[PATCH 1/3] libertas_spi: Use workqueue in hw_host_to_card
Vasily Khoruzhick
anarsoul at gmail.com
Fri Jan 21 15:44:48 EST 2011
Use workqueue to perform SPI xfers, it's necessary to fix
nasty "BUG: scheduling while atomic", because
spu_write() calls spi_sync() and spi_sync() may sleep, but
hw_host_to_card() callback can be called from atomic context.
Remove kthread completely, workqueue now does its job.
Restore intermediate buffers which were removed in commit
86c34fe89e9cad9e1ba4d1a8bbf98259035f4caf that introduced
mentioned bug.
Signed-off-by: Vasily Khoruzhick <anarsoul at gmail.com>
---
drivers/net/wireless/libertas/if_spi.c | 368 +++++++++++++++++++++-----------
1 files changed, 239 insertions(+), 129 deletions(-)
diff --git a/drivers/net/wireless/libertas/if_spi.c b/drivers/net/wireless/libertas/if_spi.c
index 0060023..f6c2cd6 100644
--- a/drivers/net/wireless/libertas/if_spi.c
+++ b/drivers/net/wireless/libertas/if_spi.c
@@ -20,10 +20,8 @@
#include <linux/moduleparam.h>
#include <linux/firmware.h>
#include <linux/jiffies.h>
-#include <linux/kthread.h>
#include <linux/list.h>
#include <linux/netdevice.h>
-#include <linux/semaphore.h>
#include <linux/slab.h>
#include <linux/spi/libertas_spi.h>
#include <linux/spi/spi.h>
@@ -34,6 +32,12 @@
#include "dev.h"
#include "if_spi.h"
+struct if_spi_packet {
+ struct list_head list;
+ u16 blen;
+ u8 buffer[0] __attribute__((aligned(4)));
+};
+
struct if_spi_card {
struct spi_device *spi;
struct lbs_private *priv;
@@ -51,18 +55,36 @@ struct if_spi_card {
unsigned long spu_reg_delay;
/* Handles all SPI communication (except for FW load) */
- struct task_struct *spi_thread;
- int run_thread;
-
- /* Used to wake up the spi_thread */
- struct semaphore spi_ready;
- struct semaphore spi_thread_terminated;
+ struct workqueue_struct *workqueue;
+ struct work_struct packet_work;
u8 cmd_buffer[IF_SPI_CMD_BUF_SIZE];
+
+ /* A buffer of incoming packets from libertas core.
+ * Since we can't sleep in hw_host_to_card, we have to buffer
+ * them. */
+ struct list_head cmd_packet_list;
+ struct list_head data_packet_list;
+
+ /* Protects cmd_packet_list and data_packet_list */
+ spinlock_t buffer_lock;
};
static void free_if_spi_card(struct if_spi_card *card)
{
+ struct list_head *cursor, *next;
+ struct if_spi_packet *packet;
+
+ list_for_each_safe(cursor, next, &card->cmd_packet_list) {
+ packet = container_of(cursor, struct if_spi_packet, list);
+ list_del(&packet->list);
+ kfree(packet);
+ }
+ list_for_each_safe(cursor, next, &card->data_packet_list) {
+ packet = container_of(cursor, struct if_spi_packet, list);
+ list_del(&packet->list);
+ kfree(packet);
+ }
spi_set_drvdata(card->spi, NULL);
kfree(card);
}
@@ -622,7 +644,7 @@ out:
/*
* SPI Transfer Thread
*
- * The SPI thread handles all SPI transfers, so there is no need for a lock.
+ * The SPI worker handles all SPI transfers, so there is no need for a lock.
*/
/* Move a command from the card to the host */
@@ -742,6 +764,40 @@ out:
return err;
}
+/* Move data or a command from the host to the card. */
+static void if_spi_h2c(struct if_spi_card *card,
+ struct if_spi_packet *packet, int type)
+{
+ int err = 0;
+ u16 int_type, port_reg;
+
+ switch (type) {
+ case MVMS_DAT:
+ int_type = IF_SPI_CIC_TX_DOWNLOAD_OVER;
+ port_reg = IF_SPI_DATA_RDWRPORT_REG;
+ break;
+ case MVMS_CMD:
+ int_type = IF_SPI_CIC_CMD_DOWNLOAD_OVER;
+ port_reg = IF_SPI_CMD_RDWRPORT_REG;
+ break;
+ default:
+ lbs_pr_err("can't transfer buffer of type %d\n", type);
+ err = -EINVAL;
+ goto out;
+ }
+
+ /* Write the data to the card */
+ err = spu_write(card, port_reg, packet->buffer, packet->blen);
+ if (err)
+ goto out;
+
+out:
+ kfree(packet);
+
+ if (err)
+ lbs_pr_err("%s: error %d\n", __func__, err);
+}
+
/* Inform the host about a card event */
static void if_spi_e2h(struct if_spi_card *card)
{
@@ -766,71 +822,88 @@ out:
lbs_pr_err("%s: error %d\n", __func__, err);
}
-static int lbs_spi_thread(void *data)
+static void if_spi_host_to_card_worker(struct work_struct *work)
{
int err;
- struct if_spi_card *card = data;
+ struct if_spi_card *card;
u16 hiStatus;
+ unsigned long flags;
+ struct if_spi_packet *packet;
- while (1) {
- /* Wait to be woken up by one of two things. First, our ISR
- * could tell us that something happened on the WLAN.
- * Secondly, libertas could call hw_host_to_card with more
- * data, which we might be able to send.
- */
- do {
- err = down_interruptible(&card->spi_ready);
- if (!card->run_thread) {
- up(&card->spi_thread_terminated);
- do_exit(0);
- }
- } while (err == -EINTR);
+ card = container_of(work, struct if_spi_card, packet_work);
- /* Read the host interrupt status register to see what we
- * can do. */
- err = spu_read_u16(card, IF_SPI_HOST_INT_STATUS_REG,
- &hiStatus);
- if (err) {
- lbs_pr_err("I/O error\n");
+ lbs_deb_enter(LBS_DEB_SPI);
+
+ /* Read the host interrupt status register to see what we
+ * can do. */
+ err = spu_read_u16(card, IF_SPI_HOST_INT_STATUS_REG,
+ &hiStatus);
+ if (err) {
+ lbs_pr_err("I/O error\n");
+ goto err;
+ }
+
+ if (hiStatus & IF_SPI_HIST_CMD_UPLOAD_RDY) {
+ err = if_spi_c2h_cmd(card);
+ if (err)
goto err;
- }
+ }
+ if (hiStatus & IF_SPI_HIST_RX_UPLOAD_RDY) {
+ err = if_spi_c2h_data(card);
+ if (err)
+ goto err;
+ }
- if (hiStatus & IF_SPI_HIST_CMD_UPLOAD_RDY) {
- err = if_spi_c2h_cmd(card);
- if (err)
- goto err;
- }
- if (hiStatus & IF_SPI_HIST_RX_UPLOAD_RDY) {
- err = if_spi_c2h_data(card);
- if (err)
- goto err;
+ /* workaround: in PS mode, the card does not set the Command
+ * Download Ready bit, but it sets TX Download Ready. */
+ if (hiStatus & IF_SPI_HIST_CMD_DOWNLOAD_RDY ||
+ (card->priv->psstate != PS_STATE_FULL_POWER &&
+ (hiStatus & IF_SPI_HIST_TX_DOWNLOAD_RDY))) {
+ /* This means two things. First of all,
+ * if there was a previous command sent, the card has
+ * successfully received it.
+ * Secondly, it is now ready to download another
+ * command.
+ */
+ lbs_host_to_card_done(card->priv);
+
+ /* Do we have any command packets from the host to
+ * send? */
+ packet = NULL;
+ spin_lock_irqsave(&card->buffer_lock, flags);
+ if (!list_empty(&card->cmd_packet_list)) {
+ packet = (struct if_spi_packet *)(card->
+ cmd_packet_list.next);
+ list_del(&packet->list);
}
+ spin_unlock_irqrestore(&card->buffer_lock, flags);
- /* workaround: in PS mode, the card does not set the Command
- * Download Ready bit, but it sets TX Download Ready. */
- if (hiStatus & IF_SPI_HIST_CMD_DOWNLOAD_RDY ||
- (card->priv->psstate != PS_STATE_FULL_POWER &&
- (hiStatus & IF_SPI_HIST_TX_DOWNLOAD_RDY))) {
- lbs_host_to_card_done(card->priv);
+ if (packet)
+ if_spi_h2c(card, packet, MVMS_CMD);
+ }
+ if (hiStatus & IF_SPI_HIST_TX_DOWNLOAD_RDY) {
+ /* Do we have any data packets from the host to
+ * send? */
+ packet = NULL;
+ spin_lock_irqsave(&card->buffer_lock, flags);
+ if (!list_empty(&card->data_packet_list)) {
+ packet = (struct if_spi_packet *)(card->
+ data_packet_list.next);
+ list_del(&packet->list);
}
+ spin_unlock_irqrestore(&card->buffer_lock, flags);
- if (hiStatus & IF_SPI_HIST_CARD_EVENT)
- if_spi_e2h(card);
+ if (packet)
+ if_spi_h2c(card, packet, MVMS_DAT);
+ }
+ if (hiStatus & IF_SPI_HIST_CARD_EVENT)
+ if_spi_e2h(card);
err:
- if (err)
- lbs_pr_err("%s: got error %d\n", __func__, err);
- }
-}
+ if (err)
+ lbs_pr_err("%s: got error %d\n", __func__, err);
-/* Block until lbs_spi_thread thread has terminated */
-static void if_spi_terminate_spi_thread(struct if_spi_card *card)
-{
- /* It would be nice to use kthread_stop here, but that function
- * can't wake threads waiting for a semaphore. */
- card->run_thread = 0;
- up(&card->spi_ready);
- down(&card->spi_thread_terminated);
+ lbs_deb_leave(LBS_DEB_SPI);
}
/*
@@ -842,18 +915,40 @@ static int if_spi_host_to_card(struct lbs_private *priv,
u8 type, u8 *buf, u16 nb)
{
int err = 0;
+ unsigned long flags;
struct if_spi_card *card = priv->card;
+ struct if_spi_packet *packet;
+ u16 blen;
lbs_deb_enter_args(LBS_DEB_SPI, "type %d, bytes %d", type, nb);
- nb = ALIGN(nb, 4);
+ if (nb == 0) {
+ lbs_pr_err("%s: invalid size requested: %d\n", __func__, nb);
+ err = -EINVAL;
+ goto out;
+ }
+ blen = ALIGN(nb, 4);
+ packet = kzalloc(sizeof(struct if_spi_packet) + blen, GFP_ATOMIC);
+ if (!packet) {
+ err = -ENOMEM;
+ goto out;
+ }
+ packet->blen = blen;
+ memcpy(packet->buffer, buf, nb);
+ memset(packet->buffer + nb, 0, blen - nb);
switch (type) {
case MVMS_CMD:
- err = spu_write(card, IF_SPI_CMD_RDWRPORT_REG, buf, nb);
+ priv->dnld_sent = DNLD_CMD_SENT;
+ spin_lock_irqsave(&card->buffer_lock, flags);
+ list_add_tail(&packet->list, &card->cmd_packet_list);
+ spin_unlock_irqrestore(&card->buffer_lock, flags);
break;
case MVMS_DAT:
- err = spu_write(card, IF_SPI_DATA_RDWRPORT_REG, buf, nb);
+ priv->dnld_sent = DNLD_DATA_SENT;
+ spin_lock_irqsave(&card->buffer_lock, flags);
+ list_add_tail(&packet->list, &card->data_packet_list);
+ spin_unlock_irqrestore(&card->buffer_lock, flags);
break;
default:
lbs_pr_err("can't transfer buffer of type %d", type);
@@ -861,6 +956,9 @@ static int if_spi_host_to_card(struct lbs_private *priv,
break;
}
+ /* Queue spi xfer work */
+ queue_work(card->workqueue, &card->packet_work);
+out:
lbs_deb_leave_args(LBS_DEB_SPI, "err=%d", err);
return err;
}
@@ -869,13 +967,14 @@ static int if_spi_host_to_card(struct lbs_private *priv,
* Host Interrupts
*
* Service incoming interrupts from the WLAN device. We can't sleep here, so
- * don't try to talk on the SPI bus, just wake up the SPI thread.
+ * don't try to talk on the SPI bus, just queue the SPI xfer work.
*/
static irqreturn_t if_spi_host_interrupt(int irq, void *dev_id)
{
struct if_spi_card *card = dev_id;
- up(&card->spi_ready);
+ queue_work(card->workqueue, &card->packet_work);
+
return IRQ_HANDLED;
}
@@ -883,56 +982,26 @@ static irqreturn_t if_spi_host_interrupt(int irq, void *dev_id)
* SPI callbacks
*/
-static int __devinit if_spi_probe(struct spi_device *spi)
+static int if_spi_init_card(struct if_spi_card *card)
{
- struct if_spi_card *card;
- struct lbs_private *priv = NULL;
- struct libertas_spi_platform_data *pdata = spi->dev.platform_data;
- int err = 0, i;
+ struct spi_device *spi = card->spi;
+ int err, i;
u32 scratch;
- struct sched_param param = { .sched_priority = 1 };
const struct firmware *helper = NULL;
const struct firmware *mainfw = NULL;
lbs_deb_enter(LBS_DEB_SPI);
- if (!pdata) {
- err = -EINVAL;
- goto out;
- }
-
- if (pdata->setup) {
- err = pdata->setup(spi);
- if (err)
- goto out;
- }
-
- /* Allocate card structure to represent this specific device */
- card = kzalloc(sizeof(struct if_spi_card), GFP_KERNEL);
- if (!card) {
- err = -ENOMEM;
- goto out;
- }
- spi_set_drvdata(spi, card);
- card->pdata = pdata;
- card->spi = spi;
- card->prev_xfer_time = jiffies;
-
- sema_init(&card->spi_ready, 0);
- sema_init(&card->spi_thread_terminated, 0);
-
- /* Initialize the SPI Interface Unit */
- err = spu_init(card, pdata->use_dummy_writes);
+ err = spu_init(card, card->pdata->use_dummy_writes);
if (err)
- goto free_card;
+ goto out;
err = spu_get_chip_revision(card, &card->card_id, &card->card_rev);
if (err)
- goto free_card;
+ goto out;
- /* Firmware load */
err = spu_read_u32(card, IF_SPI_SCRATCH_4_REG, &scratch);
if (err)
- goto free_card;
+ goto out;
if (scratch == SUCCESSFUL_FW_DOWNLOAD_MAGIC)
lbs_deb_spi("Firmware is already loaded for "
"Marvell WLAN 802.11 adapter\n");
@@ -946,7 +1015,7 @@ static int __devinit if_spi_probe(struct spi_device *spi)
lbs_pr_err("Unsupported chip_id: 0x%02x\n",
card->card_id);
err = -ENODEV;
- goto free_card;
+ goto out;
}
err = lbs_get_firmware(&card->spi->dev, NULL, NULL,
@@ -954,7 +1023,7 @@ static int __devinit if_spi_probe(struct spi_device *spi)
&mainfw);
if (err) {
lbs_pr_err("failed to find firmware (%d)\n", err);
- goto free_card;
+ goto out;
}
lbs_deb_spi("Initializing FW for Marvell WLAN 802.11 adapter "
@@ -966,15 +1035,68 @@ static int __devinit if_spi_probe(struct spi_device *spi)
spi->max_speed_hz);
err = if_spi_prog_helper_firmware(card, helper);
if (err)
- goto free_card;
+ goto out;
err = if_spi_prog_main_firmware(card, mainfw);
if (err)
- goto free_card;
+ goto out;
lbs_deb_spi("loaded FW for Marvell WLAN 802.11 adapter\n");
}
err = spu_set_interrupt_mode(card, 0, 1);
if (err)
+ goto out;
+
+out:
+ if (helper)
+ release_firmware(helper);
+ if (mainfw)
+ release_firmware(mainfw);
+
+ lbs_deb_leave_args(LBS_DEB_SPI, "err %d\n", err);
+
+ return err;
+}
+
+static int __devinit if_spi_probe(struct spi_device *spi)
+{
+ struct if_spi_card *card;
+ struct lbs_private *priv = NULL;
+ struct libertas_spi_platform_data *pdata = spi->dev.platform_data;
+ int err = 0;
+
+ lbs_deb_enter(LBS_DEB_SPI);
+
+ if (!pdata) {
+ err = -EINVAL;
+ goto out;
+ }
+
+ if (pdata->setup) {
+ err = pdata->setup(spi);
+ if (err)
+ goto out;
+ }
+
+ /* Allocate card structure to represent this specific device */
+ card = kzalloc(sizeof(struct if_spi_card), GFP_KERNEL);
+ if (!card) {
+ err = -ENOMEM;
+ goto teardown;
+ }
+ spi_set_drvdata(spi, card);
+ card->pdata = pdata;
+ card->spi = spi;
+ card->prev_xfer_time = jiffies;
+
+ INIT_LIST_HEAD(&card->cmd_packet_list);
+ INIT_LIST_HEAD(&card->data_packet_list);
+ spin_lock_init(&card->buffer_lock);
+
+ /* Initialize the SPI Interface Unit */
+
+ /* Firmware load */
+ err = if_spi_init_card(card);
+ if (err)
goto free_card;
/* Register our card with libertas.
@@ -993,27 +1115,16 @@ static int __devinit if_spi_probe(struct spi_device *spi)
priv->fw_ready = 1;
/* Initialize interrupt handling stuff. */
- card->run_thread = 1;
- card->spi_thread = kthread_run(lbs_spi_thread, card, "lbs_spi_thread");
- if (IS_ERR(card->spi_thread)) {
- card->run_thread = 0;
- err = PTR_ERR(card->spi_thread);
- lbs_pr_err("error creating SPI thread: err=%d\n", err);
- goto remove_card;
- }
- if (sched_setscheduler(card->spi_thread, SCHED_FIFO, ¶m))
- lbs_pr_err("Error setting scheduler, using default.\n");
+ card->workqueue = create_workqueue("libertas_spi");
+ INIT_WORK(&card->packet_work, if_spi_host_to_card_worker);
err = request_irq(spi->irq, if_spi_host_interrupt,
IRQF_TRIGGER_FALLING, "libertas_spi", card);
if (err) {
lbs_pr_err("can't get host irq line-- request_irq failed\n");
- goto terminate_thread;
+ goto terminate_workqueue;
}
- /* poke the IRQ handler so that we don't miss the first interrupt */
- up(&card->spi_ready);
-
/* Start the card.
* This will call register_netdev, and we'll start
* getting interrupts... */
@@ -1028,18 +1139,16 @@ static int __devinit if_spi_probe(struct spi_device *spi)
release_irq:
free_irq(spi->irq, card);
-terminate_thread:
- if_spi_terminate_spi_thread(card);
-remove_card:
+terminate_workqueue:
+ flush_workqueue(card->workqueue);
+ destroy_workqueue(card->workqueue);
lbs_remove_card(priv); /* will call free_netdev */
free_card:
free_if_spi_card(card);
+teardown:
+ if (pdata->teardown)
+ pdata->teardown(spi);
out:
- if (helper)
- release_firmware(helper);
- if (mainfw)
- release_firmware(mainfw);
-
lbs_deb_leave_args(LBS_DEB_SPI, "err %d\n", err);
return err;
}
@@ -1056,7 +1165,8 @@ static int __devexit libertas_spi_remove(struct spi_device *spi)
lbs_remove_card(priv); /* will call free_netdev */
free_irq(spi->irq, card);
- if_spi_terminate_spi_thread(card);
+ flush_workqueue(card->workqueue);
+ destroy_workqueue(card->workqueue);
if (card->pdata->teardown)
card->pdata->teardown(spi);
free_if_spi_card(card);
--
1.7.4.rc1
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