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    Subject[PATCH 10/23] wfx: add bh.c/bh.h
    Date
    From: Jérôme Pouiller <jerome.pouiller@silabs.com>

    Signed-off-by: Jérôme Pouiller <jerome.pouiller@silabs.com>
    ---
    drivers/net/wireless/silabs/wfx/bh.c | 333 +++++++++++++++++++++++++++
    drivers/net/wireless/silabs/wfx/bh.h | 33 +++
    2 files changed, 366 insertions(+)
    create mode 100644 drivers/net/wireless/silabs/wfx/bh.c
    create mode 100644 drivers/net/wireless/silabs/wfx/bh.h

    diff --git a/drivers/net/wireless/silabs/wfx/bh.c b/drivers/net/wireless/silabs/wfx/bh.c
    new file mode 100644
    index 000000000000..2ffa587aefaa
    --- /dev/null
    +++ b/drivers/net/wireless/silabs/wfx/bh.c
    @@ -0,0 +1,333 @@
    +// SPDX-License-Identifier: GPL-2.0-only
    +/*
    + * Interrupt bottom half (BH).
    + *
    + * Copyright (c) 2017-2020, Silicon Laboratories, Inc.
    + * Copyright (c) 2010, ST-Ericsson
    + */
    +#include <linux/gpio/consumer.h>
    +#include <net/mac80211.h>
    +
    +#include "bh.h"
    +#include "wfx.h"
    +#include "hwio.h"
    +#include "traces.h"
    +#include "hif_rx.h"
    +#include "hif_api_cmd.h"
    +
    +static void device_wakeup(struct wfx_dev *wdev)
    +{
    + int max_retry = 3;
    +
    + if (!wdev->pdata.gpio_wakeup)
    + return;
    + if (gpiod_get_value_cansleep(wdev->pdata.gpio_wakeup) >= 0)
    + return;
    +
    + if (wfx_api_older_than(wdev, 1, 4)) {
    + gpiod_set_value_cansleep(wdev->pdata.gpio_wakeup, 1);
    + if (!completion_done(&wdev->hif.ctrl_ready))
    + usleep_range(2000, 2500);
    + return;
    + }
    + for (;;) {
    + gpiod_set_value_cansleep(wdev->pdata.gpio_wakeup, 1);
    + // completion.h does not provide any function to wait
    + // completion without consume it (a kind of
    + // wait_for_completion_done_timeout()). So we have to emulate
    + // it.
    + if (wait_for_completion_timeout(&wdev->hif.ctrl_ready,
    + msecs_to_jiffies(2))) {
    + complete(&wdev->hif.ctrl_ready);
    + return;
    + } else if (max_retry-- > 0) {
    + // Older firmwares have a race in sleep/wake-up process.
    + // Redo the process is sufficient to unfreeze the
    + // chip.
    + dev_err(wdev->dev, "timeout while wake up chip\n");
    + gpiod_set_value_cansleep(wdev->pdata.gpio_wakeup, 0);
    + usleep_range(2000, 2500);
    + } else {
    + dev_err(wdev->dev, "max wake-up retries reached\n");
    + return;
    + }
    + }
    +}
    +
    +static void device_release(struct wfx_dev *wdev)
    +{
    + if (!wdev->pdata.gpio_wakeup)
    + return;
    +
    + gpiod_set_value_cansleep(wdev->pdata.gpio_wakeup, 0);
    +}
    +
    +static int rx_helper(struct wfx_dev *wdev, size_t read_len, int *is_cnf)
    +{
    + struct sk_buff *skb;
    + struct hif_msg *hif;
    + size_t alloc_len;
    + size_t computed_len;
    + int release_count;
    + int piggyback = 0;
    +
    + WARN(read_len > round_down(0xFFF, 2) * sizeof(u16),
    + "%s: request exceed WFx capability", __func__);
    +
    + // Add 2 to take into account piggyback size
    + alloc_len = wdev->hwbus_ops->align_size(wdev->hwbus_priv, read_len + 2);
    + skb = dev_alloc_skb(alloc_len);
    + if (!skb)
    + return -ENOMEM;
    +
    + if (wfx_data_read(wdev, skb->data, alloc_len))
    + goto err;
    +
    + piggyback = le16_to_cpup((__le16 *)(skb->data + alloc_len - 2));
    + _trace_piggyback(piggyback, false);
    +
    + hif = (struct hif_msg *)skb->data;
    + WARN(hif->encrypted & 0x3, "encryption is unsupported");
    + if (WARN(read_len < sizeof(struct hif_msg), "corrupted read"))
    + goto err;
    + computed_len = le16_to_cpu(hif->len);
    + computed_len = round_up(computed_len, 2);
    + if (computed_len != read_len) {
    + dev_err(wdev->dev, "inconsistent message length: %zu != %zu\n",
    + computed_len, read_len);
    + print_hex_dump(KERN_INFO, "hif: ", DUMP_PREFIX_OFFSET, 16, 1,
    + hif, read_len, true);
    + goto err;
    + }
    +
    + if (!(hif->id & HIF_ID_IS_INDICATION)) {
    + (*is_cnf)++;
    + if (hif->id == HIF_CNF_ID_MULTI_TRANSMIT)
    + release_count = ((struct hif_cnf_multi_transmit *)hif->body)->num_tx_confs;
    + else
    + release_count = 1;
    + WARN(wdev->hif.tx_buffers_used < release_count, "corrupted buffer counter");
    + wdev->hif.tx_buffers_used -= release_count;
    + }
    + _trace_hif_recv(hif, wdev->hif.tx_buffers_used);
    +
    + if (hif->id != HIF_IND_ID_EXCEPTION && hif->id != HIF_IND_ID_ERROR) {
    + if (hif->seqnum != wdev->hif.rx_seqnum)
    + dev_warn(wdev->dev, "wrong message sequence: %d != %d\n",
    + hif->seqnum, wdev->hif.rx_seqnum);
    + wdev->hif.rx_seqnum = (hif->seqnum + 1) % (HIF_COUNTER_MAX + 1);
    + }
    +
    + skb_put(skb, le16_to_cpu(hif->len));
    + // wfx_handle_rx takes care on SKB livetime
    + wfx_handle_rx(wdev, skb);
    + if (!wdev->hif.tx_buffers_used)
    + wake_up(&wdev->hif.tx_buffers_empty);
    +
    + return piggyback;
    +
    +err:
    + if (skb)
    + dev_kfree_skb(skb);
    + return -EIO;
    +}
    +
    +static int bh_work_rx(struct wfx_dev *wdev, int max_msg, int *num_cnf)
    +{
    + size_t len;
    + int i;
    + int ctrl_reg, piggyback;
    +
    + piggyback = 0;
    + for (i = 0; i < max_msg; i++) {
    + if (piggyback & CTRL_NEXT_LEN_MASK)
    + ctrl_reg = piggyback;
    + else if (try_wait_for_completion(&wdev->hif.ctrl_ready))
    + ctrl_reg = atomic_xchg(&wdev->hif.ctrl_reg, 0);
    + else
    + ctrl_reg = 0;
    + if (!(ctrl_reg & CTRL_NEXT_LEN_MASK))
    + return i;
    + // ctrl_reg units are 16bits words
    + len = (ctrl_reg & CTRL_NEXT_LEN_MASK) * 2;
    + piggyback = rx_helper(wdev, len, num_cnf);
    + if (piggyback < 0)
    + return i;
    + if (!(piggyback & CTRL_WLAN_READY))
    + dev_err(wdev->dev, "unexpected piggyback value: ready bit not set: %04x\n",
    + piggyback);
    + }
    + if (piggyback & CTRL_NEXT_LEN_MASK) {
    + ctrl_reg = atomic_xchg(&wdev->hif.ctrl_reg, piggyback);
    + complete(&wdev->hif.ctrl_ready);
    + if (ctrl_reg)
    + dev_err(wdev->dev, "unexpected IRQ happened: %04x/%04x\n",
    + ctrl_reg, piggyback);
    + }
    + return i;
    +}
    +
    +static void tx_helper(struct wfx_dev *wdev, struct hif_msg *hif)
    +{
    + int ret;
    + void *data;
    + bool is_encrypted = false;
    + size_t len = le16_to_cpu(hif->len);
    +
    + WARN(len < sizeof(*hif), "try to send corrupted data");
    +
    + hif->seqnum = wdev->hif.tx_seqnum;
    + wdev->hif.tx_seqnum = (wdev->hif.tx_seqnum + 1) % (HIF_COUNTER_MAX + 1);
    +
    + data = hif;
    + WARN(len > wdev->hw_caps.size_inp_ch_buf,
    + "%s: request exceed WFx capability: %zu > %d\n", __func__,
    + len, wdev->hw_caps.size_inp_ch_buf);
    + len = wdev->hwbus_ops->align_size(wdev->hwbus_priv, len);
    + ret = wfx_data_write(wdev, data, len);
    + if (ret)
    + goto end;
    +
    + wdev->hif.tx_buffers_used++;
    + _trace_hif_send(hif, wdev->hif.tx_buffers_used);
    +end:
    + if (is_encrypted)
    + kfree(data);
    +}
    +
    +static int bh_work_tx(struct wfx_dev *wdev, int max_msg)
    +{
    + struct hif_msg *hif;
    + int i;
    +
    + for (i = 0; i < max_msg; i++) {
    + hif = NULL;
    + if (wdev->hif.tx_buffers_used < wdev->hw_caps.num_inp_ch_bufs) {
    + if (try_wait_for_completion(&wdev->hif_cmd.ready)) {
    + WARN(!mutex_is_locked(&wdev->hif_cmd.lock), "data locking error");
    + hif = wdev->hif_cmd.buf_send;
    + } else {
    + hif = wfx_tx_queues_get(wdev);
    + }
    + }
    + if (!hif)
    + return i;
    + tx_helper(wdev, hif);
    + }
    + return i;
    +}
    +
    +/* In SDIO mode, it is necessary to make an access to a register to acknowledge
    + * last received message. It could be possible to restrict this acknowledge to
    + * SDIO mode and only if last operation was rx.
    + */
    +static void ack_sdio_data(struct wfx_dev *wdev)
    +{
    + u32 cfg_reg;
    +
    + config_reg_read(wdev, &cfg_reg);
    + if (cfg_reg & 0xFF) {
    + dev_warn(wdev->dev, "chip reports errors: %02x\n",
    + cfg_reg & 0xFF);
    + config_reg_write_bits(wdev, 0xFF, 0x00);
    + }
    +}
    +
    +static void bh_work(struct work_struct *work)
    +{
    + struct wfx_dev *wdev = container_of(work, struct wfx_dev, hif.bh);
    + int stats_req = 0, stats_cnf = 0, stats_ind = 0;
    + bool release_chip = false, last_op_is_rx = false;
    + int num_tx, num_rx;
    +
    + device_wakeup(wdev);
    + do {
    + num_tx = bh_work_tx(wdev, 32);
    + stats_req += num_tx;
    + if (num_tx)
    + last_op_is_rx = false;
    + num_rx = bh_work_rx(wdev, 32, &stats_cnf);
    + stats_ind += num_rx;
    + if (num_rx)
    + last_op_is_rx = true;
    + } while (num_rx || num_tx);
    + stats_ind -= stats_cnf;
    +
    + if (last_op_is_rx)
    + ack_sdio_data(wdev);
    + if (!wdev->hif.tx_buffers_used && !work_pending(work)) {
    + device_release(wdev);
    + release_chip = true;
    + }
    + _trace_bh_stats(stats_ind, stats_req, stats_cnf,
    + wdev->hif.tx_buffers_used, release_chip);
    +}
    +
    +/*
    + * An IRQ from chip did occur
    + */
    +void wfx_bh_request_rx(struct wfx_dev *wdev)
    +{
    + u32 cur, prev;
    +
    + control_reg_read(wdev, &cur);
    + prev = atomic_xchg(&wdev->hif.ctrl_reg, cur);
    + complete(&wdev->hif.ctrl_ready);
    + queue_work(system_highpri_wq, &wdev->hif.bh);
    +
    + if (!(cur & CTRL_NEXT_LEN_MASK))
    + dev_err(wdev->dev, "unexpected control register value: length field is 0: %04x\n",
    + cur);
    + if (prev != 0)
    + dev_err(wdev->dev, "received IRQ but previous data was not (yet) read: %04x/%04x\n",
    + prev, cur);
    +}
    +
    +/*
    + * Driver want to send data
    + */
    +void wfx_bh_request_tx(struct wfx_dev *wdev)
    +{
    + queue_work(system_highpri_wq, &wdev->hif.bh);
    +}
    +
    +/*
    + * If IRQ is not available, this function allow to manually poll the control
    + * register and simulate an IRQ ahen an event happened.
    + *
    + * Note that the device has a bug: If an IRQ raise while host read control
    + * register, the IRQ is lost. So, use this function carefully (only duing
    + * device initialisation).
    + */
    +void wfx_bh_poll_irq(struct wfx_dev *wdev)
    +{
    + ktime_t now, start;
    + u32 reg;
    +
    + WARN(!wdev->poll_irq, "unexpected IRQ polling can mask IRQ");
    + start = ktime_get();
    + for (;;) {
    + control_reg_read(wdev, &reg);
    + now = ktime_get();
    + if (reg & 0xFFF)
    + break;
    + if (ktime_after(now, ktime_add_ms(start, 1000))) {
    + dev_err(wdev->dev, "time out while polling control register\n");
    + return;
    + }
    + udelay(200);
    + }
    + wfx_bh_request_rx(wdev);
    +}
    +
    +void wfx_bh_register(struct wfx_dev *wdev)
    +{
    + INIT_WORK(&wdev->hif.bh, bh_work);
    + init_completion(&wdev->hif.ctrl_ready);
    + init_waitqueue_head(&wdev->hif.tx_buffers_empty);
    +}
    +
    +void wfx_bh_unregister(struct wfx_dev *wdev)
    +{
    + flush_work(&wdev->hif.bh);
    +}
    diff --git a/drivers/net/wireless/silabs/wfx/bh.h b/drivers/net/wireless/silabs/wfx/bh.h
    new file mode 100644
    index 000000000000..78c49329e22a
    --- /dev/null
    +++ b/drivers/net/wireless/silabs/wfx/bh.h
    @@ -0,0 +1,33 @@
    +/* SPDX-License-Identifier: GPL-2.0-only */
    +/*
    + * Interrupt bottom half.
    + *
    + * Copyright (c) 2017-2020, Silicon Laboratories, Inc.
    + * Copyright (c) 2010, ST-Ericsson
    + */
    +#ifndef WFX_BH_H
    +#define WFX_BH_H
    +
    +#include <linux/atomic.h>
    +#include <linux/wait.h>
    +#include <linux/workqueue.h>
    +
    +struct wfx_dev;
    +
    +struct wfx_hif {
    + struct work_struct bh;
    + struct completion ctrl_ready;
    + wait_queue_head_t tx_buffers_empty;
    + atomic_t ctrl_reg;
    + int rx_seqnum;
    + int tx_seqnum;
    + int tx_buffers_used;
    +};
    +
    +void wfx_bh_register(struct wfx_dev *wdev);
    +void wfx_bh_unregister(struct wfx_dev *wdev);
    +void wfx_bh_request_rx(struct wfx_dev *wdev);
    +void wfx_bh_request_tx(struct wfx_dev *wdev);
    +void wfx_bh_poll_irq(struct wfx_dev *wdev);
    +
    +#endif /* WFX_BH_H */
    --
    2.28.0
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