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MIPS: CPS: Warn if a core doesn't start 

When debugging core bringup it is useful to see the state of the CPC
sequencer, so output that value if the core hasn't started within a
reasonable amount of time (1 second). This avoids simply appearing to
the user to hang if a secondary core fails to start.

Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Andrew Bresticker <abrestic@chromium.org>
Cc: linux-kernel@vger.kernel.org
Cc: Niklas Cassel <niklas.cassel@axis.com>
Cc: Ezequiel Garcia <ezequiel.garcia@imgtec.com>
Cc: Markos Chandras <markos.chandras@imgtec.com>
Patchwork: https://patchwork.linux-mips.org/patch/11205/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
This commit is contained in:
Paul Burton 2015-09-22 11:12:14 -07:00 committed by Ralf Baechle
parent 192fbc2025
commit a8c20614b0
1 changed files with 25 additions and 1 deletions
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26
arch/mips/kernel/smp-cps.c
View File

@ -8,6 +8,7 @@
* option) any later version.
*/
#include <linux/delay.h>
#include <linux/io.h>
#include <linux/irqchip/mips-gic.h>
#include <linux/sched.h>
@ -188,7 +189,8 @@ static void __init cps_prepare_cpus(unsigned int max_cpus)
static void boot_core(unsigned core)
{
u32 access;
u32 access, stat, seq_state;
unsigned timeout;
/* Select the appropriate core */
write_gcr_cl_other(core << CM_GCR_Cx_OTHER_CORENUM_SHF);
@ -208,6 +210,28 @@ static void boot_core(unsigned core)
/* Reset the core */
mips_cpc_lock_other(core);
write_cpc_co_cmd(CPC_Cx_CMD_RESET);
timeout = 100;
while (true) {
stat = read_cpc_co_stat_conf();
seq_state = stat & CPC_Cx_STAT_CONF_SEQSTATE_MSK;
/* U6 == coherent execution, ie. the core is up */
if (seq_state == CPC_Cx_STAT_CONF_SEQSTATE_U6)
break;
/* Delay a little while before we start warning */
if (timeout) {
timeout--;
mdelay(10);
continue;
}
pr_warn("Waiting for core %u to start... STAT_CONF=0x%x\n",
core, stat);
mdelay(1000);
}
mips_cpc_unlock_other();
} else {
/* Take the core out of reset */