--- /dev/null
+/*
+ * 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);
+}
Code Review / kvmfornfv.git / blobdiff