diff options
Diffstat (limited to 'drivers/counter/intel-qep.c')
-rw-r--r-- | drivers/counter/intel-qep.c | 526 |
1 files changed, 526 insertions, 0 deletions
diff --git a/drivers/counter/intel-qep.c b/drivers/counter/intel-qep.c new file mode 100644 index 000000000..af5942e66 --- /dev/null +++ b/drivers/counter/intel-qep.c @@ -0,0 +1,526 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Intel Quadrature Encoder Peripheral driver + * + * Copyright (C) 2019-2021 Intel Corporation + * + * Author: Felipe Balbi (Intel) + * Author: Jarkko Nikula <jarkko.nikula@linux.intel.com> + * Author: Raymond Tan <raymond.tan@intel.com> + */ +#include <linux/counter.h> +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/mutex.h> +#include <linux/pci.h> +#include <linux/pm_runtime.h> + +#define INTEL_QEPCON 0x00 +#define INTEL_QEPFLT 0x04 +#define INTEL_QEPCOUNT 0x08 +#define INTEL_QEPMAX 0x0c +#define INTEL_QEPWDT 0x10 +#define INTEL_QEPCAPDIV 0x14 +#define INTEL_QEPCNTR 0x18 +#define INTEL_QEPCAPBUF 0x1c +#define INTEL_QEPINT_STAT 0x20 +#define INTEL_QEPINT_MASK 0x24 + +/* QEPCON */ +#define INTEL_QEPCON_EN BIT(0) +#define INTEL_QEPCON_FLT_EN BIT(1) +#define INTEL_QEPCON_EDGE_A BIT(2) +#define INTEL_QEPCON_EDGE_B BIT(3) +#define INTEL_QEPCON_EDGE_INDX BIT(4) +#define INTEL_QEPCON_SWPAB BIT(5) +#define INTEL_QEPCON_OP_MODE BIT(6) +#define INTEL_QEPCON_PH_ERR BIT(7) +#define INTEL_QEPCON_COUNT_RST_MODE BIT(8) +#define INTEL_QEPCON_INDX_GATING_MASK GENMASK(10, 9) +#define INTEL_QEPCON_INDX_GATING(n) (((n) & 3) << 9) +#define INTEL_QEPCON_INDX_PAL_PBL INTEL_QEPCON_INDX_GATING(0) +#define INTEL_QEPCON_INDX_PAL_PBH INTEL_QEPCON_INDX_GATING(1) +#define INTEL_QEPCON_INDX_PAH_PBL INTEL_QEPCON_INDX_GATING(2) +#define INTEL_QEPCON_INDX_PAH_PBH INTEL_QEPCON_INDX_GATING(3) +#define INTEL_QEPCON_CAP_MODE BIT(11) +#define INTEL_QEPCON_FIFO_THRE_MASK GENMASK(14, 12) +#define INTEL_QEPCON_FIFO_THRE(n) ((((n) - 1) & 7) << 12) +#define INTEL_QEPCON_FIFO_EMPTY BIT(15) + +/* QEPFLT */ +#define INTEL_QEPFLT_MAX_COUNT(n) ((n) & 0x1fffff) + +/* QEPINT */ +#define INTEL_QEPINT_FIFOCRIT BIT(5) +#define INTEL_QEPINT_FIFOENTRY BIT(4) +#define INTEL_QEPINT_QEPDIR BIT(3) +#define INTEL_QEPINT_QEPRST_UP BIT(2) +#define INTEL_QEPINT_QEPRST_DOWN BIT(1) +#define INTEL_QEPINT_WDT BIT(0) + +#define INTEL_QEPINT_MASK_ALL GENMASK(5, 0) + +#define INTEL_QEP_CLK_PERIOD_NS 10 + +struct intel_qep { + struct mutex lock; + struct device *dev; + void __iomem *regs; + bool enabled; + /* Context save registers */ + u32 qepcon; + u32 qepflt; + u32 qepmax; +}; + +static inline u32 intel_qep_readl(struct intel_qep *qep, u32 offset) +{ + return readl(qep->regs + offset); +} + +static inline void intel_qep_writel(struct intel_qep *qep, + u32 offset, u32 value) +{ + writel(value, qep->regs + offset); +} + +static void intel_qep_init(struct intel_qep *qep) +{ + u32 reg; + + reg = intel_qep_readl(qep, INTEL_QEPCON); + reg &= ~INTEL_QEPCON_EN; + intel_qep_writel(qep, INTEL_QEPCON, reg); + qep->enabled = false; + /* + * Make sure peripheral is disabled by flushing the write with + * a dummy read + */ + reg = intel_qep_readl(qep, INTEL_QEPCON); + + reg &= ~(INTEL_QEPCON_OP_MODE | INTEL_QEPCON_FLT_EN); + reg |= INTEL_QEPCON_EDGE_A | INTEL_QEPCON_EDGE_B | + INTEL_QEPCON_EDGE_INDX | INTEL_QEPCON_COUNT_RST_MODE; + intel_qep_writel(qep, INTEL_QEPCON, reg); + intel_qep_writel(qep, INTEL_QEPINT_MASK, INTEL_QEPINT_MASK_ALL); +} + +static int intel_qep_count_read(struct counter_device *counter, + struct counter_count *count, u64 *val) +{ + struct intel_qep *const qep = counter_priv(counter); + + pm_runtime_get_sync(qep->dev); + *val = intel_qep_readl(qep, INTEL_QEPCOUNT); + pm_runtime_put(qep->dev); + + return 0; +} + +static const enum counter_function intel_qep_count_functions[] = { + COUNTER_FUNCTION_QUADRATURE_X4, +}; + +static int intel_qep_function_read(struct counter_device *counter, + struct counter_count *count, + enum counter_function *function) +{ + *function = COUNTER_FUNCTION_QUADRATURE_X4; + + return 0; +} + +static const enum counter_synapse_action intel_qep_synapse_actions[] = { + COUNTER_SYNAPSE_ACTION_BOTH_EDGES, +}; + +static int intel_qep_action_read(struct counter_device *counter, + struct counter_count *count, + struct counter_synapse *synapse, + enum counter_synapse_action *action) +{ + *action = COUNTER_SYNAPSE_ACTION_BOTH_EDGES; + return 0; +} + +static const struct counter_ops intel_qep_counter_ops = { + .count_read = intel_qep_count_read, + .function_read = intel_qep_function_read, + .action_read = intel_qep_action_read, +}; + +#define INTEL_QEP_SIGNAL(_id, _name) { \ + .id = (_id), \ + .name = (_name), \ +} + +static struct counter_signal intel_qep_signals[] = { + INTEL_QEP_SIGNAL(0, "Phase A"), + INTEL_QEP_SIGNAL(1, "Phase B"), + INTEL_QEP_SIGNAL(2, "Index"), +}; + +#define INTEL_QEP_SYNAPSE(_signal_id) { \ + .actions_list = intel_qep_synapse_actions, \ + .num_actions = ARRAY_SIZE(intel_qep_synapse_actions), \ + .signal = &intel_qep_signals[(_signal_id)], \ +} + +static struct counter_synapse intel_qep_count_synapses[] = { + INTEL_QEP_SYNAPSE(0), + INTEL_QEP_SYNAPSE(1), + INTEL_QEP_SYNAPSE(2), +}; + +static int intel_qep_ceiling_read(struct counter_device *counter, + struct counter_count *count, u64 *ceiling) +{ + struct intel_qep *qep = counter_priv(counter); + + pm_runtime_get_sync(qep->dev); + *ceiling = intel_qep_readl(qep, INTEL_QEPMAX); + pm_runtime_put(qep->dev); + + return 0; +} + +static int intel_qep_ceiling_write(struct counter_device *counter, + struct counter_count *count, u64 max) +{ + struct intel_qep *qep = counter_priv(counter); + int ret = 0; + + /* Intel QEP ceiling configuration only supports 32-bit values */ + if (max != (u32)max) + return -ERANGE; + + mutex_lock(&qep->lock); + if (qep->enabled) { + ret = -EBUSY; + goto out; + } + + pm_runtime_get_sync(qep->dev); + intel_qep_writel(qep, INTEL_QEPMAX, max); + pm_runtime_put(qep->dev); + +out: + mutex_unlock(&qep->lock); + return ret; +} + +static int intel_qep_enable_read(struct counter_device *counter, + struct counter_count *count, u8 *enable) +{ + struct intel_qep *qep = counter_priv(counter); + + *enable = qep->enabled; + + return 0; +} + +static int intel_qep_enable_write(struct counter_device *counter, + struct counter_count *count, u8 val) +{ + struct intel_qep *qep = counter_priv(counter); + u32 reg; + bool changed; + + mutex_lock(&qep->lock); + changed = val ^ qep->enabled; + if (!changed) + goto out; + + pm_runtime_get_sync(qep->dev); + reg = intel_qep_readl(qep, INTEL_QEPCON); + if (val) { + /* Enable peripheral and keep runtime PM always on */ + reg |= INTEL_QEPCON_EN; + pm_runtime_get_noresume(qep->dev); + } else { + /* Let runtime PM be idle and disable peripheral */ + pm_runtime_put_noidle(qep->dev); + reg &= ~INTEL_QEPCON_EN; + } + intel_qep_writel(qep, INTEL_QEPCON, reg); + pm_runtime_put(qep->dev); + qep->enabled = val; + +out: + mutex_unlock(&qep->lock); + return 0; +} + +static int intel_qep_spike_filter_ns_read(struct counter_device *counter, + struct counter_count *count, + u64 *length) +{ + struct intel_qep *qep = counter_priv(counter); + u32 reg; + + pm_runtime_get_sync(qep->dev); + reg = intel_qep_readl(qep, INTEL_QEPCON); + if (!(reg & INTEL_QEPCON_FLT_EN)) { + pm_runtime_put(qep->dev); + return 0; + } + reg = INTEL_QEPFLT_MAX_COUNT(intel_qep_readl(qep, INTEL_QEPFLT)); + pm_runtime_put(qep->dev); + + *length = (reg + 2) * INTEL_QEP_CLK_PERIOD_NS; + + return 0; +} + +static int intel_qep_spike_filter_ns_write(struct counter_device *counter, + struct counter_count *count, + u64 length) +{ + struct intel_qep *qep = counter_priv(counter); + u32 reg; + bool enable; + int ret = 0; + + /* + * Spike filter length is (MAX_COUNT + 2) clock periods. + * Disable filter when userspace writes 0, enable for valid + * nanoseconds values and error out otherwise. + */ + do_div(length, INTEL_QEP_CLK_PERIOD_NS); + if (length == 0) { + enable = false; + length = 0; + } else if (length >= 2) { + enable = true; + length -= 2; + } else { + return -EINVAL; + } + + if (length > INTEL_QEPFLT_MAX_COUNT(length)) + return -ERANGE; + + mutex_lock(&qep->lock); + if (qep->enabled) { + ret = -EBUSY; + goto out; + } + + pm_runtime_get_sync(qep->dev); + reg = intel_qep_readl(qep, INTEL_QEPCON); + if (enable) + reg |= INTEL_QEPCON_FLT_EN; + else + reg &= ~INTEL_QEPCON_FLT_EN; + intel_qep_writel(qep, INTEL_QEPFLT, length); + intel_qep_writel(qep, INTEL_QEPCON, reg); + pm_runtime_put(qep->dev); + +out: + mutex_unlock(&qep->lock); + return ret; +} + +static int intel_qep_preset_enable_read(struct counter_device *counter, + struct counter_count *count, + u8 *preset_enable) +{ + struct intel_qep *qep = counter_priv(counter); + u32 reg; + + pm_runtime_get_sync(qep->dev); + reg = intel_qep_readl(qep, INTEL_QEPCON); + pm_runtime_put(qep->dev); + + *preset_enable = !(reg & INTEL_QEPCON_COUNT_RST_MODE); + + return 0; +} + +static int intel_qep_preset_enable_write(struct counter_device *counter, + struct counter_count *count, u8 val) +{ + struct intel_qep *qep = counter_priv(counter); + u32 reg; + int ret = 0; + + mutex_lock(&qep->lock); + if (qep->enabled) { + ret = -EBUSY; + goto out; + } + + pm_runtime_get_sync(qep->dev); + reg = intel_qep_readl(qep, INTEL_QEPCON); + if (val) + reg &= ~INTEL_QEPCON_COUNT_RST_MODE; + else + reg |= INTEL_QEPCON_COUNT_RST_MODE; + + intel_qep_writel(qep, INTEL_QEPCON, reg); + pm_runtime_put(qep->dev); + +out: + mutex_unlock(&qep->lock); + + return ret; +} + +static struct counter_comp intel_qep_count_ext[] = { + COUNTER_COMP_ENABLE(intel_qep_enable_read, intel_qep_enable_write), + COUNTER_COMP_CEILING(intel_qep_ceiling_read, intel_qep_ceiling_write), + COUNTER_COMP_PRESET_ENABLE(intel_qep_preset_enable_read, + intel_qep_preset_enable_write), + COUNTER_COMP_COUNT_U64("spike_filter_ns", + intel_qep_spike_filter_ns_read, + intel_qep_spike_filter_ns_write), +}; + +static struct counter_count intel_qep_counter_count[] = { + { + .id = 0, + .name = "Channel 1 Count", + .functions_list = intel_qep_count_functions, + .num_functions = ARRAY_SIZE(intel_qep_count_functions), + .synapses = intel_qep_count_synapses, + .num_synapses = ARRAY_SIZE(intel_qep_count_synapses), + .ext = intel_qep_count_ext, + .num_ext = ARRAY_SIZE(intel_qep_count_ext), + }, +}; + +static int intel_qep_probe(struct pci_dev *pci, const struct pci_device_id *id) +{ + struct counter_device *counter; + struct intel_qep *qep; + struct device *dev = &pci->dev; + void __iomem *regs; + int ret; + + counter = devm_counter_alloc(dev, sizeof(*qep)); + if (!counter) + return -ENOMEM; + qep = counter_priv(counter); + + ret = pcim_enable_device(pci); + if (ret) + return ret; + + pci_set_master(pci); + + ret = pcim_iomap_regions(pci, BIT(0), pci_name(pci)); + if (ret) + return ret; + + regs = pcim_iomap_table(pci)[0]; + if (!regs) + return -ENOMEM; + + qep->dev = dev; + qep->regs = regs; + mutex_init(&qep->lock); + + intel_qep_init(qep); + pci_set_drvdata(pci, qep); + + counter->name = pci_name(pci); + counter->parent = dev; + counter->ops = &intel_qep_counter_ops; + counter->counts = intel_qep_counter_count; + counter->num_counts = ARRAY_SIZE(intel_qep_counter_count); + counter->signals = intel_qep_signals; + counter->num_signals = ARRAY_SIZE(intel_qep_signals); + qep->enabled = false; + + pm_runtime_put(dev); + pm_runtime_allow(dev); + + ret = devm_counter_add(&pci->dev, counter); + if (ret < 0) + return dev_err_probe(&pci->dev, ret, "Failed to add counter\n"); + + return 0; +} + +static void intel_qep_remove(struct pci_dev *pci) +{ + struct intel_qep *qep = pci_get_drvdata(pci); + struct device *dev = &pci->dev; + + pm_runtime_forbid(dev); + if (!qep->enabled) + pm_runtime_get(dev); + + intel_qep_writel(qep, INTEL_QEPCON, 0); +} + +static int __maybe_unused intel_qep_suspend(struct device *dev) +{ + struct pci_dev *pdev = to_pci_dev(dev); + struct intel_qep *qep = pci_get_drvdata(pdev); + + qep->qepcon = intel_qep_readl(qep, INTEL_QEPCON); + qep->qepflt = intel_qep_readl(qep, INTEL_QEPFLT); + qep->qepmax = intel_qep_readl(qep, INTEL_QEPMAX); + + return 0; +} + +static int __maybe_unused intel_qep_resume(struct device *dev) +{ + struct pci_dev *pdev = to_pci_dev(dev); + struct intel_qep *qep = pci_get_drvdata(pdev); + + /* + * Make sure peripheral is disabled when restoring registers and + * control register bits that are writable only when the peripheral + * is disabled + */ + intel_qep_writel(qep, INTEL_QEPCON, 0); + intel_qep_readl(qep, INTEL_QEPCON); + + intel_qep_writel(qep, INTEL_QEPFLT, qep->qepflt); + intel_qep_writel(qep, INTEL_QEPMAX, qep->qepmax); + intel_qep_writel(qep, INTEL_QEPINT_MASK, INTEL_QEPINT_MASK_ALL); + + /* Restore all other control register bits except enable status */ + intel_qep_writel(qep, INTEL_QEPCON, qep->qepcon & ~INTEL_QEPCON_EN); + intel_qep_readl(qep, INTEL_QEPCON); + + /* Restore enable status */ + intel_qep_writel(qep, INTEL_QEPCON, qep->qepcon); + + return 0; +} + +static UNIVERSAL_DEV_PM_OPS(intel_qep_pm_ops, + intel_qep_suspend, intel_qep_resume, NULL); + +static const struct pci_device_id intel_qep_id_table[] = { + /* EHL */ + { PCI_VDEVICE(INTEL, 0x4bc3), }, + { PCI_VDEVICE(INTEL, 0x4b81), }, + { PCI_VDEVICE(INTEL, 0x4b82), }, + { PCI_VDEVICE(INTEL, 0x4b83), }, + { } /* Terminating Entry */ +}; +MODULE_DEVICE_TABLE(pci, intel_qep_id_table); + +static struct pci_driver intel_qep_driver = { + .name = "intel-qep", + .id_table = intel_qep_id_table, + .probe = intel_qep_probe, + .remove = intel_qep_remove, + .driver = { + .pm = &intel_qep_pm_ops, + } +}; + +module_pci_driver(intel_qep_driver); + +MODULE_AUTHOR("Felipe Balbi (Intel)"); +MODULE_AUTHOR("Jarkko Nikula <jarkko.nikula@linux.intel.com>"); +MODULE_AUTHOR("Raymond Tan <raymond.tan@intel.com>"); +MODULE_LICENSE("GPL"); +MODULE_DESCRIPTION("Intel Quadrature Encoder Peripheral driver"); +MODULE_IMPORT_NS(COUNTER); |