Cypress HyperBus is Low Signal Count, High Performance Double Data Rate Bus interface between a host system master and one or more slave interfaces. HyperBus is used to connect microprocessor, microcontroller, or ASIC devices with random access NOR flash memory(called HyperFlash) or self refresh DRAM(called HyperRAM). Its a 8-bit data bus (DQ[7:0]) with Read-Write Data Strobe (RWDS) signal and either Single-ended clock(3.0V parts) or Differential clock (1.8V parts). It uses ChipSelect lines to select b/w multiple slaves. At bus level, it follows a separate protocol described in HyperBus specification[1]. HyperFlash follows CFI AMD/Fujitsu Extended Command Set (0x0002) similar to that of existing parallel NORs. Since Hyperbus is x8 DDR bus, its equivalent to x16 parallel NOR flash wrt bits per clk. But Hyperbus operates at >166MHz frequencies. HyperRAM provides direct random read/write access to flash memory array. Framework is modelled along the lines of spi-nor framework. HyperBus memory controller(HBMC) drivers call hyperbus_register_device() to register a single HyperFlash device. HyperFlash core parses MMIO access information from DT, sets up the map_info struct, probes CFI flash and registers it with MTD framework. This is an early RFC, to know if its okay to use maps framework and existing CFI compliant flash support code to support Hyperflash Also would like input on different types of HBMC master IPs out there and their programming sequences. Would appreciate any testing/review. Tested on modified TI AM654 EVM with Cypress Hyperflash S26KS512 by creating a UBIFS partition and writing and reading files to it. Stress tested by writing/reading 16MB flash repeatedly at different offsets using dd commmand. HyperBus specification can be found at[1] HyperFlash datasheet can be found at[2] TI's HBMC controller details at[3] [1] https://www.cypress.com/file/213356/download [2] https://www.cypress.com/file/213346/download [3] http://www.ti.com/lit/ug/spruid7b/spruid7b.pdf Table 12-5741. HyperFlash Access Sequence Change log: Since v4: Fix Rob's comments on dt-bindings of TI HBMC driver Since v3: * Drop reading QRY string twice in hyperbus_calibrate() * Fix doc/misc comments on v3. Since RFC v2: * use map_word_xxx() for handling status register to support interleaved flashes as suggested by Joakim Tjernlund <Joakim.Tjernlund@xxxxxxxxxxxx> * Report error status/messages on erase/program failure by looking at status register bits. * Add "cfi-flash" as fallback compatible for cypress,hyperflash * Add support to select between HyperBus and OSPI using mmio mux Since RFC v1: * Re-work Hyperbus core to provide separate struct representation for controller and slave devices * Rename all files and func names to have hyperbus_ prefix * Provide default calibration routine for use by controller drivers * Fix up errors with patch spliting * Address comments by Sergei Shtylyov <sergei.shtylyov@xxxxxxxxxxxxxxxxxx> Vignesh Raghavendra (5): mtd: cfi_cmdset_0002: Add support for polling status register dt-bindings: mtd: Add binding documentation for HyperFlash mtd: Add support for HyperBus memory devices dt-bindings: mtd: Add bindings for TI's AM654 HyperBus memory controller mtd: hyperbus: Add driver for TI's HyperBus memory controller .../bindings/mtd/cypress,hyperflash.txt | 13 ++ .../devicetree/bindings/mtd/ti,am654-hbmc.txt | 51 +++++ MAINTAINERS | 8 + drivers/mtd/Kconfig | 2 + drivers/mtd/Makefile | 1 + drivers/mtd/chips/cfi_cmdset_0002.c | 90 +++++++++ drivers/mtd/hyperbus/Kconfig | 23 +++ drivers/mtd/hyperbus/Makefile | 4 + drivers/mtd/hyperbus/hbmc-am654.c | 110 ++++++++++ drivers/mtd/hyperbus/hyperbus-core.c | 191 ++++++++++++++++++ include/linux/mtd/cfi.h | 5 + include/linux/mtd/hyperbus.h | 91 +++++++++ 12 files changed, 589 insertions(+) create mode 100644 Documentation/devicetree/bindings/mtd/cypress,hyperflash.txt create mode 100644 Documentation/devicetree/bindings/mtd/ti,am654-hbmc.txt create mode 100644 drivers/mtd/hyperbus/Kconfig create mode 100644 drivers/mtd/hyperbus/Makefile create mode 100644 drivers/mtd/hyperbus/hbmc-am654.c create mode 100644 drivers/mtd/hyperbus/hyperbus-core.c create mode 100644 include/linux/mtd/hyperbus.h -- 2.21.0
