In a Linux system, Iomem_resource information is exported to/proc/iomem.

We take the high-pass IPQ4019 chip as an example to illustrate

Step1 the situation of Iomem_resource in/proc/iomem

[[Email protected]:~]# Cat/proc/iomem

060f8800-060f88ff:qscratch_base

The 078AF000-078AF1FF:MSM_SERIAL_HSL//step1 78af000 is the physical address of the serial port on the SOC. See the device information below

078b5000-078b55ff:spi_qsd

....

88000000-8fffffff:system RAM//This is the physical address of the memory.

Step2 from the/sys information about device registration

[Email protected]:d evices]# pwd

/sys/bus/platform/devices

[[email protected]:d evices]# ls

....

60F8800.USB2 pmu.4

78af000.serialqca,scm_restart_reason.5//Step 2 This 78af000 is from the device tree.

78b5000.spi qcom,sps.2

Step 3 Learn about the serial port information in the device tree source file

See: Qca/src/linux/arch/arm/boot/dts/qcom-ipq40xx.dtsi 734

[Email protected] {

compatible = "qcom,msm-uartdm-v1.4", "QCOM,MSM-UARTDM";

Reg = <0x78af000 0x200>; Reg represents the address space for this device. You can use this address to access the device's registers, and so on.

Interrupts = <0 107 0>;

Status = "Disabled";

clocks = <&GCC Gcc_blsp1_uart1_apps_clk>

<&GCC gcc_blsp1_ahb_clk>;

Clock-names = "core", "Iface";

};

Step4 Serial port driver is how to enter the registration of Iomem_reserouce

Msm_serial_hs_lite.c

Msm_hsl_request_port function

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Request_mem_region ()//register the resources with the iomem_reserouce. And check if this resource is being used by someone else.

Resource = Platform_get_resource (Pdev, Ioresource_mem, 0); Get IO resources from plateform devices

Uport->membase = Ioremap (uport->mapbase,//use Ioremap to map again.

Resource_size (Resource));

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In a Linux system, Iomem_resource information is exported to/proc/iomem.