diff options
Diffstat (limited to 'drivers/soc/tegra/fuse/fuse-tegra20.c')
| -rw-r--r-- | drivers/soc/tegra/fuse/fuse-tegra20.c | 214 |
1 files changed, 214 insertions, 0 deletions
diff --git a/drivers/soc/tegra/fuse/fuse-tegra20.c b/drivers/soc/tegra/fuse/fuse-tegra20.c new file mode 100644 index 000000000..5eff6f097 --- /dev/null +++ b/drivers/soc/tegra/fuse/fuse-tegra20.c @@ -0,0 +1,214 @@ +/* + * Copyright (c) 2013-2014, NVIDIA CORPORATION. All rights reserved. + * + * This program is free software; you can redistribute it and/or modify it + * under the terms and conditions of the GNU General Public License, + * version 2, as published by the Free Software Foundation. + * + * This program is distributed in the hope it will be useful, but WITHOUT + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for + * more details. + * + * You should have received a copy of the GNU General Public License + * along with this program. If not, see <http://www.gnu.org/licenses/>. + * + * Based on drivers/misc/eeprom/sunxi_sid.c + */ + +#include <linux/device.h> +#include <linux/clk.h> +#include <linux/completion.h> +#include <linux/dmaengine.h> +#include <linux/dma-mapping.h> +#include <linux/err.h> +#include <linux/io.h> +#include <linux/kernel.h> +#include <linux/kobject.h> +#include <linux/of_device.h> +#include <linux/platform_device.h> +#include <linux/random.h> + +#include <soc/tegra/fuse.h> + +#include "fuse.h" + +#define FUSE_BEGIN 0x100 +#define FUSE_SIZE 0x1f8 +#define FUSE_UID_LOW 0x08 +#define FUSE_UID_HIGH 0x0c + +static phys_addr_t fuse_phys; +static struct clk *fuse_clk; +static void __iomem __initdata *fuse_base; + +static DEFINE_MUTEX(apb_dma_lock); +static DECLARE_COMPLETION(apb_dma_wait); +static struct dma_chan *apb_dma_chan; +static struct dma_slave_config dma_sconfig; +static u32 *apb_buffer; +static dma_addr_t apb_buffer_phys; + +static void apb_dma_complete(void *args) +{ + complete(&apb_dma_wait); +} + +static u32 tegra20_fuse_readl(const unsigned int offset) +{ + int ret; + u32 val = 0; + struct dma_async_tx_descriptor *dma_desc; + + mutex_lock(&apb_dma_lock); + + dma_sconfig.src_addr = fuse_phys + FUSE_BEGIN + offset; + ret = dmaengine_slave_config(apb_dma_chan, &dma_sconfig); + if (ret) + goto out; + + dma_desc = dmaengine_prep_slave_single(apb_dma_chan, apb_buffer_phys, + sizeof(u32), DMA_DEV_TO_MEM, + DMA_PREP_INTERRUPT | DMA_CTRL_ACK); + if (!dma_desc) + goto out; + + dma_desc->callback = apb_dma_complete; + dma_desc->callback_param = NULL; + + reinit_completion(&apb_dma_wait); + + clk_prepare_enable(fuse_clk); + + dmaengine_submit(dma_desc); + dma_async_issue_pending(apb_dma_chan); + ret = wait_for_completion_timeout(&apb_dma_wait, msecs_to_jiffies(50)); + + if (WARN(ret == 0, "apb read dma timed out")) + dmaengine_terminate_all(apb_dma_chan); + else + val = *apb_buffer; + + clk_disable_unprepare(fuse_clk); +out: + mutex_unlock(&apb_dma_lock); + + return val; +} + +static const struct of_device_id tegra20_fuse_of_match[] = { + { .compatible = "nvidia,tegra20-efuse" }, + {}, +}; + +static int apb_dma_init(void) +{ + dma_cap_mask_t mask; + + dma_cap_zero(mask); + dma_cap_set(DMA_SLAVE, mask); + apb_dma_chan = dma_request_channel(mask, NULL, NULL); + if (!apb_dma_chan) + return -EPROBE_DEFER; + + apb_buffer = dma_alloc_coherent(NULL, sizeof(u32), &apb_buffer_phys, + GFP_KERNEL); + if (!apb_buffer) { + dma_release_channel(apb_dma_chan); + return -ENOMEM; + } + + dma_sconfig.src_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES; + dma_sconfig.dst_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES; + dma_sconfig.src_maxburst = 1; + dma_sconfig.dst_maxburst = 1; + + return 0; +} + +static int tegra20_fuse_probe(struct platform_device *pdev) +{ + struct resource *res; + int err; + + fuse_clk = devm_clk_get(&pdev->dev, NULL); + if (IS_ERR(fuse_clk)) { + dev_err(&pdev->dev, "missing clock"); + return PTR_ERR(fuse_clk); + } + + res = platform_get_resource(pdev, IORESOURCE_MEM, 0); + if (!res) + return -EINVAL; + fuse_phys = res->start; + + err = apb_dma_init(); + if (err) + return err; + + if (tegra_fuse_create_sysfs(&pdev->dev, FUSE_SIZE, tegra20_fuse_readl)) + return -ENODEV; + + dev_dbg(&pdev->dev, "loaded\n"); + + return 0; +} + +static struct platform_driver tegra20_fuse_driver = { + .probe = tegra20_fuse_probe, + .driver = { + .name = "tegra20_fuse", + .of_match_table = tegra20_fuse_of_match, + } +}; + +static int __init tegra20_fuse_init(void) +{ + return platform_driver_register(&tegra20_fuse_driver); +} +postcore_initcall(tegra20_fuse_init); + +/* Early boot code. This code is called before the devices are created */ + +u32 __init tegra20_fuse_early(const unsigned int offset) +{ + return readl_relaxed(fuse_base + FUSE_BEGIN + offset); +} + +bool __init tegra20_spare_fuse_early(int spare_bit) +{ + u32 offset = spare_bit * 4; + bool value; + + value = tegra20_fuse_early(offset + 0x100); + + return value; +} + +static void __init tegra20_fuse_add_randomness(void) +{ + u32 randomness[7]; + + randomness[0] = tegra_sku_info.sku_id; + randomness[1] = tegra_read_straps(); + randomness[2] = tegra_read_chipid(); + randomness[3] = tegra_sku_info.cpu_process_id << 16; + randomness[3] |= tegra_sku_info.core_process_id; + randomness[4] = tegra_sku_info.cpu_speedo_id << 16; + randomness[4] |= tegra_sku_info.soc_speedo_id; + randomness[5] = tegra20_fuse_early(FUSE_UID_LOW); + randomness[6] = tegra20_fuse_early(FUSE_UID_HIGH); + + add_device_randomness(randomness, sizeof(randomness)); +} + +void __init tegra20_init_fuse_early(void) +{ + fuse_base = ioremap(TEGRA_FUSE_BASE, TEGRA_FUSE_SIZE); + + tegra_init_revision(); + tegra20_init_speedo_data(&tegra_sku_info); + tegra20_fuse_add_randomness(); + + iounmap(fuse_base); +} |