From: Sergei Shtylyov <sshtylyov@ru•mvista.com>
To: John Linn <john.linn@xilinx•com>
Cc: linuxppc-dev@ozlabs•org
Subject: Re: [PATCH 2/3] [POWERPC][V3] Xilinx: of_serial support for Xilinx uart 16550.
Date: Thu, 03 Apr 2008 16:25:30 +0400 [thread overview]
Message-ID: <47F4CCBA.9060706@ru.mvista.com> (raw)
In-Reply-To: <20080402232213.5D87515B8067@mail37-sin.bigfish.com>
Hello.
John Linn wrote:
> The Xilinx 16550 uart core is not a standard 16550 because it uses
> word-based addressing rather than byte-based addressing. With
> additional properties it is compatible with the open firmware
> 'ns16550' compatible binding.
> This code updates the of_serial driver to handle the reg-offset
> and reg-shift properties to enable this core to be used.
> Signed-off-by: John Linn <john.linn@xilinx•com>
> ---
> diff --git a/drivers/serial/of_serial.c b/drivers/serial/of_serial.c
> index 2efb892..73c47a5 100644
> --- a/drivers/serial/of_serial.c
> +++ b/drivers/serial/of_serial.c
> @@ -31,7 +31,8 @@ static int __devinit of_platform_serial_setup(struct of_device *ofdev,
> struct resource resource;
> struct device_node *np = ofdev->node;
> const unsigned int *clk, *spd;
> - int ret;
> + const u32 *prop;
> + int ret, prop_size;
>
> memset(port, 0, sizeof *port);
> spd = of_get_property(np, "current-speed", NULL);
> @@ -49,6 +50,17 @@ static int __devinit of_platform_serial_setup(struct of_device *ofdev,
>
> spin_lock_init(&port->lock);
> port->mapbase = resource.start;
> +
> + /* Check for shifted address mapping */
> + prop = of_get_property(np, "reg-offset", &prop_size);
> + if (prop && (prop_size == sizeof(u32)))
> + port->mapbase += *prop;
I disagree. That trick leads to I/O resource misaccounting/misreporting.
You should teach 8250.c about the offset trick instead, just as it's been
taught the shift trick in its time.
> +
> + /* Check for registers offset within the devices address range */
> + prop = of_get_property(np, "reg-shift", &prop_size);
> + if (prop && (prop_size == sizeof(u32)))
> + port->regshift = *prop;
> +
> port->irq = irq_of_parse_and_map(np, 0);
> port->iotype = UPIO_MEM;
> port->type = type;
WBR, Sergei
prev parent reply other threads:[~2008-04-03 12:26 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-04-02 23:22 [PATCH 2/3] [POWERPC][V3] Xilinx: of_serial support for Xilinx uart 16550 John Linn
2008-04-02 23:34 ` Arnd Bergmann
2008-04-03 2:43 ` Grant Likely
2008-04-03 4:16 ` Arnd Bergmann
2008-04-03 13:29 ` John Linn
2008-04-03 22:36 ` [PATCH 2/3] [POWERPC][V3] Xilinx: of_serial support for Xilinxuart 16550 Stephen Neuendorffer
2008-04-05 14:45 ` [PATCH 2/3] [POWERPC][V3] Xilinx: of_serial support for Xilinx uart 16550 Josh Boyer
2008-04-08 2:44 ` David Gibson
2008-04-03 12:25 ` Sergei Shtylyov [this message]
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