diff options
author | Mike Frysinger <vapier@gentoo.org> | 2008-12-10 17:33:54 (GMT) |
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committer | Mike Frysinger <vapier@gentoo.org> | 2009-02-06 02:25:35 (GMT) |
commit | f790ef6ff12381cb0e43de54fb2b0f1204ad8ed6 (patch) | |
tree | d3ed348b909eb996a03f1d5d00c29aeb11f1f09d /cpu/blackfin/initcode.c | |
parent | 97f265f14f23050f3cb997f617f3a6917b843ea2 (diff) | |
download | u-boot-fsl-qoriq-f790ef6ff12381cb0e43de54fb2b0f1204ad8ed6.tar.xz |
Blackfin: dynamically update UART speed when initializing
Previously, booting over the UART required the baud rate to be known ahead
of time. Using a bit of tricky simple math, we can calculate the new board
rate based on the old divisors.
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
Signed-off-by: Robin Getz <rgetz@blackfin.uclinux.org>
Diffstat (limited to 'cpu/blackfin/initcode.c')
-rw-r--r-- | cpu/blackfin/initcode.c | 62 |
1 files changed, 24 insertions, 38 deletions
diff --git a/cpu/blackfin/initcode.c b/cpu/blackfin/initcode.c index 704b791..ae0016d 100644 --- a/cpu/blackfin/initcode.c +++ b/cpu/blackfin/initcode.c @@ -20,7 +20,7 @@ #include "serial.h" __attribute__((always_inline)) -static inline uint32_t serial_init(void) +static inline void serial_init(void) { #ifdef __ADSPBF54x__ # ifdef BFIN_BOOT_UART_USE_RTS @@ -61,25 +61,16 @@ static inline uint32_t serial_init(void) } #endif - uint32_t old_baud; - if (BFIN_DEBUG_EARLY_SERIAL || CONFIG_BFIN_BOOT_MODE == BFIN_BOOT_UART) - old_baud = serial_early_get_baud(); - else - old_baud = CONFIG_BAUDRATE; - if (BFIN_DEBUG_EARLY_SERIAL) { + int ucen = *pUART_GCTL & UCEN; serial_early_init(); /* If the UART is off, that means we need to program * the baud rate ourselves initially. */ - if (!old_baud) { - old_baud = CONFIG_BAUDRATE; + if (ucen != UCEN) serial_early_set_baud(CONFIG_BAUDRATE); - } } - - return old_baud; } __attribute__((always_inline)) @@ -93,30 +84,6 @@ static inline void serial_deinit(void) #endif } -/* We need to reset the baud rate when we have early debug turned on - * or when we are booting over the UART. - * XXX: we should fix this to calc the old baud and restore it rather - * than hardcoding it via CONFIG_LDR_LOAD_BAUD ... but we have - * to figure out how to avoid the division in the baud calc ... - */ -__attribute__((always_inline)) -static inline void serial_reset_baud(uint32_t baud) -{ - if (!BFIN_DEBUG_EARLY_SERIAL && CONFIG_BFIN_BOOT_MODE != BFIN_BOOT_UART) - return; - -#ifndef CONFIG_LDR_LOAD_BAUD -# define CONFIG_LDR_LOAD_BAUD 115200 -#endif - - if (CONFIG_BFIN_BOOT_MODE == BFIN_BOOT_BYPASS) - serial_early_set_baud(baud); - else if (CONFIG_BFIN_BOOT_MODE == BFIN_BOOT_UART) - serial_early_set_baud(CONFIG_LDR_LOAD_BAUD); - else - serial_early_set_baud(CONFIG_BAUDRATE); -} - __attribute__((always_inline)) static inline void serial_putc(char c) { @@ -239,7 +206,14 @@ static inline void serial_putc(char c) BOOTROM_CALLED_FUNC_ATTR void initcode(ADI_BOOT_DATA *bootstruct) { - uint32_t old_baud = serial_init(); + /* Save the clock pieces that are used in baud rate calculation */ + unsigned int sdivB, divB, vcoB; + serial_init(); + if (BFIN_DEBUG_EARLY_SERIAL || CONFIG_BFIN_BOOT_MODE == BFIN_BOOT_UART) { + sdivB = bfin_read_PLL_DIV() & 0xf; + vcoB = (bfin_read_PLL_CTL() >> 9) & 0x3f; + divB = serial_early_get_div(); + } #ifdef CONFIG_HW_WATCHDOG # ifndef CONFIG_HW_WATCHDOG_TIMEOUT_INITCODE @@ -334,8 +308,20 @@ void initcode(ADI_BOOT_DATA *bootstruct) /* Since we've changed the SCLK above, we may need to update * the UART divisors (UART baud rates are based on SCLK). + * Do the division by hand as there are no native instructions + * for dividing which means we'd generate a libgcc reference. */ - serial_reset_baud(old_baud); + if (CONFIG_BFIN_BOOT_MODE == BFIN_BOOT_UART) { + unsigned int sdivR, vcoR; + sdivR = bfin_read_PLL_DIV() & 0xf; + vcoR = (bfin_read_PLL_CTL() >> 9) & 0x3f; + int dividend = sdivB * divB * vcoR; + int divisor = vcoB * sdivR; + unsigned int quotient; + for (quotient = 0; dividend > 0; ++quotient) + dividend -= divisor; + serial_early_put_div(quotient - ANOMALY_05000230); + } serial_putc('F'); |