Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame^] | 1 | /* |
| 2 | * arch/ppc/boot/simple/mpc52xx_tty.c |
| 3 | * |
| 4 | * Minimal serial functions needed to send messages out a MPC52xx |
| 5 | * Programmable Serial Controller (PSC). |
| 6 | * |
| 7 | * Author: Dale Farnsworth <dfarnsworth@mvista.com> |
| 8 | * |
| 9 | * 2003-2004 (c) MontaVista, Software, Inc. This file is licensed under the |
| 10 | * terms of the GNU General Public License version 2. This program is licensed |
| 11 | * "as is" without any warranty of any kind, whether express or implied. |
| 12 | */ |
| 13 | |
| 14 | #include <linux/config.h> |
| 15 | #include <linux/types.h> |
| 16 | #include <asm/uaccess.h> |
| 17 | #include <asm/mpc52xx.h> |
| 18 | #include <asm/mpc52xx_psc.h> |
| 19 | #include <asm/serial.h> |
| 20 | #include <asm/io.h> |
| 21 | #include <asm/time.h> |
| 22 | |
| 23 | |
| 24 | #ifdef MPC52xx_PF_CONSOLE_PORT |
| 25 | #define MPC52xx_CONSOLE MPC52xx_PSCx_OFFSET(MPC52xx_PF_CONSOLE_PORT) |
| 26 | #define MPC52xx_PSC_CONFIG_SHIFT ((MPC52xx_PF_CONSOLE_PORT-1)<<2) |
| 27 | #else |
| 28 | #error "MPC52xx_PF_CONSOLE_PORT not defined" |
| 29 | #endif |
| 30 | |
| 31 | static struct mpc52xx_psc __iomem *psc = |
| 32 | (struct mpc52xx_psc __iomem *) MPC52xx_PA(MPC52xx_CONSOLE); |
| 33 | |
| 34 | /* The decrementer counts at the system bus clock frequency |
| 35 | * divided by four. The most accurate time base is connected to the |
| 36 | * rtc. We read the decrementer change during one rtc tick |
| 37 | * and multiply by 4 to get the system bus clock frequency. Since a |
| 38 | * rtc tick is one seconds, and that's pretty long, we change the rtc |
| 39 | * dividers temporarly to set them 64x faster ;) |
| 40 | */ |
| 41 | static int |
| 42 | mpc52xx_ipbfreq(void) |
| 43 | { |
| 44 | struct mpc52xx_rtc __iomem *rtc = |
| 45 | (struct mpc52xx_rtc __iomem *) MPC52xx_PA(MPC52xx_RTC_OFFSET); |
| 46 | struct mpc52xx_cdm __iomem *cdm = |
| 47 | (struct mpc52xx_cdm __iomem *) MPC52xx_PA(MPC52xx_CDM_OFFSET); |
| 48 | int current_time, previous_time; |
| 49 | int tbl_start, tbl_end; |
| 50 | int xlbfreq, ipbfreq; |
| 51 | |
| 52 | out_be32(&rtc->dividers, 0x8f1f0000); /* Set RTC 64x faster */ |
| 53 | previous_time = in_be32(&rtc->time); |
| 54 | while ((current_time = in_be32(&rtc->time)) == previous_time) ; |
| 55 | tbl_start = get_tbl(); |
| 56 | previous_time = current_time; |
| 57 | while ((current_time = in_be32(&rtc->time)) == previous_time) ; |
| 58 | tbl_end = get_tbl(); |
| 59 | out_be32(&rtc->dividers, 0xffff0000); /* Restore RTC */ |
| 60 | |
| 61 | xlbfreq = (tbl_end - tbl_start) << 8; |
| 62 | ipbfreq = (in_8(&cdm->ipb_clk_sel) & 1) ? xlbfreq / 2 : xlbfreq; |
| 63 | |
| 64 | return ipbfreq; |
| 65 | } |
| 66 | |
| 67 | unsigned long |
| 68 | serial_init(int ignored, void *ignored2) |
| 69 | { |
| 70 | struct mpc52xx_gpio __iomem *gpio = |
| 71 | (struct mpc52xx_gpio __iomem *) MPC52xx_PA(MPC52xx_GPIO_OFFSET); |
| 72 | int divisor; |
| 73 | int mode1; |
| 74 | int mode2; |
| 75 | u32 val32; |
| 76 | |
| 77 | static int been_here = 0; |
| 78 | |
| 79 | if (been_here) |
| 80 | return 0; |
| 81 | |
| 82 | been_here = 1; |
| 83 | |
| 84 | val32 = in_be32(&gpio->port_config); |
| 85 | val32 &= ~(0x7 << MPC52xx_PSC_CONFIG_SHIFT); |
| 86 | val32 |= MPC52xx_GPIO_PSC_CONFIG_UART_WITHOUT_CD |
| 87 | << MPC52xx_PSC_CONFIG_SHIFT; |
| 88 | out_be32(&gpio->port_config, val32); |
| 89 | |
| 90 | out_8(&psc->command, MPC52xx_PSC_RST_TX |
| 91 | | MPC52xx_PSC_RX_DISABLE | MPC52xx_PSC_TX_ENABLE); |
| 92 | out_8(&psc->command, MPC52xx_PSC_RST_RX); |
| 93 | |
| 94 | out_be32(&psc->sicr, 0x0); |
| 95 | out_be16(&psc->mpc52xx_psc_clock_select, 0xdd00); |
| 96 | out_be16(&psc->tfalarm, 0xf8); |
| 97 | |
| 98 | out_8(&psc->command, MPC52xx_PSC_SEL_MODE_REG_1 |
| 99 | | MPC52xx_PSC_RX_ENABLE |
| 100 | | MPC52xx_PSC_TX_ENABLE); |
| 101 | |
| 102 | divisor = ((mpc52xx_ipbfreq() |
| 103 | / (CONFIG_SERIAL_MPC52xx_CONSOLE_BAUD * 16)) + 1) >> 1; |
| 104 | |
| 105 | mode1 = MPC52xx_PSC_MODE_8_BITS | MPC52xx_PSC_MODE_PARNONE |
| 106 | | MPC52xx_PSC_MODE_ERR; |
| 107 | mode2 = MPC52xx_PSC_MODE_ONE_STOP; |
| 108 | |
| 109 | out_8(&psc->ctur, divisor>>8); |
| 110 | out_8(&psc->ctlr, divisor); |
| 111 | out_8(&psc->command, MPC52xx_PSC_SEL_MODE_REG_1); |
| 112 | out_8(&psc->mode, mode1); |
| 113 | out_8(&psc->mode, mode2); |
| 114 | |
| 115 | return 0; /* ignored */ |
| 116 | } |
| 117 | |
| 118 | void |
| 119 | serial_putc(void *ignored, const char c) |
| 120 | { |
| 121 | serial_init(0, NULL); |
| 122 | |
| 123 | while (!(in_be16(&psc->mpc52xx_psc_status) & MPC52xx_PSC_SR_TXEMP)) ; |
| 124 | out_8(&psc->mpc52xx_psc_buffer_8, c); |
| 125 | while (!(in_be16(&psc->mpc52xx_psc_status) & MPC52xx_PSC_SR_TXEMP)) ; |
| 126 | } |
| 127 | |
| 128 | char |
| 129 | serial_getc(void *ignored) |
| 130 | { |
| 131 | while (!(in_be16(&psc->mpc52xx_psc_status) & MPC52xx_PSC_SR_RXRDY)) ; |
| 132 | |
| 133 | return in_8(&psc->mpc52xx_psc_buffer_8); |
| 134 | } |
| 135 | |
| 136 | int |
| 137 | serial_tstc(void *ignored) |
| 138 | { |
| 139 | return (in_be16(&psc->mpc52xx_psc_status) & MPC52xx_PSC_SR_RXRDY) != 0; |
| 140 | } |