From 09db4678bfbb429df259e1ce43854a0e2720c355 Mon Sep 17 00:00:00 2001 From: William Breathitt Gray Date: Wed, 29 Sep 2021 12:16:05 +0900 Subject: counter: 104-quad-8: Replace mutex with spinlock This patch replaces the mutex I/O lock with a spinlock. This is in preparation for a subsequent patch adding IRQ support for 104-QUAD-8 devices; we can't sleep in an interrupt context, so we'll need to use a spinlock instead. Acked-by: Syed Nayyar Waris Signed-off-by: William Breathitt Gray Link: https://lore.kernel.org/r/3f74491dec66de10d062978bcb7b9c2b3bdea86c.1632884256.git.vilhelm.gray@gmail.com Signed-off-by: Jonathan Cameron --- drivers/counter/104-quad-8.c | 89 ++++++++++++++++++++++++++------------------ 1 file changed, 52 insertions(+), 37 deletions(-) diff --git a/drivers/counter/104-quad-8.c b/drivers/counter/104-quad-8.c index c587f295d720..a56751bf1e9b 100644 --- a/drivers/counter/104-quad-8.c +++ b/drivers/counter/104-quad-8.c @@ -16,6 +16,7 @@ #include #include #include +#include #define QUAD8_EXTENT 32 @@ -43,7 +44,7 @@ MODULE_PARM_DESC(base, "ACCES 104-QUAD-8 base addresses"); * @base: base port address of the device */ struct quad8 { - struct mutex lock; + spinlock_t lock; struct counter_device counter; unsigned int fck_prescaler[QUAD8_NUM_COUNTERS]; unsigned int preset[QUAD8_NUM_COUNTERS]; @@ -124,6 +125,7 @@ static int quad8_count_read(struct counter_device *counter, unsigned int flags; unsigned int borrow; unsigned int carry; + unsigned long irqflags; int i; flags = inb(base_offset + 1); @@ -133,7 +135,7 @@ static int quad8_count_read(struct counter_device *counter, /* Borrow XOR Carry effectively doubles count range */ *val = (unsigned long)(borrow ^ carry) << 24; - mutex_lock(&priv->lock); + spin_lock_irqsave(&priv->lock, irqflags); /* Reset Byte Pointer; transfer Counter to Output Latch */ outb(QUAD8_CTR_RLD | QUAD8_RLD_RESET_BP | QUAD8_RLD_CNTR_OUT, @@ -142,7 +144,7 @@ static int quad8_count_read(struct counter_device *counter, for (i = 0; i < 3; i++) *val |= (unsigned long)inb(base_offset) << (8 * i); - mutex_unlock(&priv->lock); + spin_unlock_irqrestore(&priv->lock, irqflags); return 0; } @@ -152,13 +154,14 @@ static int quad8_count_write(struct counter_device *counter, { struct quad8 *const priv = counter->priv; const int base_offset = priv->base + 2 * count->id; + unsigned long irqflags; int i; /* Only 24-bit values are supported */ if (val > 0xFFFFFF) return -ERANGE; - mutex_lock(&priv->lock); + spin_lock_irqsave(&priv->lock, irqflags); /* Reset Byte Pointer */ outb(QUAD8_CTR_RLD | QUAD8_RLD_RESET_BP, base_offset + 1); @@ -183,7 +186,7 @@ static int quad8_count_write(struct counter_device *counter, /* Reset Error flag */ outb(QUAD8_CTR_RLD | QUAD8_RLD_RESET_E, base_offset + 1); - mutex_unlock(&priv->lock); + spin_unlock_irqrestore(&priv->lock, irqflags); return 0; } @@ -201,8 +204,9 @@ static int quad8_function_read(struct counter_device *counter, { struct quad8 *const priv = counter->priv; const int id = count->id; + unsigned long irqflags; - mutex_lock(&priv->lock); + spin_lock_irqsave(&priv->lock, irqflags); if (priv->quadrature_mode[id]) switch (priv->quadrature_scale[id]) { @@ -219,7 +223,7 @@ static int quad8_function_read(struct counter_device *counter, else *function = COUNTER_FUNCTION_PULSE_DIRECTION; - mutex_unlock(&priv->lock); + spin_unlock_irqrestore(&priv->lock, irqflags); return 0; } @@ -234,10 +238,11 @@ static int quad8_function_write(struct counter_device *counter, unsigned int *const scale = priv->quadrature_scale + id; unsigned int *const synchronous_mode = priv->synchronous_mode + id; const int base_offset = priv->base + 2 * id + 1; + unsigned long irqflags; unsigned int mode_cfg; unsigned int idr_cfg; - mutex_lock(&priv->lock); + spin_lock_irqsave(&priv->lock, irqflags); mode_cfg = priv->count_mode[id] << 1; idr_cfg = priv->index_polarity[id] << 1; @@ -272,7 +277,7 @@ static int quad8_function_write(struct counter_device *counter, break; default: /* should never reach this path */ - mutex_unlock(&priv->lock); + spin_unlock_irqrestore(&priv->lock, irqflags); return -EINVAL; } } @@ -280,7 +285,7 @@ static int quad8_function_write(struct counter_device *counter, /* Load mode configuration to Counter Mode Register */ outb(QUAD8_CTR_CMR | mode_cfg, base_offset); - mutex_unlock(&priv->lock); + spin_unlock_irqrestore(&priv->lock, irqflags); return 0; } @@ -406,9 +411,10 @@ static int quad8_index_polarity_set(struct counter_device *counter, struct quad8 *const priv = counter->priv; const size_t channel_id = signal->id - 16; const int base_offset = priv->base + 2 * channel_id + 1; + unsigned long irqflags; unsigned int idr_cfg = index_polarity << 1; - mutex_lock(&priv->lock); + spin_lock_irqsave(&priv->lock, irqflags); idr_cfg |= priv->synchronous_mode[channel_id]; @@ -417,7 +423,7 @@ static int quad8_index_polarity_set(struct counter_device *counter, /* Load Index Control configuration to Index Control Register */ outb(QUAD8_CTR_IDR | idr_cfg, base_offset); - mutex_unlock(&priv->lock); + spin_unlock_irqrestore(&priv->lock, irqflags); return 0; } @@ -446,15 +452,16 @@ static int quad8_synchronous_mode_set(struct counter_device *counter, struct quad8 *const priv = counter->priv; const size_t channel_id = signal->id - 16; const int base_offset = priv->base + 2 * channel_id + 1; + unsigned long irqflags; unsigned int idr_cfg = synchronous_mode; - mutex_lock(&priv->lock); + spin_lock_irqsave(&priv->lock, irqflags); idr_cfg |= priv->index_polarity[channel_id] << 1; /* Index function must be non-synchronous in non-quadrature mode */ if (synchronous_mode && !priv->quadrature_mode[channel_id]) { - mutex_unlock(&priv->lock); + spin_unlock_irqrestore(&priv->lock, irqflags); return -EINVAL; } @@ -463,7 +470,7 @@ static int quad8_synchronous_mode_set(struct counter_device *counter, /* Load Index Control configuration to Index Control Register */ outb(QUAD8_CTR_IDR | idr_cfg, base_offset); - mutex_unlock(&priv->lock); + spin_unlock_irqrestore(&priv->lock, irqflags); return 0; } @@ -510,6 +517,7 @@ static int quad8_count_mode_write(struct counter_device *counter, unsigned int count_mode; unsigned int mode_cfg; const int base_offset = priv->base + 2 * count->id + 1; + unsigned long irqflags; /* Map Generic Counter count mode to 104-QUAD-8 count mode */ switch (cnt_mode) { @@ -530,7 +538,7 @@ static int quad8_count_mode_write(struct counter_device *counter, return -EINVAL; } - mutex_lock(&priv->lock); + spin_lock_irqsave(&priv->lock, irqflags); priv->count_mode[count->id] = count_mode; @@ -544,7 +552,7 @@ static int quad8_count_mode_write(struct counter_device *counter, /* Load mode configuration to Counter Mode Register */ outb(QUAD8_CTR_CMR | mode_cfg, base_offset); - mutex_unlock(&priv->lock); + spin_unlock_irqrestore(&priv->lock, irqflags); return 0; } @@ -564,9 +572,10 @@ static int quad8_count_enable_write(struct counter_device *counter, { struct quad8 *const priv = counter->priv; const int base_offset = priv->base + 2 * count->id; + unsigned long irqflags; unsigned int ior_cfg; - mutex_lock(&priv->lock); + spin_lock_irqsave(&priv->lock, irqflags); priv->ab_enable[count->id] = enable; @@ -575,7 +584,7 @@ static int quad8_count_enable_write(struct counter_device *counter, /* Load I/O control configuration */ outb(QUAD8_CTR_IOR | ior_cfg, base_offset + 1); - mutex_unlock(&priv->lock); + spin_unlock_irqrestore(&priv->lock, irqflags); return 0; } @@ -626,16 +635,17 @@ static int quad8_count_preset_write(struct counter_device *counter, struct counter_count *count, u64 preset) { struct quad8 *const priv = counter->priv; + unsigned long irqflags; /* Only 24-bit values are supported */ if (preset > 0xFFFFFF) return -ERANGE; - mutex_lock(&priv->lock); + spin_lock_irqsave(&priv->lock, irqflags); quad8_preset_register_set(priv, count->id, preset); - mutex_unlock(&priv->lock); + spin_unlock_irqrestore(&priv->lock, irqflags); return 0; } @@ -644,8 +654,9 @@ static int quad8_count_ceiling_read(struct counter_device *counter, struct counter_count *count, u64 *ceiling) { struct quad8 *const priv = counter->priv; + unsigned long irqflags; - mutex_lock(&priv->lock); + spin_lock_irqsave(&priv->lock, irqflags); /* Range Limit and Modulo-N count modes use preset value as ceiling */ switch (priv->count_mode[count->id]) { @@ -659,7 +670,7 @@ static int quad8_count_ceiling_read(struct counter_device *counter, break; } - mutex_unlock(&priv->lock); + spin_unlock_irqrestore(&priv->lock, irqflags); return 0; } @@ -668,23 +679,24 @@ static int quad8_count_ceiling_write(struct counter_device *counter, struct counter_count *count, u64 ceiling) { struct quad8 *const priv = counter->priv; + unsigned long irqflags; /* Only 24-bit values are supported */ if (ceiling > 0xFFFFFF) return -ERANGE; - mutex_lock(&priv->lock); + spin_lock_irqsave(&priv->lock, irqflags); /* Range Limit and Modulo-N count modes use preset value as ceiling */ switch (priv->count_mode[count->id]) { case 1: case 3: quad8_preset_register_set(priv, count->id, ceiling); - mutex_unlock(&priv->lock); + spin_unlock_irqrestore(&priv->lock, irqflags); return 0; } - mutex_unlock(&priv->lock); + spin_unlock_irqrestore(&priv->lock, irqflags); return -EINVAL; } @@ -706,12 +718,13 @@ static int quad8_count_preset_enable_write(struct counter_device *counter, { struct quad8 *const priv = counter->priv; const int base_offset = priv->base + 2 * count->id + 1; + unsigned long irqflags; unsigned int ior_cfg; /* Preset enable is active low in Input/Output Control register */ preset_enable = !preset_enable; - mutex_lock(&priv->lock); + spin_lock_irqsave(&priv->lock, irqflags); priv->preset_enable[count->id] = preset_enable; @@ -720,7 +733,7 @@ static int quad8_count_preset_enable_write(struct counter_device *counter, /* Load I/O control configuration to Input / Output Control Register */ outb(QUAD8_CTR_IOR | ior_cfg, base_offset); - mutex_unlock(&priv->lock); + spin_unlock_irqrestore(&priv->lock, irqflags); return 0; } @@ -731,22 +744,23 @@ static int quad8_signal_cable_fault_read(struct counter_device *counter, { struct quad8 *const priv = counter->priv; const size_t channel_id = signal->id / 2; + unsigned long irqflags; bool disabled; unsigned int status; - mutex_lock(&priv->lock); + spin_lock_irqsave(&priv->lock, irqflags); disabled = !(priv->cable_fault_enable & BIT(channel_id)); if (disabled) { - mutex_unlock(&priv->lock); + spin_unlock_irqrestore(&priv->lock, irqflags); return -EINVAL; } /* Logic 0 = cable fault */ status = inb(priv->base + QUAD8_DIFF_ENCODER_CABLE_STATUS); - mutex_unlock(&priv->lock); + spin_unlock_irqrestore(&priv->lock, irqflags); /* Mask respective channel and invert logic */ *cable_fault = !(status & BIT(channel_id)); @@ -772,9 +786,10 @@ static int quad8_signal_cable_fault_enable_write(struct counter_device *counter, { struct quad8 *const priv = counter->priv; const size_t channel_id = signal->id / 2; + unsigned long irqflags; unsigned int cable_fault_enable; - mutex_lock(&priv->lock); + spin_lock_irqsave(&priv->lock, irqflags); if (enable) priv->cable_fault_enable |= BIT(channel_id); @@ -786,7 +801,7 @@ static int quad8_signal_cable_fault_enable_write(struct counter_device *counter, outb(cable_fault_enable, priv->base + QUAD8_DIFF_ENCODER_CABLE_STATUS); - mutex_unlock(&priv->lock); + spin_unlock_irqrestore(&priv->lock, irqflags); return 0; } @@ -809,8 +824,9 @@ static int quad8_signal_fck_prescaler_write(struct counter_device *counter, struct quad8 *const priv = counter->priv; const size_t channel_id = signal->id / 2; const int base_offset = priv->base + 2 * channel_id; + unsigned long irqflags; - mutex_lock(&priv->lock); + spin_lock_irqsave(&priv->lock, irqflags); priv->fck_prescaler[channel_id] = prescaler; @@ -822,7 +838,7 @@ static int quad8_signal_fck_prescaler_write(struct counter_device *counter, outb(QUAD8_CTR_RLD | QUAD8_RLD_RESET_BP | QUAD8_RLD_PRESET_PSC, base_offset + 1); - mutex_unlock(&priv->lock); + spin_unlock_irqrestore(&priv->lock, irqflags); return 0; } @@ -991,8 +1007,7 @@ static int quad8_probe(struct device *dev, unsigned int id) priv->counter.priv = priv; priv->base = base[id]; - /* Initialize mutex */ - mutex_init(&priv->lock); + spin_lock_init(&priv->lock); /* Reset all counters and disable interrupt function */ outb(QUAD8_CHAN_OP_RESET_COUNTERS, base[id] + QUAD8_REG_CHAN_OP); -- cgit v1.2.1