1 /* 2 * Hardware Random Number Generator support for Cavium Networks 3 * Octeon processor family. 4 * 5 * This file is subject to the terms and conditions of the GNU General Public 6 * License. See the file "COPYING" in the main directory of this archive 7 * for more details. 8 * 9 * Copyright (C) 2009 Cavium Networks 10 */ 11 12 #include <linux/module.h> 13 #include <linux/platform_device.h> 14 #include <linux/device.h> 15 #include <linux/hw_random.h> 16 #include <linux/io.h> 17 #include <linux/gfp.h> 18 19 #include <asm/octeon/octeon.h> 20 #include <asm/octeon/cvmx-rnm-defs.h> 21 22 struct octeon_rng { 23 struct hwrng ops; 24 void __iomem *control_status; 25 void __iomem *result; 26 }; 27 28 static int octeon_rng_init(struct hwrng *rng) 29 { 30 union cvmx_rnm_ctl_status ctl; 31 struct octeon_rng *p = container_of(rng, struct octeon_rng, ops); 32 33 ctl.u64 = 0; 34 ctl.s.ent_en = 1; /* Enable the entropy source. */ 35 ctl.s.rng_en = 1; /* Enable the RNG hardware. */ 36 cvmx_write_csr((u64)p->control_status, ctl.u64); 37 return 0; 38 } 39 40 static void octeon_rng_cleanup(struct hwrng *rng) 41 { 42 union cvmx_rnm_ctl_status ctl; 43 struct octeon_rng *p = container_of(rng, struct octeon_rng, ops); 44 45 ctl.u64 = 0; 46 /* Disable everything. */ 47 cvmx_write_csr((u64)p->control_status, ctl.u64); 48 } 49 50 static int octeon_rng_data_read(struct hwrng *rng, u32 *data) 51 { 52 struct octeon_rng *p = container_of(rng, struct octeon_rng, ops); 53 54 *data = cvmx_read64_uint32((u64)p->result); 55 return sizeof(u32); 56 } 57 58 static int octeon_rng_probe(struct platform_device *pdev) 59 { 60 struct resource *res_ports; 61 struct resource *res_result; 62 struct octeon_rng *rng; 63 int ret; 64 struct hwrng ops = { 65 .name = "octeon", 66 .init = octeon_rng_init, 67 .cleanup = octeon_rng_cleanup, 68 .data_read = octeon_rng_data_read 69 }; 70 71 rng = devm_kzalloc(&pdev->dev, sizeof(*rng), GFP_KERNEL); 72 if (!rng) 73 return -ENOMEM; 74 75 res_ports = platform_get_resource(pdev, IORESOURCE_MEM, 0); 76 if (!res_ports) 77 return -ENOENT; 78 79 res_result = platform_get_resource(pdev, IORESOURCE_MEM, 1); 80 if (!res_result) 81 return -ENOENT; 82 83 84 rng->control_status = devm_ioremap_nocache(&pdev->dev, 85 res_ports->start, 86 sizeof(u64)); 87 if (!rng->control_status) 88 return -ENOENT; 89 90 rng->result = devm_ioremap_nocache(&pdev->dev, 91 res_result->start, 92 sizeof(u64)); 93 if (!rng->result) 94 return -ENOENT; 95 96 rng->ops = ops; 97 98 platform_set_drvdata(pdev, &rng->ops); 99 ret = devm_hwrng_register(&pdev->dev, &rng->ops); 100 if (ret) 101 return -ENOENT; 102 103 dev_info(&pdev->dev, "Octeon Random Number Generator\n"); 104 105 return 0; 106 } 107 108 static struct platform_driver octeon_rng_driver = { 109 .driver = { 110 .name = "octeon_rng", 111 }, 112 .probe = octeon_rng_probe, 113 }; 114 115 module_platform_driver(octeon_rng_driver); 116 117 MODULE_AUTHOR("David Daney"); 118 MODULE_LICENSE("GPL"); 119