_sdio *bus, uint maxframes)
                 __skb_queue_head_init(&pktq);
                 if (bus->txglom)
                         pkt_num = min_t(u8, bus->tx_max - bus->tx_seq,
-                                        brcmf_sdio_txglomsz);
+                                        bus->sdiodev->txglomsz);
                 pkt_num = min_t(u32, pkt_num,
                                 brcmu_pktq_mlen(&bus->txq, ~bus->flowcontrol));
                 spin_lock_bh(&bus->txqlock);
diff --git a/drivers/net/wireless/brcm80211/brcmfmac/sdio_host.h b/drivers/net/wireless/brcm80211/brcmfmac/sdio_host.h
index 5e53eb1b2ffa..3deab7959a0d 100644
--- a/drivers/net/wireless/brcm80211/brcmfmac/sdio_host.h
+++ b/drivers/net/wireless/brcm80211/brcmfmac/sdio_host.h
@@ -180,6 +180,8 @@ struct brcmf_sdio_dev {
         uint max_request_size;
         ushort max_segment_count;
         uint max_segment_size;
+        uint txglomsz;
+        struct sg_table sgtable;
 };
 
 /* sdio core registers */