u-boot/drivers/clk/at91/clk-utmi.c
Eugen Hristev e9cd3d7024 clk: at91: utmi: add timeout for utmi lock
In case the slow clock is not properly configured, the UTMI clock
cannot lock the PLL, because UPLLCOUNT will "wait X slow clock cycles".
In this case U-boot will loop indefinitely.
Added a timeout in this case, to start U-boot even if UTMI clock is
not enabled, so the user can use different media if needed, or investigate.

Signed-off-by: Eugen Hristev <eugen.hristev@microchip.com>
2018-08-13 14:03:57 -04:00

142 lines
3 KiB
C

// SPDX-License-Identifier: GPL-2.0+
/*
* Copyright (C) 2016 Atmel Corporation
* Wenyou.Yang <wenyou.yang@atmel.com>
*/
#include <common.h>
#include <clk-uclass.h>
#include <dm.h>
#include <syscon.h>
#include <linux/io.h>
#include <mach/at91_pmc.h>
#include <mach/sama5_sfr.h>
#include "pmc.h"
/*
* The purpose of this clock is to generate a 480 MHz signal. A different
* rate can't be configured.
*/
#define UTMI_RATE 480000000
static int utmi_clk_enable(struct clk *clk)
{
struct pmc_platdata *plat = dev_get_platdata(clk->dev);
struct at91_pmc *pmc = plat->reg_base;
struct clk clk_dev;
ulong clk_rate;
u32 utmi_ref_clk_freq;
u32 tmp;
int err;
int timeout = 2000000;
if (readl(&pmc->sr) & AT91_PMC_LOCKU)
return 0;
/*
* If mainck rate is different from 12 MHz, we have to configure the
* FREQ field of the SFR_UTMICKTRIM register to generate properly
* the utmi clock.
*/
err = clk_get_by_index(clk->dev, 0, &clk_dev);
if (err)
return -EINVAL;
clk_rate = clk_get_rate(&clk_dev);
switch (clk_rate) {
case 12000000:
utmi_ref_clk_freq = 0;
break;
case 16000000:
utmi_ref_clk_freq = 1;
break;
case 24000000:
utmi_ref_clk_freq = 2;
break;
/*
* Not supported on SAMA5D2 but it's not an issue since MAINCK
* maximum value is 24 MHz.
*/
case 48000000:
utmi_ref_clk_freq = 3;
break;
default:
printf("UTMICK: unsupported mainck rate\n");
return -EINVAL;
}
if (plat->regmap_sfr) {
err = regmap_read(plat->regmap_sfr, AT91_SFR_UTMICKTRIM, &tmp);
if (err)
return -EINVAL;
tmp &= ~AT91_UTMICKTRIM_FREQ;
tmp |= utmi_ref_clk_freq;
err = regmap_write(plat->regmap_sfr, AT91_SFR_UTMICKTRIM, tmp);
if (err)
return -EINVAL;
} else if (utmi_ref_clk_freq) {
printf("UTMICK: sfr node required\n");
return -EINVAL;
}
tmp = readl(&pmc->uckr);
tmp |= AT91_PMC_UPLLEN |
AT91_PMC_UPLLCOUNT |
AT91_PMC_BIASEN;
writel(tmp, &pmc->uckr);
while ((--timeout) && !(readl(&pmc->sr) & AT91_PMC_LOCKU))
;
if (!timeout) {
printf("UTMICK: timeout waiting for UPLL lock\n");
return -ETIMEDOUT;
}
return 0;
}
static ulong utmi_clk_get_rate(struct clk *clk)
{
/* UTMI clk rate is fixed. */
return UTMI_RATE;
}
static struct clk_ops utmi_clk_ops = {
.enable = utmi_clk_enable,
.get_rate = utmi_clk_get_rate,
};
static int utmi_clk_ofdata_to_platdata(struct udevice *dev)
{
struct pmc_platdata *plat = dev_get_platdata(dev);
struct udevice *syscon;
uclass_get_device_by_phandle(UCLASS_SYSCON, dev,
"regmap-sfr", &syscon);
if (syscon)
plat->regmap_sfr = syscon_get_regmap(syscon);
return 0;
}
static int utmi_clk_probe(struct udevice *dev)
{
return at91_pmc_core_probe(dev);
}
static const struct udevice_id utmi_clk_match[] = {
{ .compatible = "atmel,at91sam9x5-clk-utmi" },
{}
};
U_BOOT_DRIVER(at91sam9x5_utmi_clk) = {
.name = "at91sam9x5-utmi-clk",
.id = UCLASS_CLK,
.of_match = utmi_clk_match,
.probe = utmi_clk_probe,
.ofdata_to_platdata = utmi_clk_ofdata_to_platdata,
.platdata_auto_alloc_size = sizeof(struct pmc_platdata),
.ops = &utmi_clk_ops,
};