はじめに
の続きとして、
Google Tensor G2 の Edge TPU のデバイスドライバからわかったこと！(その2)
その1の後半で取り上げて、GXP のデバイスドライバのソースコードも眺めてみたら、もう少しわかったことがありました。
GXP のソースコード
Google Tensor G2 の Edge TPU (janeiro) の下記のmailbox の部分にあった、EXT_DSP_MAILBOXES がありました。
#define EDGETPU_NUM_VII_MAILBOXES 7 #define EDGETPU_NUM_P2P_MAILBOXES 0 #define EDGETPU_NUM_EXT_DSP_MAILBOXES 4 #define EDGETPU_NUM_EXT_AOC_MAILBOXES 1 #define EDGETPU_NUM_EXT_MAILBOXES (EDGETPU_NUM_EXT_DSP_MAILBOXES + EDGETPU_NUM_EXT_AOC_MAILBOXES) #define EDGETPU_NUM_MAILBOXES (EDGETPU_NUM_VII_MAILBOXES + EDGETPU_NUM_EXT_MAILBOXES + 1)
これに対して、GXP の gxp.h の中に下記のようなコードを見つけました。
struct gxp_tpu_mbx_queue_ioctl { __u32 tpu_fd; /* TPU virtual device group fd */ /* * Bitfield indicating which virtual cores to allocate and map the * buffers for. * To map for virtual core X, set bit X in this field, i.e. `1 << X`. * * This field is not used by the unmap IOCTL, which always unmaps the * buffers for all cores it had been mapped for. */ __u32 virtual_core_list; /* * The user address of an edgetpu_mailbox_attr struct, containing * cmd/rsp queue size, mailbox priority and other relevant info. * This structure is defined in edgetpu.h in the TPU driver. */ __u64 attr_ptr; }; /* * Map TPU-DSP mailbox cmd/rsp queue buffers. * * The client must have allocated a virtual device. */ #define GXP_MAP_TPU_MBX_QUEUE \ _IOW(GXP_IOCTL_BASE, 13, struct gxp_tpu_mbx_queue_ioctl) /* * Un-map TPU-DSP mailbox cmd/rsp queue buffers previously mapped by * GXP_MAP_TPU_MBX_QUEUE. * * Only the @tpu_fd field will be used. Other fields will be fetched * from the kernel's internal records. It is recommended to use the argument * that was passed in GXP_MAP_TPU_MBX_QUEUE to un-map the buffers. * * The client must have allocated a virtual device. */ #define GXP_UNMAP_TPU_MBX_QUEUE \ _IOW(GXP_IOCTL_BASE, 14, struct gxp_tpu_mbx_queue_ioctl)
また、gxp-platform.c にも、TPUというコードがあります。
#if (IS_ENABLED(CONFIG_GXP_TEST) || IS_ENABLED(CONFIG_ANDROID)) && !IS_ENABLED(CONFIG_GXP_GEM5) #include <soc/google/tpu-ext.h> #endif
edgetpu_ext_driver_cmd コマンドを使っています。
static int gxp_map_tpu_mbx_queue(struct gxp_client *client, struct gxp_tpu_mbx_queue_ioctl __user *argp) { #if (IS_ENABLED(CONFIG_GXP_TEST) || IS_ENABLED(CONFIG_ANDROID)) && !IS_ENABLED(CONFIG_GXP_GEM5) struct gxp_dev *gxp = client->gxp; struct edgetpu_ext_mailbox_info *mbx_info; struct gxp_tpu_mbx_queue_ioctl ibuf; struct edgetpu_ext_client_info gxp_tpu_info; u32 phys_core_list = 0; u32 virtual_core_list; u32 core_count; int ret = 0; if (!gxp->tpu_dev.mbx_paddr) { dev_err(gxp->dev, "%s: TPU is not available for interop\n", __func__); return -EINVAL; } if (copy_from_user(&ibuf, argp, sizeof(ibuf))) return -EFAULT; down_write(&client->semaphore); if (!check_client_has_available_vd(client, "GXP_MAP_TPU_MBX_QUEUE")) { ret = -ENODEV; goto out_unlock_client_semaphore; } down_read(&gxp->vd_semaphore); virtual_core_list = ibuf.virtual_core_list; core_count = hweight_long(virtual_core_list); phys_core_list = gxp_vd_virt_core_list_to_phys_core_list( client->vd, virtual_core_list); if (!phys_core_list) { dev_err(gxp->dev, "%s: invalid virtual core list 0x%x\n", __func__, virtual_core_list); ret = -EINVAL; goto out; } mbx_info = kmalloc(sizeof(struct edgetpu_ext_mailbox_info) + core_count * sizeof(struct edgetpu_ext_mailbox_descriptor), GFP_KERNEL); if (!mbx_info) { ret = -ENOMEM; goto out; } if (client->tpu_file) { dev_err(gxp->dev, "Mappings already exist for TPU mailboxes"); ret = -EBUSY; goto out_free; } gxp_tpu_info.tpu_fd = ibuf.tpu_fd; gxp_tpu_info.mbox_map = phys_core_list; gxp_tpu_info.attr = (struct edgetpu_mailbox_attr __user *)ibuf.attr_ptr; ret = edgetpu_ext_driver_cmd(gxp->tpu_dev.dev, EDGETPU_EXTERNAL_CLIENT_TYPE_DSP, ALLOCATE_EXTERNAL_MAILBOX, &gxp_tpu_info, mbx_info); if (ret) { dev_err(gxp->dev, "Failed to allocate ext TPU mailboxes %d", ret); goto out_free; } /* * If someone is attacking us through this interface - * it's possible that ibuf.tpu_fd here is already a different file from * the one passed to edgetpu_ext_driver_cmd() (if the runtime closes the * FD and opens another file exactly between the TPU driver call above * and the fget below). * But the worst consequence of this attack is we fget() ourselves (GXP * FD), which only leads to memory leak (because the file object has a * reference to itself). The race is also hard to hit so we don't insist * on preventing it. */ client->tpu_file = fget(ibuf.tpu_fd); if (!client->tpu_file) { edgetpu_ext_driver_cmd(gxp->tpu_dev.dev, EDGETPU_EXTERNAL_CLIENT_TYPE_DSP, FREE_EXTERNAL_MAILBOX, &gxp_tpu_info, NULL); ret = -EINVAL; goto out_free; } /* Align queue size to page size for iommu map. */ mbx_info->cmdq_size = ALIGN(mbx_info->cmdq_size, PAGE_SIZE); mbx_info->respq_size = ALIGN(mbx_info->respq_size, PAGE_SIZE); ret = gxp_dma_map_tpu_buffer(gxp, client->vd, virtual_core_list, phys_core_list, mbx_info); if (ret) { dev_err(gxp->dev, "Failed to map TPU mailbox buffer %d", ret); fput(client->tpu_file); client->tpu_file = NULL; edgetpu_ext_driver_cmd(gxp->tpu_dev.dev, EDGETPU_EXTERNAL_CLIENT_TYPE_DSP, FREE_EXTERNAL_MAILBOX, &gxp_tpu_info, NULL); goto out_free; } client->mbx_desc.phys_core_list = phys_core_list; client->mbx_desc.virt_core_list = virtual_core_list; client->mbx_desc.cmdq_size = mbx_info->cmdq_size; client->mbx_desc.respq_size = mbx_info->respq_size; out_free: kfree(mbx_info); out: up_read(&gxp->vd_semaphore); out_unlock_client_semaphore: up_write(&client->semaphore); return ret; #else return -ENODEV; #endif } static int gxp_unmap_tpu_mbx_queue(struct gxp_client *client, struct gxp_tpu_mbx_queue_ioctl __user *argp) { #if (IS_ENABLED(CONFIG_GXP_TEST) || IS_ENABLED(CONFIG_ANDROID)) && !IS_ENABLED(CONFIG_GXP_GEM5) struct gxp_dev *gxp = client->gxp; struct gxp_tpu_mbx_queue_ioctl ibuf; struct edgetpu_ext_client_info gxp_tpu_info; int ret = 0; if (copy_from_user(&ibuf, argp, sizeof(ibuf))) return -EFAULT; down_write(&client->semaphore); if (!client->vd) { dev_err(gxp->dev, "GXP_UNMAP_TPU_MBX_QUEUE requires the client allocate a VIRTUAL_DEVICE\n"); ret = -ENODEV; goto out; } if (!client->tpu_file) { dev_err(gxp->dev, "No mappings exist for TPU mailboxes"); ret = -EINVAL; goto out; } gxp_dma_unmap_tpu_buffer(gxp, client->vd, client->mbx_desc); gxp_tpu_info.tpu_fd = ibuf.tpu_fd; edgetpu_ext_driver_cmd(gxp->tpu_dev.dev, EDGETPU_EXTERNAL_CLIENT_TYPE_DSP, FREE_EXTERNAL_MAILBOX, &gxp_tpu_info, NULL); fput(client->tpu_file); client->tpu_file = NULL; out: up_write(&client->semaphore); return ret; #else return -ENODEV; #endif }
static int gxp_platform_probe(struct platform_device *pdev) の中で TPU を使っています。tpu-device がデバイス名のようです。tpu-device から reg から tpu mailbox のレジスタのベースアドレスを見つけています。
tpu_found = true; /* Get TPU device from device tree */ np = of_parse_phandle(dev->of_node, "tpu-device", 0); if (IS_ERR_OR_NULL(np)) { dev_warn(dev, "No tpu-device in device tree\n"); tpu_found = false; } tpu_pdev = of_find_device_by_node(np); if (!tpu_pdev) { dev_err(dev, "TPU device not found\n"); tpu_found = false; } /* get tpu mailbox register base */ ret = of_property_read_u64_index(np, "reg", 0, &base_addr); of_node_put(np); if (ret) { dev_warn(dev, "Unable to get tpu-device base address\n"); tpu_found = false; } /* get gxp-tpu mailbox register offset */ ret = of_property_read_u64(dev->of_node, "gxp-tpu-mbx-offset", &offset); if (ret) { dev_warn(dev, "Unable to get tpu-device mailbox offset\n"); tpu_found = false; } if (tpu_found) { gxp->tpu_dev.dev = &tpu_pdev->dev; get_device(gxp->tpu_dev.dev); gxp->tpu_dev.mbx_paddr = base_addr + offset; } else { dev_warn(dev, "TPU will not be available for interop\n"); gxp->tpu_dev.mbx_paddr = 0; } ret = gxp_dma_init(gxp); if (ret) { dev_err(dev, "Failed to initialize GXP DMA interface\n"); goto err_put_tpu_dev; }
Makefile にもありました
# Access TPU driver's exported symbols. KBUILD_EXTRA_SYMBOLS += ../google-modules/edgetpu/janeiro/drivers/edgetpu/Module.symvers
ZEBU
gxp-config.h に、ZEBU なる文字がありました。これ、Synopsys の ZEBU のことでしょうか？
#if defined(CONFIG_GXP_ZEBU) || defined(CONFIG_GXP_IP_ZEBU) #define GXP_TIME_DELAY_FACTOR 20 #else #define GXP_TIME_DELAY_FACTOR 1 #endif
Makefile にもありました。
# If building via make directly, specify target platform by adding # "GXP_PLATFORM=<target>" # With one of the following values: # - CLOUDRIPPER # - ZEBU # - IP_ZEBU # Defaults to building for CLOUDRIPPER if not otherwise specified. GXP_PLATFORM ?= CLOUDRIPPER GXP_CHIP ?= AMALTHEA
CLOUDRIPPER は、どうやら、Google Tensor G2 開発用ボードの codename のようです。G1 開発用ボードは、Slider のようです。
