From: David Brownell <dbrownell@xxxxxxxxxxxxxxxxxxxxx>
Add TWL4030 infrastructure for shared SIH interrupts.
This is basically what the twl4030 GPIO IRQ code does, but
switching to a workqueue to handle each irqchip's mask/unmask
and set_type operations instead of a kthread that must figure
out what to do each time it wakes up.
Signed-off-by: David Brownell <dbrownell@xxxxxxxxxxxxxxxxxxxxx>
---
drivers/mfd/twl4030-core.c | 2
drivers/mfd/twl4030-irq.c | 322 +++++++++++++++++++++++++++++++++++++++++-
include/linux/i2c/twl4030.h | 2
3 files changed, 323 insertions(+), 3 deletions(-)
--- a/drivers/mfd/twl4030-core.c
+++ b/drivers/mfd/twl4030-core.c
@@ -757,8 +757,6 @@ twl4030_probe(struct i2c_client *client,
status = twl_init_irq(client->irq, pdata->irq_base, pdata->irq_end);
if (status < 0)
goto fail;
- dev_info(&client->dev, "IRQ %d chains IRQs %d..%d\n",
- client->irq, pdata->irq_base, pdata->irq_end - 1);
}
status = add_children(pdata);
--- a/drivers/mfd/twl4030-irq.c
+++ b/drivers/mfd/twl4030-irq.c
@@ -366,6 +366,300 @@ static inline void activate_irq(int irq)
#endif
}
+/*----------------------------------------------------------------------*/
+
+static DEFINE_SPINLOCK(sih_agent_lock);
+
+static struct workqueue_struct *wq;
+
+struct sih_agent {
+ int irq_base;
+ const struct sih *sih;
+
+ u32 imr;
+ bool imr_change_pending;
+ struct work_struct mask_work;
+
+ u32 edge_change;
+ struct work_struct edge_work;
+};
+
+static void twl4030_sih_do_mask(struct work_struct *work)
+{
+ struct sih_agent *agent;
+ const struct sih *sih;
+ union {
+ u8 bytes[4];
+ u32 word;
+ } imr;
+ int status;
+
+ agent = container_of(work, struct sih_agent, mask_work);
+
+ /* see what work we have */
+ spin_lock_irq(&sih_agent_lock);
+ if (agent->imr_change_pending) {
+ sih = agent->sih;
+ /* byte[0] gets overwritten as we write ... */
+ imr.word = cpu_to_le32(agent->imr << 8);
+ agent->imr_change_pending = false;
+ } else
+ sih = NULL;
+ spin_unlock_irq(&sih_agent_lock);
+ if (!sih)
+ return;
+
+ /* write the whole mask ... simpler than subsetting it */
+ status = twl4030_i2c_write(sih->module, imr.bytes,
+ sih->mask[irq_line].imr_offset, sih->bytes_ixr);
+ if (status)
+ pr_err("twl4030: %s, %s --> %d\n", __func__,
+ "write", status);
+}
+
+static void twl4030_sih_do_edge(struct work_struct *work)
+{
+ struct sih_agent *agent;
+ const struct sih *sih;
+ u8 bytes[6];
+ u32 edge_change;
+ int status;
+
+ agent = container_of(work, struct sih_agent, edge_work);
+
+ /* see what work we have */
+ spin_lock_irq(&sih_agent_lock);
+ edge_change = agent->edge_change;
+ agent->edge_change = 0;;
+ sih = edge_change ? agent->sih : NULL;
+ spin_unlock_irq(&sih_agent_lock);
+ if (!sih)
+ return;
+
+ /* Read, reserving first byte for write scratch. Yes, this
+ * could be cached for some speedup ... but be careful about
+ * any processor on the other IRQ line, EDR registers are
+ * shared.
+ */
+ status = twl4030_i2c_read(sih->module, bytes + 1,
+ sih->edr_offset, sih->bytes_edr);
+ if (status) {
+ pr_err("twl4030: %s, %s --> %d\n", __func__,
+ "read", status);
+ return;
+ }
+
+ /* Modify only the bits we know must change */
+ while (edge_change) {
+ int i = fls(edge_change) - 1;
+ struct irq_desc *d = irq_desc + i + agent->irq_base;
+ int byte = 1 + (i >> 2);
+ int off = (i & 0x3) * 2;
+
+ bytes[byte] &= ~(0x03 << off);
+
+ spin_lock_irq(&d->lock);
+ if (d->status & IRQ_TYPE_EDGE_RISING)
+ bytes[byte] |= BIT(off + 1);
+ if (d->status & IRQ_TYPE_EDGE_FALLING)
+ bytes[byte] |= BIT(off + 0);
+ spin_unlock_irq(&d->lock);
+
+ edge_change &= ~BIT(i);
+ }
+
+ /* Write */
+ status = twl4030_i2c_write(sih->module, bytes,
+ sih->edr_offset, sih->bytes_edr);
+ if (status)
+ pr_err("twl4030: %s, %s --> %d\n", __func__,
+ "write", status);
+}
+
+/*----------------------------------------------------------------------*/
+
+/*
+ * All irq_chip methods get issued from code holding irq_desc[irq].lock,
+ * which can't perform the underlying I2C operations (because they sleep).
+ * So we must hand them off to a thread (workqueue) and cope with asynch
+ * completion, potentially including some re-ordering, of these requests.
+ */
+
+static void twl4030_sih_mask(unsigned irq)
+{
+ struct sih_agent *sih = get_irq_chip_data(irq);
+ unsigned long flags;
+
+ spin_lock_irqsave(&sih_agent_lock, flags);
+ sih->imr |= BIT(irq - sih->irq_base);
+ sih->imr_change_pending = true;
+ queue_work(wq, &sih->mask_work);
+ spin_unlock_irqrestore(&sih_agent_lock, flags);
+}
+
+static void twl4030_sih_unmask(unsigned irq)
+{
+ struct sih_agent *sih = get_irq_chip_data(irq);
+ unsigned long flags;
+
+ spin_lock_irqsave(&sih_agent_lock, flags);
+ sih->imr &= ~BIT(irq - sih->irq_base);
+ sih->imr_change_pending = true;
+ queue_work(wq, &sih->mask_work);
+ spin_unlock_irqrestore(&sih_agent_lock, flags);
+}
+
+static int twl4030_sih_set_type(unsigned irq, unsigned trigger)
+{
+ struct sih_agent *sih = get_irq_chip_data(irq);
+ struct irq_desc *desc = irq_desc + irq;
+ unsigned long flags;
+
+ if (trigger & ~(IRQ_TYPE_EDGE_FALLING | IRQ_TYPE_EDGE_RISING))
+ return -EINVAL;
+
+ spin_lock_irqsave(&sih_agent_lock, flags);
+ if ((desc->status & IRQ_TYPE_SENSE_MASK) != trigger) {
+ desc->status &= ~IRQ_TYPE_SENSE_MASK;
+ desc->status |= trigger;
+ sih->edge_change |= BIT(irq - sih->irq_base);
+ queue_work(wq, &sih->edge_work);
+ }
+ spin_unlock_irqrestore(&sih_agent_lock, flags);
+ return 0;
+}
+
+static struct irq_chip twl4030_sih_irq_chip = {
+ .name = "twl4030",
+ .mask = twl4030_sih_mask,
+ .unmask = twl4030_sih_unmask,
+ .set_type = twl4030_sih_set_type,
+};
+
+/*----------------------------------------------------------------------*/
+
+static inline int sih_read_isr(const struct sih *sih)
+{
+ int status;
+ union {
+ u8 bytes[4];
+ u32 word;
+ } isr;
+
+ /* FIXME need retry-on-error ... */
+
+ isr.word = 0;
+ status = twl4030_i2c_read(sih->module, isr.bytes,
+ sih->mask[irq_line].isr_offset, sih->bytes_ixr);
+
+ return (status < 0) ? status : le32_to_cpu(isr.word);
+}
+
+/*
+ * Generic handler for SIH interrupts ... we "know" this is called
+ * in task context, with IRQs enabled.
+ */
+static void handle_twl4030_sih(unsigned irq, struct irq_desc *desc)
+{
+ struct sih_agent *agent = get_irq_data(irq);
+ const struct sih *sih = agent->sih;
+ int isr;
+
+ /* reading ISR acks the IRQs, using clear-on-read mode */
+ local_irq_enable();
+ isr = sih_read_isr(sih);
+ local_irq_disable();
+
+ if (isr < 0) {
+ pr_err("twl4030: %s SIH, read ISR error %d\n",
+ sih->name, isr);
+ /* REVISIT: recover; eventually mask it all, etc */
+ return;
+ }
+
+ while (isr) {
+ irq = fls(isr);
+ irq--;
+ isr &= ~BIT(irq);
+
+ if (irq < sih->bits)
+ generic_handle_irq(agent->irq_base + irq);
+ else
+ pr_err("twl4030: %s SIH, invalid ISR bit %d\n",
+ sih->name, irq);
+ }
+}
+
+static unsigned twl4030_irq_next;
+
+/* returns the first IRQ used by this SIH bank,
+ * or negative errno
+ */
+int twl4030_sih_setup(int module)
+{
+ int sih_mod;
+ const struct sih *sih = NULL;
+ struct sih_agent *agent;
+ int i, irq;
+ int status = -EINVAL;
+ unsigned irq_base = twl4030_irq_next;
+
+ /* only support modules with standard clear-on-read for now */
+ for (sih_mod = 0, sih = sih_modules;
+ sih_mod < ARRAY_SIZE(sih_modules);
+ sih_mod++, sih++) {
+ if (sih->module == module && sih->set_cor) {
+ if (!WARN((irq_base + sih->bits) > NR_IRQS,
+ "irq %d for %s too big\n",
+ irq_base + sih->bits,
+ sih->name))
+ status = 0;
+ break;
+ }
+ }
+ if (status < 0)
+ return status;
+
+ agent = kzalloc(sizeof *agent, GFP_KERNEL);
+ if (!agent)
+ return -ENOMEM;
+
+ status = 0;
+
+ agent->irq_base = irq_base;
+ agent->sih = sih;
+ agent->imr = ~0;
+ INIT_WORK(&agent->mask_work, twl4030_sih_do_mask);
+ INIT_WORK(&agent->edge_work, twl4030_sih_do_edge);
+
+ for (i = 0; i < sih->bits; i++) {
+ irq = irq_base + i;
+
+ set_irq_chip_and_handler(irq, &twl4030_sih_irq_chip,
+ handle_edge_irq);
+ set_irq_chip_data(irq, agent);
+ activate_irq(irq);
+ }
+
+ status = irq_base;
+ twl4030_irq_next += i;
+
+ /* replace generic PIH handler (handle_simple_irq) */
+ irq = sih_mod + twl4030_irq_base;
+ set_irq_data(irq, agent);
+ set_irq_chained_handler(irq, handle_twl4030_sih);
+
+ pr_info("twl4030: %s (irq %d) chaining IRQs %d..%d\n", sih->name,
+ irq, irq_base, twl4030_irq_next - 1);
+
+ return status;
+}
+
+/* FIXME need a call to reverse twl4030_sih_setup() ... */
+
+
+/*----------------------------------------------------------------------*/
+
/* FIXME pass in which interrupt line we'll use ... */
#define twl_irq_line 0
@@ -375,6 +669,7 @@ int twl_init_irq(int irq_num, unsigned i
int status;
int i;
+ struct task_struct *task;
/*
* Mask and clear all TWL4030 interrupts since initially we do
@@ -384,6 +679,12 @@ int twl_init_irq(int irq_num, unsigned i
if (status < 0)
return status;
+ wq = create_singlethread_workqueue("twl4030-irqchip");
+ if (!wq) {
+ pr_err("twl4030: workqueue FAIL\n");
+ return -ESRCH;
+ }
+
twl4030_irq_base = irq_base;
/* install an irq handler for each of the SIH modules;
@@ -392,17 +693,36 @@ int twl_init_irq(int irq_num, unsigned i
twl4030_irq_chip = dummy_irq_chip;
twl4030_irq_chip.name = "twl4030";
+ twl4030_sih_irq_chip.ack = dummy_irq_chip.ack;
+
for (i = irq_base; i < irq_end; i++) {
set_irq_chip_and_handler(i, &twl4030_irq_chip,
handle_simple_irq);
activate_irq(i);
}
+ twl4030_irq_next = i;
+ pr_info("twl4030: %s (irq %d) chaining IRQs %d..%d\n", "PIH",
+ irq_num, irq_base, twl4030_irq_next - 1);
/* install an irq handler to demultiplex the TWL4030 interrupt */
- set_irq_data(irq_num, start_twl4030_irq_thread(irq_num));
+ task = start_twl4030_irq_thread(irq_num);
+ if (!task) {
+ pr_err("twl4030: irq thread FAIL\n");
+ status = -ESRCH;
+ goto fail;
+ }
+
+ set_irq_data(irq_num, task);
set_irq_chained_handler(irq_num, handle_twl4030_pih);
return status;
+
+fail:
+ for (i = irq_base; i < irq_end; i++)
+ set_irq_chip_and_handler(i, NULL, NULL);
+ destroy_workqueue(wq);
+ wq = NULL;
+ return status;
}
int twl_exit_irq(void)
--- a/include/linux/i2c/twl4030.h
+++ b/include/linux/i2c/twl4030.h
@@ -277,6 +277,8 @@ struct twl4030_platform_data {
/*----------------------------------------------------------------------*/
+int twl4030_sih_setup(int module);
+
/*
* FIXME completely stop using TWL4030_IRQ_BASE ... instead, pass the
* IRQ data to subsidiary devices using platform device resources.
--
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