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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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