On Thu, Apr 07, 2016 at 04:28:26PM +1000, Russell Currey wrote:
>In the "ibm,configure-pe" and "ibm,configure-bridge" RTAS calls, the
>spec states that values of 9900-9905 can be returned, indicating that
>software should delay for 10^x (where x is the last digit, i.e. 990x)
>milliseconds and attempt the call again. Currently, the kernel doesn't
>know about this, and respecting it fixes some PCI failures when the
>hypervisor is busy.
>
>The delay is capped at 0.2 seconds.
>
>Cc: <sta...@vger.kernel.org> # 3.10+
>Signed-off-by: Russell Currey <rus...@russell.cc>
Acked-by: Gavin Shan <gws...@linux.vnet.ibm.com>
>---
>V3 changelog:
> - Refactorings and rewordings thanks to Gavin
> - Treat return values >9902 as 9902 thanks to Tyrel
>---
> arch/powerpc/platforms/pseries/eeh_pseries.c | 51 ++++++++++++++++++++--------
> 1 file changed, 36 insertions(+), 15 deletions(-)
>
>diff --git a/arch/powerpc/platforms/pseries/eeh_pseries.c
>b/arch/powerpc/platforms/pseries/eeh_pseries.c
>index ac3ffd9..405baaf 100644
>--- a/arch/powerpc/platforms/pseries/eeh_pseries.c
>+++ b/arch/powerpc/platforms/pseries/eeh_pseries.c
>@@ -615,29 +615,50 @@ static int pseries_eeh_configure_bridge(struct eeh_pe
>*pe)
> {
> int config_addr;
> int ret;
>+ /* Waiting 0.2s maximum before skipping configuration */
>+ int max_wait = 200;
>
> /* Figure out the PE address */
> config_addr = pe->config_addr;
> if (pe->addr)
> config_addr = pe->addr;
>
>- /* Use new configure-pe function, if supported */
>- if (ibm_configure_pe != RTAS_UNKNOWN_SERVICE) {
>- ret = rtas_call(ibm_configure_pe, 3, 1, NULL,
>- config_addr, BUID_HI(pe->phb->buid),
>- BUID_LO(pe->phb->buid));
>- } else if (ibm_configure_bridge != RTAS_UNKNOWN_SERVICE) {
>- ret = rtas_call(ibm_configure_bridge, 3, 1, NULL,
>- config_addr, BUID_HI(pe->phb->buid),
>- BUID_LO(pe->phb->buid));
>- } else {
>- return -EFAULT;
>- }
>+ while (max_wait > 0) {
>+ /* Use new configure-pe function, if supported */
>+ if (ibm_configure_pe != RTAS_UNKNOWN_SERVICE) {
>+ ret = rtas_call(ibm_configure_pe, 3, 1, NULL,
>+ config_addr, BUID_HI(pe->phb->buid),
>+ BUID_LO(pe->phb->buid));
>+ } else if (ibm_configure_bridge != RTAS_UNKNOWN_SERVICE) {
>+ ret = rtas_call(ibm_configure_bridge, 3, 1, NULL,
>+ config_addr, BUID_HI(pe->phb->buid),
>+ BUID_LO(pe->phb->buid));
>+ } else {
>+ return -EFAULT;
>+ }
>
>- if (ret)
>- pr_warn("%s: Unable to configure bridge PHB#%d-PE#%x (%d)\n",
>- __func__, pe->phb->global_number, pe->addr, ret);
>+ if (!ret)
>+ return ret;
>+
>+ /*
>+ * If RTAS returns a delay value that's above 100ms, cut it
>+ * down to 100ms in case firmware made a mistake. For more
>+ * on how these delay values work see rtas_busy_delay_time
>+ */
>+ if (ret > RTAS_EXTENDED_DELAY_MIN+2 &&
>+ ret <= RTAS_EXTENDED_DELAY_MAX)
>+ ret = RTAS_EXTENDED_DELAY_MIN+2;
>+
>+ max_wait -= rtas_busy_delay_time(ret);
>+
>+ if (max_wait < 0)
>+ break;
>+
>+ rtas_busy_delay(ret);
>+ }
>
>+ pr_warn("%s: Unable to configure bridge PHB#%d-PE#%x (%d)\n",
>+ __func__, pe->phb->global_number, pe->addr, ret);
> return ret;
> }
>
>--
>2.8.0
>
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