diff options
Diffstat (limited to 'drivers/soc/tegra/fuse/fuse-tegra20.c')
| -rw-r--r-- | drivers/soc/tegra/fuse/fuse-tegra20.c | 168 |
1 files changed, 168 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..16aaa2857 --- /dev/null +++ b/drivers/soc/tegra/fuse/fuse-tegra20.c @@ -0,0 +1,168 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Copyright (c) 2013-2014, NVIDIA CORPORATION. All rights reserved. + * + * 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_UID_LOW 0x08 +#define FUSE_UID_HIGH 0x0c + +static u32 tegra20_fuse_read_early(struct tegra_fuse *fuse, unsigned int offset) +{ + return readl_relaxed(fuse->base + FUSE_BEGIN + offset); +} + +static void apb_dma_complete(void *args) +{ + struct tegra_fuse *fuse = args; + + complete(&fuse->apbdma.wait); +} + +static u32 tegra20_fuse_read(struct tegra_fuse *fuse, unsigned int offset) +{ + unsigned long flags = DMA_PREP_INTERRUPT | DMA_CTRL_ACK; + struct dma_async_tx_descriptor *dma_desc; + unsigned long time_left; + u32 value = 0; + int err; + + mutex_lock(&fuse->apbdma.lock); + + fuse->apbdma.config.src_addr = fuse->phys + FUSE_BEGIN + offset; + + err = dmaengine_slave_config(fuse->apbdma.chan, &fuse->apbdma.config); + if (err) + goto out; + + dma_desc = dmaengine_prep_slave_single(fuse->apbdma.chan, + fuse->apbdma.phys, + sizeof(u32), DMA_DEV_TO_MEM, + flags); + if (!dma_desc) + goto out; + + dma_desc->callback = apb_dma_complete; + dma_desc->callback_param = fuse; + + reinit_completion(&fuse->apbdma.wait); + + clk_prepare_enable(fuse->clk); + + dmaengine_submit(dma_desc); + dma_async_issue_pending(fuse->apbdma.chan); + time_left = wait_for_completion_timeout(&fuse->apbdma.wait, + msecs_to_jiffies(50)); + + if (WARN(time_left == 0, "apb read dma timed out")) + dmaengine_terminate_all(fuse->apbdma.chan); + else + value = *fuse->apbdma.virt; + + clk_disable_unprepare(fuse->clk); + +out: + mutex_unlock(&fuse->apbdma.lock); + return value; +} + +static bool dma_filter(struct dma_chan *chan, void *filter_param) +{ + struct device_node *np = chan->device->dev->of_node; + + return of_device_is_compatible(np, "nvidia,tegra20-apbdma"); +} + +static int tegra20_fuse_probe(struct tegra_fuse *fuse) +{ + dma_cap_mask_t mask; + + dma_cap_zero(mask); + dma_cap_set(DMA_SLAVE, mask); + + fuse->apbdma.chan = dma_request_channel(mask, dma_filter, NULL); + if (!fuse->apbdma.chan) + return -EPROBE_DEFER; + + fuse->apbdma.virt = dma_alloc_coherent(fuse->dev, sizeof(u32), + &fuse->apbdma.phys, + GFP_KERNEL); + if (!fuse->apbdma.virt) { + dma_release_channel(fuse->apbdma.chan); + return -ENOMEM; + } + + fuse->apbdma.config.src_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES; + fuse->apbdma.config.dst_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES; + fuse->apbdma.config.src_maxburst = 1; + fuse->apbdma.config.dst_maxburst = 1; + fuse->apbdma.config.direction = DMA_DEV_TO_MEM; + fuse->apbdma.config.device_fc = false; + + init_completion(&fuse->apbdma.wait); + mutex_init(&fuse->apbdma.lock); + fuse->read = tegra20_fuse_read; + + return 0; +} + +static const struct tegra_fuse_info tegra20_fuse_info = { + .read = tegra20_fuse_read, + .size = 0x1f8, + .spare = 0x100, +}; + +/* Early boot code. This code is called before the devices are created */ + +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.soc_process_id; + randomness[4] = tegra_sku_info.cpu_speedo_id << 16; + randomness[4] |= tegra_sku_info.soc_speedo_id; + randomness[5] = tegra_fuse_read_early(FUSE_UID_LOW); + randomness[6] = tegra_fuse_read_early(FUSE_UID_HIGH); + + add_device_randomness(randomness, sizeof(randomness)); +} + +static void __init tegra20_fuse_init(struct tegra_fuse *fuse) +{ + fuse->read_early = tegra20_fuse_read_early; + + tegra_init_revision(); + fuse->soc->speedo_init(&tegra_sku_info); + tegra20_fuse_add_randomness(); +} + +const struct tegra_fuse_soc tegra20_fuse_soc = { + .init = tegra20_fuse_init, + .speedo_init = tegra20_init_speedo_data, + .probe = tegra20_fuse_probe, + .info = &tegra20_fuse_info, + .soc_attr_group = &tegra_soc_attr_group, +}; |