[PATCH] drivers/fsi: Add slave interrupt polling
Christopher Bostic
cbostic at linux.vnet.ibm.com
Thu Feb 2 09:22:01 AEDT 2017
Scan slaves present for asserting interrupt signals in the si1s
register and call a registered client's interrupt handler as
appropriate.
Signed-off-by: Eddie James <eajames at us.ibm.com>
Signed-off-by: Christopher Bostic <cbostic at linux.vnet.ibm.com>
---
drivers/fsi/fsi-core.c | 99 +++++++++++++++++++++++++++++++++++++++++++
drivers/fsi/fsi-master-gpio.c | 1 +
drivers/fsi/fsi-master.h | 2 +
include/linux/fsi.h | 5 +++
4 files changed, 107 insertions(+)
diff --git a/drivers/fsi/fsi-core.c b/drivers/fsi/fsi-core.c
index 72e0ca3..4df7218 100644
--- a/drivers/fsi/fsi-core.c
+++ b/drivers/fsi/fsi-core.c
@@ -15,11 +15,15 @@
#include <linux/device.h>
#include <linux/fsi.h>
+#include <linux/kthread.h>
#include <linux/module.h>
#include <linux/slab.h>
+#include <linux/jiffies.h>
#include "fsi-master.h"
+#define DEBUG
+
#define FSI_N_SLAVES 4
#define FSI_SLAVE_CONF_NEXT_MASK 0x80000000
@@ -36,7 +40,11 @@
#define FSI_PEEK_BASE 0x410
#define FSI_SLAVE_BASE 0x800
+#define FSI_IPOLL_PERIOD msecs_to_jiffies(fsi_ipoll_period_ms)
+
static const int engine_page_size = 0x400;
+static struct task_struct *master_ipoll;
+static unsigned int fsi_ipoll_period_ms = 100;
static atomic_t master_idx = ATOMIC_INIT(-1);
@@ -60,6 +68,8 @@ static int fsi_slave_write(struct fsi_slave *slave, uint32_t addr,
* FSI slave engine control register offsets
*/
#define FSI_SMODE 0x0 /* R/W: Mode register */
+#define FSI_SI1M 0x18 /* R/W: IRQ mask */
+#define FSI_SI1S 0x1C /* R: IRQ status */
/*
* SMODE fields
@@ -197,6 +207,7 @@ static int fsi_slave_scan(struct fsi_slave *slave)
uint32_t engine_addr;
uint32_t conf;
int rc, i;
+ uint8_t si1s_bit = 1;
INIT_LIST_HEAD(&slave->my_engines);
@@ -253,6 +264,7 @@ static int fsi_slave_scan(struct fsi_slave *slave)
dev->unit = i;
dev->addr = engine_addr;
dev->size = slots * engine_page_size;
+ dev->si1s_bit = si1s_bit++;
dev_info(&slave->dev,
"engine[%i]: type %x, version %x, addr %x size %x\n",
@@ -507,6 +519,56 @@ static void fsi_master_unscan(struct fsi_master *master)
master->slave_list = false;
}
+static void fsi_master_irq(struct fsi_master *master, int link, uint32_t si1s)
+{
+ struct fsi_slave *slave;
+ struct fsi_device *fsi_dev;
+
+ if (list_empty(&master->my_slaves))
+ return;
+
+ slave = list_first_entry(&master->my_slaves, struct fsi_slave,
+ list_link);
+
+ list_for_each_entry(fsi_dev, &slave->my_engines, link) {
+ if (si1s & (0x80000000 >> fsi_dev->si1s_bit) &&
+ fsi_dev->irq_handler)
+ fsi_dev->irq_handler(0, &fsi_dev->dev);
+ }
+}
+
+static int fsi_master_ipoll(void *data)
+{
+ int rc;
+ uint32_t si1s;
+ unsigned long elapsed = 0;
+ unsigned long previous_jiffies = jiffies;
+ struct fsi_master *master = data;
+
+ while (!kthread_should_stop()) {
+ if (!master->ipoll)
+ goto done;
+
+ /* Ignore errors for now */
+ rc = master->read(master, 0, 0, FSI_SLAVE_BASE + FSI_SI1S,
+ &si1s, sizeof(uint32_t));
+ if (rc)
+ goto done;
+
+ if (si1s & master->ipoll)
+ fsi_master_irq(master, 0, si1s);
+done:
+ elapsed = jiffies - previous_jiffies;
+ if (elapsed < FSI_IPOLL_PERIOD) {
+ set_current_state(TASK_UNINTERRUPTIBLE);
+ schedule_timeout(FSI_IPOLL_PERIOD - elapsed);
+ }
+ previous_jiffies = jiffies;
+ }
+
+ return 0;
+}
+
int fsi_master_register(struct fsi_master *master)
{
if (!master || !master->dev)
@@ -524,9 +586,36 @@ void fsi_master_unregister(struct fsi_master *master)
{
fsi_master_unscan(master);
put_device(master->dev);
+ if (master_ipoll) {
+ kthread_stop(master_ipoll);
+ master_ipoll = NULL;
+ }
}
EXPORT_SYMBOL_GPL(fsi_master_unregister);
+/*
+ * TODO: move this to master->start_ipoll( ) -each master may have its
+ * own way of doing this
+ */
+int fsi_master_start_ipoll(struct fsi_master *master)
+{
+ if (master_ipoll) {
+ dev_err(master->dev, "Already polling for irqs\n");
+ return -EALREADY;
+ }
+ master_ipoll = kthread_create(fsi_master_ipoll, master,
+ "fsi_master_ipoll");
+ if (IS_ERR(master_ipoll)) {
+ dev_err(master->dev, "Couldn't create ipoll thread rc:%d\n",
+ (int)PTR_ERR(master_ipoll));
+ return PTR_ERR(master_ipoll);
+ }
+ wake_up_process(master_ipoll);
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(fsi_master_start_ipoll);
+
/* FSI core & Linux bus type definitions */
static int fsi_bus_match(struct device *dev, struct device_driver *drv)
@@ -566,6 +655,16 @@ void fsi_driver_unregister(struct fsi_driver *fsi_drv)
}
EXPORT_SYMBOL_GPL(fsi_driver_unregister);
+int fsi_enable_irq(struct fsi_device *dev)
+{
+ return 0;
+}
+EXPORT_SYMBOL_GPL(fsi_enable_irq);
+
+void fsi_disable_irq(struct fsi_device *dev)
+{
+}
+
struct bus_type fsi_bus_type = {
.name = "fsi",
.match = fsi_bus_match,
diff --git a/drivers/fsi/fsi-master-gpio.c b/drivers/fsi/fsi-master-gpio.c
index 83c7cf0..73d9985 100644
--- a/drivers/fsi/fsi-master-gpio.c
+++ b/drivers/fsi/fsi-master-gpio.c
@@ -457,6 +457,7 @@ static ssize_t store_scan(struct device *dev,
/* clear out any old scan data if present */
fsi_master_unregister(&master->master);
fsi_master_register(&master->master);
+ fsi_master_start_ipoll(&master->master);
return count;
}
diff --git a/drivers/fsi/fsi-master.h b/drivers/fsi/fsi-master.h
index 454af2b..3737404 100644
--- a/drivers/fsi/fsi-master.h
+++ b/drivers/fsi/fsi-master.h
@@ -25,6 +25,7 @@ struct fsi_master {
struct device *dev;
int idx;
int n_links;
+ uint32_t ipoll;
int (*read)(struct fsi_master *, int link,
uint8_t slave, uint32_t addr,
void *val, size_t size);
@@ -37,6 +38,7 @@ struct fsi_master {
extern int fsi_master_register(struct fsi_master *master);
extern void fsi_master_unregister(struct fsi_master *master);
+extern int fsi_master_start_ipoll(struct fsi_master *master);
/**
* crc4 helper: Given a starting crc4 state @c, calculate the crc4 vaue of @x,
diff --git a/include/linux/fsi.h b/include/linux/fsi.h
index 2721255..d22d0c5 100644
--- a/include/linux/fsi.h
+++ b/include/linux/fsi.h
@@ -23,9 +23,11 @@ struct fsi_device {
u8 engine_type;
u8 version;
u8 unit;
+ u8 si1s_bit;
struct fsi_slave *slave;
uint32_t addr;
uint32_t size;
+ int (*irq_handler)(int, void *);
};
extern int fsi_device_read(struct fsi_device *dev, uint32_t addr,
@@ -69,4 +71,7 @@ extern void fsi_driver_unregister(struct fsi_driver *);
extern struct bus_type fsi_bus_type;
+extern int fsi_enable_irq(struct fsi_device *dev);
+extern void fsi_disable_irq(struct fsi_device *dev);
+
#endif /* LINUX_FSI_H */
--
1.8.2.2
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