Hello,
Ok, have implemented the test_and_clear_bit.
On Tuesday 22 February 2011, Subhasish Ghosh wrote:
@@ -122,13 +122,10 @@ static void omapl_pru_tx_chars(struct
omapl_pru_suart
*soft_uart, u32 uart_no)
if (!(suart_get_duplex(soft_uart, uart_no) & ePRU_SUART_HALF_TX))
return;
- if (down_trylock(&soft_uart->port_sem[uart_no]))
- return;
-
if (uart_circ_empty(xmit) ||
uart_tx_stopped(&soft_uart->port[uart_no])) {
pruss_suart_stop_tx(&soft_uart->port[uart_no]);
- up(&soft_uart->port_sem[uart_no]);
+ soft_uart->tx_empty[uart_no] = true;
return;
}
@@ -259,7 +256,6 @@ static irqreturn_t pruss_suart_interrupt(s32 irq,
void
*dev_id)
pru_intr_clr_isrstatus(dev, uart_num,
PRU_TX_INTR);
pru_softuart_clr_tx_status(dev,
&soft_uart->suart_hdl
[port->line]);
- up(&soft_uart->port_sem[port->line]);
omapl_pru_tx_chars(soft_uart, port->line);
}
} while (txrx_flag & (PRU_RX_INTR | PRU_TX_INTR));
@@ -294,7 +290,10 @@ static void pruss_suart_start_tx(struct uart_port
*port)
suart_intr_setmask(dev,
soft_uart->suart_hdl[port->line].uart_num,
PRU_TX_INTR, CHN_TXRX_IE_MASK_CMPLT);
- omapl_pru_tx_chars(soft_uart, port->line);
+ if (soft_uart->tx_empty[port->line] == true) {
+ soft_uart->tx_empty[port->line] = false;
+ omapl_pru_tx_chars(soft_uart, port->line);
+ }
}
This looks racy, and I think you at least need to take the spinlock in
pruss_suart_start_tx(), but I don't fully understand the intention of the
code.
I guess you could also use a bitmask for tx_empty and use
test_and_clear_bit()
on that to guarantee atomicity.
Arnd
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