76d57ce6ef
Provide an API to initialize a UART clock. Refactor existing davinci_serial_init() to separate out the part which enables the clock. This will later be used to help DA850 DT boot support. Signed-off-by: Sekhar Nori <nsekhar@ti.com>
130 lines
3.4 KiB
C
130 lines
3.4 KiB
C
/*
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* TI DaVinci serial driver
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*
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* Copyright (C) 2006 Texas Instruments.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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*
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*/
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#include <linux/kernel.h>
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#include <linux/init.h>
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#include <linux/serial_8250.h>
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#include <linux/serial_reg.h>
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#include <linux/platform_device.h>
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#include <linux/delay.h>
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#include <linux/clk.h>
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#include <linux/io.h>
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#include <mach/serial.h>
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#include <mach/cputype.h>
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static inline unsigned int serial_read_reg(struct plat_serial8250_port *up,
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int offset)
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{
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offset <<= up->regshift;
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WARN_ONCE(!up->membase, "unmapped read: uart[%d]\n", offset);
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return (unsigned int)__raw_readl(up->membase + offset);
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}
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static inline void serial_write_reg(struct plat_serial8250_port *p, int offset,
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int value)
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{
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offset <<= p->regshift;
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WARN_ONCE(!p->membase, "unmapped write: uart[%d]\n", offset);
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__raw_writel(value, p->membase + offset);
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}
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static void __init davinci_serial_reset(struct plat_serial8250_port *p)
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{
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unsigned int pwremu = 0;
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serial_write_reg(p, UART_IER, 0); /* disable all interrupts */
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/* reset both transmitter and receiver: bits 14,13 = UTRST, URRST */
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serial_write_reg(p, UART_DAVINCI_PWREMU, pwremu);
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mdelay(10);
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pwremu |= (0x3 << 13);
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pwremu |= 0x1;
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serial_write_reg(p, UART_DAVINCI_PWREMU, pwremu);
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if (cpu_is_davinci_dm646x())
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serial_write_reg(p, UART_DM646X_SCR,
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UART_DM646X_SCR_TX_WATERMARK);
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}
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/* Enable UART clock and obtain its rate */
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int __init davinci_serial_setup_clk(unsigned instance, unsigned int *rate)
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{
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char name[16];
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struct clk *clk;
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struct davinci_soc_info *soc_info = &davinci_soc_info;
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struct device *dev = &soc_info->serial_dev->dev;
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sprintf(name, "uart%d", instance);
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clk = clk_get(dev, name);
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if (IS_ERR(clk)) {
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pr_err("%s:%d: failed to get UART%d clock\n",
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__func__, __LINE__, instance);
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return PTR_ERR(clk);
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}
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clk_prepare_enable(clk);
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if (rate)
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*rate = clk_get_rate(clk);
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return 0;
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}
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int __init davinci_serial_init(struct davinci_uart_config *info)
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{
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int i, ret;
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struct davinci_soc_info *soc_info = &davinci_soc_info;
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struct device *dev = &soc_info->serial_dev->dev;
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struct plat_serial8250_port *p = dev->platform_data;
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/*
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* Make sure the serial ports are muxed on at this point.
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* You have to mux them off in device drivers later on if not needed.
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*/
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for (i = 0; p->flags; i++, p++) {
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if (!(info->enabled_uarts & (1 << i)))
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continue;
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ret = davinci_serial_setup_clk(i, &p->uartclk);
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if (ret)
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continue;
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if (!p->membase && p->mapbase) {
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p->membase = ioremap(p->mapbase, SZ_4K);
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if (p->membase)
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p->flags &= ~UPF_IOREMAP;
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else
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pr_err("uart regs ioremap failed\n");
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}
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if (p->membase && p->type != PORT_AR7)
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davinci_serial_reset(p);
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}
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return platform_device_register(soc_info->serial_dev);
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}
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