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fsi: Add mechanism to set the tSendDelay and tEchoDelay values 

Those values control the amount of "dummy" clocks between commands and
between a command and its response.

This adds a way to configure them from sysfs (to be later extended to
defaults in the device-tree). The default remains 16 (the HW default).

This is only supported if the backend supports the new link_config()
callback to configure the generation of those delays.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Reviewed-by: Joel Stanley <joel@jms.id.au>
---
hifive-unleashed-5.1
Benjamin Herrenschmidt 2018-05-29 15:01:07 +10:00
parent 935f963638
commit a2e7da86cc
2 changed files with 93 additions and 18 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

109
drivers/fsi/fsi-core.c
View File

@ -81,6 +81,8 @@ struct fsi_slave {
int id;
int link;
uint32_t size; /* size of slave address space */
u8 t_send_delay;
u8 t_echo_delay;
};
#define to_fsi_master(d) container_of(d, struct fsi_master, dev)
@ -239,15 +241,15 @@ static inline uint32_t fsi_smode_sid(int x)
return (x & FSI_SMODE_SID_MASK) << FSI_SMODE_SID_SHIFT;
}
static uint32_t fsi_slave_smode(int id)
static uint32_t fsi_slave_smode(int id, u8 t_senddly, u8 t_echodly)
{
return FSI_SMODE_WSC | FSI_SMODE_ECRC
| fsi_smode_sid(id)
| fsi_smode_echodly(0xf) | fsi_smode_senddly(0xf)
| fsi_smode_echodly(t_echodly - 1) | fsi_smode_senddly(t_senddly - 1)
| fsi_smode_lbcrr(0x8);
}
static int fsi_slave_set_smode(struct fsi_master *master, int link, int id)
static int fsi_slave_set_smode(struct fsi_slave *slave)
{
uint32_t smode;
__be32 data;
@ -255,11 +257,12 @@ static int fsi_slave_set_smode(struct fsi_master *master, int link, int id)
/* set our smode register with the slave ID field to 0; this enables
* extended slave addressing
*/
smode = fsi_slave_smode(id);
smode = fsi_slave_smode(slave->id, slave->t_send_delay, slave->t_echo_delay);
data = cpu_to_be32(smode);
return fsi_master_write(master, link, id, FSI_SLAVE_BASE + FSI_SMODE,
&data, sizeof(data));
return fsi_master_write(slave->master, slave->link, slave->id,
FSI_SLAVE_BASE + FSI_SMODE,
&data, sizeof(data));
}
static int fsi_slave_handle_error(struct fsi_slave *slave, bool write,
@ -268,7 +271,7 @@ static int fsi_slave_handle_error(struct fsi_slave *slave, bool write,
struct fsi_master *master = slave->master;
int rc, link;
uint32_t reg;
uint8_t id;
uint8_t id, send_delay, echo_delay;
if (discard_errors)
return -1;
@ -299,15 +302,26 @@ static int fsi_slave_handle_error(struct fsi_slave *slave, bool write,
}
}
send_delay = slave->t_send_delay;
echo_delay = slave->t_echo_delay;
/* getting serious, reset the slave via BREAK */
rc = fsi_master_break(master, link);
if (rc)
return rc;
rc = fsi_slave_set_smode(master, link, id);
slave->t_send_delay = send_delay;
slave->t_echo_delay = echo_delay;
rc = fsi_slave_set_smode(slave);
if (rc)
return rc;
if (master->link_config)
master->link_config(master, link,
slave->t_send_delay,
slave->t_echo_delay);
return fsi_slave_report_and_clear_errors(slave);
}
@ -659,6 +673,50 @@ static struct device_node *fsi_slave_find_of_node(struct fsi_master *master,
return NULL;
}
static ssize_t slave_send_echo_show(struct device *dev,
struct device_attribute *attr,
char *buf)
{
struct fsi_slave *slave = to_fsi_slave(dev);
return sprintf(buf, "%u\n", slave->t_send_delay);
}
static ssize_t slave_send_echo_store(struct device *dev,
struct device_attribute *attr, const char *buf, size_t count)
{
struct fsi_slave *slave = to_fsi_slave(dev);
struct fsi_master *master = slave->master;
unsigned long val;
int rc;
if (kstrtoul(buf, 0, &val) < 0)
return -EINVAL;
if (val < 1 || val > 16)
return -EINVAL;
if (!master->link_config)
return -ENXIO;
/* Current HW mandates that send and echo delay are identical */
slave->t_send_delay = val;
slave->t_echo_delay = val;
rc = fsi_slave_set_smode(slave);
if (rc < 0)
return rc;
if (master->link_config)
master->link_config(master, slave->link,
slave->t_send_delay,
slave->t_echo_delay);
return count;
}
static DEVICE_ATTR(send_echo_delays, 0600,
slave_send_echo_show, slave_send_echo_store);
static int fsi_slave_init(struct fsi_master *master, int link, uint8_t id)
{
uint32_t chip_id;
@ -691,14 +749,6 @@ static int fsi_slave_init(struct fsi_master *master, int link, uint8_t id)
dev_dbg(&master->dev, "fsi: found chip %08x at %02x:%02x:%02x\n",
chip_id, master->idx, link, id);
rc = fsi_slave_set_smode(master, link, id);
if (rc) {
dev_warn(&master->dev,
"can't set smode on slave:%02x:%02x %d\n",
link, id, rc);
return -ENODEV;
}
/* If we're behind a master that doesn't provide a self-running bus
* clock, put the slave into async mode
*/
@ -727,6 +777,21 @@ static int fsi_slave_init(struct fsi_master *master, int link, uint8_t id)
slave->link = link;
slave->id = id;
slave->size = FSI_SLAVE_SIZE_23b;
slave->t_send_delay = 16;
slave->t_echo_delay = 16;
rc = fsi_slave_set_smode(slave);
if (rc) {
dev_warn(&master->dev,
"can't set smode on slave:%02x:%02x %d\n",
link, id, rc);
kfree(slave);
return -ENODEV;
}
if (master->link_config)
master->link_config(master, link,
slave->t_send_delay,
slave->t_echo_delay);
dev_set_name(&slave->dev, "slave@%02x:%02x", link, id);
rc = device_register(&slave->dev);
@ -745,6 +810,10 @@ static int fsi_slave_init(struct fsi_master *master, int link, uint8_t id)
if (rc)
dev_warn(&slave->dev, "failed to create term attr: %d\n", rc);
rc = device_create_file(&slave->dev, &dev_attr_send_echo_delays);
if (rc)
dev_warn(&slave->dev, "failed to create delay attr: %d\n", rc);
rc = fsi_slave_scan(slave);
if (rc)
dev_dbg(&master->dev, "failed during slave scan with: %d\n",
@ -815,12 +884,16 @@ static int fsi_master_link_enable(struct fsi_master *master, int link)
*/
static int fsi_master_break(struct fsi_master *master, int link)
{
int rc = 0;
trace_fsi_master_break(master, link);
if (master->send_break)
return master->send_break(master, link);
rc = master->send_break(master, link);
if (master->link_config)
master->link_config(master, link, 16, 16);
return 0;
return rc;
}
static int fsi_master_scan(struct fsi_master *master)

2
drivers/fsi/fsi-master.h
View File

@ -33,6 +33,8 @@ struct fsi_master {
int (*term)(struct fsi_master *, int link, uint8_t id);
int (*send_break)(struct fsi_master *, int link);
int (*link_enable)(struct fsi_master *, int link);
int (*link_config)(struct fsi_master *, int link,
u8 t_send_delay, u8 t_echo_delay);
};
#define dev_to_fsi_master(d) container_of(d, struct fsi_master, dev)