diff options
Diffstat (limited to 'drivers/net/wwan/qcom_bam_dmux.c')
| -rw-r--r-- | drivers/net/wwan/qcom_bam_dmux.c | 907 |
1 files changed, 907 insertions, 0 deletions
diff --git a/drivers/net/wwan/qcom_bam_dmux.c b/drivers/net/wwan/qcom_bam_dmux.c new file mode 100644 index 000000000000..5dfa2eba6014 --- /dev/null +++ b/drivers/net/wwan/qcom_bam_dmux.c @@ -0,0 +1,907 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Qualcomm BAM-DMUX WWAN network driver + * Copyright (c) 2020, Stephan Gerhold <stephan@gerhold.net> + */ + +#include <linux/atomic.h> +#include <linux/bitops.h> +#include <linux/completion.h> +#include <linux/dma-mapping.h> +#include <linux/dmaengine.h> +#include <linux/if_arp.h> +#include <linux/interrupt.h> +#include <linux/mod_devicetable.h> +#include <linux/module.h> +#include <linux/netdevice.h> +#include <linux/platform_device.h> +#include <linux/pm_runtime.h> +#include <linux/soc/qcom/smem_state.h> +#include <linux/spinlock.h> +#include <linux/wait.h> +#include <linux/workqueue.h> +#include <net/pkt_sched.h> + +#define BAM_DMUX_BUFFER_SIZE SZ_2K +#define BAM_DMUX_HDR_SIZE sizeof(struct bam_dmux_hdr) +#define BAM_DMUX_MAX_DATA_SIZE (BAM_DMUX_BUFFER_SIZE - BAM_DMUX_HDR_SIZE) +#define BAM_DMUX_NUM_SKB 32 + +#define BAM_DMUX_HDR_MAGIC 0x33fc + +#define BAM_DMUX_AUTOSUSPEND_DELAY 1000 +#define BAM_DMUX_REMOTE_TIMEOUT msecs_to_jiffies(2000) + +enum { + BAM_DMUX_CMD_DATA, + BAM_DMUX_CMD_OPEN, + BAM_DMUX_CMD_CLOSE, +}; + +enum { + BAM_DMUX_CH_DATA_0, + BAM_DMUX_CH_DATA_1, + BAM_DMUX_CH_DATA_2, + BAM_DMUX_CH_DATA_3, + BAM_DMUX_CH_DATA_4, + BAM_DMUX_CH_DATA_5, + BAM_DMUX_CH_DATA_6, + BAM_DMUX_CH_DATA_7, + BAM_DMUX_NUM_CH +}; + +struct bam_dmux_hdr { + u16 magic; + u8 signal; + u8 cmd; + u8 pad; + u8 ch; + u16 len; +}; + +struct bam_dmux_skb_dma { + struct bam_dmux *dmux; + struct sk_buff *skb; + dma_addr_t addr; +}; + +struct bam_dmux { + struct device *dev; + + int pc_irq; + bool pc_state, pc_ack_state; + struct qcom_smem_state *pc, *pc_ack; + u32 pc_mask, pc_ack_mask; + wait_queue_head_t pc_wait; + struct completion pc_ack_completion; + + struct dma_chan *rx, *tx; + struct bam_dmux_skb_dma rx_skbs[BAM_DMUX_NUM_SKB]; + struct bam_dmux_skb_dma tx_skbs[BAM_DMUX_NUM_SKB]; + spinlock_t tx_lock; /* Protect tx_skbs, tx_next_skb */ + unsigned int tx_next_skb; + atomic_long_t tx_deferred_skb; + struct work_struct tx_wakeup_work; + + DECLARE_BITMAP(remote_channels, BAM_DMUX_NUM_CH); + struct work_struct register_netdev_work; + struct net_device *netdevs[BAM_DMUX_NUM_CH]; +}; + +struct bam_dmux_netdev { + struct bam_dmux *dmux; + u8 ch; +}; + +static void bam_dmux_pc_vote(struct bam_dmux *dmux, bool enable) +{ + reinit_completion(&dmux->pc_ack_completion); + qcom_smem_state_update_bits(dmux->pc, dmux->pc_mask, + enable ? dmux->pc_mask : 0); +} + +static void bam_dmux_pc_ack(struct bam_dmux *dmux) +{ + qcom_smem_state_update_bits(dmux->pc_ack, dmux->pc_ack_mask, + dmux->pc_ack_state ? 0 : dmux->pc_ack_mask); + dmux->pc_ack_state = !dmux->pc_ack_state; +} + +static bool bam_dmux_skb_dma_map(struct bam_dmux_skb_dma *skb_dma, + enum dma_data_direction dir) +{ + struct device *dev = skb_dma->dmux->dev; + + skb_dma->addr = dma_map_single(dev, skb_dma->skb->data, skb_dma->skb->len, dir); + if (dma_mapping_error(dev, skb_dma->addr)) { + dev_err(dev, "Failed to DMA map buffer\n"); + skb_dma->addr = 0; + return false; + } + + return true; +} + +static void bam_dmux_skb_dma_unmap(struct bam_dmux_skb_dma *skb_dma, + enum dma_data_direction dir) +{ + dma_unmap_single(skb_dma->dmux->dev, skb_dma->addr, skb_dma->skb->len, dir); + skb_dma->addr = 0; +} + +static void bam_dmux_tx_wake_queues(struct bam_dmux *dmux) +{ + int i; + + dev_dbg(dmux->dev, "wake queues\n"); + + for (i = 0; i < BAM_DMUX_NUM_CH; ++i) { + struct net_device *netdev = dmux->netdevs[i]; + + if (netdev && netif_running(netdev)) + netif_wake_queue(netdev); + } +} + +static void bam_dmux_tx_stop_queues(struct bam_dmux *dmux) +{ + int i; + + dev_dbg(dmux->dev, "stop queues\n"); + + for (i = 0; i < BAM_DMUX_NUM_CH; ++i) { + struct net_device *netdev = dmux->netdevs[i]; + + if (netdev) + netif_stop_queue(netdev); + } +} + +static void bam_dmux_tx_done(struct bam_dmux_skb_dma *skb_dma) +{ + struct bam_dmux *dmux = skb_dma->dmux; + unsigned long flags; + + pm_runtime_mark_last_busy(dmux->dev); + pm_runtime_put_autosuspend(dmux->dev); + + if (skb_dma->addr) + bam_dmux_skb_dma_unmap(skb_dma, DMA_TO_DEVICE); + + spin_lock_irqsave(&dmux->tx_lock, flags); + skb_dma->skb = NULL; + if (skb_dma == &dmux->tx_skbs[dmux->tx_next_skb % BAM_DMUX_NUM_SKB]) + bam_dmux_tx_wake_queues(dmux); + spin_unlock_irqrestore(&dmux->tx_lock, flags); +} + +static void bam_dmux_tx_callback(void *data) +{ + struct bam_dmux_skb_dma *skb_dma = data; + struct sk_buff *skb = skb_dma->skb; + + bam_dmux_tx_done(skb_dma); + dev_consume_skb_any(skb); +} + +static bool bam_dmux_skb_dma_submit_tx(struct bam_dmux_skb_dma *skb_dma) +{ + struct bam_dmux *dmux = skb_dma->dmux; + struct dma_async_tx_descriptor *desc; + + desc = dmaengine_prep_slave_single(dmux->tx, skb_dma->addr, + skb_dma->skb->len, DMA_MEM_TO_DEV, + DMA_PREP_INTERRUPT); + if (!desc) { + dev_err(dmux->dev, "Failed to prepare TX DMA buffer\n"); + return false; + } + + desc->callback = bam_dmux_tx_callback; + desc->callback_param = skb_dma; + desc->cookie = dmaengine_submit(desc); + return true; +} + +static struct bam_dmux_skb_dma * +bam_dmux_tx_queue(struct bam_dmux *dmux, struct sk_buff *skb) +{ + struct bam_dmux_skb_dma *skb_dma; + unsigned long flags; + + spin_lock_irqsave(&dmux->tx_lock, flags); + + skb_dma = &dmux->tx_skbs[dmux->tx_next_skb % BAM_DMUX_NUM_SKB]; + if (skb_dma->skb) { + bam_dmux_tx_stop_queues(dmux); + spin_unlock_irqrestore(&dmux->tx_lock, flags); + return NULL; + } + skb_dma->skb = skb; + + dmux->tx_next_skb++; + if (dmux->tx_skbs[dmux->tx_next_skb % BAM_DMUX_NUM_SKB].skb) + bam_dmux_tx_stop_queues(dmux); + + spin_unlock_irqrestore(&dmux->tx_lock, flags); + return skb_dma; +} + +static int bam_dmux_send_cmd(struct bam_dmux_netdev *bndev, u8 cmd) +{ + struct bam_dmux *dmux = bndev->dmux; + struct bam_dmux_skb_dma *skb_dma; + struct bam_dmux_hdr *hdr; + struct sk_buff *skb; + int ret; + + skb = alloc_skb(sizeof(*hdr), GFP_KERNEL); + if (!skb) + return -ENOMEM; + + hdr = skb_put_zero(skb, sizeof(*hdr)); + hdr->magic = BAM_DMUX_HDR_MAGIC; + hdr->cmd = cmd; + hdr->ch = bndev->ch; + + skb_dma = bam_dmux_tx_queue(dmux, skb); + if (!skb_dma) { + ret = -EAGAIN; + goto free_skb; + } + + ret = pm_runtime_get_sync(dmux->dev); + if (ret < 0) + goto tx_fail; + + if (!bam_dmux_skb_dma_map(skb_dma, DMA_TO_DEVICE)) { + ret = -ENOMEM; + goto tx_fail; + } + + if (!bam_dmux_skb_dma_submit_tx(skb_dma)) { + ret = -EIO; + goto tx_fail; + } + + dma_async_issue_pending(dmux->tx); + return 0; + +tx_fail: + bam_dmux_tx_done(skb_dma); +free_skb: + dev_kfree_skb(skb); + return ret; +} + +static int bam_dmux_netdev_open(struct net_device *netdev) +{ + struct bam_dmux_netdev *bndev = netdev_priv(netdev); + int ret; + + ret = bam_dmux_send_cmd(bndev, BAM_DMUX_CMD_OPEN); + if (ret) + return ret; + + netif_start_queue(netdev); + return 0; +} + +static int bam_dmux_netdev_stop(struct net_device *netdev) +{ + struct bam_dmux_netdev *bndev = netdev_priv(netdev); + + netif_stop_queue(netdev); + bam_dmux_send_cmd(bndev, BAM_DMUX_CMD_CLOSE); + return 0; +} + +static unsigned int needed_room(unsigned int avail, unsigned int needed) +{ + if (avail >= needed) + return 0; + return needed - avail; +} + +static int bam_dmux_tx_prepare_skb(struct bam_dmux_netdev *bndev, + struct sk_buff *skb) +{ + unsigned int head = needed_room(skb_headroom(skb), BAM_DMUX_HDR_SIZE); + unsigned int pad = sizeof(u32) - skb->len % sizeof(u32); + unsigned int tail = needed_room(skb_tailroom(skb), pad); + struct bam_dmux_hdr *hdr; + int ret; + + if (head || tail || skb_cloned(skb)) { + ret = pskb_expand_head(skb, head, tail, GFP_ATOMIC); + if (ret) + return ret; + } + + hdr = skb_push(skb, sizeof(*hdr)); + hdr->magic = BAM_DMUX_HDR_MAGIC; + hdr->signal = 0; + hdr->cmd = BAM_DMUX_CMD_DATA; + hdr->pad = pad; + hdr->ch = bndev->ch; + hdr->len = skb->len - sizeof(*hdr); + if (pad) + skb_put_zero(skb, pad); + + return 0; +} + +static netdev_tx_t bam_dmux_netdev_start_xmit(struct sk_buff *skb, + struct net_device *netdev) +{ + struct bam_dmux_netdev *bndev = netdev_priv(netdev); + struct bam_dmux *dmux = bndev->dmux; + struct bam_dmux_skb_dma *skb_dma; + int active, ret; + + skb_dma = bam_dmux_tx_queue(dmux, skb); + if (!skb_dma) + return NETDEV_TX_BUSY; + + active = pm_runtime_get(dmux->dev); + if (active < 0 && active != -EINPROGRESS) + goto drop; + + ret = bam_dmux_tx_prepare_skb(bndev, skb); + if (ret) + goto drop; + + if (!bam_dmux_skb_dma_map(skb_dma, DMA_TO_DEVICE)) + goto drop; + + if (active <= 0) { + /* Cannot sleep here so mark skb for wakeup handler and return */ + if (!atomic_long_fetch_or(BIT(skb_dma - dmux->tx_skbs), + &dmux->tx_deferred_skb)) + queue_pm_work(&dmux->tx_wakeup_work); + return NETDEV_TX_OK; + } + + if (!bam_dmux_skb_dma_submit_tx(skb_dma)) + goto drop; + + dma_async_issue_pending(dmux->tx); + return NETDEV_TX_OK; + +drop: + bam_dmux_tx_done(skb_dma); + dev_kfree_skb_any(skb); + return NETDEV_TX_OK; +} + +static void bam_dmux_tx_wakeup_work(struct work_struct *work) +{ + struct bam_dmux *dmux = container_of(work, struct bam_dmux, tx_wakeup_work); + unsigned long pending; + int ret, i; + + ret = pm_runtime_resume_and_get(dmux->dev); + if (ret < 0) { + dev_err(dmux->dev, "Failed to resume: %d\n", ret); + return; + } + + pending = atomic_long_xchg(&dmux->tx_deferred_skb, 0); + if (!pending) + goto out; + + dev_dbg(dmux->dev, "pending skbs after wakeup: %#lx\n", pending); + for_each_set_bit(i, &pending, BAM_DMUX_NUM_SKB) { + bam_dmux_skb_dma_submit_tx(&dmux->tx_skbs[i]); + } + dma_async_issue_pending(dmux->tx); + +out: + pm_runtime_mark_last_busy(dmux->dev); + pm_runtime_put_autosuspend(dmux->dev); +} + +static const struct net_device_ops bam_dmux_ops = { + .ndo_open = bam_dmux_netdev_open, + .ndo_stop = bam_dmux_netdev_stop, + .ndo_start_xmit = bam_dmux_netdev_start_xmit, +}; + +static const struct device_type wwan_type = { + .name = "wwan", +}; + +static void bam_dmux_netdev_setup(struct net_device *dev) +{ + dev->netdev_ops = &bam_dmux_ops; + + dev->type = ARPHRD_RAWIP; + SET_NETDEV_DEVTYPE(dev, &wwan_type); + dev->flags = IFF_POINTOPOINT | IFF_NOARP; + + dev->mtu = ETH_DATA_LEN; + dev->max_mtu = BAM_DMUX_MAX_DATA_SIZE; + dev->needed_headroom = sizeof(struct bam_dmux_hdr); + dev->needed_tailroom = sizeof(u32); /* word-aligned */ + dev->tx_queue_len = DEFAULT_TX_QUEUE_LEN; + + /* This perm addr will be used as interface identifier by IPv6 */ + dev->addr_assign_type = NET_ADDR_RANDOM; + eth_random_addr(dev->perm_addr); +} + +static void bam_dmux_register_netdev_work(struct work_struct *work) +{ + struct bam_dmux *dmux = container_of(work, struct bam_dmux, register_netdev_work); + struct bam_dmux_netdev *bndev; + struct net_device *netdev; + int ch, ret; + + for_each_set_bit(ch, dmux->remote_channels, BAM_DMUX_NUM_CH) { + if (dmux->netdevs[ch]) + continue; + + netdev = alloc_netdev(sizeof(*bndev), "wwan%d", NET_NAME_ENUM, + bam_dmux_netdev_setup); + if (!netdev) + return; + + SET_NETDEV_DEV(netdev, dmux->dev); + netdev->dev_port = ch; + + bndev = netdev_priv(netdev); + bndev->dmux = dmux; + bndev->ch = ch; + + ret = register_netdev(netdev); + if (ret) { + dev_err(dmux->dev, "Failed to register netdev for channel %u: %d\n", + ch, ret); + free_netdev(netdev); + return; + } + + dmux->netdevs[ch] = netdev; + } +} + +static void bam_dmux_rx_callback(void *data); + +static bool bam_dmux_skb_dma_submit_rx(struct bam_dmux_skb_dma *skb_dma) +{ + struct bam_dmux *dmux = skb_dma->dmux; + struct dma_async_tx_descriptor *desc; + + desc = dmaengine_prep_slave_single(dmux->rx, skb_dma->addr, + skb_dma->skb->len, DMA_DEV_TO_MEM, + DMA_PREP_INTERRUPT); + if (!desc) { + dev_err(dmux->dev, "Failed to prepare RX DMA buffer\n"); + return false; + } + + desc->callback = bam_dmux_rx_callback; + desc->callback_param = skb_dma; + desc->cookie = dmaengine_submit(desc); + return true; +} + +static bool bam_dmux_skb_dma_queue_rx(struct bam_dmux_skb_dma *skb_dma, gfp_t gfp) +{ + if (!skb_dma->skb) { + skb_dma->skb = __netdev_alloc_skb(NULL, BAM_DMUX_BUFFER_SIZE, gfp); + if (!skb_dma->skb) + return false; + skb_put(skb_dma->skb, BAM_DMUX_BUFFER_SIZE); + } + + return bam_dmux_skb_dma_map(skb_dma, DMA_FROM_DEVICE) && + bam_dmux_skb_dma_submit_rx(skb_dma); +} + +static void bam_dmux_cmd_data(struct bam_dmux_skb_dma *skb_dma) +{ + struct bam_dmux *dmux = skb_dma->dmux; + struct sk_buff *skb = skb_dma->skb; + struct bam_dmux_hdr *hdr = (struct bam_dmux_hdr *)skb->data; + struct net_device *netdev = dmux->netdevs[hdr->ch]; + + if (!netdev || !netif_running(netdev)) { + dev_warn(dmux->dev, "Data for inactive channel %u\n", hdr->ch); + return; + } + + if (hdr->len > BAM_DMUX_MAX_DATA_SIZE) { + dev_err(dmux->dev, "Data larger than buffer? (%u > %u)\n", + hdr->len, (u16)BAM_DMUX_MAX_DATA_SIZE); + return; + } + + skb_dma->skb = NULL; /* Hand over to network stack */ + + skb_pull(skb, sizeof(*hdr)); + skb_trim(skb, hdr->len); + skb->dev = netdev; + + /* Only Raw-IP/QMAP is supported by this driver */ + switch (skb->data[0] & 0xf0) { + case 0x40: + skb->protocol = htons(ETH_P_IP); + break; + case 0x60: + skb->protocol = htons(ETH_P_IPV6); + break; + default: + skb->protocol = htons(ETH_P_MAP); + break; + } + + netif_receive_skb(skb); +} + +static void bam_dmux_cmd_open(struct bam_dmux *dmux, struct bam_dmux_hdr *hdr) +{ + struct net_device *netdev = dmux->netdevs[hdr->ch]; + + dev_dbg(dmux->dev, "open channel: %u\n", hdr->ch); + + if (__test_and_set_bit(hdr->ch, dmux->remote_channels)) { + dev_warn(dmux->dev, "Channel already open: %u\n", hdr->ch); + return; + } + + if (netdev) { + netif_device_attach(netdev); + } else { + /* Cannot sleep here, schedule work to register the netdev */ + schedule_work(&dmux->register_netdev_work); + } +} + +static void bam_dmux_cmd_close(struct bam_dmux *dmux, struct bam_dmux_hdr *hdr) +{ + struct net_device *netdev = dmux->netdevs[hdr->ch]; + + dev_dbg(dmux->dev, "close channel: %u\n", hdr->ch); + + if (!__test_and_clear_bit(hdr->ch, dmux->remote_channels)) { + dev_err(dmux->dev, "Channel not open: %u\n", hdr->ch); + return; + } + + if (netdev) + netif_device_detach(netdev); +} + +static void bam_dmux_rx_callback(void *data) +{ + struct bam_dmux_skb_dma *skb_dma = data; + struct bam_dmux *dmux = skb_dma->dmux; + struct sk_buff *skb = skb_dma->skb; + struct bam_dmux_hdr *hdr = (struct bam_dmux_hdr *)skb->data; + + bam_dmux_skb_dma_unmap(skb_dma, DMA_FROM_DEVICE); + + if (hdr->magic != BAM_DMUX_HDR_MAGIC) { + dev_err(dmux->dev, "Invalid magic in header: %#x\n", hdr->magic); + goto out; + } + + if (hdr->ch >= BAM_DMUX_NUM_CH) { + dev_dbg(dmux->dev, "Unsupported channel: %u\n", hdr->ch); + goto out; + } + + switch (hdr->cmd) { + case BAM_DMUX_CMD_DATA: + bam_dmux_cmd_data(skb_dma); + break; + case BAM_DMUX_CMD_OPEN: + bam_dmux_cmd_open(dmux, hdr); + break; + case BAM_DMUX_CMD_CLOSE: + bam_dmux_cmd_close(dmux, hdr); + break; + default: + dev_err(dmux->dev, "Unsupported command %u on channel %u\n", + hdr->cmd, hdr->ch); + break; + } + +out: + if (bam_dmux_skb_dma_queue_rx(skb_dma, GFP_ATOMIC)) + dma_async_issue_pending(dmux->rx); +} + +static bool bam_dmux_power_on(struct bam_dmux *dmux) +{ + struct device *dev = dmux->dev; + struct dma_slave_config dma_rx_conf = { + .direction = DMA_DEV_TO_MEM, + .src_maxburst = BAM_DMUX_BUFFER_SIZE, + }; + int i; + + dmux->rx = dma_request_chan(dev, "rx"); + if (IS_ERR(dmux->rx)) { + dev_err(dev, "Failed to request RX DMA channel: %pe\n", dmux->rx); + dmux->rx = NULL; + return false; + } + dmaengine_slave_config(dmux->rx, &dma_rx_conf); + + for (i = 0; i < BAM_DMUX_NUM_SKB; i++) { + if (!bam_dmux_skb_dma_queue_rx(&dmux->rx_skbs[i], GFP_KERNEL)) + return false; + } + dma_async_issue_pending(dmux->rx); + + return true; +} + +static void bam_dmux_free_skbs(struct bam_dmux_skb_dma skbs[], + enum dma_data_direction dir) +{ + int i; + + for (i = 0; i < BAM_DMUX_NUM_SKB; i++) { + struct bam_dmux_skb_dma *skb_dma = &skbs[i]; + + if (skb_dma->addr) + bam_dmux_skb_dma_unmap(skb_dma, dir); + if (skb_dma->skb) { + dev_kfree_skb(skb_dma->skb); + skb_dma->skb = NULL; + } + } +} + +static void bam_dmux_power_off(struct bam_dmux *dmux) +{ + if (dmux->tx) { + dmaengine_terminate_sync(dmux->tx); + dma_release_channel(dmux->tx); + dmux->tx = NULL; + } + + if (dmux->rx) { + dmaengine_terminate_sync(dmux->rx); + dma_release_channel(dmux->rx); + dmux->rx = NULL; + } + + bam_dmux_free_skbs(dmux->rx_skbs, DMA_FROM_DEVICE); +} + +static irqreturn_t bam_dmux_pc_irq(int irq, void *data) +{ + struct bam_dmux *dmux = data; + bool new_state = !dmux->pc_state; + + dev_dbg(dmux->dev, "pc: %u\n", new_state); + + if (new_state) { + if (bam_dmux_power_on(dmux)) + bam_dmux_pc_ack(dmux); + else + bam_dmux_power_off(dmux); + } else { + bam_dmux_power_off(dmux); + bam_dmux_pc_ack(dmux); + } + + dmux->pc_state = new_state; + wake_up_all(&dmux->pc_wait); + + return IRQ_HANDLED; +} + +static irqreturn_t bam_dmux_pc_ack_irq(int irq, void *data) +{ + struct bam_dmux *dmux = data; + + dev_dbg(dmux->dev, "pc ack\n"); + complete_all(&dmux->pc_ack_completion); + + return IRQ_HANDLED; +} + +static int bam_dmux_runtime_suspend(struct device *dev) +{ + struct bam_dmux *dmux = dev_get_drvdata(dev); + + dev_dbg(dev, "runtime suspend\n"); + bam_dmux_pc_vote(dmux, false); + + return 0; +} + +static int __maybe_unused bam_dmux_runtime_resume(struct device *dev) +{ + struct bam_dmux *dmux = dev_get_drvdata(dev); + + dev_dbg(dev, "runtime resume\n"); + + /* Wait until previous power down was acked */ + if (!wait_for_completion_timeout(&dmux->pc_ack_completion, + BAM_DMUX_REMOTE_TIMEOUT)) + return -ETIMEDOUT; + + /* Vote for power state */ + bam_dmux_pc_vote(dmux, true); + + /* Wait for ack */ + if (!wait_for_completion_timeout(&dmux->pc_ack_completion, + BAM_DMUX_REMOTE_TIMEOUT)) { + bam_dmux_pc_vote(dmux, false); + return -ETIMEDOUT; + } + + /* Wait until we're up */ + if (!wait_event_timeout(dmux->pc_wait, dmux->pc_state, + BAM_DMUX_REMOTE_TIMEOUT)) { + bam_dmux_pc_vote(dmux, false); + return -ETIMEDOUT; + } + + /* Ensure that we actually initialized successfully */ + if (!dmux->rx) { + bam_dmux_pc_vote(dmux, false); + return -ENXIO; + } + + /* Request TX channel if necessary */ + if (dmux->tx) + return 0; + + dmux->tx = dma_request_chan(dev, "tx"); + if (IS_ERR(dmux->rx)) { + dev_err(dev, "Failed to request TX DMA channel: %pe\n", dmux->tx); + dmux->tx = NULL; + bam_dmux_runtime_suspend(dev); + return -ENXIO; + } + + return 0; +} + +static int bam_dmux_probe(struct platform_device *pdev) +{ + struct device *dev = &pdev->dev; + struct bam_dmux *dmux; + int ret, pc_ack_irq, i; + unsigned int bit; + + dmux = devm_kzalloc(dev, sizeof(*dmux), GFP_KERNEL); + if (!dmux) + return -ENOMEM; + + dmux->dev = dev; + platform_set_drvdata(pdev, dmux); + + dmux->pc_irq = platform_get_irq_byname(pdev, "pc"); + if (dmux->pc_irq < 0) + return dmux->pc_irq; + + pc_ack_irq = platform_get_irq_byname(pdev, "pc-ack"); + if (pc_ack_irq < 0) + return pc_ack_irq; + + dmux->pc = devm_qcom_smem_state_get(dev, "pc", &bit); + if (IS_ERR(dmux->pc)) + return dev_err_probe(dev, PTR_ERR(dmux->pc), + "Failed to get pc state\n"); + dmux->pc_mask = BIT(bit); + + dmux->pc_ack = devm_qcom_smem_state_get(dev, "pc-ack", &bit); + if (IS_ERR(dmux->pc_ack)) + return dev_err_probe(dev, PTR_ERR(dmux->pc_ack), + "Failed to get pc-ack state\n"); + dmux->pc_ack_mask = BIT(bit); + + init_waitqueue_head(&dmux->pc_wait); + init_completion(&dmux->pc_ack_completion); + complete_all(&dmux->pc_ack_completion); + + spin_lock_init(&dmux->tx_lock); + INIT_WORK(&dmux->tx_wakeup_work, bam_dmux_tx_wakeup_work); + INIT_WORK(&dmux->register_netdev_work, bam_dmux_register_netdev_work); + + for (i = 0; i < BAM_DMUX_NUM_SKB; i++) { + dmux->rx_skbs[i].dmux = dmux; + dmux->tx_skbs[i].dmux = dmux; + } + + /* Runtime PM manages our own power vote. + * Note that the RX path may be active even if we are runtime suspended, + * since it is controlled by the remote side. + */ + pm_runtime_set_autosuspend_delay(dev, BAM_DMUX_AUTOSUSPEND_DELAY); + pm_runtime_use_autosuspend(dev); + pm_runtime_enable(dev); + + ret = devm_request_threaded_irq(dev, pc_ack_irq, NULL, bam_dmux_pc_ack_irq, + IRQF_ONESHOT, NULL, dmux); + if (ret) + return ret; + + ret = devm_request_threaded_irq(dev, dmux->pc_irq, NULL, bam_dmux_pc_irq, + IRQF_ONESHOT, NULL, dmux); + if (ret) + return ret; + + ret = irq_get_irqchip_state(dmux->pc_irq, IRQCHIP_STATE_LINE_LEVEL, + &dmux->pc_state); + if (ret) + return ret; + + /* Check if remote finished initialization before us */ + if (dmux->pc_state) { + if (bam_dmux_power_on(dmux)) + bam_dmux_pc_ack(dmux); + else + bam_dmux_power_off(dmux); + } + + return 0; +} + +static int bam_dmux_remove(struct platform_device *pdev) +{ + struct bam_dmux *dmux = platform_get_drvdata(pdev); + struct device *dev = dmux->dev; + LIST_HEAD(list); + int i; + + /* Unregister network interfaces */ + cancel_work_sync(&dmux->register_netdev_work); + rtnl_lock(); + for (i = 0; i < BAM_DMUX_NUM_CH; ++i) + if (dmux->netdevs[i]) + unregister_netdevice_queue(dmux->netdevs[i], &list); + unregister_netdevice_many(&list); + rtnl_unlock(); + cancel_work_sync(&dmux->tx_wakeup_work); + + /* Drop our own power vote */ + pm_runtime_disable(dev); + pm_runtime_dont_use_autosuspend(dev); + bam_dmux_runtime_suspend(dev); + pm_runtime_set_suspended(dev); + + /* Try to wait for remote side to drop power vote */ + if (!wait_event_timeout(dmux->pc_wait, !dmux->rx, BAM_DMUX_REMOTE_TIMEOUT)) + dev_err(dev, "Timed out waiting for remote side to suspend\n"); + + /* Make sure everything is cleaned up before we return */ + disable_irq(dmux->pc_irq); + bam_dmux_power_off(dmux); + bam_dmux_free_skbs(dmux->tx_skbs, DMA_TO_DEVICE); + + return 0; +} + +static const struct dev_pm_ops bam_dmux_pm_ops = { + SET_RUNTIME_PM_OPS(bam_dmux_runtime_suspend, bam_dmux_runtime_resume, NULL) +}; + +static const struct of_device_id bam_dmux_of_match[] = { + { .compatible = "qcom,bam-dmux" }, + { /* sentinel */ } +}; +MODULE_DEVICE_TABLE(of, bam_dmux_of_match); + +static struct platform_driver bam_dmux_driver = { + .probe = bam_dmux_probe, + .remove = bam_dmux_remove, + .driver = { + .name = "bam-dmux", + .pm = &bam_dmux_pm_ops, + .of_match_table = bam_dmux_of_match, + }, +}; +module_platform_driver(bam_dmux_driver); + +MODULE_LICENSE("GPL v2"); +MODULE_DESCRIPTION("Qualcomm BAM-DMUX WWAN Network Driver"); +MODULE_AUTHOR("Stephan Gerhold <stephan@gerhold.net>"); |