@@ -32,6 +32,7 @@
#include <linux/debugfs.h>
#include <linux/vmalloc.h>
#include <linux/platform_data/brcmfmac-sdio.h>
+#include <linux/moduleparam.h>
#include <asm/unaligned.h>
#include <defs.h>
#include <brcmu_wifi.h>
@@ -110,6 +111,8 @@ 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
@@ -360,6 +363,8 @@ struct brcmf_sdio_hdrinfo {
u16 len_left;
u16 len_nxtfrm;
u8 dat_offset;
+ bool lastfrm;
+ u16 tail_pad;
};
/* misc chip info needed by some of the routines */
@@ -455,6 +460,8 @@ struct brcmf_sdio {
bool sleeping; /* SDIO bus sleeping */
u8 tx_hdrlen; /* sdio bus header length for tx packet */
+ bool txglom; /* host tx glomming enable flag */
+ struct sk_buff *txglom_sgpad; /* scatter-gather padding buffer */
};
/* clkstate */
@@ -479,6 +486,10 @@ 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,
@@ -1102,10 +1113,18 @@ static void brcmf_sdbrcm_free_glom(struct brcmf_sdio *bus)
* host and WiFi dongle which contains information needed for SDIO core and
* firmware
*
- * It consists of 2 parts: hw header and software header
+ * It consists of 3 parts: hardware header, hardware extension header and
+ * software header
* hardware header (frame tag) - 4 bytes
* Byte 0~1: Frame length
* Byte 2~3: Checksum, bit-wise inverse of frame length
+ * hardware extension header - 8 bytes
+ * Tx glom mode only, N/A for Rx or normal Tx
+ * Byte 0~1: Packet length excluding hw frame tag
+ * Byte 2: Reserved
+ * Byte 3: Frame flags, bit 0: last frame indication
+ * Byte 4~5: Reserved
+ * Byte 6~7: Tail padding length
* software header - 8 bytes
* Byte 0: Rx/Tx sequence number
* Byte 1: 4 MSB Channel number, 4 LSB arbitrary flag
@@ -1116,6 +1135,7 @@ static void brcmf_sdbrcm_free_glom(struct brcmf_sdio *bus)
* Byte 6~7: Reserved
*/
#define SDPCM_HWHDR_LEN 4
+#define SDPCM_HWEXT_LEN 8
#define SDPCM_SWHDR_LEN 8
#define SDPCM_HDRLEN (SDPCM_HWHDR_LEN + SDPCM_SWHDR_LEN)
/* software header */
@@ -1265,18 +1285,28 @@ static inline void brcmf_sdio_update_hwhdr(u8 *header, u16 frm_length)
static void brcmf_sdio_hdpack(struct brcmf_sdio *bus, u8 *header,
struct brcmf_sdio_hdrinfo *hd_info)
{
- u32 sw_header;
+ u32 hdrval;
+ u8 hdr_offset;
brcmf_sdio_update_hwhdr(header, hd_info->len);
-
- sw_header = bus->tx_seq;
- sw_header |= (hd_info->channel << SDPCM_CHANNEL_SHIFT) &
- SDPCM_CHANNEL_MASK;
- sw_header |= (hd_info->dat_offset << SDPCM_DOFFSET_SHIFT) &
- SDPCM_DOFFSET_MASK;
- *(((__le32 *)header) + 1) = cpu_to_le32(sw_header);
- *(((__le32 *)header) + 2) = 0;
- trace_brcmf_sdpcm_hdr(SDPCM_TX, header);
+ hdr_offset = SDPCM_HWHDR_LEN;
+
+ if (bus->txglom) {
+ hdrval = (hd_info->len - hdr_offset) | (hd_info->lastfrm << 24);
+ *((__le32 *)(header + hdr_offset)) = cpu_to_le32(hdrval);
+ hdrval = (u16)hd_info->tail_pad << 16;
+ *(((__le32 *)(header + hdr_offset)) + 1) = cpu_to_le32(hdrval);
+ hdr_offset += SDPCM_HWEXT_LEN;
+ }
+
+ hdrval = hd_info->seq_num;
+ hdrval |= (hd_info->channel << SDPCM_CHANNEL_SHIFT) &
+ SDPCM_CHANNEL_MASK;
+ hdrval |= (hd_info->dat_offset << SDPCM_DOFFSET_SHIFT) &
+ SDPCM_DOFFSET_MASK;
+ *((__le32 *)(header + hdr_offset)) = cpu_to_le32(hdrval);
+ *(((__le32 *)(header + hdr_offset)) + 1) = 0;
+ trace_brcmf_sdpcm_hdr(SDPCM_TX + !!(bus->txglom), header);
}
static u8 brcmf_sdbrcm_rxglom(struct brcmf_sdio *bus, u8 rxseq)
@@ -1876,6 +1906,34 @@ brcmf_sdbrcm_wait_event_wakeup(struct brcmf_sdio *bus)
return;
}
+static int brcmf_sdio_txpkt_hdalign(struct brcmf_sdio *bus, struct sk_buff *pkt)
+{
+ u16 head_align, head_pad;
+ u8 *dat_buf;
+
+ /* SDIO ADMA requires at least 32 bit alignment */
+ head_align = 4;
+ if (bus->sdiodev->pdata && bus->sdiodev->pdata->sd_head_align > 4)
+ head_align = bus->sdiodev->pdata->sd_head_align;
+
+ dat_buf = (u8 *)(pkt->data);
+
+ /* Check head padding */
+ head_pad = ((unsigned long)dat_buf % head_align);
+ if (head_pad) {
+ if (skb_headroom(pkt) < head_pad) {
+ bus->sdiodev->bus_if->tx_realloc++;
+ head_pad = 0;
+ if (skb_cow(pkt, head_pad))
+ return -ENOMEM;
+ }
+ skb_push(pkt, head_pad);
+ dat_buf = (u8 *)(pkt->data);
+ memset(dat_buf, 0, head_pad + bus->tx_hdrlen);
+ }
+ return head_pad;
+}
+
/**
* struct brcmf_skbuff_cb reserves first two bytes in sk_buff::cb for
* bus layer usage.
@@ -1885,16 +1943,18 @@ brcmf_sdbrcm_wait_event_wakeup(struct brcmf_sdio *bus)
/* bit mask of data length chopped from the previous packet */
#define ALIGN_SKB_CHOP_LEN_MASK 0x7fff
-static int brcmf_sdio_txpkt_prep_sg(struct brcmf_sdio_dev *sdiodev,
+static int brcmf_sdio_txpkt_prep_sg(struct brcmf_sdio *bus,
struct sk_buff_head *pktq,
- struct sk_buff *pkt, uint chan)
+ struct sk_buff *pkt, u16 total_len)
{
+ struct brcmf_sdio_dev *sdiodev;
struct sk_buff *pkt_pad;
- u16 tail_pad, tail_chop, sg_align;
+ u16 tail_pad, tail_chop, sg_align, chain_pad;
unsigned int blksize;
- u8 *dat_buf;
- int ntail;
+ bool lastfrm;
+ int ntail, ret;
+ sdiodev = bus->sdiodev;
blksize = sdiodev->func[SDIO_FUNC_2]->cur_blksize;
sg_align = 4;
if (sdiodev->pdata && sdiodev->pdata->sd_sgentry_align > 4)
@@ -1903,14 +1963,23 @@ static int brcmf_sdio_txpkt_prep_sg(struct brcmf_sdio_dev *sdiodev,
WARN_ON(blksize % sg_align);
/* Check tail padding */
- pkt_pad = NULL;
+ lastfrm = skb_queue_is_last(pktq, pkt);
+ tail_pad = 0;
tail_chop = pkt->len % sg_align;
- tail_pad = sg_align - tail_chop;
- tail_pad += blksize - (pkt->len + tail_pad) % blksize;
+ if (tail_chop)
+ tail_pad = sg_align - tail_chop;
+ chain_pad = (total_len + tail_pad) % blksize;
+ if (lastfrm && chain_pad)
+ tail_pad += blksize - chain_pad;
if (skb_tailroom(pkt) < tail_pad && pkt->len > blksize) {
- pkt_pad = brcmu_pkt_buf_get_skb(tail_pad + tail_chop);
+ pkt_pad = bus->txglom_sgpad;
+ if (pkt_pad == NULL)
+ brcmu_pkt_buf_get_skb(tail_pad + tail_chop);
if (pkt_pad == NULL)
return -ENOMEM;
+ ret = brcmf_sdio_txpkt_hdalign(bus, pkt_pad);
+ if (unlikely(ret < 0))
+ return ret;
memcpy(pkt_pad->data,
pkt->data + pkt->len - tail_chop,
tail_chop);
@@ -1925,14 +1994,10 @@ static int brcmf_sdio_txpkt_prep_sg(struct brcmf_sdio_dev *sdiodev,
return -ENOMEM;
if (skb_linearize(pkt))
return -ENOMEM;
- dat_buf = (u8 *)(pkt->data);
__skb_put(pkt, tail_pad);
}
- if (pkt_pad)
- return pkt->len + tail_chop;
- else
- return pkt->len - tail_pad;
+ return tail_pad;
}
/**
@@ -1951,58 +2016,66 @@ static int
brcmf_sdio_txpkt_prep(struct brcmf_sdio *bus, struct sk_buff_head *pktq,
uint chan)
{
- u16 head_pad, head_align;
+ u16 head_pad, total_len;
struct sk_buff *pkt_next;
- u8 *dat_buf;
- int err;
+ u8 txseq;
+ int ret;
struct brcmf_sdio_hdrinfo hd_info = {0};
- /* SDIO ADMA requires at least 32 bit alignment */
- head_align = 4;
- if (bus->sdiodev->pdata && bus->sdiodev->pdata->sd_head_align > 4)
- head_align = bus->sdiodev->pdata->sd_head_align;
+ txseq = bus->tx_seq;
+ total_len = 0;
+ skb_queue_walk(pktq, pkt_next) {
+ /* alignment packet inserted in previous
+ * loop cycle can be skipped as it is
+ * already properly aligned and does not
+ * need an sdpcm header.
+ */
+ if (*(u32 *)(pkt_next->cb) & ALIGN_SKB_FLAG)
+ continue;
- pkt_next = pktq->next;
- dat_buf = (u8 *)(pkt_next->data);
+ /* align packet data pointer */
+ ret = brcmf_sdio_txpkt_hdalign(bus, pkt_next);
+ if (ret < 0)
+ return ret;
+ head_pad = (u16)ret;
+ if (head_pad)
+ memset(pkt_next->data, 0, head_pad + bus->tx_hdrlen);
- /* Check head padding */
- head_pad = ((unsigned long)dat_buf % head_align);
- if (head_pad) {
- if (skb_headroom(pkt_next) < head_pad) {
- bus->sdiodev->bus_if->tx_realloc++;
- head_pad = 0;
- if (skb_cow(pkt_next, head_pad))
- return -ENOMEM;
- }
- skb_push(pkt_next, head_pad);
- dat_buf = (u8 *)(pkt_next->data);
- memset(dat_buf, 0, head_pad + bus->tx_hdrlen);
- }
+ total_len += pkt_next->len;
- if (bus->sdiodev->sg_support && pktq->qlen > 1) {
- err = brcmf_sdio_txpkt_prep_sg(bus->sdiodev, pktq,
- pkt_next, chan);
- if (err < 0)
- return err;
- hd_info.len = (u16)err;
- } else {
hd_info.len = pkt_next->len;
- }
-
- hd_info.channel = chan;
- hd_info.dat_offset = head_pad + bus->tx_hdrlen;
-
- /* Now fill the header */
- brcmf_sdio_hdpack(bus, dat_buf, &hd_info);
-
- if (BRCMF_BYTES_ON() &&
- ((BRCMF_CTL_ON() && chan == SDPCM_CONTROL_CHANNEL) ||
- (BRCMF_DATA_ON() && chan != SDPCM_CONTROL_CHANNEL)))
- brcmf_dbg_hex_dump(true, pkt_next, hd_info.len, "Tx Frame:\n");
- else if (BRCMF_HDRS_ON())
- brcmf_dbg_hex_dump(true, pkt_next, head_pad + bus->tx_hdrlen,
- "Tx Header:\n");
+ hd_info.lastfrm = skb_queue_is_last(pktq, pkt_next);
+ if (bus->txglom && pktq->qlen > 1) {
+ ret = brcmf_sdio_txpkt_prep_sg(bus, pktq,
+ pkt_next, total_len);
+ if (ret < 0)
+ return ret;
+ hd_info.tail_pad = (u16)ret;
+ total_len += (u16)ret;
+ }
+ hd_info.channel = chan;
+ hd_info.dat_offset = head_pad + bus->tx_hdrlen;
+ hd_info.seq_num = txseq++;
+
+ /* Now fill the header */
+ brcmf_sdio_hdpack(bus, pkt_next->data, &hd_info);
+
+ if (BRCMF_BYTES_ON() &&
+ ((BRCMF_CTL_ON() && chan == SDPCM_CONTROL_CHANNEL) ||
+ (BRCMF_DATA_ON() && chan != SDPCM_CONTROL_CHANNEL)))
+ brcmf_dbg_hex_dump(true, pkt_next, hd_info.len,
+ "Tx Frame:\n");
+ else if (BRCMF_HDRS_ON())
+ brcmf_dbg_hex_dump(true, pkt_next,
+ head_pad + bus->tx_hdrlen,
+ "Tx Header:\n");
+ }
+ /* Hardware length tag of the first packet should be total
+ * length of the chain (including padding)
+ */
+ if (bus->txglom)
+ brcmf_sdio_update_hwhdr(pktq->next->data, total_len);
return 0;
}
@@ -2020,6 +2093,7 @@ brcmf_sdio_txpkt_postp(struct brcmf_sdio *bus, struct sk_buff_head *pktq)
{
u8 *hdr;
u32 dat_offset;
+ u16 tail_pad;
u32 dummy_flags, chop_len;
struct sk_buff *pkt_next, *tmp, *pkt_prev;
@@ -2029,42 +2103,42 @@ brcmf_sdio_txpkt_postp(struct brcmf_sdio *bus, struct sk_buff_head *pktq)
chop_len = dummy_flags & ALIGN_SKB_CHOP_LEN_MASK;
if (chop_len) {
pkt_prev = pkt_next->prev;
- memcpy(pkt_prev->data + pkt_prev->len,
- pkt_next->data, chop_len);
skb_put(pkt_prev, chop_len);
}
__skb_unlink(pkt_next, pktq);
brcmu_pkt_buf_free_skb(pkt_next);
} else {
- hdr = pkt_next->data + SDPCM_HWHDR_LEN;
+ hdr = pkt_next->data + bus->tx_hdrlen - SDPCM_SWHDR_LEN;
dat_offset = le32_to_cpu(*(__le32 *)hdr);
dat_offset = (dat_offset & SDPCM_DOFFSET_MASK) >>
SDPCM_DOFFSET_SHIFT;
skb_pull(pkt_next, dat_offset);
+ if (bus->txglom) {
+ tail_pad = le16_to_cpu(*(__le16 *)(hdr - 2));
+ skb_trim(pkt_next, pkt_next->len - tail_pad);
+ }
}
}
}
/* Writes a HW/SW header into the packet and sends it. */
/* Assumes: (a) header space already there, (b) caller holds lock */
-static int brcmf_sdbrcm_txpkt(struct brcmf_sdio *bus, struct sk_buff *pkt,
+static int brcmf_sdbrcm_txpkt(struct brcmf_sdio *bus, struct sk_buff_head *pktq,
uint chan)
{
int ret;
int i;
- struct sk_buff_head localq;
+ struct sk_buff *pkt_next, *tmp;
brcmf_dbg(TRACE, "Enter\n");
- __skb_queue_head_init(&localq);
- __skb_queue_tail(&localq, pkt);
- ret = brcmf_sdio_txpkt_prep(bus, &localq, chan);
+ ret = brcmf_sdio_txpkt_prep(bus, pktq, chan);
if (ret)
goto done;
sdio_claim_host(bus->sdiodev->func[1]);
ret = brcmf_sdcard_send_pkt(bus->sdiodev, bus->sdiodev->sbwad,
- SDIO_FUNC_2, F2SYNC, &localq);
+ SDIO_FUNC_2, F2SYNC, pktq);
bus->sdcnt.f2txdata++;
if (ret < 0) {
@@ -2088,42 +2162,56 @@ static int brcmf_sdbrcm_txpkt(struct brcmf_sdio *bus, struct sk_buff *pkt,
if ((hi == 0) && (lo == 0))
break;
}
-
}
sdio_release_host(bus->sdiodev->func[1]);
- if (ret == 0)
- bus->tx_seq = (bus->tx_seq + 1) % SDPCM_SEQ_WRAP;
done:
- brcmf_sdio_txpkt_postp(bus, &localq);
- __skb_dequeue_tail(&localq);
- brcmf_txcomplete(bus->sdiodev->dev, pkt, ret == 0);
+ brcmf_sdio_txpkt_postp(bus, pktq);
+ if (ret == 0)
+ bus->tx_seq = (bus->tx_seq + pktq->qlen) % SDPCM_SEQ_WRAP;
+ skb_queue_walk_safe(pktq, pkt_next, tmp) {
+ __skb_unlink(pkt_next, pktq);
+ brcmf_txcomplete(bus->sdiodev->dev, pkt_next, ret == 0);
+ }
return ret;
}
static uint brcmf_sdbrcm_sendfromq(struct brcmf_sdio *bus, uint maxframes)
{
struct sk_buff *pkt;
+ struct sk_buff_head pktq;
u32 intstatus = 0;
- int ret = 0, prec_out;
+ int ret = 0, prec_out, i;
uint cnt = 0;
- u8 tx_prec_map;
+ u8 tx_prec_map, pkt_num;
brcmf_dbg(TRACE, "Enter\n");
tx_prec_map = ~bus->flowcontrol;
/* Send frames until the limit or some other event */
- for (cnt = 0; (cnt < maxframes) && data_ok(bus); cnt++) {
+ for (cnt = 0; (cnt < maxframes) && data_ok(bus);) {
+ pkt_num = 1;
+ __skb_queue_head_init(&pktq);
+ if (bus->txglom)
+ pkt_num = min_t(u8, bus->tx_max - bus->tx_seq,
+ brcmf_sdio_txglomsz);
+ pkt_num = min_t(u32, pkt_num,
+ brcmu_pktq_mlen(&bus->txq, ~bus->flowcontrol));
spin_lock_bh(&bus->txqlock);
- pkt = brcmu_pktq_mdeq(&bus->txq, tx_prec_map, &prec_out);
- if (pkt == NULL) {
- spin_unlock_bh(&bus->txqlock);
- break;
+ for (i = 0; i < pkt_num; i++) {
+ pkt = brcmu_pktq_mdeq(&bus->txq, tx_prec_map,
+ &prec_out);
+ if (pkt == NULL)
+ break;
+ __skb_queue_tail(&pktq, pkt);
}
spin_unlock_bh(&bus->txqlock);
+ if (i == 0)
+ break;
- ret = brcmf_sdbrcm_txpkt(bus, pkt, SDPCM_DATA_CHANNEL);
+ ret = brcmf_sdbrcm_txpkt(bus, &pktq, SDPCM_DATA_CHANNEL);
+ cnt += i;
/* In poll mode, need to check for other events */
if (!bus->intr && cnt) {
@@ -2670,7 +2758,7 @@ static int
brcmf_sdbrcm_bus_txctl(struct device *dev, unsigned char *msg, uint msglen)
{
u8 *frame;
- u16 len;
+ u16 len, pad;
uint retries = 0;
u8 doff = 0;
int ret = -1;
@@ -2697,13 +2785,15 @@ brcmf_sdbrcm_bus_txctl(struct device *dev, unsigned char *msg, uint msglen)
doff += bus->tx_hdrlen;
/* Round send length to next SDIO block */
+ pad = 0;
if (bus->roundup && bus->blocksize && (len > bus->blocksize)) {
- u16 pad = bus->blocksize - (len % bus->blocksize);
- if ((pad <= bus->roundup) && (pad < bus->blocksize))
- len += pad;
+ pad = bus->blocksize - (len % bus->blocksize);
+ if ((pad > bus->roundup) || (pad >= bus->blocksize))
+ pad = 0;
} else if (len % BRCMF_SDALIGN) {
- len += BRCMF_SDALIGN - (len % BRCMF_SDALIGN);
+ pad = BRCMF_SDALIGN - (len % BRCMF_SDALIGN);
}
+ len += pad;
/* Satisfy length-alignment requirements */
if (len & (ALIGNMENT - 1))
@@ -2719,8 +2809,16 @@ brcmf_sdbrcm_bus_txctl(struct device *dev, unsigned char *msg, uint msglen)
hd_info.len = (u16)msglen;
hd_info.channel = SDPCM_CONTROL_CHANNEL;
hd_info.dat_offset = doff;
+ hd_info.seq_num = bus->tx_seq;
+ if (bus->txglom) {
+ hd_info.lastfrm = true;
+ hd_info.tail_pad = pad;
+ }
brcmf_sdio_hdpack(bus, frame, &hd_info);
+ if (bus->txglom)
+ brcmf_sdio_update_hwhdr(frame, len);
+
if (!data_ok(bus)) {
brcmf_dbg(INFO, "No bus credit bus->tx_max %d, bus->tx_seq %d\n",
bus->tx_max, bus->tx_seq);
@@ -3435,11 +3533,15 @@ static int brcmf_sdbrcm_bus_preinit(struct device *dev)
struct brcmf_bus *bus_if = dev_get_drvdata(dev);
struct brcmf_sdio_dev *sdiodev = bus_if->bus_priv.sdio;
struct brcmf_sdio *bus = sdiodev->bus;
+ uint pad_size;
u32 value;
u8 idx;
int err;
- /* sdio bus core specific dcmd */
+ /* the commands below use the terms tx and rx from
+ * a device perspective, ie. bus:txglom affects the
+ * bus transfers from device to host.
+ */
idx = brcmf_sdio_chip_getinfidx(bus->ci, BCMA_CORE_SDIO_DEV);
if (bus->ci->c_inf[idx].rev < 12) {
/* for sdio core rev < 12, disable txgloming */
@@ -3456,6 +3558,32 @@ static int brcmf_sdbrcm_bus_preinit(struct device *dev)
err = brcmf_iovar_data_set(dev, "bus:txglomalign", &value,
sizeof(u32));
}
+
+ if (err < 0)
+ goto done;
+
+ bus->tx_hdrlen = SDPCM_HWHDR_LEN + SDPCM_SWHDR_LEN;
+ if (sdiodev->sg_support) {
+ bus->txglom = false;
+ value = 1;
+ pad_size = bus->sdiodev->func[2]->cur_blksize << 1;
+ bus->txglom_sgpad = brcmu_pkt_buf_get_skb(pad_size);
+ if (!bus->txglom_sgpad)
+ brcmf_err("allocating txglom padding skb failed, reduced performance\n");
+
+ err = brcmf_iovar_data_set(bus->sdiodev->dev, "bus:rxglom",
+ &value, sizeof(u32));
+ if (err < 0) {
+ /* bus:rxglom is allowed to fail */
+ err = 0;
+ } else {
+ bus->txglom = true;
+ bus->tx_hdrlen += SDPCM_HWEXT_LEN;
+ }
+ }
+ brcmf_bus_add_txhdrlen(bus->sdiodev->dev, bus->tx_hdrlen);
+
+done:
return err;
}
@@ -3929,6 +4057,7 @@ static void brcmf_sdbrcm_release(struct brcmf_sdio *bus)
brcmf_sdbrcm_release_dongle(bus);
}
+ brcmu_pkt_buf_free_skb(bus->txglom_sgpad);
brcmf_sdbrcm_release_malloc(bus);
kfree(bus);
@@ -4034,8 +4163,6 @@ void *brcmf_sdbrcm_probe(u32 regsva, struct brcmf_sdio_dev *sdiodev)
brcmf_sdio_debugfs_create(bus);
brcmf_dbg(INFO, "completed!!\n");
- brcmf_bus_add_txhdrlen(bus->sdiodev->dev, bus->tx_hdrlen);
-
/* if firmware path present try to download and bring up bus */
ret = brcmf_bus_start(bus->sdiodev->dev);
if (ret != 0) {