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From: bigeasy@linutronix.de (Sebastian Andrzej Siewior)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH 06/16] tty: serial: Add 8250-core based omap driver
Date: Tue, 16 Sep 2014 19:01:29 +0200
Message-ID: <54186CE9.5030303@linutronix.de> (raw)
In-Reply-To: <54118E1B.5070706@hurleysoftware.com>

On 09/11/2014 01:57 PM, Peter Hurley wrote:
> Hi Sebastian,

Hi Peter,

> Nice work. Minor comments within.

Thanks.

> After this is merged, it may be worth investigating how to use Yoshihiro's
> newly-added 8250-based tunable RX trigger interface for omap.

We need to overwrite the FCR callback. First because we can support
trigger levels 1?64 and it it split across two registers and second
because a change here results also in different DMA attributes.

>> +++ b/drivers/tty/serial/8250/8250_omap.c
>> @@ -0,0 +1,911 @@
>> +/*
>> + * 8250-core based driver for the OMAP internal UART
>> + *
>> + *  Copyright (C) 2014 Sebastian Andrzej Siewior
> 
> + * based on omap-serial.c, Copyright (C) 2010 Texas Instruments.
> 
> or something like that, since this is (partly) based on omap-serial.c

of course.

>> + *
>> + */
>> +
?
>> +	/*
>> +	 * Ask the core to calculate the divisor for us.
>> +	 */
>> +	baud = uart_get_baud_rate(port, termios, old,
>> +			port->uartclk / 16 / 0xffff,
>> +			port->uartclk / 13);
>> +	omap_8250_get_divisor(port, baud, priv);
>> +
>> +	/*
>> +	 * Ok, we're now changing the port state. Do it with
>> +	 * interrupts disabled.
>> +	 */
>> +	pm_runtime_get_sync(port->dev);
>> +	spin_lock_irqsave(&port->lock, flags);
>                    ^^^
>         spin_lock_irq(&port->lock);
> 
> The serial core calls the ->set_termios() method with interrupts enabled.

Okay, this could work.

>> +
>> +	/*
>> +	 * Update the per-port timeout.
>> +	 */
>> +	uart_update_timeout(port, termios->c_cflag, baud);
>> +
>> +	up->port.read_status_mask = UART_LSR_OE | UART_LSR_THRE | UART_LSR_DR;
>> +	if (termios->c_iflag & INPCK)
>> +		up->port.read_status_mask |= UART_LSR_FE | UART_LSR_PE;
>> +	if (termios->c_iflag & (BRKINT | PARMRK))
>                                 ^
>                               IGNBRK |
> 
> Otherwise, the read_status_mask will mask out the BI condition, so
> uart_insert_char() will send '\0' byte as TTY_NORMAL.
> 
> The 8250 and omap RX path differed so the omap driver didn't need this
> change, whereas the 8250 driver does.

Updated.

>> +		up->port.read_status_mask |= UART_LSR_BI;
>> +
>> +	/*
?
>> +
>> +	priv->efr = 0;
>> +	if (termios->c_cflag & CRTSCTS && up->port.flags & UPF_HARD_FLOW) {
>> +		/* Enable AUTORTS and AUTOCTS */
>> +		priv->efr |= UART_EFR_CTS | UART_EFR_RTS;
>> +
>> +		/* Ensure MCR RTS is asserted */
>> +		up->mcr |= UART_MCR_RTS;
>> +	}
>> +
>> +	if (up->port.flags & UPF_SOFT_FLOW) {
> 
> I'm aware that this is basically from the omap driver but can someone clear
> up if omap hardware can actually do UPF_HARD_FLOW and UPF_SOFT_FLOW
> simultaneously? The datasheets that I've looked at say no.

The one that I have here for am335x says:
"The UART module can use hardware or software flow control to manage
transmission and reception".
So yes, you are right about this. I changed this to do UPF_HARD_FLOW if
possible + else UPF_SOFT_FLOW.

> Regards,
> Peter Hurley

Sebastian

  reply index

Thread overview: 97+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-09-10 19:29 [PATCH 00/16 v9] omap 8250 based uart + DMA Sebastian Andrzej Siewior
2014-09-10 19:29 ` [PATCH 01/16] tty: serial: 8250_core: allow to set ->throttle / ->unthrottle callbacks Sebastian Andrzej Siewior
2014-09-10 19:29 ` [PATCH 02/16] tty: serial: 8250_core: add run time pm Sebastian Andrzej Siewior
2014-09-29  9:46   ` Frans Klaver
2014-09-29 13:39     ` Sebastian Andrzej Siewior
2014-09-10 19:29 ` [PATCH 03/16] tty: serial: 8250_core: read only RX if there is something in the FIFO Sebastian Andrzej Siewior
2015-02-09 13:34   ` Nicolas Schichan
2015-02-09 23:34     ` Peter Hurley
2015-02-10  9:32       ` Sebastian Andrzej Siewior
2015-02-10 12:04       ` Nicolas Schichan
2015-02-10 17:46         ` Peter Hurley
2015-02-11 20:01           ` Peter Hurley
2015-02-11 20:03             ` Tony Lindgren
2015-02-11 20:42               ` Peter Hurley
2015-02-12  8:45                 ` Sebastian Andrzej Siewior
2015-02-12  9:40                   ` Russell King - ARM Linux
2015-02-12 16:32                   ` Peter Hurley
2015-02-12 19:23                     ` Sebastian Andrzej Siewior
2015-02-12 19:55                       ` Peter Hurley
2015-02-12 20:34                         ` Sebastian Andrzej Siewior
2015-02-13 18:51                         ` Sebastian Andrzej Siewior
2015-02-13 23:15                           ` Russell King - ARM Linux
2015-02-15 17:32                             ` [PATCH] serial: 8250: Revert "tty: serial: 8250_core: read only RX if there is something in the FIFO" Sebastian Andrzej Siewior
2015-05-12 20:25                               ` Tony Lindgren
2014-09-10 19:29 ` [PATCH 04/16] tty: serial: 8250_core: use the ->line argument as a hint in serial8250_find_match_or_unused() Sebastian Andrzej Siewior
2014-09-10 19:30 ` [PATCH 05/16] tty: serial: 8250_core: remove UART_IER_RDI in serial8250_stop_rx() Sebastian Andrzej Siewior
2014-09-11 11:19   ` Heikki Krogerus
2014-09-10 19:30 ` [PATCH 06/16] tty: serial: Add 8250-core based omap driver Sebastian Andrzej Siewior
2014-09-11 11:57   ` Peter Hurley
2014-09-16 17:01     ` Sebastian Andrzej Siewior [this message]
2014-09-29  9:38   ` Frans Klaver
2014-09-29 13:27     ` Sebastian Andrzej Siewior
2014-09-29 13:34       ` Frans Klaver
2014-09-10 19:30 ` [PATCH 07/16] tty: serial: 8250_dma: handle error on TX submit Sebastian Andrzej Siewior
2014-09-10 19:30 ` [PATCH 08/16] tty: serial: 8250_dma: enqueue RX dma again on completion Sebastian Andrzej Siewior
2014-09-10 19:30 ` [PATCH 09/16] tty: serial: 8250_dma: Add a TX trigger workaround for AM33xx Sebastian Andrzej Siewior
2014-09-11 11:17   ` Heikki Krogerus
2014-09-11 11:42     ` Sebastian Andrzej Siewior
2014-09-11 12:32       ` Peter Hurley
2014-09-11 12:50         ` Sebastian Andrzej Siewior
2014-09-11 14:35           ` Peter Hurley
2014-09-15 17:01             ` Sebastian Andrzej Siewior
2014-09-16 16:55               ` Sebastian Andrzej Siewior
2014-09-17 12:20                 ` Peter Hurley
2014-09-17 16:25                   ` Sebastian Andrzej Siewior
2014-09-29 16:15                   ` Sebastian Andrzej Siewior
2014-09-11 15:11           ` Frans Klaver
2014-09-11 16:04             ` Sebastian Andrzej Siewior
2014-09-11 17:04               ` Frans Klaver
2014-09-12  7:23                 ` Sebastian Andrzej Siewior
     [not found]                   ` <20140912094010.GE28458@ci00147.xsens-tech.local>
2014-09-12  9:51                     ` Sebastian Andrzej Siewior
2014-09-12 10:28                       ` Frans Klaver
2014-09-15 16:42                         ` Sebastian Andrzej Siewior
2014-09-16  9:05                           ` Frans Klaver
2014-09-16 12:42                             ` Frans Klaver
2014-09-16 14:23                               ` Frans Klaver
2014-09-17 10:28                           ` Frans Klaver
2014-09-21 20:41                             ` Sebastian Andrzej Siewior
2014-09-22  9:28                               ` Frans Klaver
2014-09-24  7:56                                 ` Sebastian Andrzej Siewior
2014-09-25 15:14                                 ` Sebastian Andrzej Siewior
2014-09-25 15:18                                   ` Frans Klaver
2014-09-29  8:50                                   ` Frans Klaver
2014-09-29  9:54                                     ` Sebastian Andrzej Siewior
2014-09-29 10:30                                       ` Frans Klaver
2014-09-30  8:44                                         ` Frans Klaver
2014-10-02 10:27                                           ` Sebastian Andrzej Siewior
2014-10-13 14:55                                             ` Frans Klaver
2014-09-23 17:03                               ` Peter Hurley
2014-09-24  7:53                                 ` Sebastian Andrzej Siewior
2014-09-25 10:42                                   ` Sebastian Andrzej Siewior
2014-09-25 11:31                                     ` Peter Hurley
2014-09-25 13:11                                       ` Sebastian Andrzej Siewior
2014-09-17 16:34       ` Sebastian Andrzej Siewior
2014-09-19 10:22         ` Heikki Krogerus
2014-09-19 10:58           ` Sebastian Andrzej Siewior
2014-09-19 11:25             ` Peter Hurley
2014-09-22  7:46             ` Heikki Krogerus
2014-09-25  9:24               ` Sebastian Andrzej Siewior
2014-09-10 19:30 ` [PATCH 10/16] tty: serial: 8250_dma: optimize the xmit path due to UART_BUG_DMA_TX Sebastian Andrzej Siewior
2014-09-10 19:30 ` [PATCH 11/16] tty: serial: 8250_dma: keep own book keeping about RX transfers Sebastian Andrzej Siewior
2014-09-10 19:30 ` [PATCH 12/16] tty: serial: 8250_dma: handle the UART RDI event while DMA remains idle Sebastian Andrzej Siewior
2014-09-29  9:23   ` Frans Klaver
2014-09-10 19:30 ` [PATCH 13/16] tty: serial: 8250_dma: add pm runtime Sebastian Andrzej Siewior
2014-09-29  9:26   ` Frans Klaver
2014-09-29  9:56     ` Sebastian Andrzej Siewior
2014-09-10 19:30 ` [PATCH 14/16] arm: dts: am33xx: add DMA properties for UART Sebastian Andrzej Siewior
2014-09-10 19:30 ` [PATCH 15/16] arm: dts: dra7: " Sebastian Andrzej Siewior
2014-09-10 19:30 ` [PATCH 16/16] tty: serial: 8250: omap: add dma support Sebastian Andrzej Siewior
2014-09-12 22:43 ` [PATCH 00/16 v9] omap 8250 based uart + DMA Tony Lindgren
2014-09-15 11:50   ` Sebastian Andrzej Siewior
2014-09-16 12:57     ` Sebastian Andrzej Siewior
2014-09-16 16:48       ` Tony Lindgren
2014-09-16 21:30         ` Tony Lindgren
2014-09-17  8:38           ` Sebastian Andrzej Siewior
2014-09-17  9:05 ` Sebastian Andrzej Siewior
2014-09-26 16:02   ` Greg KH

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