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Subject[PATCH 20/21] X86_64, UV: Remove Obsolete GRU MMR address translation
From: Dimitri Sivanich <sivanich@sgi.com>

Use no-op messages in place of cross-partition interrupts when nacking a
put message in the GRU. This allows us to remove MMR's as a destination
from the GRU driver.

Signed-off-by: Dimitri Sivanich <sivanich@sgi.com>
Signed-off-by: Mike Travis <travis@sgi.com>
Tested-by: John Estabrook <estabrook@sgi.com>
Tested-by: Gary Kroening <gfk@sgi.com>
---
arch/x86/include/asm/uv/uv_hub.h | 10 ----------
drivers/misc/sgi-gru/grukservices.c | 36 ++++++++++++++++++++----------------
2 files changed, 20 insertions(+), 26 deletions(-)

--- linux.orig/arch/x86/include/asm/uv/uv_hub.h
+++ linux/arch/x86/include/asm/uv/uv_hub.h
@@ -642,16 +642,6 @@ static inline unsigned long uv_read_glob
return readq(uv_global_mmr64_address(pnode, offset));
}

-/*
- * Global MMR space addresses when referenced by the GRU. (GRU does
- * NOT use socket addressing).
- */
-static inline unsigned long uv_global_gru_mmr_address(int pnode, unsigned long offset)
-{
- return UV_GLOBAL_GRU_MMR_BASE | offset |
- ((unsigned long)pnode << uv_hub_info->m_val);
-}
-
static inline void uv_write_global_mmr8(int pnode, unsigned long offset, unsigned char val)
{
writeb(val, uv_global_mmr64_address(pnode, offset));
--- linux.orig/drivers/misc/sgi-gru/grukservices.c
+++ linux/drivers/misc/sgi-gru/grukservices.c
@@ -718,8 +718,8 @@ cberr:
static int send_message_put_nacked(void *cb, struct gru_message_queue_desc *mqd,
void *mesg, int lines)
{
- unsigned long m, *val = mesg, gpa, save;
- int ret;
+ unsigned long m;
+ int ret, loops = 200; /* experimentally determined */

m = mqd->mq_gpa + (gru_get_amo_value_head(cb) << 6);
if (lines == 2) {
@@ -735,22 +735,26 @@ static int send_message_put_nacked(void
return MQE_OK;

/*
- * Send a cross-partition interrupt to the SSI that contains the target
- * message queue. Normally, the interrupt is automatically delivered by
- * hardware but some error conditions require explicit delivery.
- * Use the GRU to deliver the interrupt. Otherwise partition failures
+ * Send a noop message in order to deliver a cross-partition interrupt
+ * to the SSI that contains the target message queue. Normally, the
+ * interrupt is automatically delivered by hardware following mesq
+ * operations, but some error conditions require explicit delivery.
+ * The noop message will trigger delivery. Otherwise partition failures
* could cause unrecovered errors.
*/
- gpa = uv_global_gru_mmr_address(mqd->interrupt_pnode, UVH_IPI_INT);
- save = *val;
- *val = uv_hub_ipi_value(mqd->interrupt_apicid, mqd->interrupt_vector,
- dest_Fixed);
- gru_vstore_phys(cb, gpa, gru_get_tri(mesg), IAA_REGISTER, IMA);
- ret = gru_wait(cb);
- *val = save;
- if (ret != CBS_IDLE)
- return MQE_UNEXPECTED_CB_ERR;
- return MQE_OK;
+ do {
+ ret = send_noop_message(cb, mqd, mesg);
+ } while ((ret == MQIE_AGAIN || ret == MQE_CONGESTION) && (loops-- > 0));
+
+ if (ret == MQIE_AGAIN || ret == MQE_CONGESTION) {
+ /* Don't indicate to the app to resend the message, as it's */
+ /* already been successfully sent. We simply send an OK */
+ /* (rather than fail the send with MQE_UNEXPECTED_CB_ERR), */
+ /* assuming that the other side is receiving enough */
+ /* interrupts to get this message processed anyway. */
+ ret = MQE_OK;
+ }
+ return ret;
}

/*
--

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