1 /*
2  * VFIO platform driver specialized for Calxeda xgmac reset
3  * reset code is inherited from calxeda xgmac native driver
4  *
5  * Copyright 2010-2011 Calxeda, Inc.
6  * Copyright (c) 2015 Linaro Ltd.
7  *              www.linaro.org
8  *
9  * This program is free software; you can redistribute it and/or modify it
10  * under the terms and conditions of the GNU General Public License,
11  * version 2, as published by the Free Software Foundation.
12  *
13  * This program is distributed in the hope it will be useful, but WITHOUT
14  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
15  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
16  * more details.
17  *
18  * You should have received a copy of the GNU General Public License along with
19  * this program.  If not, see <http://www.gnu.org/licenses/>.
20  */
21 
22 #include <linux/module.h>
23 #include <linux/kernel.h>
24 #include <linux/init.h>
25 #include <linux/io.h>
26 
27 #include "vfio_platform_private.h"
28 
29 #define DRIVER_VERSION  "0.1"
30 #define DRIVER_AUTHOR   "Eric Auger <eric.auger@linaro.org>"
31 #define DRIVER_DESC     "Reset support for Calxeda xgmac vfio platform device"
32 
33 #define CALXEDAXGMAC_COMPAT "calxeda,hb-xgmac"
34 
35 /* XGMAC Register definitions */
36 #define XGMAC_CONTROL           0x00000000      /* MAC Configuration */
37 
38 /* DMA Control and Status Registers */
39 #define XGMAC_DMA_CONTROL       0x00000f18      /* Ctrl (Operational Mode) */
40 #define XGMAC_DMA_INTR_ENA      0x00000f1c      /* Interrupt Enable */
41 
42 /* DMA Control registe defines */
43 #define DMA_CONTROL_ST          0x00002000      /* Start/Stop Transmission */
44 #define DMA_CONTROL_SR          0x00000002      /* Start/Stop Receive */
45 
46 /* Common MAC defines */
47 #define MAC_ENABLE_TX           0x00000008      /* Transmitter Enable */
48 #define MAC_ENABLE_RX           0x00000004      /* Receiver Enable */
49 
50 static inline void xgmac_mac_disable(void __iomem *ioaddr)
51 {
52 	u32 value = readl(ioaddr + XGMAC_DMA_CONTROL);
53 
54 	value &= ~(DMA_CONTROL_ST | DMA_CONTROL_SR);
55 	writel(value, ioaddr + XGMAC_DMA_CONTROL);
56 
57 	value = readl(ioaddr + XGMAC_CONTROL);
58 	value &= ~(MAC_ENABLE_TX | MAC_ENABLE_RX);
59 	writel(value, ioaddr + XGMAC_CONTROL);
60 }
61 
62 int vfio_platform_calxedaxgmac_reset(struct vfio_platform_device *vdev)
63 {
64 	struct vfio_platform_region reg = vdev->regions[0];
65 
66 	if (!reg.ioaddr) {
67 		reg.ioaddr =
68 			ioremap_nocache(reg.addr, reg.size);
69 		if (!reg.ioaddr)
70 			return -ENOMEM;
71 	}
72 
73 	/* disable IRQ */
74 	writel(0, reg.ioaddr + XGMAC_DMA_INTR_ENA);
75 
76 	/* Disable the MAC core */
77 	xgmac_mac_disable(reg.ioaddr);
78 
79 	return 0;
80 }
81 EXPORT_SYMBOL_GPL(vfio_platform_calxedaxgmac_reset);
82 
83 MODULE_VERSION(DRIVER_VERSION);
84 MODULE_LICENSE("GPL v2");
85 MODULE_AUTHOR(DRIVER_AUTHOR);
86 MODULE_DESCRIPTION(DRIVER_DESC);
87