linux/drivers/ptp/ptp_dte.c

354 lines
8.3 KiB
C

/*
* Copyright 2017 Broadcom
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as
* published by the Free Software Foundation version 2.
*
* This program is distributed "as is" WITHOUT ANY WARRANTY of any
* kind, whether express or implied; without even the implied warranty
* of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*/
#include <linux/err.h>
#include <linux/io.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/ptp_clock_kernel.h>
#include <linux/types.h>
#define DTE_NCO_LOW_TIME_REG 0x00
#define DTE_NCO_TIME_REG 0x04
#define DTE_NCO_OVERFLOW_REG 0x08
#define DTE_NCO_INC_REG 0x0c
#define DTE_NCO_SUM2_MASK 0xffffffff
#define DTE_NCO_SUM2_SHIFT 4ULL
#define DTE_NCO_SUM3_MASK 0xff
#define DTE_NCO_SUM3_SHIFT 36ULL
#define DTE_NCO_SUM3_WR_SHIFT 8
#define DTE_NCO_TS_WRAP_MASK 0xfff
#define DTE_NCO_TS_WRAP_LSHIFT 32
#define DTE_NCO_INC_DEFAULT 0x80000000
#define DTE_NUM_REGS_TO_RESTORE 4
/* Full wrap around is 44bits in ns (~4.887 hrs) */
#define DTE_WRAP_AROUND_NSEC_SHIFT 44
/* 44 bits NCO */
#define DTE_NCO_MAX_NS 0xFFFFFFFFFFFLL
/* 125MHz with 3.29 reg cfg */
#define DTE_PPB_ADJ(ppb) (u32)(div64_u64((((u64)abs(ppb) * BIT(28)) +\
62500000ULL), 125000000ULL))
/* ptp dte priv structure */
struct ptp_dte {
void __iomem *regs;
struct ptp_clock *ptp_clk;
struct ptp_clock_info caps;
struct device *dev;
u32 ts_ovf_last;
u32 ts_wrap_cnt;
spinlock_t lock;
u32 reg_val[DTE_NUM_REGS_TO_RESTORE];
};
static void dte_write_nco(void __iomem *regs, s64 ns)
{
u32 sum2, sum3;
sum2 = (u32)((ns >> DTE_NCO_SUM2_SHIFT) & DTE_NCO_SUM2_MASK);
/* compensate for ignoring sum1 */
if (sum2 != DTE_NCO_SUM2_MASK)
sum2++;
/* to write sum3, bits [15:8] needs to be written */
sum3 = (u32)(((ns >> DTE_NCO_SUM3_SHIFT) & DTE_NCO_SUM3_MASK) <<
DTE_NCO_SUM3_WR_SHIFT);
writel(0, (regs + DTE_NCO_LOW_TIME_REG));
writel(sum2, (regs + DTE_NCO_TIME_REG));
writel(sum3, (regs + DTE_NCO_OVERFLOW_REG));
}
static s64 dte_read_nco(void __iomem *regs)
{
u32 sum2, sum3;
s64 ns;
/*
* ignoring sum1 (4 bits) gives a 16ns resolution, which
* works due to the async register read.
*/
sum3 = readl(regs + DTE_NCO_OVERFLOW_REG) & DTE_NCO_SUM3_MASK;
sum2 = readl(regs + DTE_NCO_TIME_REG);
ns = ((s64)sum3 << DTE_NCO_SUM3_SHIFT) |
((s64)sum2 << DTE_NCO_SUM2_SHIFT);
return ns;
}
static void dte_write_nco_delta(struct ptp_dte *ptp_dte, s64 delta)
{
s64 ns;
ns = dte_read_nco(ptp_dte->regs);
/* handle wraparound conditions */
if ((delta < 0) && (abs(delta) > ns)) {
if (ptp_dte->ts_wrap_cnt) {
ns += DTE_NCO_MAX_NS + delta;
ptp_dte->ts_wrap_cnt--;
} else {
ns = 0;
}
} else {
ns += delta;
if (ns > DTE_NCO_MAX_NS) {
ptp_dte->ts_wrap_cnt++;
ns -= DTE_NCO_MAX_NS;
}
}
dte_write_nco(ptp_dte->regs, ns);
ptp_dte->ts_ovf_last = (ns >> DTE_NCO_TS_WRAP_LSHIFT) &
DTE_NCO_TS_WRAP_MASK;
}
static s64 dte_read_nco_with_ovf(struct ptp_dte *ptp_dte)
{
u32 ts_ovf;
s64 ns = 0;
ns = dte_read_nco(ptp_dte->regs);
/*Timestamp overflow: 8 LSB bits of sum3, 4 MSB bits of sum2 */
ts_ovf = (ns >> DTE_NCO_TS_WRAP_LSHIFT) & DTE_NCO_TS_WRAP_MASK;
/* Check for wrap around */
if (ts_ovf < ptp_dte->ts_ovf_last)
ptp_dte->ts_wrap_cnt++;
ptp_dte->ts_ovf_last = ts_ovf;
/* adjust for wraparounds */
ns += (s64)(BIT_ULL(DTE_WRAP_AROUND_NSEC_SHIFT) * ptp_dte->ts_wrap_cnt);
return ns;
}
static int ptp_dte_adjfreq(struct ptp_clock_info *ptp, s32 ppb)
{
u32 nco_incr;
unsigned long flags;
struct ptp_dte *ptp_dte = container_of(ptp, struct ptp_dte, caps);
if (abs(ppb) > ptp_dte->caps.max_adj) {
dev_err(ptp_dte->dev, "ppb adj too big\n");
return -EINVAL;
}
if (ppb < 0)
nco_incr = DTE_NCO_INC_DEFAULT - DTE_PPB_ADJ(ppb);
else
nco_incr = DTE_NCO_INC_DEFAULT + DTE_PPB_ADJ(ppb);
spin_lock_irqsave(&ptp_dte->lock, flags);
writel(nco_incr, ptp_dte->regs + DTE_NCO_INC_REG);
spin_unlock_irqrestore(&ptp_dte->lock, flags);
return 0;
}
static int ptp_dte_adjtime(struct ptp_clock_info *ptp, s64 delta)
{
unsigned long flags;
struct ptp_dte *ptp_dte = container_of(ptp, struct ptp_dte, caps);
spin_lock_irqsave(&ptp_dte->lock, flags);
dte_write_nco_delta(ptp_dte, delta);
spin_unlock_irqrestore(&ptp_dte->lock, flags);
return 0;
}
static int ptp_dte_gettime(struct ptp_clock_info *ptp, struct timespec64 *ts)
{
unsigned long flags;
struct ptp_dte *ptp_dte = container_of(ptp, struct ptp_dte, caps);
spin_lock_irqsave(&ptp_dte->lock, flags);
*ts = ns_to_timespec64(dte_read_nco_with_ovf(ptp_dte));
spin_unlock_irqrestore(&ptp_dte->lock, flags);
return 0;
}
static int ptp_dte_settime(struct ptp_clock_info *ptp,
const struct timespec64 *ts)
{
unsigned long flags;
struct ptp_dte *ptp_dte = container_of(ptp, struct ptp_dte, caps);
spin_lock_irqsave(&ptp_dte->lock, flags);
/* Disable nco increment */
writel(0, ptp_dte->regs + DTE_NCO_INC_REG);
dte_write_nco(ptp_dte->regs, timespec64_to_ns(ts));
/* reset overflow and wrap counter */
ptp_dte->ts_ovf_last = 0;
ptp_dte->ts_wrap_cnt = 0;
/* Enable nco increment */
writel(DTE_NCO_INC_DEFAULT, ptp_dte->regs + DTE_NCO_INC_REG);
spin_unlock_irqrestore(&ptp_dte->lock, flags);
return 0;
}
static int ptp_dte_enable(struct ptp_clock_info *ptp,
struct ptp_clock_request *rq, int on)
{
return -EOPNOTSUPP;
}
static const struct ptp_clock_info ptp_dte_caps = {
.owner = THIS_MODULE,
.name = "DTE PTP timer",
.max_adj = 50000000,
.n_ext_ts = 0,
.n_pins = 0,
.pps = 0,
.adjfreq = ptp_dte_adjfreq,
.adjtime = ptp_dte_adjtime,
.gettime64 = ptp_dte_gettime,
.settime64 = ptp_dte_settime,
.enable = ptp_dte_enable,
};
static int ptp_dte_probe(struct platform_device *pdev)
{
struct ptp_dte *ptp_dte;
struct device *dev = &pdev->dev;
struct resource *res;
ptp_dte = devm_kzalloc(dev, sizeof(struct ptp_dte), GFP_KERNEL);
if (!ptp_dte)
return -ENOMEM;
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
ptp_dte->regs = devm_ioremap_resource(dev, res);
if (IS_ERR(ptp_dte->regs)) {
dev_err(dev,
"%s: io remap failed\n", __func__);
return PTR_ERR(ptp_dte->regs);
}
spin_lock_init(&ptp_dte->lock);
ptp_dte->dev = dev;
ptp_dte->caps = ptp_dte_caps;
ptp_dte->ptp_clk = ptp_clock_register(&ptp_dte->caps, &pdev->dev);
if (IS_ERR(ptp_dte->ptp_clk)) {
dev_err(dev,
"%s: Failed to register ptp clock\n", __func__);
return PTR_ERR(ptp_dte->ptp_clk);
}
platform_set_drvdata(pdev, ptp_dte);
dev_info(dev, "ptp clk probe done\n");
return 0;
}
static int ptp_dte_remove(struct platform_device *pdev)
{
struct ptp_dte *ptp_dte = platform_get_drvdata(pdev);
u8 i;
ptp_clock_unregister(ptp_dte->ptp_clk);
for (i = 0; i < DTE_NUM_REGS_TO_RESTORE; i++)
writel(0, ptp_dte->regs + (i * sizeof(u32)));
return 0;
}
#ifdef CONFIG_PM_SLEEP
static int ptp_dte_suspend(struct device *dev)
{
struct platform_device *pdev = to_platform_device(dev);
struct ptp_dte *ptp_dte = platform_get_drvdata(pdev);
u8 i;
for (i = 0; i < DTE_NUM_REGS_TO_RESTORE; i++) {
ptp_dte->reg_val[i] =
readl(ptp_dte->regs + (i * sizeof(u32)));
}
/* disable the nco */
writel(0, ptp_dte->regs + DTE_NCO_INC_REG);
return 0;
}
static int ptp_dte_resume(struct device *dev)
{
struct platform_device *pdev = to_platform_device(dev);
struct ptp_dte *ptp_dte = platform_get_drvdata(pdev);
u8 i;
for (i = 0; i < DTE_NUM_REGS_TO_RESTORE; i++) {
if ((i * sizeof(u32)) != DTE_NCO_OVERFLOW_REG)
writel(ptp_dte->reg_val[i],
(ptp_dte->regs + (i * sizeof(u32))));
else
writel(((ptp_dte->reg_val[i] &
DTE_NCO_SUM3_MASK) << DTE_NCO_SUM3_WR_SHIFT),
(ptp_dte->regs + (i * sizeof(u32))));
}
return 0;
}
static const struct dev_pm_ops ptp_dte_pm_ops = {
.suspend = ptp_dte_suspend,
.resume = ptp_dte_resume
};
#define PTP_DTE_PM_OPS (&ptp_dte_pm_ops)
#else
#define PTP_DTE_PM_OPS NULL
#endif
static const struct of_device_id ptp_dte_of_match[] = {
{ .compatible = "brcm,ptp-dte", },
{},
};
MODULE_DEVICE_TABLE(of, ptp_dte_of_match);
static struct platform_driver ptp_dte_driver = {
.driver = {
.name = "ptp-dte",
.pm = PTP_DTE_PM_OPS,
.of_match_table = ptp_dte_of_match,
},
.probe = ptp_dte_probe,
.remove = ptp_dte_remove,
};
module_platform_driver(ptp_dte_driver);
MODULE_AUTHOR("Broadcom");
MODULE_DESCRIPTION("Broadcom DTE PTP Clock driver");
MODULE_LICENSE("GPL v2");