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Subject[ 06/95] ARM: LPC32xx: serial.c: HW bug workaround
3.2-stable review patch.  If anyone has any objections, please let me know.

------------------
From: Roland Stigge <stigge@antcom.de>

commit 2707208ee8a80dbbd5426f5aa1a934f766825bb5 upstream.

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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
arch/arm/mach-lpc32xx/serial.c | 18 ++++++++++++++++++
1 file changed, 18 insertions(+)
--- a/arch/arm/mach-lpc32xx/serial.c
+++ b/arch/arm/mach-lpc32xx/serial.c
@@ -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[] _
.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[] _
.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[] _
.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[] _
.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 */



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