media: apple: isp: Maybe fix some DMA ordering issues

Maybe.

Signed-off-by: Asahi Lina <lina@asahilina.net>

Author: hoshinolina

drivers/media/platform/apple/isp/isp-fw.c

@@ -338,7 +338,7 @@ static int isp_firmware_boot_stage2(struct apple_isp *isp)
 
 	isp_gpio_write32(isp, ISP_GPIO_0, args_iova);
 	isp_gpio_write32(isp, ISP_GPIO_1, args_iova >> 32);
-	wmb();
+	dma_wmb();
 
 	/* Wait for ISP_GPIO_7 to 0xf7fbdff9 -> 0x8042006 */
 	isp_gpio_write32(isp, ISP_GPIO_7, 0xf7fbdff9);
@@ -500,7 +500,7 @@ static int isp_firmware_boot_stage3(struct apple_isp *isp)
 			memcpy(msg_virt, &msg, sizeof(msg));
 		}
 	}
-	wmb();
+	dma_wmb();
 
 	/* Wait for ISP_GPIO_3 to 0x8042006 -> 0x0 */
 	isp_gpio_write32(isp, ISP_GPIO_3, 0x8042006);

drivers/media/platform/apple/isp/isp-ipc.c

@@ -78,7 +78,14 @@ static inline void chan_write_msg_index(struct apple_isp *isp,
 					struct isp_channel *chan,
 					struct isp_message *msg, u32 index)
 {
-	memcpy(chan_msg_virt(chan, index), msg, sizeof(*msg));
+	u64 *p0 = chan_msg_virt(chan, index);
+	memcpy(p0 + 1, &msg->arg1, sizeof(*msg) - 8);
+
+	/* Make sure we write arg0 last, since that indicates message validity. */
+
+	dma_wmb();
+	*p0 = msg->arg0;
+	dma_wmb();
 }
 
 static inline void chan_write_msg(struct apple_isp *isp,
@@ -164,7 +171,7 @@ int ipc_chan_send(struct apple_isp *isp, struct isp_channel *chan,
 	long t;
 
 	chan_write_msg(isp, chan, &chan->req);
-	wmb();
+	dma_wmb();
 
 	isp_mbox_write32(isp, ISP_MBOX_IRQ_DOORBELL, chan->doorbell);