RE: [PATCH] [V3] uartlite: move from byte accesses to word accesses

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> -----Original Message-----
> From: glikely@xxxxxxxxxxxx [mailto:glikely@xxxxxxxxxxxx] On Behalf Of Grant Likely
> Sent: Wednesday, March 17, 2010 10:21 AM
> To: John Linn
> Cc: linux-serial@xxxxxxxxxxxxxxx; jacmet@xxxxxxxxxx; michal.simek@xxxxxxxxxxxxx;
> john.williams@xxxxxxxxxxxxx
> Subject: Re: [PATCH] [V3] uartlite: move from byte accesses to word accesses
> 
> On Wed, Mar 17, 2010 at 9:40 AM, John Linn <john.linn@xxxxxxxxxx> wrote:
> > Byte accesses for I/O devices in Xilinx IP is going to be less
> > desired in the future such that the driver is being changed to
> > use 32 bit accesses.
> >
> > This change facilitates using the uartlite IP over a PCIe bus
> > which only allows 32 bit accesses.
> >
> > Signed-off-by: John Linn <john.linn@xxxxxxxxxx>
> >
> > ---
> >
> > V2 - updated the commit message based on Peter's comments
> >
> > V3 - removed u8 casting based on Peter's comments, cleaned up and
> > simplified the change by using raw I/O functions rather than
> > using in_be32 & out_be32 functions.
> 
> The __raw_{read,write}l() functions aren't the best choice here.  User
> ioread32be(), iowrite32be() instead if you want them to work
> cross-architecture (see include/asm-generic/iomap.h).

Maybe the ioread functions will work better than the in/out_be32 as they 
were not working like I wanted. 

I'm still trying to get my head wrapped around the right I/O functions to use since there are so many options.

I'll look at your suggestions.

Thanks,
John

> 
> g.
> 
> > ---
> >  drivers/serial/uartlite.c |   32 ++++++++++++++++----------------
> >  1 files changed, 16 insertions(+), 16 deletions(-)
> >
> > diff --git a/drivers/serial/uartlite.c b/drivers/serial/uartlite.c
> > index ab2ab3c..bdf08c7 100644
> > --- a/drivers/serial/uartlite.c
> > +++ b/drivers/serial/uartlite.c
> > @@ -86,7 +86,7 @@ static int ulite_receive(struct uart_port *port, int stat)
> >        /* stats */
> >        if (stat & ULITE_STATUS_RXVALID) {
> >                port->icount.rx++;
> > -               ch = readb(port->membase + ULITE_RX);
> > +               ch = __raw_readl(port->membase + ULITE_RX);
> >
> >                if (stat & ULITE_STATUS_PARITY)
> >                        port->icount.parity++;
> > @@ -131,7 +131,7 @@ static int ulite_transmit(struct uart_port *port, int stat)
> >                return 0;
> >
> >        if (port->x_char) {
> > -               writeb(port->x_char, port->membase + ULITE_TX);
> > +               __raw_writel(port->x_char, port->membase + ULITE_TX);
> >                port->x_char = 0;
> >                port->icount.tx++;
> >                return 1;
> > @@ -140,7 +140,7 @@ static int ulite_transmit(struct uart_port *port, int stat)
> >        if (uart_circ_empty(xmit) || uart_tx_stopped(port))
> >                return 0;
> >
> > -       writeb(xmit->buf[xmit->tail], port->membase + ULITE_TX);
> > +       __raw_writel(xmit->buf[xmit->tail], port->membase + ULITE_TX);
> >        xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE-1);
> >        port->icount.tx++;
> >
> > @@ -157,7 +157,7 @@ static irqreturn_t ulite_isr(int irq, void *dev_id)
> >        int busy, n = 0;
> >
> >        do {
> > -               int stat = readb(port->membase + ULITE_STATUS);
> > +               int stat = __raw_readl(port->membase + ULITE_STATUS);
> >                busy  = ulite_receive(port, stat);
> >                busy |= ulite_transmit(port, stat);
> >                n++;
> > @@ -178,7 +178,7 @@ static unsigned int ulite_tx_empty(struct uart_port *port)
> >        unsigned int ret;
> >
> >        spin_lock_irqsave(&port->lock, flags);
> > -       ret = readb(port->membase + ULITE_STATUS);
> > +       ret = __raw_readl(port->membase + ULITE_STATUS);
> >        spin_unlock_irqrestore(&port->lock, flags);
> >
> >        return ret & ULITE_STATUS_TXEMPTY ? TIOCSER_TEMT : 0;
> > @@ -201,7 +201,7 @@ static void ulite_stop_tx(struct uart_port *port)
> >
> >  static void ulite_start_tx(struct uart_port *port)
> >  {
> > -       ulite_transmit(port, readb(port->membase + ULITE_STATUS));
> > +       ulite_transmit(port, __raw_readl(port->membase + ULITE_STATUS));
> >  }
> >
> >  static void ulite_stop_rx(struct uart_port *port)
> > @@ -230,17 +230,17 @@ static int ulite_startup(struct uart_port *port)
> >        if (ret)
> >                return ret;
> >
> > -       writeb(ULITE_CONTROL_RST_RX | ULITE_CONTROL_RST_TX,
> > +       __raw_writel(ULITE_CONTROL_RST_RX | ULITE_CONTROL_RST_TX,
> >               port->membase + ULITE_CONTROL);
> > -       writeb(ULITE_CONTROL_IE, port->membase + ULITE_CONTROL);
> > +       __raw_writel(ULITE_CONTROL_IE, port->membase + ULITE_CONTROL);
> >
> >        return 0;
> >  }
> >
> >  static void ulite_shutdown(struct uart_port *port)
> >  {
> > -       writeb(0, port->membase + ULITE_CONTROL);
> > -       readb(port->membase + ULITE_CONTROL); /* dummy */
> > +       __raw_writel(0, port->membase + ULITE_CONTROL);
> > +       __raw_readl(port->membase + ULITE_CONTROL); /* dummy */
> >        free_irq(port->irq, port);
> >  }
> >
> > @@ -352,7 +352,7 @@ static void ulite_console_wait_tx(struct uart_port *port)
> >
> >        /* Spin waiting for TX fifo to have space available */
> >        for (i = 0; i < 100000; i++) {
> > -               val = readb(port->membase + ULITE_STATUS);
> > +               val = __raw_readl(port->membase + ULITE_STATUS);
> >                if ((val & ULITE_STATUS_TXFULL) == 0)
> >                        break;
> >                cpu_relax();
> > @@ -362,7 +362,7 @@ static void ulite_console_wait_tx(struct uart_port *port)
> >  static void ulite_console_putchar(struct uart_port *port, int ch)
> >  {
> >        ulite_console_wait_tx(port);
> > -       writeb(ch, port->membase + ULITE_TX);
> > +       __raw_writel(ch, port->membase + ULITE_TX);
> >  }
> >
> >  static void ulite_console_write(struct console *co, const char *s,
> > @@ -379,8 +379,8 @@ static void ulite_console_write(struct console *co, const char *s,
> >                spin_lock_irqsave(&port->lock, flags);
> >
> >        /* save and disable interrupt */
> > -       ier = readb(port->membase + ULITE_STATUS) & ULITE_STATUS_IE;
> > -       writeb(0, port->membase + ULITE_CONTROL);
> > +       ier = __raw_readl(port->membase + ULITE_STATUS) & ULITE_STATUS_IE;
> > +       __raw_writel(0, port->membase + ULITE_CONTROL);
> >
> >        uart_console_write(port, s, count, ulite_console_putchar);
> >
> > @@ -388,7 +388,7 @@ static void ulite_console_write(struct console *co, const char *s,
> >
> >        /* restore interrupt state */
> >        if (ier)
> > -               writeb(ULITE_CONTROL_IE, port->membase + ULITE_CONTROL);
> > +               __raw_writel(ULITE_CONTROL_IE, port->membase + ULITE_CONTROL);
> >
> >        if (locked)
> >                spin_unlock_irqrestore(&port->lock, flags);
> > @@ -601,7 +601,7 @@ ulite_of_probe(struct of_device *op, const struct of_device_id *match)
> >
> >        id = of_get_property(op->node, "port-number", NULL);
> >
> > -       return ulite_assign(&op->dev, id ? *id : -1, res.start+3, irq);
> > +       return ulite_assign(&op->dev, id ? *id : -1, res.start, irq);
> >  }
> >
> >  static int __devexit ulite_of_remove(struct of_device *op)
> > --
> > 1.6.2.1
> >
> >
> >
> > This email and any attachments are intended for the sole use of the named recipient(s) and
> contain(s) confidential information that may be proprietary, privileged or copyrighted under
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> message or any attachments. Delete this email message and any attachments immediately.
> >
> >
> >
> 
> 
> 
> --
> Grant Likely, B.Sc., P.Eng.
> Secret Lab Technologies Ltd.


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