[PATCH] powerpc: Enable support for 32 bit MSI-X vectors

From: Brian King <brking@linux.vnet.ibm.com>
To: linuxppc-dev@lists.ozlabs.org
Cc: Brian King <brking@linux.vnet.ibm.com>,
	brking@pobox.com, drc@linux.vnet.ibm.com
Subject: [PATCH] powerpc: Enable support for 32 bit MSI-X vectors
Date: Wed, 17 Jan 2024 15:46:32 -0600	[thread overview]
Message-ID: <20240117214632.134539-1-brking@linux.vnet.ibm.com> (raw)

Some devices are not capable of addressing 64 bits
via DMA, which includes MSI-X vectors. This allows
us to ensure these devices use MSI-X vectors in
32 bit space.

Signed-off-by: Brian King <brking@linux.vnet.ibm.com>
---
 arch/powerpc/platforms/pseries/msi.c | 11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/arch/powerpc/platforms/pseries/msi.c b/arch/powerpc/platforms/pseries/msi.c
index 423ee1d5bd94..6dfb55b52d36 100644
--- a/arch/powerpc/platforms/pseries/msi.c
+++ b/arch/powerpc/platforms/pseries/msi.c
@@ -26,6 +26,7 @@ static int query_token, change_token;
 #define RTAS_CHANGE_MSI_FN	3
 #define RTAS_CHANGE_MSIX_FN	4
 #define RTAS_CHANGE_32MSI_FN	5
+#define RTAS_CHANGE_32MSIX_FN	6
 
 /* RTAS Helpers */
 
@@ -41,7 +42,7 @@ static int rtas_change_msi(struct pci_dn *pdn, u32 func, u32 num_irqs)
 	seq_num = 1;
 	do {
 		if (func == RTAS_CHANGE_MSI_FN || func == RTAS_CHANGE_MSIX_FN ||
-		    func == RTAS_CHANGE_32MSI_FN)
+		    func == RTAS_CHANGE_32MSI_FN || func == RTAS_CHANGE_32MSIX_FN)
 			rc = rtas_call(change_token, 6, 4, rtas_ret, addr,
 					BUID_HI(buid), BUID_LO(buid),
 					func, num_irqs, seq_num);
@@ -406,8 +407,12 @@ static int rtas_prepare_msi_irqs(struct pci_dev *pdev, int nvec_in, int type,
 
 		if (use_32bit_msi_hack && rc > 0)
 			rtas_hack_32bit_msi_gen2(pdev);
-	} else
-		rc = rtas_change_msi(pdn, RTAS_CHANGE_MSIX_FN, nvec);
+	} else {
+		if (pdev->no_64bit_msi)
+			rc = rtas_change_msi(pdn, RTAS_CHANGE_32MSIX_FN, nvec);
+		else
+			rc = rtas_change_msi(pdn, RTAS_CHANGE_MSIX_FN, nvec);
+	}
 
 	if (rc != nvec) {
 		if (nvec != nvec_in) {
-- 
2.39.3

