[ 05/68] ARM: LPC32xx: serial.c: HW bug workaround
From: Greg KH <gregkh@linuxfoundation.org>
Date: 2012-03-09 20:07:48
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3.0-stable review patch. If anyone has any objections, please let me know. ------------------ From: Roland Stigge <redacted> 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 <redacted> 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 */