greybus: uart: wait for credits on shutdown
We should try to wait until all credits are accounted for before returning from shutdown. For this purpose add a helper function that will wait on completion, and call it form the shutdown. This helper will also be useful when "wait until sent" is implemented. Signed-off-by: Axel Haslam <ahaslam@baylibre.com> Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>hifive-unleashed-5.1
parent
2b3b87f056
commit
5dad5c314b
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@ -29,6 +29,7 @@
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#include <linux/kdev_t.h>
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#include <linux/kdev_t.h>
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#include <linux/kfifo.h>
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#include <linux/kfifo.h>
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#include <linux/workqueue.h>
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#include <linux/workqueue.h>
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#include <linux/completion.h>
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#include "greybus.h"
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#include "greybus.h"
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#include "gbphy.h"
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#include "gbphy.h"
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@ -39,6 +40,7 @@
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#define GB_UART_WRITE_FIFO_SIZE PAGE_SIZE
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#define GB_UART_WRITE_FIFO_SIZE PAGE_SIZE
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#define GB_UART_WRITE_ROOM_MARGIN 1 /* leave some space in fifo */
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#define GB_UART_WRITE_ROOM_MARGIN 1 /* leave some space in fifo */
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#define GB_UART_FIRMWARE_CREDITS 4096
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#define GB_UART_FIRMWARE_CREDITS 4096
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#define GB_UART_CREDIT_WAIT_TIMEOUT_MSEC 10000
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struct gb_tty_line_coding {
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struct gb_tty_line_coding {
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__le32 rate;
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__le32 rate;
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@ -71,6 +73,7 @@ struct gb_tty {
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struct kfifo write_fifo;
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struct kfifo write_fifo;
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bool close_pending;
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bool close_pending;
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unsigned int credits;
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unsigned int credits;
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struct completion credits_complete;
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};
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};
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static struct tty_driver *gb_tty_driver;
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static struct tty_driver *gb_tty_driver;
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@ -197,6 +200,9 @@ static int gb_uart_receive_credits_handler(struct gb_operation *op)
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*/
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*/
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tty_port_tty_wakeup(&gb_tty->port);
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tty_port_tty_wakeup(&gb_tty->port);
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if (gb_tty->credits == GB_UART_FIRMWARE_CREDITS)
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complete(&gb_tty->credits_complete);
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return ret;
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return ret;
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}
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}
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@ -317,6 +323,24 @@ static int send_break(struct gb_tty *gb_tty, u8 state)
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&request, sizeof(request), NULL, 0);
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&request, sizeof(request), NULL, 0);
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}
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}
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static int gb_uart_wait_for_all_credits(struct gb_tty *gb_tty)
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{
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int ret;
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if (gb_tty->credits == GB_UART_FIRMWARE_CREDITS)
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return 0;
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ret = wait_for_completion_timeout(&gb_tty->credits_complete,
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msecs_to_jiffies(GB_UART_CREDIT_WAIT_TIMEOUT_MSEC));
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if (!ret) {
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dev_err(&gb_tty->gbphy_dev->dev,
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"time out waiting for credits\n");
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return -ETIMEDOUT;
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}
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return 0;
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}
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static int gb_uart_flush(struct gb_tty *gb_tty, u8 flags)
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static int gb_uart_flush(struct gb_tty *gb_tty, u8 flags)
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{
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{
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struct gb_uart_serial_flush_request request;
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struct gb_uart_serial_flush_request request;
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@ -765,12 +789,18 @@ static void gb_tty_port_shutdown(struct tty_port *port)
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kfifo_reset_out(&gb_tty->write_fifo);
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kfifo_reset_out(&gb_tty->write_fifo);
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spin_unlock_irqrestore(&gb_tty->write_lock, flags);
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spin_unlock_irqrestore(&gb_tty->write_lock, flags);
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if (gb_tty->credits == GB_UART_FIRMWARE_CREDITS)
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goto out;
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ret = gb_uart_flush(gb_tty, GB_SERIAL_FLAG_FLUSH_TRANSMITTER);
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ret = gb_uart_flush(gb_tty, GB_SERIAL_FLAG_FLUSH_TRANSMITTER);
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if (ret) {
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if (ret) {
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dev_err(&gb_tty->gbphy_dev->dev,
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dev_err(&gb_tty->gbphy_dev->dev,
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"error flushing transmitter: %d\n", ret);
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"error flushing transmitter: %d\n", ret);
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}
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}
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gb_uart_wait_for_all_credits(gb_tty);
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out:
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gb_tty->close_pending = false;
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gb_tty->close_pending = false;
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}
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}
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@ -842,6 +872,7 @@ static int gb_uart_probe(struct gbphy_device *gbphy_dev,
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goto exit_buf_free;
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goto exit_buf_free;
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gb_tty->credits = GB_UART_FIRMWARE_CREDITS;
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gb_tty->credits = GB_UART_FIRMWARE_CREDITS;
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init_completion(&gb_tty->credits_complete);
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minor = alloc_minor(gb_tty);
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minor = alloc_minor(gb_tty);
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if (minor < 0) {
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if (minor < 0) {
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