[RFC] libertas: remove TX queues from GSPI driver
Andrey Yurovsky
andrey at cozybit.com
Fri Jun 19 18:39:28 EDT 2009
Posting this as an RFC in case others want to help test it. This
work-in-progress patch removes the redundant command and data TX queues
from the Libertas GSPI driver, it also therefore removes a memcpy from
if_spi_host_to_card and the locking mechanisms for the queues in
question. The goal is to improve performance and reduce overhead by
simplifying the TX path.
The driver works after this patch, however IEEE PS is somewhat broken
(especially temporarily waking the device to issue commands). This is
caused, in part, by the IRQ handler preempting the libertas main thread
(for example, when the main thread calls if_spi_host_to_card and an IRQ
comes in) so we need a synchronization solution that allows interrupt
servicing to be done when it's safe to do so, that is we need to lock
the bus properly.
Signed-off-by: Andrey Yurovsky <andrey at cozybit.com>
---
drivers/net/wireless/libertas/if_spi.c | 133 ++------------------------------
1 files changed, 7 insertions(+), 126 deletions(-)
diff --git a/drivers/net/wireless/libertas/if_spi.c b/drivers/net/wireless/libertas/if_spi.c
index 956566b..622cbc7 100644
--- a/drivers/net/wireless/libertas/if_spi.c
+++ b/drivers/net/wireless/libertas/if_spi.c
@@ -32,12 +32,6 @@
#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;
@@ -66,33 +60,12 @@ struct if_spi_card {
struct semaphore spi_thread_terminated;
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;
-
BUG_ON(card->run_thread);
- 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);
}
@@ -774,40 +747,6 @@ 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)
{
@@ -837,8 +776,6 @@ static int lbs_spi_thread(void *data)
int err;
struct if_spi_card *card = data;
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
@@ -877,43 +814,10 @@ static int lbs_spi_thread(void *data)
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);
-
- 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 (packet)
- if_spi_h2c(card, packet, MVMS_DAT);
- }
if (hiStatus & IF_SPI_HIST_CARD_EVENT)
if_spi_e2h(card);
@@ -942,40 +846,20 @@ 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);
- 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);
+ nb = ALIGN(nb, 4);
switch (type) {
case MVMS_CMD:
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);
+ err = spu_write(card, IF_SPI_CMD_RDWRPORT_REG, buf, nb);
break;
case MVMS_DAT:
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);
+ err = spu_write(card, IF_SPI_DATA_RDWRPORT_REG, buf, nb);
break;
default:
lbs_pr_err("can't transfer buffer of type %d", type);
@@ -983,9 +867,6 @@ static int if_spi_host_to_card(struct lbs_private *priv,
break;
}
- /* Wake up the spi thread */
- up(&card->spi_ready);
-out:
lbs_deb_leave_args(LBS_DEB_SPI, "err=%d", err);
return err;
}
@@ -1062,9 +943,6 @@ static int __devinit if_spi_probe(struct spi_device *spi)
sema_init(&card->spi_ready, 0);
sema_init(&card->spi_thread_terminated, 0);
- 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 */
err = spu_init(card, pdata->use_dummy_writes);
@@ -1138,6 +1016,9 @@ static int __devinit if_spi_probe(struct spi_device *spi)
goto terminate_thread;
}
+ /* poke the interrupt handler, otherwise we miss the first interrupt */
+ up(&card->spi_ready);
+
/* Start the card.
* This will call register_netdev, and we'll start
* getting interrupts... */
--
1.5.6.3
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