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169 lines
4.4 KiB
169 lines
4.4 KiB
/*
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* Copyright (c) 2013-2014, NVIDIA CORPORATION. All rights reserved.
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms and conditions of the GNU General Public License,
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* version 2, as published by the Free Software Foundation.
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*
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* This program is distributed in the hope it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
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* more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*
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* Based on drivers/misc/eeprom/sunxi_sid.c
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*/
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#include <linux/device.h>
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#include <linux/clk.h>
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#include <linux/completion.h>
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#include <linux/dmaengine.h>
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#include <linux/dma-mapping.h>
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#include <linux/err.h>
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#include <linux/io.h>
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#include <linux/kernel.h>
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#include <linux/kobject.h>
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#include <linux/of_device.h>
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#include <linux/platform_device.h>
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#include <linux/random.h>
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#include <soc/tegra/fuse.h>
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#include "fuse.h"
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#define FUSE_BEGIN 0x100
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#define FUSE_UID_LOW 0x08
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#define FUSE_UID_HIGH 0x0c
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static u32 tegra20_fuse_read_early(struct tegra_fuse *fuse, unsigned int offset)
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{
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return readl_relaxed(fuse->base + FUSE_BEGIN + offset);
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}
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static void apb_dma_complete(void *args)
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{
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struct tegra_fuse *fuse = args;
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complete(&fuse->apbdma.wait);
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}
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static u32 tegra20_fuse_read(struct tegra_fuse *fuse, unsigned int offset)
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{
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unsigned long flags = DMA_PREP_INTERRUPT | DMA_CTRL_ACK;
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struct dma_async_tx_descriptor *dma_desc;
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unsigned long time_left;
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u32 value = 0;
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int err;
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mutex_lock(&fuse->apbdma.lock);
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fuse->apbdma.config.src_addr = fuse->apbdma.phys + FUSE_BEGIN + offset;
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err = dmaengine_slave_config(fuse->apbdma.chan, &fuse->apbdma.config);
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if (err)
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goto out;
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dma_desc = dmaengine_prep_slave_single(fuse->apbdma.chan,
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fuse->apbdma.phys,
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sizeof(u32), DMA_DEV_TO_MEM,
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flags);
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if (!dma_desc)
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goto out;
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dma_desc->callback = apb_dma_complete;
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dma_desc->callback_param = fuse;
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reinit_completion(&fuse->apbdma.wait);
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clk_prepare_enable(fuse->clk);
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dmaengine_submit(dma_desc);
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dma_async_issue_pending(fuse->apbdma.chan);
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time_left = wait_for_completion_timeout(&fuse->apbdma.wait,
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msecs_to_jiffies(50));
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if (WARN(time_left == 0, "apb read dma timed out"))
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dmaengine_terminate_all(fuse->apbdma.chan);
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else
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value = *fuse->apbdma.virt;
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clk_disable_unprepare(fuse->clk);
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out:
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mutex_unlock(&fuse->apbdma.lock);
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return value;
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}
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static int tegra20_fuse_probe(struct tegra_fuse *fuse)
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{
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dma_cap_mask_t mask;
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dma_cap_zero(mask);
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dma_cap_set(DMA_SLAVE, mask);
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fuse->apbdma.chan = dma_request_channel(mask, NULL, NULL);
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if (!fuse->apbdma.chan)
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return -EPROBE_DEFER;
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fuse->apbdma.virt = dma_alloc_coherent(fuse->dev, sizeof(u32),
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&fuse->apbdma.phys,
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GFP_KERNEL);
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if (!fuse->apbdma.virt) {
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dma_release_channel(fuse->apbdma.chan);
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return -ENOMEM;
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}
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fuse->apbdma.config.src_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
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fuse->apbdma.config.dst_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
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fuse->apbdma.config.src_maxburst = 1;
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fuse->apbdma.config.dst_maxburst = 1;
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init_completion(&fuse->apbdma.wait);
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mutex_init(&fuse->apbdma.lock);
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fuse->read = tegra20_fuse_read;
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return 0;
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}
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static const struct tegra_fuse_info tegra20_fuse_info = {
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.read = tegra20_fuse_read,
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.size = 0x1f8,
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.spare = 0x100,
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};
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/* Early boot code. This code is called before the devices are created */
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static void __init tegra20_fuse_add_randomness(void)
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{
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u32 randomness[7];
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randomness[0] = tegra_sku_info.sku_id;
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randomness[1] = tegra_read_straps();
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randomness[2] = tegra_read_chipid();
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randomness[3] = tegra_sku_info.cpu_process_id << 16;
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randomness[3] |= tegra_sku_info.soc_process_id;
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randomness[4] = tegra_sku_info.cpu_speedo_id << 16;
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randomness[4] |= tegra_sku_info.soc_speedo_id;
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randomness[5] = tegra_fuse_read_early(FUSE_UID_LOW);
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randomness[6] = tegra_fuse_read_early(FUSE_UID_HIGH);
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add_device_randomness(randomness, sizeof(randomness));
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}
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static void __init tegra20_fuse_init(struct tegra_fuse *fuse)
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{
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fuse->read_early = tegra20_fuse_read_early;
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tegra_init_revision();
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fuse->soc->speedo_init(&tegra_sku_info);
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tegra20_fuse_add_randomness();
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}
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const struct tegra_fuse_soc tegra20_fuse_soc = {
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.init = tegra20_fuse_init,
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.speedo_init = tegra20_init_speedo_data,
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.probe = tegra20_fuse_probe,
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.info = &tegra20_fuse_info,
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};
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