Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
From:   Conor Dooley <conor.dooley@microchip.com>
To:     Jassi Brar <jassisinghbrar@gmail.com>
CC:     Conor Dooley <conor.dooley@microchip.com>,
        Daire McNamara <daire.mcnamara@microchip.com>,
        <linux-riscv@lists.infradead.org>, <linux-kernel@vger.kernel.org>
Subject: [PATCH v2 1/7] mailbox: mpfs: fix an incorrect mask width
Date:   Fri, 20 Jan 2023 14:37:29 +0000
Message-ID: <20230120143734.3438755-2-conor.dooley@microchip.com>
In-Reply-To: <20230120143734.3438755-1-conor.dooley@microchip.com>
References: <20230120143734.3438755-1-conor.dooley@microchip.com>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Content-Type: text/plain
Precedence: bulk

The system controller registers on PolarFire SoC are 32 bits wide, so
16 + 16 as the first input to GENMASK_ULL() gives a 33 bit wide mask.
It probably should have been immediately obvious when it was pointed
out during review that the width required using GENMASK_ULL() - but I
scarcely knew what I was doing at the time and missed it.
The mistake ends up being moot as it is a mask after all, but it is
incorrect and should be fixed.

No functional change intended.

Signed-off-by: Conor Dooley <conor.dooley@microchip.com>
---
 drivers/mailbox/mailbox-mpfs.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/mailbox/mailbox-mpfs.c b/drivers/mailbox/mailbox-mpfs.c
index 853901acaeec..d37560e91116 100644
--- a/drivers/mailbox/mailbox-mpfs.c
+++ b/drivers/mailbox/mailbox-mpfs.c
@@ -39,7 +39,7 @@
 #define SCB_CTRL_NOTIFY_MASK BIT(SCB_CTRL_NOTIFY)
 
 #define SCB_CTRL_POS (16)
-#define SCB_CTRL_MASK GENMASK_ULL(SCB_CTRL_POS + SCB_MASK_WIDTH, SCB_CTRL_POS)
+#define SCB_CTRL_MASK GENMASK(SCB_CTRL_POS + SCB_MASK_WIDTH - 1, SCB_CTRL_POS)
 
 /* SCBCTRL service status register */
 
@@ -118,6 +118,7 @@ static int mpfs_mbox_send_data(struct mbox_chan *chan, void *data)
 	}
 
 	opt_sel = ((msg->mbox_offset << 7u) | (msg->cmd_opcode & 0x7fu));
+
 	tx_trigger = (opt_sel << SCB_CTRL_POS) & SCB_CTRL_MASK;
 	tx_trigger |= SCB_CTRL_REQ_MASK | SCB_STATUS_NOTIFY_MASK;
 	writel_relaxed(tx_trigger, mbox->ctrl_base + SERVICES_CR_OFFSET);
-- 
2.39.0