mei: dma ring buffers allocation

Allocate DMA ring buffers from managed coherent memory.

Signed-off-by: Tomas Winkler <tomas.winkler@intel.com>
Signed-off-by: Alexander Usyskin <alexander.usyskin@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/misc/mei/Makefile

@@ -9,6 +9,7 @@ mei-objs += hbm.o
 mei-objs += interrupt.o
 mei-objs += client.o
 mei-objs += main.o
+mei-objs += dma-ring.o
 mei-objs += bus.o
 mei-objs += bus-fixup.o
 mei-$(CONFIG_DEBUG_FS) += debugfs.o

drivers/misc/mei/dma-ring.c

@@ -0,0 +1,99 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright(c) 2016 - 2018 Intel Corporation. All rights reserved.
+ */
+#include <linux/dma-mapping.h>
+#include <linux/mei.h>
+
+#include "mei_dev.h"
+
+/**
+ * mei_dmam_dscr_alloc() - allocate a managed coherent buffer
+ *     for the dma descriptor
+ * @dev: mei_device
+ * @dscr: dma descriptor
+ *
+ * Return:
+ * * 0       - on success or zero allocation request
+ * * -EINVAL - if size is not power of 2
+ * * -ENOMEM - of allocation has failed
+ */
+static int mei_dmam_dscr_alloc(struct mei_device *dev,
+			       struct mei_dma_dscr *dscr)
+{
+	if (!dscr->size)
+		return 0;
+
+	if (WARN_ON(!is_power_of_2(dscr->size)))
+		return -EINVAL;
+
+	if (dscr->vaddr)
+		return 0;
+
+	dscr->vaddr = dmam_alloc_coherent(dev->dev, dscr->size, &dscr->daddr,
+					  GFP_KERNEL);
+	if (!dscr->vaddr)
+		return -ENOMEM;
+
+	return 0;
+}
+
+/**
+ * mei_dmam_dscr_free() - free a managed coherent buffer
+ *     from the dma descriptor
+ * @dev: mei_device
+ * @dscr: dma descriptor
+ */
+static void mei_dmam_dscr_free(struct mei_device *dev,
+			       struct mei_dma_dscr *dscr)
+{
+	if (!dscr->vaddr)
+		return;
+
+	dmam_free_coherent(dev->dev, dscr->size, dscr->vaddr, dscr->daddr);
+	dscr->vaddr = NULL;
+}
+
+/**
+ * mei_dmam_ring_free() - free dma ring buffers
+ * @dev: mei device
+ */
+void mei_dmam_ring_free(struct mei_device *dev)
+{
+	int i;
+
+	for (i = 0; i < DMA_DSCR_NUM; i++)
+		mei_dmam_dscr_free(dev, &dev->dr_dscr[i]);
+}
+
+/**
+ * mei_dmam_ring_alloc() - allocate dma ring buffers
+ * @dev: mei device
+ *
+ * Return: -ENOMEM on allocation failure 0 otherwise
+ */
+int mei_dmam_ring_alloc(struct mei_device *dev)
+{
+	int i;
+
+	for (i = 0; i < DMA_DSCR_NUM; i++)
+		if (mei_dmam_dscr_alloc(dev, &dev->dr_dscr[i]))
+			goto err;
+
+	return 0;
+
+err:
+	mei_dmam_ring_free(dev);
+	return -ENOMEM;
+}
+
+/**
+ * mei_dma_ring_is_allocated() - check if dma ring is allocated
+ * @dev: mei device
+ *
+ * Return: true if dma ring is allocated
+ */
+bool mei_dma_ring_is_allocated(struct mei_device *dev)
+{
+	return !!dev->dr_dscr[DMA_DSCR_HOST].vaddr;
+}

drivers/misc/mei/hw-me.c

@@ -1471,15 +1471,21 @@ struct mei_device *mei_me_dev_init(struct pci_dev *pdev,
 {
 	struct mei_device *dev;
 	struct mei_me_hw *hw;
+	int i;
 
 	dev = devm_kzalloc(&pdev->dev, sizeof(struct mei_device) +
 			   sizeof(struct mei_me_hw), GFP_KERNEL);
 	if (!dev)
 		return NULL;
+
 	hw = to_me_hw(dev);
 
+	for (i = 0; i < DMA_DSCR_NUM; i++)
+		dev->dr_dscr[i].size = cfg->dma_size[i];
+
 	mei_device_init(dev, &pdev->dev, &mei_me_hw_ops);
 	hw->cfg = cfg;
+
 	return dev;
 }
 

drivers/misc/mei/mei_dev.h

@@ -122,6 +122,19 @@ struct mei_msg_data {
 	unsigned char *data;
 };
 
+/**
+ * struct mei_dma_dscr - dma address descriptor
+ *
+ * @vaddr: dma buffer virtual address
+ * @daddr: dma buffer physical address
+ * @size : dma buffer size
+ */
+struct mei_dma_dscr {
+	void *vaddr;
+	dma_addr_t daddr;
+	size_t size;
+};
+
 /* Maximum number of processed FW status registers */
 #define MEI_FW_STATUS_MAX 6
 /* Minimal  buffer for FW status string (8 bytes in dw + space or '\0') */
@@ -409,6 +422,7 @@ struct mei_fw_version {
  * @rd_msg_hdr  : read message header storage
  *
  * @hbuf_is_ready : query if the host host/write buffer is ready
+ * @dr_dscr: DMA ring descriptors: TX, RX, and CTRL
  *
  * @version     : HBM protocol version in use
  * @hbm_f_pg_supported  : hbm feature pgi protocol
@@ -488,6 +502,8 @@ struct mei_device {
 	/* write buffer */
 	bool hbuf_is_ready;
 
+	struct mei_dma_dscr dr_dscr[DMA_DSCR_NUM];
+
 	struct hbm_version version;
 	unsigned int hbm_f_pg_supported:1;
 	unsigned int hbm_f_dc_supported:1;
@@ -578,6 +594,10 @@ int mei_restart(struct mei_device *dev);
 void mei_stop(struct mei_device *dev);
 void mei_cancel_work(struct mei_device *dev);
 
+int mei_dmam_ring_alloc(struct mei_device *dev);
+void mei_dmam_ring_free(struct mei_device *dev);
+bool mei_dma_ring_is_allocated(struct mei_device *dev);
+
 /*
  *  MEI interrupt functions prototype
  */