bus: mhi: host: allow MHI client drivers to provide the firmware via a pointer

Currently MHI loads the firmware image from the path provided by client
devices. ath11k needs to support firmware image embedded along with meta
data (named as firmware-2.bin). So allow the client driver to request the
firmware file from user space on it's own and provide the firmware image
data and size to MHI via a pointer struct mhi_controller::fw_data.

This is an optional feature, if fw_data is NULL MHI load the firmware using
the name from struct mhi_controller::fw_image string as before.

Tested with ath11k and WCN6855 hw2.0.

Signed-off-by: Kalle Valo <[e-mail]>
Reviewed-by: Manivannan Sadhasivam <[e-mail]>
Reviewed-by: Jeffrey Hugo <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
[mani: wrapped commit message to 75 columns]
Signed-off-by: Manivannan Sadhasivam <[e-mail]>

drivers/bus/mhi/host/boot.c

···
 }
 
 static void mhi_firmware_copy(struct mhi_controller *mhi_cntrl,
-			      const struct firmware *firmware,
+			      const u8 *buf, size_t remainder,
 			      struct image_info *img_info)
 {
-	size_t remainder = firmware->size;
 	size_t to_cpy;
-	const u8 *buf = firmware->data;
 	struct mhi_buf *mhi_buf = img_info->mhi_buf;
 	struct bhi_vec_entry *bhi_vec = img_info->bhi_vec;
 
···
 	struct device *dev = &mhi_cntrl->mhi_dev->dev;
 	enum mhi_pm_state new_state;
 	const char *fw_name;
+	const u8 *fw_data;
 	void *buf;
 	dma_addr_t dma_addr;
-	size_t size;
+	size_t size, fw_sz;
 	int i, ret;
 
 	if (MHI_PM_IN_ERROR_STATE(mhi_cntrl->pm_state)) {
···
 	fw_name = (mhi_cntrl->ee == MHI_EE_EDL) ?
 		mhi_cntrl->edl_image : mhi_cntrl->fw_image;
 
+	/* check if the driver has already provided the firmware data */
+	if (!fw_name && mhi_cntrl->fbc_download &&
+	    mhi_cntrl->fw_data && mhi_cntrl->fw_sz) {
+		if (!mhi_cntrl->sbl_size) {
+			dev_err(dev, "fw_data provided but no sbl_size\n");
+			goto error_fw_load;
+		}
+
+		size = mhi_cntrl->sbl_size;
+		fw_data = mhi_cntrl->fw_data;
+		fw_sz = mhi_cntrl->fw_sz;
+		goto skip_req_fw;
+	}
+
 	if (!fw_name || (mhi_cntrl->fbc_download && (!mhi_cntrl->sbl_size ||
 						     !mhi_cntrl->seg_len))) {
 		dev_err(dev,
···
 	if (size > firmware->size)
 		size = firmware->size;
 
+	fw_data = firmware->data;
+	fw_sz = firmware->size;
+
+skip_req_fw:
 	buf = dma_alloc_coherent(mhi_cntrl->cntrl_dev, size, &dma_addr,
 				 GFP_KERNEL);
 	if (!buf) {
···
 	}
 
 	/* Download image using BHI */
-	memcpy(buf, firmware->data, size);
+	memcpy(buf, fw_data, size);
 	ret = mhi_fw_load_bhi(mhi_cntrl, dma_addr, size);
 	dma_free_coherent(mhi_cntrl->cntrl_dev, size, buf, dma_addr);
 
···
 	}
 
 	/* Wait for ready since EDL image was loaded */
-	if (fw_name == mhi_cntrl->edl_image) {
+	if (fw_name && fw_name == mhi_cntrl->edl_image) {
 		release_firmware(firmware);
 		goto fw_load_ready_state;
 	}
···
 	 * device transitioning into MHI READY state
 	 */
 	if (mhi_cntrl->fbc_download) {
-		ret = mhi_alloc_bhie_table(mhi_cntrl, &mhi_cntrl->fbc_image,
-					   firmware->size);
+		ret = mhi_alloc_bhie_table(mhi_cntrl, &mhi_cntrl->fbc_image, fw_sz);
 		if (ret) {
 			release_firmware(firmware);
 			goto error_fw_load;
 		}
 
 		/* Load the firmware into BHIE vec table */
-		mhi_firmware_copy(mhi_cntrl, firmware, mhi_cntrl->fbc_image);
+		mhi_firmware_copy(mhi_cntrl, fw_data, fw_sz, mhi_cntrl->fbc_image);
 	}
 
 	release_firmware(firmware);

include/linux/mhi.h

···
  * @iova_start: IOMMU starting address for data (required)
  * @iova_stop: IOMMU stop address for data (required)
  * @fw_image: Firmware image name for normal booting (optional)
+ * @fw_data: Firmware image data content for normal booting, used only
+ *           if fw_image is NULL and fbc_download is true (optional)
+ * @fw_sz: Firmware image data size for normal booting, used only if fw_image
+ *         is NULL and fbc_download is true (optional)
  * @edl_image: Firmware image name for emergency download mode (optional)
  * @rddm_size: RAM dump size that host should allocate for debugging purpose
  * @sbl_size: SBL image size downloaded through BHIe (optional)
···
 	dma_addr_t iova_start;
 	dma_addr_t iova_stop;
 	const char *fw_image;
+	const u8 *fw_data;
+	size_t fw_sz;
 	const char *edl_image;
 	size_t rddm_size;
 	size_t sbl_size;