diff options
Diffstat (limited to 'doc')
| -rw-r--r-- | doc/develop/driver-model/nvmxip.rst | 45 | ||||
| -rw-r--r-- | doc/device-tree-bindings/nvmxip/nvmxip_qspi.txt | 56 |
2 files changed, 100 insertions, 1 deletions
diff --git a/doc/develop/driver-model/nvmxip.rst b/doc/develop/driver-model/nvmxip.rst index fe087b13d2..09afdbcccf 100644 --- a/doc/develop/driver-model/nvmxip.rst +++ b/doc/develop/driver-model/nvmxip.rst @@ -25,7 +25,33 @@ The NVMXIP Uclass provides the following drivers: the Uclass creates a block device and binds it with the nvmxip-blk. The Uclass driver implemented by drivers/mtd/nvmxip/nvmxip-uclass.c - The implementation is generic and can be used by different platforms. + nvmxip_qspi driver : + + The driver probed with the DT and is the parent of the blk#<id> device. + nvmxip_qspi can be reused by other platforms. If the platform + has custom settings to apply before using the flash, then the platform + can provide its own parent driver belonging to UCLASS_NVMXIP and reuse + nvmxip-blk. The custom driver can be implemented like nvmxip_qspi in + addition to the platform custom settings. + The nvmxip_qspi driver belongs to UCLASS_NVMXIP. + The driver implemented by drivers/mtd/nvmxip/nvmxip_qspi.c + + For example, if we have two NVMXIP devices described in the DT + The devices hierarchy is as follows: + +:: + + => dm tree + + Class Index Probed Driver Name + ----------------------------------------------------------- + ... + nvmxip 0 [ + ] nvmxip_qspi |-- nvmxip-qspi1@08000000 + blk 3 [ + ] nvmxip-blk | `-- nvmxip-qspi1@08000000.blk#1 + nvmxip 1 [ + ] nvmxip_qspi |-- nvmxip-qspi2@08200000 + blk 4 [ + ] nvmxip-blk | `-- nvmxip-qspi2@08200000.blk#2 + +The implementation is generic and can be used by different platforms. Supported hardware -------------------------------- @@ -43,6 +69,23 @@ config NVMXIP handles the read operation. This driver is HW agnostic and can support multiple flash devices at the same time. +config NVMXIP_QSPI + This option allows the emulation of a block storage device on top of a QSPI XIP flash. + Any platform that needs to emulate one or multiple QSPI XIP flash devices can turn this + option on to enable the functionality. NVMXIP config is selected automatically. + Platforms that need to add custom treatments before accessing to the flash, can + write their own driver (same as nvmxip_qspi in addition to the custom settings). + +Device Tree nodes +-------------------- + +Multiple QSPI XIP flash devices can be used at the same time by describing them through DT +nodes. + +Please refer to the documentation of the DT binding at: + +doc/device-tree-bindings/nvmxip/nvmxip_qspi.txt + Contributors ------------ * Abdellatif El Khlifi <abdellatif.elkhlifi@arm.com> diff --git a/doc/device-tree-bindings/nvmxip/nvmxip_qspi.txt b/doc/device-tree-bindings/nvmxip/nvmxip_qspi.txt new file mode 100644 index 0000000000..cc60e9efdc --- /dev/null +++ b/doc/device-tree-bindings/nvmxip/nvmxip_qspi.txt @@ -0,0 +1,56 @@ +Specifying NVMXIP information for devices +====================================== + +QSPI XIP flash device nodes +--------------------------- + +Each flash device should have its own node. + +Each node must specify the following fields: + +1) + compatible = "nvmxip,qspi"; + +This allows to bind the flash device with the nvmxip_qspi driver +If a platform has its own driver, please provide your own compatible +string. + +2) + reg = <0x0 0x08000000 0x0 0x00200000>; + +The start address and size of the flash device. The values give here are an +example (when the cell size is 2). + +When cell size is 1, the reg field looks like this: + + reg = <0x08000000 0x00200000>; + +3) + + lba_shift = <9>; + +The number of bit shifts used to calculate the size in bytes of one block. +In this example the block size is 1 << 9 = 2 ^ 9 = 512 bytes + +4) + + lba = <4096>; + +The number of blocks. + +Example of multiple flash devices +---------------------------------------------------- + + nvmxip-qspi1@08000000 { + compatible = "nvmxip,qspi"; + reg = <0x0 0x08000000 0x0 0x00200000>; + lba_shift = <9>; + lba = <4096>; + }; + + nvmxip-qspi2@08200000 { + compatible = "nvmxip,qspi"; + reg = <0x0 0x08200000 0x0 0x00100000>; + lba_shift = <9>; + lba = <2048>; + }; |