[Skiboot] [PATCH v4 4/8] phb4/capp: Update and re-factor phb4_set_capi_mode()

[Vaibhav Jain]

Presently phb4_set_capi_mode() performs certain CAPP checks
like, checking of CAPP ucode loaded or checks if CAPP is still in
recovery, even when the requested mode is to switch to PCI mode.

Hence this patch updates and re-factors phb4_set_capi_mode() to make
sure CAPP related checks are only performed when request to enable
CAPP is made by mode==OPAL_PHB_CAPI_MODE_CAPI/DMA_TVT1. We also update
other possible modes requests to return a more appropriate status code
based on if CAPP is activated or not.

Reviewed-by: Andrew Donnellan <andrew.donnellan at au1.ibm.com>
Reviewed-by: Christophe Lombard <clombard at linux.vnet.ibm.com>
Signed-off-by: Vaibhav Jain <vaibhav at linux.ibm.com>
---
Change-log

v4:
* None. Respinning the patchset.

v3:
* Updated the code to use capp_xscom_read() instead of xscom_read().

* Moved the check for CAPP recovery in progress from MODE_CAPI/DMA to
  all CAPP mode switch requests. This preserves existing behaviour
  expected by CX5 driver. [ Christophe ]

* Fixed a minor spelling. [ Andrew ]

v2
* Using 'struct capp* instead of global 'capi_lock' to indicate that
  CAPP is now attached to a PHB [Andrew] Code formatting that removed
  the use of a confusing tertiary operator. [Andrew]
---
 hw/phb4.c | 88 +++++++++++++++++++++++++++++++++----------------------
 1 file changed, 53 insertions(+), 35 deletions(-)

diff --git a/hw/phb4.c b/hw/phb4.c
index a0431d4f..e712b230 100644
--- a/hw/phb4.c
+++ b/hw/phb4.c
@@ -4441,54 +4441,72 @@ static int64_t phb4_set_capi_mode(struct phb *phb, uint64_t mode,
 	struct proc_chip *chip = get_chip(p->chip_id);
 	struct capp *capp = p->capp;
 	uint64_t reg, ret;
-	uint32_t offset;
-
-	if (capp == NULL)
-		return OPAL_UNSUPPORTED;
 
-	if (!capp_ucode_loaded(chip, p->index)) {
-		PHBERR(p, "CAPP: ucode not loaded\n");
-		return OPAL_RESOURCE;
-	}
-
-	/* mark the capp attached to the phb */
-	capp->phb = phb;
-	capp->attached_pe = pe_number;
+	/* cant do a mode switch when capp is in recovery mode */
+	ret = capp_xscom_read(capp, CAPP_ERR_STATUS_CTRL, &reg);
+	if (ret != OPAL_SUCCESS)
+		return ret;
 
-	offset = PHB4_CAPP_REG_OFFSET(p);
-	xscom_read(p->chip_id, CAPP_ERR_STATUS_CTRL + offset, &reg);
-	if ((reg & PPC_BIT(5))) {
-		PHBERR(p, "CAPP: recovery failed (%016llx)\n", reg);
-		return OPAL_HARDWARE;
-	} else if ((reg & PPC_BIT(0)) && (!(reg & PPC_BIT(1)))) {
+	if ((reg & PPC_BIT(0)) && (!(reg & PPC_BIT(1)))) {
 		PHBDBG(p, "CAPP: recovery in progress\n");
 		return OPAL_BUSY;
 	}
 
+
 	switch (mode) {
-	case OPAL_PHB_CAPI_MODE_CAPI:
-		ret = enable_capi_mode(p, pe_number,
-					CAPP_MAX_STQ_ENGINES |
-					CAPP_MIN_DMA_READ_ENGINES);
-		disable_fast_reboot("CAPP being enabled");
+
+	case OPAL_PHB_CAPI_MODE_DMA: /* Enabled by default on p9 */
+	case OPAL_PHB_CAPI_MODE_SNOOP_ON:
+		/* nothing to do on P9 if CAPP is already enabled */
+		ret = p->capp->phb ? OPAL_SUCCESS : OPAL_UNSUPPORTED;
 		break;
-	case OPAL_PHB_CAPI_MODE_DMA_TVT1:
-		ret = enable_capi_mode(p, pe_number,
-					CAPP_MIN_STQ_ENGINES |
-					CAPP_MAX_DMA_READ_ENGINES);
-		disable_fast_reboot("CAPP being enabled");
+
+	case OPAL_PHB_CAPI_MODE_SNOOP_OFF:
+	case OPAL_PHB_CAPI_MODE_PCIE: /* Not supported at the moment */
+		ret = p->capp->phb ? OPAL_UNSUPPORTED : OPAL_SUCCESS;
 		break;
-	case OPAL_PHB_CAPI_MODE_SNOOP_ON:
-		/* nothing to do P9 if CAPP is alreay enabled */
-		ret = OPAL_SUCCESS;
+
+	case OPAL_PHB_CAPI_MODE_CAPI: /* Fall Through */
+	case OPAL_PHB_CAPI_MODE_DMA_TVT1:
+		/* Check if ucode is available */
+		if (!capp_ucode_loaded(chip, p->index)) {
+			PHBERR(p, "CAPP: ucode not loaded\n");
+			ret = OPAL_RESOURCE;
+			break;
+		}
+
+		/*
+		 * Mark the CAPP attached to the PHB right away so that
+		 * if a MCE happens during CAPP init we can handle it.
+		 * In case of an error in CAPP init we remove the PHB
+		 * from the attached_mask later.
+		 */
+		capp->phb = phb;
+		capp->attached_pe = pe_number;
+
+		if (mode == OPAL_PHB_CAPI_MODE_DMA_TVT1)
+			ret = enable_capi_mode(p, pe_number,
+					       CAPP_MIN_STQ_ENGINES |
+					       CAPP_MAX_DMA_READ_ENGINES);
+
+		else
+			ret = enable_capi_mode(p, pe_number,
+					       CAPP_MAX_STQ_ENGINES |
+					       CAPP_MIN_DMA_READ_ENGINES);
+		if (ret == OPAL_SUCCESS) {
+			/* Disable fast reboot for CAPP */
+			disable_fast_reboot("CAPP being enabled");
+		} else {
+			/* In case of an error mark the PHB detached */
+			capp->phb = NULL;
+			capp->attached_pe = phb4_get_reserved_pe_number(phb);
+		}
 		break;
 
-	case OPAL_PHB_CAPI_MODE_PCIE: /* shouldn't be called on p9*/
-	case OPAL_PHB_CAPI_MODE_DMA: /* Enabled by default on p9 */
-	case OPAL_PHB_CAPI_MODE_SNOOP_OFF: /* shouldn't be called on p9*/
 	default:
 		ret = OPAL_UNSUPPORTED;
-	}
+		break;
+	};
 
 	return ret;
 }
-- 
2.20.1