Return-Path: Subject: Re: [PATCH v4] Bluetooth: btwilink driver From: Marcel Holtmann To: pavan_savoy@ti.com Cc: padovan@profusion.mobi, linux-bluetooth@vger.kernel.org, linux-kernel@vger.kernel.org In-Reply-To: <1287525975-17187-1-git-send-email-pavan_savoy@ti.com> References: <1287525975-17187-1-git-send-email-pavan_savoy@ti.com> Content-Type: text/plain; charset="UTF-8" Date: Wed, 10 Nov 2010 15:08:48 +0900 Message-ID: <1289369328.9615.262.camel@aeonflux> Mime-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: Hi Pavan, > diff --git a/drivers/bluetooth/Kconfig b/drivers/bluetooth/Kconfig > index 02deef4..8e0de9a 100644 > --- a/drivers/bluetooth/Kconfig > +++ b/drivers/bluetooth/Kconfig > @@ -219,4 +219,14 @@ config BT_ATH3K > Say Y here to compile support for "Atheros firmware download driver" > into the kernel or say M to compile it as module (ath3k). > > +config BT_WILINK > + tristate "Texas Instruments WiLink7 driver" > + depends on TI_ST > + help > + This enables the Bluetooth driver for Texas Instrument's BT/FM/GPS > + combo devices. This makes use of shared transport line discipline > + core driver to communicate with the BT core of the combo chip. > + > + Say Y here to compile support for Texas Instrument's WiLink7 driver > + into the kernel or say M to compile it as module. > endmenu > diff --git a/drivers/bluetooth/Makefile b/drivers/bluetooth/Makefile > index 71bdf13..f4460f4 100644 > --- a/drivers/bluetooth/Makefile > +++ b/drivers/bluetooth/Makefile > @@ -18,6 +18,7 @@ obj-$(CONFIG_BT_HCIBTSDIO) += btsdio.o > obj-$(CONFIG_BT_ATH3K) += ath3k.o > obj-$(CONFIG_BT_MRVL) += btmrvl.o > obj-$(CONFIG_BT_MRVL_SDIO) += btmrvl_sdio.o > +obj-$(CONFIG_BT_WILINK) += btwilink.o > > btmrvl-y := btmrvl_main.o > btmrvl-$(CONFIG_DEBUG_FS) += btmrvl_debugfs.o > diff --git a/drivers/bluetooth/btwilink.c b/drivers/bluetooth/btwilink.c > new file mode 100644 > index 0000000..218efd6 > --- /dev/null > +++ b/drivers/bluetooth/btwilink.c > @@ -0,0 +1,411 @@ > +/* > + * Texas Instrument's Bluetooth Driver For Shared Transport. > + * > + * Bluetooth Driver acts as interface between HCI core and > + * TI Shared Transport Layer. > + * > + * Copyright (C) 2009-2010 Texas Instruments > + * Author: Raja Mani > + * Pavan Savoy > + * > + * This program is free software; you can redistribute it and/or modify > + * it under the terms of the GNU General Public License version 2 as > + * published by the Free Software Foundation. > + * > + * This program is distributed in the hope that it will be useful, > + * but WITHOUT ANY WARRANTY; without even the implied warranty of > + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the > + * GNU General Public License for more details. > + * > + * You should have received a copy of the GNU General Public License > + * along with this program; if not, write to the Free Software > + * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA > + * > + */ > + > +#include > +#include > +#include > + > +#include > + > +/* Bluetooth Driver Version */ > +#define VERSION "1.0" > + > +/* Number of seconds to wait for registration completion > + * when ST returns PENDING status. > + */ > +#define BT_REGISTER_TIMEOUT 6000 /* 6 sec */ > + > +/** > + * struct ti_st - driver operation structure > + * @hdev: hci device pointer which binds to bt driver > + * @reg_status: ST registration callback status > + * @st_write: write function provided by the ST driver > + * to be used by the driver during send_frame. > + * @wait_reg_completion - completion sync between ti_st_open > + * and ti_st_registration_completion_cb. > + */ > +struct ti_st { > + struct hci_dev *hdev; > + char reg_status; > + long (*st_write) (struct sk_buff *); > + struct completion wait_reg_completion; > +}; > + > +static int reset; > + > +/* Increments HCI counters based on pocket ID (cmd,acl,sco) */ > +static inline void ti_st_tx_complete(struct ti_st *hst, int pkt_type) > +{ > + struct hci_dev *hdev; > + hdev = hst->hdev; please do this properly. Just write it like this: struct hci_dev *hdev = hst->hdev; + > + /* Update HCI stat counters */ > + switch (pkt_type) { > + case HCI_COMMAND_PKT: > + hdev->stat.cmd_tx++; > + break; > + > + case HCI_ACLDATA_PKT: > + hdev->stat.acl_tx++; > + break; > + > + case HCI_SCODATA_PKT: > + hdev->stat.sco_tx++; > + break; > + } > +} > + > +/* ------- Interfaces to Shared Transport ------ */ > + > +/* Called by ST layer to indicate protocol registration completion > + * status.ti_st_open() function will wait for signal from this > + * API when st_register() function returns ST_PENDING. > + */ > +static void st_registration_completion_cb(void *priv_data, char data) > +{ > + struct ti_st *lhst = priv_data; > + > + /* Save registration status for use in ti_st_open() */ > + lhst->reg_status = data; > + /* complete the wait in ti_st_open() */ > + complete(&lhst->wait_reg_completion); > +} > + > +/* Called by Shared Transport layer when receive data is > + * available */ > +static long st_receive(void *priv_data, struct sk_buff *skb) > +{ > + int err; > + struct ti_st *lhst = priv_data; I really prefer if the variable with the assignment comes first. > + if (!skb) > + return -EFAULT; > + > + if (!lhst) { > + kfree_skb(skb); > + return -EFAULT; > + } > + > + skb->dev = (struct net_device *)lhst->hdev; Don't do this cast. See the other drivers where we just use (void *) cast. > + /* Forward skb to HCI core layer */ > + err = hci_recv_frame(skb); > + if (err) { > + kfree_skb(skb); > + BT_ERR("Unable to push skb to HCI core(%d)", err); > + return err; > + } So first of all, I prefer if you check like this: if (err < 0) { And then second, you are double freeing the SKB here. The hci_recv_frame will free the SKB in an error case. > + > + lhst->hdev->stat.byte_rx += skb->len; > + > + return 0; > +} > + > +/* ------- Interfaces to HCI layer ------ */ > +/* protocol structure registered with shared transport */ > +static struct st_proto_s ti_st_proto = { > + .type = ST_BT, > + .recv = st_receive, > + .reg_complete_cb = st_registration_completion_cb, > + .priv_data = NULL, > +}; Please don't bother with NULL assignment. It should not be needed. > +/* Called from HCI core to initialize the device */ > +static int ti_st_open(struct hci_dev *hdev) > +{ > + unsigned long timeleft; > + struct ti_st *hst; > + int err; > + > + BT_DBG("%s %p", hdev->name, hdev); > + > + /* provide contexts for callbacks from ST */ > + hst = hdev->driver_data; > + ti_st_proto.priv_data = hst; > + > + err = st_register(&ti_st_proto); > + if (err == -EINPROGRESS) { > + /* Prepare wait-for-completion handler data structures. > + * Needed to synchronize this and > + * st_registration_completion_cb() functions. > + */ > + init_completion(&hst->wait_reg_completion); > + > + /* Reset ST registration callback status flag , this value > + * will be updated in ti_st_registration_completion_cb() > + * function whenever it called from ST driver. > + */ > + hst->reg_status = -EINPROGRESS; > + > + /* ST is busy with either protocol registration or firmware > + * download. Wait until the registration callback is called > + */ > + BT_DBG(" waiting for registration completion signal from ST"); > + > + timeleft = wait_for_completion_timeout > + (&hst->wait_reg_completion, > + msecs_to_jiffies(BT_REGISTER_TIMEOUT)); > + if (!timeleft) { > + BT_ERR("Timeout(%d sec),didn't get reg " > + "completion signal from ST", > + BT_REGISTER_TIMEOUT / 1000); > + return -ETIMEDOUT; > + } > + > + /* Is ST registration callback called with ERROR status? */ > + if (hst->reg_status != 0) { > + BT_ERR("ST registration completed with invalid " > + "status %d", hst->reg_status); > + return -EAGAIN; > + } > + err = 0; > + } else if (err == -EPERM) { > + BT_ERR("st_register failed %d", err); > + return err; > + } > + > + hst->st_write = ti_st_proto.write; > + if (!hst->st_write) { > + BT_ERR("undefined ST write function"); > + > + /* Undo registration with ST */ > + err = st_unregister(ST_BT); > + if (err) > + BT_ERR("st_unregister() failed with error %d", err); > + > + hst->st_write = NULL; > + return err; > + } > + > + /* Registration with ST layer is successful, > + * hardware is ready to accept commands from HCI core. > + */ > + set_bit(HCI_RUNNING, &hdev->flags); > + > + return err; > +} I really don't like what you are doing here. So please use test_and_set_bit and clear it in an error case. Also you need to handle all error cases. Just not only two. Where is the ti_st_proto.write coming from? > + > +/* Close device */ > +static int ti_st_close(struct hci_dev *hdev) > +{ > + int err; > + struct ti_st *hst = hdev->driver_data; > + > + /* continue to unregister from transport */ > + err = st_unregister(ST_BT); > + if (err) > + BT_ERR("st_unregister() failed with error %d", err); > + > + hst->st_write = NULL; > + > + return err; > +} You need a test_and_clear_bit for HCI_RUNNING. There is a huge imbalance here. Have you tested this with consecutive hciconfig hci0 up/down executions actually? > +static int ti_st_send_frame(struct sk_buff *skb) > +{ > + struct hci_dev *hdev; > + struct ti_st *hst; > + long len; > + > + if (!skb) > + return -ENOMEM; Pointless check. The core will not call this function with a NULL pointer SKB. > + > + hdev = (struct hci_dev *)skb->dev; > + if (!hdev) > + return -ENODEV; Even this can't really happen. Have you seen such a case? > + if (!test_bit(HCI_RUNNING, &hdev->flags)) > + return -EBUSY; > + > + hst = hdev->driver_data; > + > + /* Prepend skb with frame type */ > + memcpy(skb_push(skb, 1), &bt_cb(skb)->pkt_type, 1); > + > + BT_DBG(" %s: type %d len %d", hdev->name, bt_cb(skb)->pkt_type, > + skb->len); > + > + /* Insert skb to shared transport layer's transmit queue. > + * Freeing skb memory is taken care in shared transport layer, > + * so don't free skb memory here. > + */ > + if (!hst->st_write) { > + kfree_skb(skb); > + BT_ERR(" Could not write to ST (st_write is NULL)"); > + return -EAGAIN; > + } I don't like these crappy checks on every packet. That is just stupid. You have checked for st_write when open happens and you set the hdev to HCI_RUNNING. Are you saying this could change during the lifetime of the hdev? If so then you have a serious problem here. > + len = hst->st_write(skb); > + if (len < 0) { > + kfree_skb(skb); > + BT_ERR(" ST write failed (%ld)", len); > + return -EAGAIN; > + } > + > + /* ST accepted our skb. So, Go ahead and do rest */ > + hdev->stat.byte_tx += len; > + ti_st_tx_complete(hst, bt_cb(skb)->pkt_type); > + > + return 0; > +} What is the reason for this deferred stats update. That code looks pretty much hackish to me. > +static void ti_st_destruct(struct hci_dev *hdev) > +{ > + if (!hdev) > + return; > + > + BT_DBG("%s", hdev->name); > + > + /* free ti_st memory */ > + kfree(hdev->driver_data); > + > + return; > +} What are you checking here for? Why do you think that hdev would not be valid? This is what the btusb and btsdio drivers do: static void btusb_destruct(struct hci_dev *hdev) { struct btusb_data *data = hdev->driver_data; BT_DBG("%s", hdev->name); kfree(data); } > +/* Creates new HCI device */ > +static int ti_st_register_dev(struct ti_st *hst) > +{ > + int err; > + struct hci_dev *hdev; I prefer if err is last in the variable list. > + > + /* Initialize and register HCI device */ > + hdev = hci_alloc_dev(); > + if (!hdev) > + return -ENOMEM; > + > + BT_DBG("hdev %p", hdev); > + > + hst->hdev = hdev; > + hdev->bus = HCI_UART; > + hdev->driver_data = hst; > + hdev->open = ti_st_open; > + hdev->close = ti_st_close; > + hdev->flush = NULL; Please implement a flush callback. > + hdev->send = ti_st_send_frame; > + hdev->destruct = ti_st_destruct; > + hdev->owner = THIS_MODULE; > + > + if (reset) > + set_bit(HCI_QUIRK_NO_RESET, &hdev->quirks); Why do you need this? This should only be crappy devices. Something like Bluetooth 1.0b old devices. > + err = hci_register_dev(hdev); > + if (err < 0) { > + BT_ERR("Can't register HCI device error %d", err); > + hci_free_dev(hdev); > + return err; > + } > + > + BT_DBG(" HCI device registered (hdev %p)", hdev); > + return 0; > +} > + > + No double empty lines please. > +static int bt_ti_probe(struct platform_device *pdev) > +{ > + int err; > + static struct ti_st *hst; See above. > + > + BT_DBG(" Bluetooth Driver Version %s", VERSION); This should be in the module_init function. And should be a BT_INFO and be precise what driver this actually this. > + > + hst = kzalloc(sizeof(struct ti_st), GFP_KERNEL); > + if (!hst) > + return -ENOMEM; > + > + /* Expose "hciX" device to user space */ > + err = ti_st_register_dev(hst); > + if (err) { > + kfree(hst); > + return err; > + } Is this ti_st_register device use anywhere else. Then please just include that code in here to make this clear. All other drivers do all the work in their probe() callback. > + > + dev_set_drvdata(&pdev->dev, hst); > + return err; > +} > + > +static int bt_ti_remove(struct platform_device *pdev) > +{ > + struct ti_st *hst; > + struct hci_dev *hdev; > + > + hst = dev_get_drvdata(&pdev->dev); Here I would prefer this: struct ti_st *hst = dev_get_drvdata(&pdev->dev); > + > + if (!hst) > + return -EFAULT; > + > + /* Deallocate local resource's memory */ > + hdev = hst->hdev; That comment doesn't match what you are doing here. > + > + if (!hdev) { > + BT_ERR("Invalid hdev memory"); > + kfree(hst); > + return -EFAULT; > + } No need to check for hdev here. If probe fails, then remove should never be called, right? And just to be safe you might wanna add this: dev_set_drvdata(&pdev->dev, NULL); > + > + ti_st_close(hdev); > + hci_unregister_dev(hdev); > + /* Free HCI device memory */ > + hci_free_dev(hdev); > + > + return 0; > +} > + > +static struct platform_driver btwilink_driver = { > + .probe = bt_ti_probe, > + .remove = bt_ti_remove, > + .driver = { > + .name = "btwilink", > + .owner = THIS_MODULE, > + }, > +}; > + > +/* ------- Module Init/Exit interfaces ------ */ > +static int __init bt_drv_init(void) > +{ > + long ret; > + > + ret = platform_driver_register(&btwilink_driver); > + if (ret != 0) { > + BT_ERR("btwilink platform driver registration failed"); > + return ret; > + } > + return 0; > +} please just do like we do with all other drivers; BT_INFO(...) return platform_driver_register(&btwilink_driver); > + > +static void __exit bt_drv_exit(void) > +{ > + platform_driver_unregister(&btwilink_driver); > +} > + > +module_init(bt_drv_init); > +module_exit(bt_drv_exit); And this should be btwilink_init and btwilink_exit. Please don't try to grab some generic namespace. > + > +/* ------ Module Info ------ */ > + > +module_param(reset, bool, 0644); > +MODULE_PARM_DESC(reset, "Send HCI reset command on initialization"); As mentioned above, that one seems wrong to me. You need to know what your device supports. And by default it should allow sending HCI_Reset at init. If not, then just that quirk. No need for module parameter here. > +MODULE_AUTHOR("Raja Mani "); > +MODULE_DESCRIPTION("Bluetooth Driver for TI Shared Transport" VERSION); > +MODULE_VERSION(VERSION); > +MODULE_LICENSE("GPL"); Regards Marcel