Re: [RFC PATCH 5/5] PTP: Add support for Intel PMC Timed GPIO Controller

From: Shannon Nelson
Date: Tue Jul 16 2019 - 15:13:43 EST

On 7/16/19 12:20 AM, Felipe Balbi wrote:
Add a driver supporting Intel Timed GPIO controller available as part
of some Intel PMCs.

Signed-off-by: Felipe Balbi <felipe.balbi@xxxxxxxxxxxxxxx>

Hi Felipe, just a couple of quick comments:

There are several places where a line is continued on the next line, but should be indented to match the opening parenthesis on a function call or 'if' expression.

Shouldn't there be a kthread_stop() in intel_pmc_tgpio_remove(), or did I miss that somewhere?

Cheers,
sln


---
drivers/ptp/Kconfig | 8 +
drivers/ptp/Makefile | 1 +
drivers/ptp/ptp-intel-pmc-tgpio.c | 378 ++++++++++++++++++++++++++++++
3 files changed, 387 insertions(+)
create mode 100644 drivers/ptp/ptp-intel-pmc-tgpio.c

diff --git a/drivers/ptp/Kconfig b/drivers/ptp/Kconfig
index 9b8fee5178e8..bb0fce70a783 100644
--- a/drivers/ptp/Kconfig
+++ b/drivers/ptp/Kconfig
@@ -107,6 +107,14 @@ config PTP_1588_CLOCK_PCH
To compile this driver as a module, choose M here: the module
will be called ptp_pch.
+config PTP_INTEL_PMC_TGPIO
+ tristate "Intel PMC Timed GPIO"
+ depends on X86
+ depends on ACPI
+ imply PTP_1588_CLOCK
+ help
+ This driver adds support for Intel PMC Timed GPIO Controller
+
config PTP_1588_CLOCK_KVM
tristate "KVM virtual PTP clock"
depends on PTP_1588_CLOCK
diff --git a/drivers/ptp/Makefile b/drivers/ptp/Makefile
index 677d1d178a3e..ff89c90ace82 100644
--- a/drivers/ptp/Makefile
+++ b/drivers/ptp/Makefile
@@ -7,6 +7,7 @@ ptp-y := ptp_clock.o ptp_chardev.o ptp_sysfs.o
obj-$(CONFIG_PTP_1588_CLOCK) += ptp.o
obj-$(CONFIG_PTP_1588_CLOCK_DTE) += ptp_dte.o
obj-$(CONFIG_PTP_1588_CLOCK_IXP46X) += ptp_ixp46x.o
+obj-$(CONFIG_PTP_INTEL_PMC_TGPIO) += ptp-intel-pmc-tgpio.o
obj-$(CONFIG_PTP_1588_CLOCK_PCH) += ptp_pch.o
obj-$(CONFIG_PTP_1588_CLOCK_KVM) += ptp_kvm.o
obj-$(CONFIG_PTP_1588_CLOCK_QORIQ) += ptp-qoriq.o
diff --git a/drivers/ptp/ptp-intel-pmc-tgpio.c b/drivers/ptp/ptp-intel-pmc-tgpio.c
new file mode 100644
index 000000000000..880ece34868a
--- /dev/null
+++ b/drivers/ptp/ptp-intel-pmc-tgpio.c
@@ -0,0 +1,378 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Intel Timed GPIO Controller Driver
+ *
+ * Copyright (C) 2018 Intel Corporation
+ * Author: Felipe Balbi <felipe.balbi@xxxxxxxxxxxxxxx>
+ */
+
+#include <linux/acpi.h>
+#include <linux/bitops.h>
+#include <linux/gpio.h>
+#include <linux/io-64-nonatomic-lo-hi.h>
+#include <linux/kthread.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/platform_device.h>
+#include <linux/ptp_clock_kernel.h>
+#include <asm/tsc.h>
+
+#define TGPIOCTL 0x00
+#define TGPIOCOMPV31_0 0x10
+#define TGPIOCOMPV63_32 0x14
+#define TGPIOPIV31_0 0x18
+#define TGPIOPIV63_32 0x1c
+#define TGPIOTCV31_0 0x20
+#define TGPIOTCV63_32 0x24
+#define TGPIOECCV31_0 0x28
+#define TGPIOECCV63_32 0x2c
+#define TGPIOEC31_0 0x30
+#define TGPIOEC63_32 0x34
+
+/* Control Register */
+#define TGPIOCTL_EN BIT(0)
+#define TGPIOCTL_DIR BIT(1)
+#define TGPIOCTL_EP GENMASK(3, 2)
+#define TGPIOCTL_EP_RISING_EDGE (0 << 2)
+#define TGPIOCTL_EP_FALLING_EDGE (1 << 2)
+#define TGPIOCTL_EP_TOGGLE_EDGE (2 << 2)
+#define TGPIOCTL_PM BIT(4)
+
+#define NSECS_PER_SEC 1000000000
+#define TGPIO_MAX_ADJ_TIME 999999900
+
+struct intel_pmc_tgpio {
+ struct ptp_clock_info info;
+ struct ptp_clock *clock;
+
+ struct mutex lock;
+ struct device *dev;
+ void __iomem *base;
+
+ struct task_struct *event_thread;
+ bool input;
+};
+#define to_intel_pmc_tgpio(i) (container_of((i), struct intel_pmc_tgpio, info))
+
+static inline u64 to_intel_pmc_tgpio_time(struct ptp_clock_time *t)
+{
+ return t->sec * NSECS_PER_SEC + t->nsec;
+}
+
+static inline u64 intel_pmc_tgpio_readq(void __iomem *base, u32 offset)
+{
+ return lo_hi_readq(base + offset);
+}
+
+static inline void intel_pmc_tgpio_writeq(void __iomem *base, u32 offset, u64 v)
+{
+ return lo_hi_writeq(v, base + offset);
+}
+
+static inline u32 intel_pmc_tgpio_readl(void __iomem *base, u32 offset)
+{
+ return readl(base + offset);
+}
+
+static inline void intel_pmc_tgpio_writel(void __iomem *base, u32 offset, u32 value)
+{
+ writel(value, base + offset);
+}
+
+static struct ptp_pin_desc intel_pmc_tgpio_pin_config[] = {
+ { \
+ .name = "pin0", \
+ .index = 0, \
+ .func = PTP_PF_NONE, \
+ .chan = 0, \
+ }
+};
+
+static int intel_pmc_tgpio_gettime64(struct ptp_clock_info *info,
+ struct timespec64 *ts)
+{
+ struct intel_pmc_tgpio *tgpio = to_intel_pmc_tgpio(info);
+ u64 now;
+
+ mutex_lock(&tgpio->lock);
+ now = get_art_ns_now();
+ *ts = ns_to_timespec64(now);
+ mutex_unlock(&tgpio->lock);
+
+ return 0;
+}
+
+static int intel_pmc_tgpio_settime64(struct ptp_clock_info *info,
+ const struct timespec64 *ts)
+{
+ return -EOPNOTSUPP;
+}
+
+static int intel_pmc_tgpio_event_thread(void *_tgpio)
+{
+ struct intel_pmc_tgpio *tgpio = _tgpio;
+ u64 reg;
+
+ while (!kthread_should_stop()) {
+ bool input;
+ int i;
+
+ mutex_lock(&tgpio->lock);
+ input = tgpio->input;
+ mutex_unlock(&tgpio->lock);
+
+ if (!input)
+ schedule();
+
+ reg = intel_pmc_tgpio_readq(tgpio->base, TGPIOEC31_0);
+
+ for (i = 0; i < reg; i++) {
+ struct ptp_clock_event event;
+
+ event.type = PTP_CLOCK_EXTTS;
+ event.index = 0;
+ event.timestamp = intel_pmc_tgpio_readq(tgpio->base,
+ TGPIOTCV31_0);
+
+ ptp_clock_event(tgpio->clock, &event);
+ }
+ schedule_timeout_interruptible(10);
+ }
+
+ return 0;
+}
+
+static int intel_pmc_tgpio_config_input(struct intel_pmc_tgpio *tgpio,
+ struct ptp_extts_request *extts, int on)
+{
+ u32 ctrl;
+ bool input;
+
+ ctrl = intel_pmc_tgpio_readl(tgpio->base, TGPIOCTL);
+ ctrl &= ~TGPIOCTL_EN;
+ intel_pmc_tgpio_writel(tgpio->base, TGPIOCTL, ctrl);
+
+ if (on) {
+ ctrl |= TGPIOCTL_DIR;
+
+ if (extts->flags & PTP_RISING_EDGE &&
+ extts->flags & PTP_FALLING_EDGE)
+ ctrl |= TGPIOCTL_EP_TOGGLE_EDGE;
+ else if (extts->flags & PTP_RISING_EDGE)
+ ctrl |= TGPIOCTL_EP_RISING_EDGE;
+ else if (extts->flags & PTP_FALLING_EDGE)
+ ctrl |= TGPIOCTL_EP_FALLING_EDGE;
+
+ /* gotta program all other bits before EN bit is set */
+ intel_pmc_tgpio_writel(tgpio->base, TGPIOCTL, ctrl);
+ ctrl |= TGPIOCTL_EN;
+ input = true;
+ } else {
+ ctrl &= ~(TGPIOCTL_DIR | TGPIOCTL_EN);
+ input = false;
+ }
+
+ intel_pmc_tgpio_writel(tgpio->base, TGPIOCTL, ctrl);
+ tgpio->input = input;
+
+ if (input)
+ wake_up_process(tgpio->event_thread);
+
+ return 0;
+}
+
+static int intel_pmc_tgpio_config_output(struct intel_pmc_tgpio *tgpio,
+ struct ptp_perout_request *perout, int on)
+{
+ u32 ctrl;
+
+ ctrl = intel_pmc_tgpio_readl(tgpio->base, TGPIOCTL);
+ if (on) {
+ struct ptp_clock_time *period = &perout->period;
+ struct ptp_clock_time *start = &perout->start;
+
+ if (ctrl & TGPIOCTL_EN)
+ return 0;
+
+ intel_pmc_tgpio_writeq(tgpio->base, TGPIOCOMPV31_0,
+ to_intel_pmc_tgpio_time(start));
+
+ intel_pmc_tgpio_writeq(tgpio->base, TGPIOPIV31_0,
+ to_intel_pmc_tgpio_time(period));
+
+ ctrl &= ~TGPIOCTL_DIR;
+ if (perout->flags & PTP_PEROUT_ONE_SHOT)
+ ctrl &= ~TGPIOCTL_PM;
+ else
+ ctrl |= TGPIOCTL_PM;
+
+ /* gotta program all other bits before EN bit is set */
+ intel_pmc_tgpio_writel(tgpio->base, TGPIOCTL, ctrl);
+
+ ctrl |= TGPIOCTL_EN;
+ intel_pmc_tgpio_writel(tgpio->base, TGPIOCTL, ctrl);
+ } else {
+ if (!(ctrl & ~TGPIOCTL_EN))
+ return 0;
+
+ ctrl &= ~(TGPIOCTL_EN | TGPIOCTL_PM);
+ intel_pmc_tgpio_writel(tgpio->base, TGPIOCTL, ctrl);
+ }
+
+ return 0;
+}
+
+static int intel_pmc_tgpio_enable(struct ptp_clock_info *info,
+ struct ptp_clock_request *req, int on)
+{
+ struct intel_pmc_tgpio *tgpio = to_intel_pmc_tgpio(info);
+ int ret = -EOPNOTSUPP;
+
+ mutex_lock(&tgpio->lock);
+ switch (req->type) {
+ case PTP_CLK_REQ_EXTTS:
+ ret = intel_pmc_tgpio_config_input(tgpio, &req->extts, on);
+ break;
+ case PTP_CLK_REQ_PEROUT:
+ ret = intel_pmc_tgpio_config_output(tgpio, &req->perout, on);
+ break;
+ default:
+ break;
+ }
+ mutex_unlock(&tgpio->lock);
+
+ return ret;
+}
+
+static int intel_pmc_tgpio_get_time_fn(ktime_t *device_time,
+ struct system_counterval_t *system_counter, void *_tgpio)
+{
+ get_tsc_ns(system_counter, device_time);
+ return 0;
+}
+
+static int intel_pmc_tgpio_getcrosststamp(struct ptp_clock_info *info,
+ struct system_device_crosststamp *cts)
+{
+ struct intel_pmc_tgpio *tgpio = to_intel_pmc_tgpio(info);
+
+ return get_device_system_crosststamp(intel_pmc_tgpio_get_time_fn, tgpio,
+ NULL, cts);
+}
+
+static int intel_pmc_tgpio_counttstamp(struct ptp_clock_info *info,
+ struct ptp_event_count_tstamp *count)
+{
+ struct intel_pmc_tgpio *tgpio = to_intel_pmc_tgpio(info);
+ u32 dt_hi_tmp;
+ u32 dt_hi;
+ u32 dt_lo;
+
+ dt_hi_tmp = intel_pmc_tgpio_readl(tgpio->base, TGPIOTCV63_32);
+ dt_lo = intel_pmc_tgpio_readl(tgpio->base, TGPIOTCV31_0);
+
+ count->event_count = intel_pmc_tgpio_readl(tgpio->base, TGPIOECCV63_32);
+ count->event_count <<= 32;
+ count->event_count |= intel_pmc_tgpio_readl(tgpio->base, TGPIOECCV31_0);
+
+ dt_hi = intel_pmc_tgpio_readl(tgpio->base, TGPIOTCV63_32);
+
+ if (dt_hi_tmp != dt_hi && dt_lo & 0x80000000)
+ count->device_time.sec = dt_hi_tmp;
+ else
+ count->device_time.sec = dt_hi;
+
+ count->device_time.nsec = dt_lo;
+
+ return 0;
+}
+
+static int intel_pmc_tgpio_verify(struct ptp_clock_info *ptp, unsigned int pin,
+ enum ptp_pin_function func, unsigned int chan)
+{
+ return 0;
+}
+
+static const struct ptp_clock_info intel_pmc_tgpio_info = {
+ .owner = THIS_MODULE,
+ .name = "Intel PMC TGPIO",
+ .max_adj = 50000000,
+ .n_pins = 1,
+ .n_ext_ts = 1,
+ .n_per_out = 1,
+ .pin_config = intel_pmc_tgpio_pin_config,
+ .gettime64 = intel_pmc_tgpio_gettime64,
+ .settime64 = intel_pmc_tgpio_settime64,
+ .enable = intel_pmc_tgpio_enable,
+ .getcrosststamp = intel_pmc_tgpio_getcrosststamp,
+ .counttstamp = intel_pmc_tgpio_counttstamp,
+ .verify = intel_pmc_tgpio_verify,
+};
+
+static int intel_pmc_tgpio_probe(struct platform_device *pdev)
+{
+ struct intel_pmc_tgpio *tgpio;
+ struct device *dev;
+ struct resource *res;
+
+ dev = &pdev->dev;
+ tgpio = devm_kzalloc(dev, sizeof(*tgpio), GFP_KERNEL);
+ if (!tgpio)
+ return -ENOMEM;
+
+ tgpio->dev = dev;
+ tgpio->info = intel_pmc_tgpio_info;
+
+ res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ tgpio->base = devm_ioremap_resource(dev, res);
+ if (!tgpio->base)
+ return -ENOMEM;
+
+ mutex_init(&tgpio->lock);
+ platform_set_drvdata(pdev, tgpio);
+
+ tgpio->event_thread = kthread_create(intel_pmc_tgpio_event_thread,
+ tgpio, dev_name(tgpio->dev));
+ if (IS_ERR(tgpio->event_thread))
+ return PTR_ERR(tgpio->event_thread);
+
+ tgpio->clock = ptp_clock_register(&tgpio->info, &pdev->dev);
+ if (IS_ERR(tgpio->clock))
+ return PTR_ERR(tgpio->clock);
+
+ wake_up_process(tgpio->event_thread);
+
+ return 0;
+}
+
+static int intel_pmc_tgpio_remove(struct platform_device *pdev)
+{
+ struct intel_pmc_tgpio *tgpio = platform_get_drvdata(pdev);
+
+ ptp_clock_unregister(tgpio->clock);
+
+ return 0;
+}
+
+static const struct acpi_device_id intel_pmc_acpi_match[] = {
+ /* TODO */
+
+ { },
+};
+
+/* MODULE_ALIAS("acpi*:TODO:*"); */
+
+static struct platform_driver intel_pmc_tgpio_driver = {
+ .probe = intel_pmc_tgpio_probe,
+ .remove = intel_pmc_tgpio_remove,
+ .driver = {
+ .name = "intel-pmc-tgpio",
+ .acpi_match_table = ACPI_PTR(intel_pmc_acpi_match),
+ },
+};
+
+module_platform_driver(intel_pmc_tgpio_driver);
+
+MODULE_AUTHOR("Felipe Balbi <felipe.balbi@xxxxxxxxxxxxxxx>");
+MODULE_LICENSE("GPL v2");
+MODULE_DESCRIPTION("Intel PMC Timed GPIO Controller Driver");