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ARM: LPC32xx: serial.c: HW bug workaround

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This patch fixes a HW bug by flushing RX FIFOs of the UARTs on init. It was
ported from NXP's git.lpclinux.com tree.

Signed-off-by: Roland Stigge <stigge@antcom.de>
Cc: stable@vger.kernel.org
This commit is contained in:
Roland Stigge 2012-02-27 17:28:02 +01:00
parent 94ed7830cb
commit 2707208ee8
1 changed files with 18 additions and 0 deletions
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18
arch/arm/mach-lpc32xx/serial.c
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@ -88,6 +88,7 @@ struct uartinit {
char *uart_ck_name;
u32 ck_mode_mask;
void __iomem *pdiv_clk_reg;
resource_size_t mapbase;
};
static struct uartinit uartinit_data[] __initdata = {
@ -97,6 +98,7 @@ static struct uartinit uartinit_data[] __initdata = {
.ck_mode_mask =
LPC32XX_UART_CLKMODE_LOAD(LPC32XX_UART_CLKMODE_ON, 5),
.pdiv_clk_reg = LPC32XX_CLKPWR_UART5_CLK_CTRL,
.mapbase = LPC32XX_UART5_BASE,
},
#endif
#ifdef CONFIG_ARCH_LPC32XX_UART3_SELECT
@ -105,6 +107,7 @@ static struct uartinit uartinit_data[] __initdata = {
.ck_mode_mask =
LPC32XX_UART_CLKMODE_LOAD(LPC32XX_UART_CLKMODE_ON, 3),
.pdiv_clk_reg = LPC32XX_CLKPWR_UART3_CLK_CTRL,
.mapbase = LPC32XX_UART3_BASE,
},
#endif
#ifdef CONFIG_ARCH_LPC32XX_UART4_SELECT
@ -113,6 +116,7 @@ static struct uartinit uartinit_data[] __initdata = {
.ck_mode_mask =
LPC32XX_UART_CLKMODE_LOAD(LPC32XX_UART_CLKMODE_ON, 4),
.pdiv_clk_reg = LPC32XX_CLKPWR_UART4_CLK_CTRL,
.mapbase = LPC32XX_UART4_BASE,
},
#endif
#ifdef CONFIG_ARCH_LPC32XX_UART6_SELECT
@ -121,6 +125,7 @@ static struct uartinit uartinit_data[] __initdata = {
.ck_mode_mask =
LPC32XX_UART_CLKMODE_LOAD(LPC32XX_UART_CLKMODE_ON, 6),
.pdiv_clk_reg = LPC32XX_CLKPWR_UART6_CLK_CTRL,
.mapbase = LPC32XX_UART6_BASE,
},
#endif
};
@ -165,6 +170,19 @@ void __init lpc32xx_serial_init(void)
/* pre-UART clock divider set to 1 */
__raw_writel(0x0101, uartinit_data[i].pdiv_clk_reg);
/*
* Force a flush of the RX FIFOs to work around a
* HW bug
*/
puart = uartinit_data[i].mapbase;
__raw_writel(0xC1, LPC32XX_UART_IIR_FCR(puart));
__raw_writel(0x00, LPC32XX_UART_DLL_FIFO(puart));
j = LPC32XX_SUART_FIFO_SIZE;
while (j--)
tmp = __raw_readl(
LPC32XX_UART_DLL_FIFO(puart));
__raw_writel(0, LPC32XX_UART_IIR_FCR(puart));
}
/* This needs to be done after all UART clocks are setup */