Initialization of eMMC host and scan of devices connected to this host

The makefile and DW-related config below the driver/mmc/host are as follows:
obj-$ (CONFIG_MMC_DW) + + DW_MMC.O
obj-$ (CONFIG_MMC_DW_PLTFM) + + DW_MMC-PLTFM.O
obj-$ (Config_mmc_dw_exynos) + + DW_MMC-EXYNOS.O
obj-$ (CONFIG_MMC_DW_K3) + + DW_MMC-K3.O
obj-$ (CONFIG_MMC_DW_PCI) + + DW_MMC-PCI.O
obj-$ (config_mmc_dw_rockchip) + + DW_MMC-ROCKCHIP.O
I opened Config_mmc_dw and Config_mmc_dw_k3.
So the entry function of DW is in the DW_MMC-K3.C
static struct Platform_driver Dw_mci_k3_pltfm_driver = {
. Probe = Dw_mci_k3_probe,
. remove = Dw_mci_pltfm_remove,
. Driver = {
. Name = "Dwmmc_k3",
. of_match_table = Dw_mci_k3_match,
. PM = &dw_mci_k3_pmops,
},
};

Module_platform_driver (Dw_mci_k3_pltfm_driver);
If you detect in DTS
static const struct OF_DEVICE_ID dw_mci_k3_match[] = {
{. compatible = "HISILICON,HI4511-DW-MSHC",. Data = &k3_drv_data,},
{. compatible = "HISILICON,HI6220-DW-MSHC",. Data = &hi6220_data,},
{},
};

The two strings are called Dw_mci_k3_probe
static int dw_mci_k3_probe (struct platform_device *pdev)
{
const struct Dw_mci_drv_data *drv_data;
const struct OF_DEVICE_ID *match;
Get Drv_data In this case is K3_drv_data
Match = Of_match_node (Dw_mci_k3_match, Pdev->dev.of_node);
Drv_data = match->data;
Call Dw_mci_pltfm_register
Return Dw_mci_pltfm_register (Pdev, drv_data);
}
int Dw_mci_pltfm_register (struct platform_device *pdev,
const struct Dw_mci_drv_data *drv_data)
{
struct DW_MCI *host;
struct resource *regs;

Host = Devm_kzalloc (&pdev->dev, sizeof (struct DW_MCI), gfp_kernel);
if (!host)
Return-enomem;
Get an IRQ
HOST->IRQ = PLATFORM_GET_IRQ (Pdev, 0);
if (Host->irq < 0)
Return host->irq;

Host->drv_data = Drv_data;
Host->dev = &pdev->dev;
host->irq_flags = 0;
Host->pdata = pdev->dev.platform_data;
Get the register address of this host
Regs = Platform_get_resource (Pdev, Ioresource_mem, 0);
Do Ioremap to Reg so that you can access this register address in kernel
Host->regs = Devm_ioremap_resource (&pdev->dev, regs);
if (Is_err (Host->regs))
Return Ptr_err (Host->regs);

/* Get registers ' physical base address * *
Host->phy_regs = regs->start;
Save Drv_data
Platform_set_drvdata (Pdev, host);
Keep probe.
return Dw_mci_probe (host);
}
In Dw_mci_probe, other variables are parse from DTS such as: Ciu/biu
HOST-&GT;BIU_CLK = Devm_clk_get (Host->dev, "Biu");
if (Is_err (HOST-&GT;BIU_CLK)) {
dev_dbg (Host->dev, "Biu clock not available\n");
} else {
ret = clk_prepare_enable (HOST-&GT;BIU_CLK);
if (ret) {
Dev_err (Host->dev, "failed to enable Biu clock\n");
return ret;
}
}

But the final order is the following paragraph.
/* We need at least one slot to succeed * *
for (i = 0; i < host->num_slots; i++) {
RET = Dw_mci_init_slot (host, i);
if (ret)
dev_dbg (Host->dev, "slot%d init failed\n", i);
Else
init_slots++;
}
In Dw_mci_init_slot, call Mmc_alloc_host/mmc_add_host to add this MMC host to kernel.
The most important thing in Mmc_alloc_host is Init_delayed_work (&host->detect, Mmc_rescan), which can be found by Mmc_rescan to discover the devices connected to the host. The specific callstack are as follows:
[11.777356] [<ffffffc00008a438>] dump_backtrace+0x0/0x164
[11.782759] [<ffffffc00008a5b8>] show_stack+0x1c/0x28
[11.787816] [<ffffffc000bbca58>] dump_stack+0x78/0x98
[11.792870] [<ffffffc000bb9348>] panic+0xe8/0x244
[11.797577] [<ffffffc00092c564>] mmc_add_card+0xc0/0x228
[11.802894] [<ffffffc00092f71c>] mmc_attach_mmc+0xa8/0x18c
[11.808382] [<ffffffc00092bb8c>] Mmc_rescan+0x2a8/0x2f8
[11.813612] [<ffffffc0000d4ef4>] PROCESS_ONE_WORK+0X154/0X3BC
[11.819362] [<ffffffc0000d52a4>] worker_thread+0x148/0x49c
[11.824852] [<ffffffc0000db200>] Kthread+0xe0/0xf8