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serial: Use -EAGAIN in getc and putc

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U-Boot serial code already handles -EAGAIN value from getc and putc
callbacks. So change drivers code to return -EAGAIN when HW is busy instead
of doing its own busy loop and waiting until HW is ready.

Signed-off-by: Pali Rohár <pali@kernel.org>
This commit is contained in:
Pali Rohár 2022-12-11 00:31:21 +01:00 committed by Tom Rini
parent 59440d83d3
commit 1138bbe05e
4 changed files with 28 additions and 36 deletions
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8
drivers/serial/serial_arc.c
View file

@ -53,8 +53,8 @@ static int arc_serial_putc(struct udevice *dev, const char c)
struct arc_serial_plat *plat = dev_get_plat(dev);
struct arc_serial_regs *const regs = plat->reg;
while (!(readb(&regs->status) & UART_TXEMPTY))
;
if (!(readb(&regs->status) & UART_TXEMPTY))
return -EAGAIN;
writeb(c, &regs->data);
@ -83,8 +83,8 @@ static int arc_serial_getc(struct udevice *dev)
struct arc_serial_plat *plat = dev_get_plat(dev);
struct arc_serial_regs *const regs = plat->reg;
while (!arc_serial_tstc(regs))
;
if (!arc_serial_tstc(regs))
return -EAGAIN;
/* Check for overflow errors */
if (readb(&regs->status) & UART_OVERFLOW_ERR)

36
drivers/serial/serial_lpuart.c
View file

@ -168,23 +168,24 @@ static void _lpuart_serial_setbrg(struct udevice *dev,
static int _lpuart_serial_getc(struct lpuart_serial_plat *plat)
{
struct lpuart_fsl *base = plat->reg;
while (!(__raw_readb(&base->us1) & (US1_RDRF | US1_OR)))
schedule();
if (!(__raw_readb(&base->us1) & (US1_RDRF | US1_OR)))
return -EAGAIN;
barrier();
return __raw_readb(&base->ud);
}
static void _lpuart_serial_putc(struct lpuart_serial_plat *plat,
static int _lpuart_serial_putc(struct lpuart_serial_plat *plat,
const char c)
{
struct lpuart_fsl *base = plat->reg;
while (!(__raw_readb(&base->us1) & US1_TDRE))
schedule();
if (!(__raw_readb(&base->us1) & US1_TDRE))
return -EAGAIN;
__raw_writeb(c, &base->ud);
return 0;
}
/* Test whether a character is in the RX buffer */
@ -328,10 +329,9 @@ static int _lpuart32_serial_getc(struct lpuart_serial_plat *plat)
u32 stat, val;
lpuart_read32(plat->flags, &base->stat, &stat);
while ((stat & STAT_RDRF) == 0) {
if ((stat & STAT_RDRF) == 0) {
lpuart_write32(plat->flags, &base->stat, STAT_FLAGS);
schedule();
lpuart_read32(plat->flags, &base->stat, &stat);
return -EAGAIN;
}
lpuart_read32(plat->flags, &base->data, &val);
@ -343,22 +343,18 @@ static int _lpuart32_serial_getc(struct lpuart_serial_plat *plat)
return val & 0x3ff;
}
static void _lpuart32_serial_putc(struct lpuart_serial_plat *plat,
static int _lpuart32_serial_putc(struct lpuart_serial_plat *plat,
const char c)
{
struct lpuart_fsl_reg32 *base = plat->reg;
u32 stat;
while (true) {
lpuart_read32(plat->flags, &base->stat, &stat);
if ((stat & STAT_TDRE))
break;
schedule();
}
lpuart_read32(plat->flags, &base->stat, &stat);
if (!(stat & STAT_TDRE))
return -EAGAIN;
lpuart_write32(plat->flags, &base->data, c);
return 0;
}
/* Test whether a character is in the RX buffer */
@ -453,11 +449,9 @@ static int lpuart_serial_putc(struct udevice *dev, const char c)
struct lpuart_serial_plat *plat = dev_get_plat(dev);
if (is_lpuart32(dev))
_lpuart32_serial_putc(plat, c);
else
_lpuart_serial_putc(plat, c);
return _lpuart32_serial_putc(plat, c);
return 0;
return _lpuart_serial_putc(plat, c);
}
static int lpuart_serial_pending(struct udevice *dev, bool input)

12
drivers/serial/serial_mpc8xx.c
View file

@ -178,14 +178,13 @@ static int serial_mpc8xx_putc(struct udevice *dev, const char c)
rtx = (struct serialbuffer __iomem *)&cpmp->cp_dpmem[CPM_SERIAL_BASE];
/* Wait for last character to go. */
if (in_be16(&rtx->txbd.cbd_sc) & BD_SC_READY)
return -EAGAIN;
out_8(&rtx->txbuf, c);
out_be16(&rtx->txbd.cbd_datlen, 1);
setbits_be16(&rtx->txbd.cbd_sc, BD_SC_READY);
while (in_be16(&rtx->txbd.cbd_sc) & BD_SC_READY)
schedule();
return 0;
}
@ -199,9 +198,8 @@ static int serial_mpc8xx_getc(struct udevice *dev)
rtx = (struct serialbuffer __iomem *)&cpmp->cp_dpmem[CPM_SERIAL_BASE];
/* Wait for character to show up. */
while (in_be16(&rtx->rxbd.cbd_sc) & BD_SC_EMPTY)
schedule();
if (in_be16(&rtx->rxbd.cbd_sc) & BD_SC_EMPTY)
return -EAGAIN;
/* the characters are read one by one,
* use the rxindex to know the next char to deliver

8
drivers/serial/serial_mvebu_a3700.c
View file

@ -40,8 +40,8 @@ static int mvebu_serial_putc(struct udevice *dev, const char ch)
struct mvebu_plat *plat = dev_get_plat(dev);
void __iomem *base = plat->base;
while (readl(base + UART_STATUS_REG) & UART_STATUS_TXFIFO_FULL)
;
if (readl(base + UART_STATUS_REG) & UART_STATUS_TXFIFO_FULL)
return -EAGAIN;
writel(ch, base + UART_TX_REG);
@ -53,8 +53,8 @@ static int mvebu_serial_getc(struct udevice *dev)
struct mvebu_plat *plat = dev_get_plat(dev);
void __iomem *base = plat->base;
while (!(readl(base + UART_STATUS_REG) & UART_STATUS_RX_RDY))
;
if (!(readl(base + UART_STATUS_REG) & UART_STATUS_RX_RDY))
return -EAGAIN;
return readl(base + UART_RX_REG) & 0xff;
}