1 files changed, 144 insertions, 2 deletions

diff --git a/drivers/misc/mei/bus.c b/drivers/misc/mei/bus.c
index 46aa3554e97b..1fbe127ff633 100644
--- a/drivers/misc/mei/bus.c
+++ b/drivers/misc/mei/bus.c
@@ -13,6 +13,7 @@
 #include <linux/slab.h>
 #include <linux/mutex.h>
 #include <linux/interrupt.h>
+#include <linux/scatterlist.h>
 #include <linux/mei_cl_bus.h>
 
 #include "mei_dev.h"
@@ -100,9 +101,18 @@ ssize_t __mei_cl_send(struct mei_cl *cl, const u8 *buf, size_t length, u8 vtag,
 	cb->internal = !!(mode & MEI_CL_IO_TX_INTERNAL);
 	cb->blocking = !!(mode & MEI_CL_IO_TX_BLOCKING);
 	memcpy(cb->buf.data, buf, length);
+	/* hack we point data to header */
+	if (mode & MEI_CL_IO_SGL) {
+		cb->ext_hdr = (struct mei_ext_hdr *)cb->buf.data;
+		cb->buf.data = NULL;
+		cb->buf.size = 0;
+	}
 
 	rets = mei_cl_write(cl, cb);
 
+	if (mode & MEI_CL_IO_SGL && rets == 0)
+		rets = length;
+
 out:
 	mutex_unlock(&bus->device_lock);
 
@@ -205,9 +215,16 @@ copy:
 		goto free;
 	}
 
-	r_length = min_t(size_t, length, cb->buf_idx);
-	memcpy(buf, cb->buf.data, r_length);
+	/* for the GSC type - copy the extended header to the buffer */
+	if (cb->ext_hdr && cb->ext_hdr->type == MEI_EXT_HDR_GSC) {
+		r_length = min_t(size_t, length, cb->ext_hdr->length * sizeof(u32));
+		memcpy(buf, cb->ext_hdr, r_length);
+	} else {
+		r_length = min_t(size_t, length, cb->buf_idx);
+		memcpy(buf, cb->buf.data, r_length);
+	}
 	rets = r_length;
+
 	if (vtag)
 		*vtag = cb->vtag;
 
@@ -823,6 +840,131 @@ out:
 EXPORT_SYMBOL_GPL(mei_cldev_disable);
 
 /**
+ * mei_cldev_send_gsc_command - sends a gsc command, by sending
+ * a gsl mei message to gsc and receiving reply from gsc
+ *
+ * @cldev: me client device
+ * @client_id: client id to send the command to
+ * @fence_id: fence id to send the command to
+ * @sg_in: scatter gather list containing addresses for rx message buffer
+ * @total_in_len: total length of data in 'in' sg, can be less than the sum of buffers sizes
+ * @sg_out: scatter gather list containing addresses for tx message buffer
+ *
+ * Return:
+ *  * written size in bytes
+ *  * < 0 on error
+ */
+ssize_t mei_cldev_send_gsc_command(struct mei_cl_device *cldev,
+				   u8 client_id, u32 fence_id,
+				   struct scatterlist *sg_in,
+				   size_t total_in_len,
+				   struct scatterlist *sg_out)
+{
+	struct mei_cl *cl;
+	struct mei_device *bus;
+	ssize_t ret = 0;
+
+	struct mei_ext_hdr_gsc_h2f *ext_hdr;
+	size_t buf_sz = sizeof(struct mei_ext_hdr_gsc_h2f);
+	int sg_out_nents, sg_in_nents;
+	int i;
+	struct scatterlist *sg;
+	struct mei_ext_hdr_gsc_f2h rx_msg;
+	unsigned int sg_len;
+
+	if (!cldev || !sg_in || !sg_out)
+		return -EINVAL;
+
+	cl = cldev->cl;
+	bus = cldev->bus;
+
+	dev_dbg(bus->dev, "client_id %u, fence_id %u\n", client_id, fence_id);
+
+	if (!bus->hbm_f_gsc_supported)
+		return -EOPNOTSUPP;
+
+	sg_out_nents = sg_nents(sg_out);
+	sg_in_nents = sg_nents(sg_in);
+	/* at least one entry in tx and rx sgls must be present */
+	if (sg_out_nents <= 0 || sg_in_nents <= 0)
+		return -EINVAL;
+
+	buf_sz += (sg_out_nents + sg_in_nents) * sizeof(struct mei_gsc_sgl);
+	ext_hdr = kzalloc(buf_sz, GFP_KERNEL);
+	if (!ext_hdr)
+		return -ENOMEM;
+
+	/* construct the GSC message */
+	ext_hdr->hdr.type = MEI_EXT_HDR_GSC;
+	ext_hdr->hdr.length = buf_sz / sizeof(u32); /* length is in dw */
+
+	ext_hdr->client_id = client_id;
+	ext_hdr->addr_type = GSC_ADDRESS_TYPE_PHYSICAL_SGL;
+	ext_hdr->fence_id = fence_id;
+	ext_hdr->input_address_count = sg_in_nents;
+	ext_hdr->output_address_count = sg_out_nents;
+	ext_hdr->reserved[0] = 0;
+	ext_hdr->reserved[1] = 0;
+
+	/* copy in-sgl to the message */
+	for (i = 0, sg = sg_in; i < sg_in_nents; i++, sg++) {
+		ext_hdr->sgl[i].low = lower_32_bits(sg_dma_address(sg));
+		ext_hdr->sgl[i].high = upper_32_bits(sg_dma_address(sg));
+		sg_len = min_t(unsigned int, sg_dma_len(sg), PAGE_SIZE);
+		ext_hdr->sgl[i].length = (sg_len <= total_in_len) ? sg_len : total_in_len;
+		total_in_len -= ext_hdr->sgl[i].length;
+	}
+
+	/* copy out-sgl to the message */
+	for (i = sg_in_nents, sg = sg_out; i < sg_in_nents + sg_out_nents; i++, sg++) {
+		ext_hdr->sgl[i].low = lower_32_bits(sg_dma_address(sg));
+		ext_hdr->sgl[i].high = upper_32_bits(sg_dma_address(sg));
+		sg_len = min_t(unsigned int, sg_dma_len(sg), PAGE_SIZE);
+		ext_hdr->sgl[i].length = sg_len;
+	}
+
+	/* send the message to GSC */
+	ret = __mei_cl_send(cl, (u8 *)ext_hdr, buf_sz, 0, MEI_CL_IO_SGL);
+	if (ret < 0) {
+		dev_err(bus->dev, "__mei_cl_send failed, returned %zd\n", ret);
+		goto end;
+	}
+	if (ret != buf_sz) {
+		dev_err(bus->dev, "__mei_cl_send returned %zd instead of expected %zd\n",
+			ret, buf_sz);
+		ret = -EIO;
+		goto end;
+	}
+
+	/* receive the reply from GSC, note that at this point sg_in should contain the reply */
+	ret = __mei_cl_recv(cl, (u8 *)&rx_msg, sizeof(rx_msg), NULL, MEI_CL_IO_SGL, 0);
+
+	if (ret != sizeof(rx_msg)) {
+		dev_err(bus->dev, "__mei_cl_recv returned %zd instead of expected %zd\n",
+			ret, sizeof(rx_msg));
+		if (ret >= 0)
+			ret = -EIO;
+		goto end;
+	}
+
+	/* check rx_msg.client_id and rx_msg.fence_id match the ones we send */
+	if (rx_msg.client_id != client_id || rx_msg.fence_id != fence_id) {
+		dev_err(bus->dev, "received client_id/fence_id  %u/%u  instead of %u/%u sent\n",
+			rx_msg.client_id, rx_msg.fence_id, client_id, fence_id);
+		ret = -EFAULT;
+		goto end;
+	}
+
+	dev_dbg(bus->dev, "gsc command: successfully written %u bytes\n",  rx_msg.written);
+	ret = rx_msg.written;
+
+end:
+	kfree(ext_hdr);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(mei_cldev_send_gsc_command);
+
+/**
  * mei_cl_device_find - find matching entry in the driver id table
  *
  * @cldev: me client device