u-boot/arch/powerpc/cpu/ppc4xx/4xx_uart.c

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/*
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* (C) Copyright 2000-2006
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* Wolfgang Denk, DENX Software Engineering, wd@denx.de.
*
* (C) Copyright 2010
* Stefan Roese, DENX Software Engineering, sr@denx.de.
*
* SPDX-License-Identifier: GPL-2.0 IBM-pibs
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*/
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#include <common.h>
#include <commproc.h>
#include <asm/processor.h>
#include <asm/io.h>
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#include <watchdog.h>
#include <asm/ppc4xx.h>
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DECLARE_GLOBAL_DATA_PTR;
#if defined(CONFIG_405GP) || \
defined(CONFIG_405EP) || defined(CONFIG_405EZ) || \
defined(CONFIG_405EX) || defined(CONFIG_440)
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#if defined(CONFIG_440)
#if defined(CONFIG_440GP)
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#define CR0_MASK 0x3fff0000
#define CR0_EXTCLK_ENA 0x00600000
#define CR0_UDIV_POS 16
#define UDIV_SUBTRACT 1
#define UART0_SDR CPC0_CR0
#define MFREG(a, d) d = mfdcr(a)
#define MTREG(a, d) mtdcr(a, d)
#else /* #if defined(CONFIG_440GP) */
/* all other 440 PPC's access clock divider via sdr register */
#define CR0_MASK 0xdfffffff
#define CR0_EXTCLK_ENA 0x00800000
#define CR0_UDIV_POS 0
#define UDIV_SUBTRACT 0
#define UART0_SDR SDR0_UART0
#define UART1_SDR SDR0_UART1
#if defined(CONFIG_440EP) || defined(CONFIG_440EPX) || \
defined(CONFIG_440GR) || defined(CONFIG_440GRX) || \
defined(CONFIG_440SP) || defined(CONFIG_440SPE) || \
defined(CONFIG_460EX) || defined(CONFIG_460GT)
#define UART2_SDR SDR0_UART2
#endif
#if defined(CONFIG_440EP) || defined(CONFIG_440EPX) || \
defined(CONFIG_440GR) || defined(CONFIG_440GRX) || \
defined(CONFIG_460EX) || defined(CONFIG_460GT)
#define UART3_SDR SDR0_UART3
#endif
#define MFREG(a, d) mfsdr(a, d)
#define MTREG(a, d) mtsdr(a, d)
#endif /* #if defined(CONFIG_440GP) */
#elif defined(CONFIG_405EP) || defined(CONFIG_405EZ)
#define UCR0_MASK 0x0000007f
#define UCR1_MASK 0x00007f00
#define UCR0_UDIV_POS 0
#define UCR1_UDIV_POS 8
#define UDIV_MAX 127
#elif defined(CONFIG_405EX)
#define MFREG(a, d) mfsdr(a, d)
#define MTREG(a, d) mtsdr(a, d)
#define CR0_MASK 0x000000ff
#define CR0_EXTCLK_ENA 0x00800000
#define CR0_UDIV_POS 0
#define UDIV_SUBTRACT 0
#define UART0_SDR SDR0_UART0
#define UART1_SDR SDR0_UART1
#else /* CONFIG_405GP */
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#define CR0_MASK 0x00001fff
#define CR0_EXTCLK_ENA 0x000000c0
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#define CR0_UDIV_POS 1
#define UDIV_MAX 32
#endif
#if defined(CONFIG_405EP) && defined(CONFIG_SYS_EXT_SERIAL_CLOCK)
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#error "External serial clock not supported on AMCC PPC405EP!"
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#endif
#if (defined(CONFIG_405EX) || defined(CONFIG_405EZ) || \
defined(CONFIG_440)) && !defined(CONFIG_SYS_EXT_SERIAL_CLOCK)
/*
* For some SoC's, the cpu clock is on divider chain A, UART on
* divider chain B ... so cpu clock is irrelevant. Get the
* "optimized" values that are subject to the 1/2 opb clock
* constraint.
*/
static u16 serial_bdiv(int baudrate, u32 *udiv)
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{
sys_info_t sysinfo;
u32 div; /* total divisor udiv * bdiv */
u32 umin; /* minimum udiv */
u16 diff; /* smallest diff */
u16 idiff; /* current diff */
u16 ibdiv; /* current bdiv */
u32 i;
u32 est; /* current estimate */
u32 max;
#if defined(CONFIG_405EZ)
u32 cpr_pllc;
u32 plloutb;
u32 reg;
#endif
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get_sys_info(&sysinfo);
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#if defined(CONFIG_405EZ)
/* check the pll feedback source */
mfcpr(CPR0_PLLC, cpr_pllc);
plloutb = ((CONFIG_SYS_CLK_FREQ * ((cpr_pllc & PLLC_SRC_MASK) ?
sysinfo.pllFwdDivB : sysinfo.pllFwdDiv) *
sysinfo.pllFbkDiv) / sysinfo.pllFwdDivB);
div = plloutb / (16 * baudrate); /* total divisor */
umin = (plloutb / get_OPB_freq()) << 1; /* 2 x OPB divisor */
max = 256; /* highest possible */
#else /* 405EZ */
div = sysinfo.freqPLB / (16 * baudrate); /* total divisor */
umin = sysinfo.pllOpbDiv << 1; /* 2 x OPB divisor */
max = 32; /* highest possible */
#endif /* 405EZ */
*udiv = diff = max;
/*
* i is the test udiv value -- start with the largest
* possible (max) to minimize serial clock and constrain
* search to umin.
*/
for (i = max; i > umin; i--) {
ibdiv = div / i;
est = i * ibdiv;
idiff = (est > div) ? (est - div) : (div - est);
if (idiff == 0) {
*udiv = i;
break; /* can't do better */
} else if (idiff < diff) {
*udiv = i; /* best so far */
diff = idiff; /* update lowest diff*/
}
}
#if defined(CONFIG_405EZ)
mfcpr(CPR0_PERD0, reg);
reg &= ~0x0000ffff;
reg |= ((*udiv - 0) << 8) | (*udiv - 0);
mtcpr(CPR0_PERD0, reg);
#endif
return div / *udiv;
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}
#endif /* #if (defined(CONFIG_405EP) ... */
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/*
* This function returns the UART clock used by the common
* NS16550 driver. Additionally the SoC internal divisors for
* optimal UART baudrate are configured.
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*/
int get_serial_clock(void)
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{
u32 clk;
u32 udiv;
#if !defined(CONFIG_405EZ)
u32 reg;
#endif
#if !defined(CONFIG_SYS_EXT_SERIAL_CLOCK)
PPC4xx_SYS_INFO sys_info;
#endif
/*
* Programming of the internal divisors is SoC specific.
* Let's handle this in some #ifdef's for the SoC's.
*/
#if defined(CONFIG_405GP)
reg = mfdcr(CPC0_CR0) & ~CR0_MASK;
#ifdef CONFIG_SYS_EXT_SERIAL_CLOCK
clk = CONFIG_SYS_EXT_SERIAL_CLOCK;
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udiv = 1;
reg |= CR0_EXTCLK_ENA;
#else /* CONFIG_SYS_EXT_SERIAL_CLOCK */
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clk = gd->cpu_clk;
#ifdef CONFIG_SYS_405_UART_ERRATA_59
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udiv = 31; /* Errata 59: stuck at 31 */
#else /* CONFIG_SYS_405_UART_ERRATA_59 */
{
u32 tmp = CONFIG_SYS_BASE_BAUD * 16;
udiv = (clk + tmp / 2) / tmp;
}
if (udiv > UDIV_MAX) /* max. n bits for udiv */
udiv = UDIV_MAX;
#endif /* CONFIG_SYS_405_UART_ERRATA_59 */
#endif /* CONFIG_SYS_EXT_SERIAL_CLOCK */
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reg |= (udiv - 1) << CR0_UDIV_POS; /* set the UART divisor */
mtdcr (CPC0_CR0, reg);
#ifdef CONFIG_SYS_EXT_SERIAL_CLOCK
clk = CONFIG_SYS_EXT_SERIAL_CLOCK;
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#else
clk = CONFIG_SYS_BASE_BAUD * 16;
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#endif
#endif
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#if defined(CONFIG_405EP)
{
u32 tmp = CONFIG_SYS_BASE_BAUD * 16;
reg = mfdcr(CPC0_UCR) & ~(UCR0_MASK | UCR1_MASK);
clk = gd->cpu_clk;
udiv = (clk + tmp / 2) / tmp;
if (udiv > UDIV_MAX) /* max. n bits for udiv */
udiv = UDIV_MAX;
}
reg |= udiv << UCR0_UDIV_POS; /* set the UART divisor */
reg |= udiv << UCR1_UDIV_POS; /* set the UART divisor */
mtdcr(CPC0_UCR, reg);
clk = CONFIG_SYS_BASE_BAUD * 16;
#endif /* CONFIG_405EP */
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#if defined(CONFIG_405EX) || defined(CONFIG_440)
MFREG(UART0_SDR, reg);
reg &= ~CR0_MASK;
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#ifdef CONFIG_SYS_EXT_SERIAL_CLOCK
reg |= CR0_EXTCLK_ENA;
udiv = 1;
clk = CONFIG_SYS_EXT_SERIAL_CLOCK;
#else /* CONFIG_SYS_EXT_SERIAL_CLOCK */
clk = gd->baudrate * serial_bdiv(gd->baudrate, &udiv) * 16;
#endif /* CONFIG_SYS_EXT_SERIAL_CLOCK */
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reg |= (udiv - UDIV_SUBTRACT) << CR0_UDIV_POS; /* set the UART divisor */
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/*
* Configure input clock to baudrate generator for all
* available serial ports here
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*/
MTREG(UART0_SDR, reg);
#if defined(UART1_SDR)
MTREG(UART1_SDR, reg);
#endif
#if defined(UART2_SDR)
MTREG(UART2_SDR, reg);
#endif
#if defined(UART3_SDR)
MTREG(UART3_SDR, reg);
#endif
#endif /* CONFIG_405EX ... */
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#if defined(CONFIG_405EZ)
clk = gd->baudrate * serial_bdiv(gd->baudrate, &udiv) * 16;
#endif /* CONFIG_405EZ */
/*
* Correct UART frequency in bd-info struct now that
* the UART divisor is available
*/
#ifdef CONFIG_SYS_EXT_SERIAL_CLOCK
gd->arch.uart_clk = CONFIG_SYS_EXT_SERIAL_CLOCK;
#else
get_sys_info(&sys_info);
gd->arch.uart_clk = sys_info.freqUART / udiv;
#endif
return clk;
}
#endif /* CONFIG_405GP */