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From: Shawn Guo <shawnguo@kernel.org>
To: Sudeep Holla <sudeep.holla@arm.com>
Cc: Peter Hurley <peter@hurleysoftware.com>,
	Jason Liu <jason.liu@linaro.org>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Timur Tabi <timur@codeaurora.org>,
	xie.baoyou@zte.com.cn, Russell King <linux@armlinux.org.uk>,
	linux-serial@vger.kernel.org,
	Andre Przywara <andre.przywara@arm.com>,
	Jun Nie <jun.nie@linaro.org>, Shawn Guo <shawn.guo@linaro.org>,
	linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH v3 1/3] tty: amba-pl011: define flag register bits for ZTE device
Date: Sat, 17 Sep 2016 13:26:05 +0800	[thread overview]
Message-ID: <20160917052605.GF7398@tiger> (raw)
In-Reply-To: <b549cd51-a81f-b693-e3c2-9e3c598d3d9e@arm.com>

On Fri, Sep 16, 2016 at 03:23:57PM +0100, Sudeep Holla wrote:
> >@@ -2303,13 +2325,16 @@ static struct console amba_console = {
> >
> > static void pl011_putc(struct uart_port *port, int c)
> > {
> >+	struct uart_amba_port *uap =
> >+		container_of(port, struct uart_amba_port, port);
> >+
> > 	while (readl(port->membase + UART01x_FR) & UART01x_FR_TXFF)
> > 		cpu_relax();
> > 	if (port->iotype == UPIO_MEM32)
> > 		writel(c, port->membase + UART01x_DR);
> > 	else
> > 		writeb(c, port->membase + UART01x_DR);
> >-	while (readl(port->membase + UART01x_FR) & UART01x_FR_BUSY)
> >+	while (readl(port->membase + UART01x_FR) & uap->vendor->fr_busy)
> > 		cpu_relax();
> > }
> 
> The above hunk won't work for early console devices. The earlycon_device
> just has uart_port and is not uart_amba_port. I don't know how to fix
> this properly but I thought we could reuse private_data in uart_port for
> early_con devices. Something like below(incomplete for other vendors,
> works only for ARM)

Hi Sudeep,

Thanks much for the report.  I think the best way to fix this is that we
revert the change for pl011_putc() function, and figure out a correct
approach adding earlycon support for ZTE hardware later.

I will send a patch to revert pl011_putc() changes shortly.

Thanks,
Shawn

WARNING: multiple messages have this Message-ID (diff)
From: shawnguo@kernel.org (Shawn Guo)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH v3 1/3] tty: amba-pl011: define flag register bits for ZTE device
Date: Sat, 17 Sep 2016 13:26:05 +0800	[thread overview]
Message-ID: <20160917052605.GF7398@tiger> (raw)
In-Reply-To: <b549cd51-a81f-b693-e3c2-9e3c598d3d9e@arm.com>

On Fri, Sep 16, 2016 at 03:23:57PM +0100, Sudeep Holla wrote:
> >@@ -2303,13 +2325,16 @@ static struct console amba_console = {
> >
> > static void pl011_putc(struct uart_port *port, int c)
> > {
> >+	struct uart_amba_port *uap =
> >+		container_of(port, struct uart_amba_port, port);
> >+
> > 	while (readl(port->membase + UART01x_FR) & UART01x_FR_TXFF)
> > 		cpu_relax();
> > 	if (port->iotype == UPIO_MEM32)
> > 		writel(c, port->membase + UART01x_DR);
> > 	else
> > 		writeb(c, port->membase + UART01x_DR);
> >-	while (readl(port->membase + UART01x_FR) & UART01x_FR_BUSY)
> >+	while (readl(port->membase + UART01x_FR) & uap->vendor->fr_busy)
> > 		cpu_relax();
> > }
> 
> The above hunk won't work for early console devices. The earlycon_device
> just has uart_port and is not uart_amba_port. I don't know how to fix
> this properly but I thought we could reuse private_data in uart_port for
> early_con devices. Something like below(incomplete for other vendors,
> works only for ARM)

Hi Sudeep,

Thanks much for the report.  I think the best way to fix this is that we
revert the change for pl011_putc() function, and figure out a correct
approach adding earlycon support for ZTE hardware later.

I will send a patch to revert pl011_putc() changes shortly.

Thanks,
Shawn

  parent reply	other threads:[~2016-09-17  5:26 UTC|newest]

Thread overview: 28+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-07-08  9:00 [PATCH v3 0/3] Complete ZTE PL011 device support Shawn Guo
2016-07-08  9:00 ` Shawn Guo
2016-07-08  9:00 ` [PATCH v3 1/3] tty: amba-pl011: define flag register bits for ZTE device Shawn Guo
2016-07-08  9:00   ` Shawn Guo
2016-09-16 14:23   ` Sudeep Holla
2016-09-16 14:23     ` Sudeep Holla
2016-09-16 16:39     ` Russell King - ARM Linux
2016-09-16 16:39       ` Russell King - ARM Linux
2016-09-16 17:11       ` Timur Tabi
2016-09-16 17:11         ` Timur Tabi
2016-09-17  5:37         ` Shawn Guo
2016-09-17  5:37           ` Shawn Guo
2016-09-17  9:17           ` Russell King - ARM Linux
2016-09-17  9:17             ` Russell King - ARM Linux
2016-09-17  5:26     ` Shawn Guo [this message]
2016-09-17  5:26       ` Shawn Guo
2016-07-08  9:00 ` [PATCH v3 2/3] tty: amba-pl011: add .get_fifosize " Shawn Guo
2016-07-08  9:00   ` Shawn Guo
2016-07-08  9:00 ` [PATCH v3 3/3] tty: amba-pl011: probe ZTE device from AMBA bus with a pseudo-ID Shawn Guo
2016-07-08  9:00   ` Shawn Guo
2016-07-14 13:26 ` [PATCH v3 0/3] Complete ZTE PL011 device support Shawn Guo
2016-07-14 13:26   ` Shawn Guo
2016-07-18 13:35   ` Russell King - ARM Linux
2016-07-18 13:35     ` Russell King - ARM Linux
2016-08-09  3:21     ` Shawn Guo
2016-08-09  3:21       ` Shawn Guo
2016-08-09  8:27       ` Greg Kroah-Hartman
2016-08-09  8:27         ` Greg Kroah-Hartman

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