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drivers/fsi: Add error handling for slave 

This change implements error handling in the FSI core, by cleaining up
and retrying failed operations, using the SISC, TERM and BREAK
facilities.

Signed-off-by: Jeremy Kerr <jk@ozlabs.org>
Signed-off-by: Christopher Bostic <cbostic@linux.vnet.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
hifive-unleashed-5.1
Jeremy Kerr 2017-06-06 16:08:52 -05:00 committed by Greg Kroah-Hartman
parent 66433b05a3
commit 1fa847d74a
1 changed files with 114 additions and 7 deletions
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121
drivers/fsi/fsi-core.c
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@ -46,7 +46,9 @@ static const int engine_page_size = 0x400;
/*
* FSI slave engine control register offsets
*/
#define FSI_SMODE 0x0 /* R/W: Mode register */
#define FSI_SMODE 0x0 /* R/W: Mode register */
#define FSI_SISC 0x8 /* R/W: Interrupt condition */
#define FSI_SSTAT 0x14 /* R : Slave status */
/*
* SMODE fields
@ -77,10 +79,14 @@ struct fsi_slave {
#define to_fsi_master(d) container_of(d, struct fsi_master, dev)
#define to_fsi_slave(d) container_of(d, struct fsi_slave, dev)
static const int slave_retries = 2;
static int discard_errors;
static int fsi_master_read(struct fsi_master *master, int link,
uint8_t slave_id, uint32_t addr, void *val, size_t size);
static int fsi_master_write(struct fsi_master *master, int link,
uint8_t slave_id, uint32_t addr, const void *val, size_t size);
static int fsi_master_break(struct fsi_master *master, int link);
/*
* fsi_device_read() / fsi_device_write() / fsi_device_peek()
@ -173,18 +179,107 @@ static int fsi_slave_calc_addr(struct fsi_slave *slave, uint32_t *addrp,
return 0;
}
int fsi_slave_report_and_clear_errors(struct fsi_slave *slave)
{
struct fsi_master *master = slave->master;
uint32_t irq, stat;
int rc, link;
uint8_t id;
link = slave->link;
id = slave->id;
rc = fsi_master_read(master, link, id, FSI_SLAVE_BASE + FSI_SISC,
&irq, sizeof(irq));
if (rc)
return rc;
rc = fsi_master_read(master, link, id, FSI_SLAVE_BASE + FSI_SSTAT,
&stat, sizeof(stat));
if (rc)
return rc;
dev_info(&slave->dev, "status: 0x%08x, sisc: 0x%08x\n",
be32_to_cpu(stat), be32_to_cpu(irq));
/* clear interrupts */
return fsi_master_write(master, link, id, FSI_SLAVE_BASE + FSI_SISC,
&irq, sizeof(irq));
}
static int fsi_slave_set_smode(struct fsi_master *master, int link, int id);
int fsi_slave_handle_error(struct fsi_slave *slave, bool write, uint32_t addr,
size_t size)
{
struct fsi_master *master = slave->master;
int rc, link;
uint32_t reg;
uint8_t id;
if (discard_errors)
return -1;
link = slave->link;
id = slave->id;
dev_dbg(&slave->dev, "handling error on %s to 0x%08x[%zd]",
write ? "write" : "read", addr, size);
/* try a simple clear of error conditions, which may fail if we've lost
* communication with the slave
*/
rc = fsi_slave_report_and_clear_errors(slave);
if (!rc)
return 0;
/* send a TERM and retry */
if (master->term) {
rc = master->term(master, link, id);
if (!rc) {
rc = fsi_master_read(master, link, id, 0,
&reg, sizeof(reg));
if (!rc)
rc = fsi_slave_report_and_clear_errors(slave);
if (!rc)
return 0;
}
}
/* 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);
if (rc)
return rc;
return fsi_slave_report_and_clear_errors(slave);
}
int fsi_slave_read(struct fsi_slave *slave, uint32_t addr,
void *val, size_t size)
{
uint8_t id = slave->id;
int rc;
int rc, err_rc, i;
rc = fsi_slave_calc_addr(slave, &addr, &id);
if (rc)
return rc;
return fsi_master_read(slave->master, slave->link, id,
addr, val, size);
for (i = 0; i < slave_retries; i++) {
rc = fsi_master_read(slave->master, slave->link,
id, addr, val, size);
if (!rc)
break;
err_rc = fsi_slave_handle_error(slave, false, addr, size);
if (err_rc)
break;
}
return rc;
}
EXPORT_SYMBOL_GPL(fsi_slave_read);
@ -192,14 +287,24 @@ int fsi_slave_write(struct fsi_slave *slave, uint32_t addr,
const void *val, size_t size)
{
uint8_t id = slave->id;
int rc;
int rc, err_rc, i;
rc = fsi_slave_calc_addr(slave, &addr, &id);
if (rc)
return rc;
return fsi_master_write(slave->master, slave->link, id,
addr, val, size);
for (i = 0; i < slave_retries; i++) {
rc = fsi_master_write(slave->master, slave->link,
id, addr, val, size);
if (!rc)
break;
err_rc = fsi_slave_handle_error(slave, true, addr, size);
if (err_rc)
break;
}
return rc;
}
EXPORT_SYMBOL_GPL(fsi_slave_write);
@ -770,3 +875,5 @@ static void fsi_exit(void)
module_init(fsi_init);
module_exit(fsi_exit);
module_param(discard_errors, int, 0664);
MODULE_PARM_DESC(discard_errors, "Don't invoke error handling on bus accesses");