Hello! On 04/12/2019 12:29 PM, Vignesh Raghavendra wrote: > 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 clock cycle. But > HyperBus operates at >166MHz frequencies. > HyperRAM provides direct random read/write access to flash memory > array. > > But, HyperBus memory controllers seem to abstract implementation details > and expose a simple MMIO interface to access connected flash. > > Add support for registering HyperFlash devices with MTD framework. MTD > maps framework along with CFI chip support framework are used to support > communicating with flash. > > Framework is modelled along the lines of spi-nor framework. HyperBus > memory controller (HBMC) drivers calls 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. > > Some HBMC masters need calibration/training sequence[3] to be carried > out, in order for DLL inside the controller to lock, by reading a known > string/pattern. This is done by repeatedly reading CFI Query > Identification String. Calibration needs to be done before trying to detect > flash as part of CFI flash probe. > > HyperRAM is not supported at the moment. > > HyperBus specification can be found at[1] > HyperFlash datasheet can be found at[2] > > [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 > > Signed-off-by: Vignesh Raghavendra <vigneshr@xxxxxx> [...] > diff --git a/drivers/mtd/hyperbus/Kconfig b/drivers/mtd/hyperbus/Kconfig > new file mode 100644 > index 000000000000..98147e28caa0 > --- /dev/null > +++ b/drivers/mtd/hyperbus/Kconfig > @@ -0,0 +1,11 @@ > +menuconfig MTD_HYPERBUS > + tristate "HyperBus support" > + select MTD_CFI > + select MTD_MAP_BANK_WIDTH_2 > + select MTD_CFI_AMDSTD > + select MTD_COMPLEX_MAPPINGS > + help > + This is the framework for the HyperBus which can be used by > + the HyperBus Controller driver to communicate with > + HyperFlash. See Cypress HyperBus specification for more > + details > diff --git a/drivers/mtd/hyperbus/Makefile b/drivers/mtd/hyperbus/Makefile > new file mode 100644 > index 000000000000..ca61dedd730d > --- /dev/null > +++ b/drivers/mtd/hyperbus/Makefile > @@ -0,0 +1,3 @@ > +# SPDX-License-Identifier: GPL-2.0 > + > +obj-$(CONFIG_MTD_HYPERBUS) += hyperbus-core.o > diff --git a/drivers/mtd/hyperbus/hyperbus-core.c b/drivers/mtd/hyperbus/hyperbus-core.c > new file mode 100644 > index 000000000000..49aeb59742c6 > --- /dev/null > +++ b/drivers/mtd/hyperbus/hyperbus-core.c > @@ -0,0 +1,192 @@ > +// SPDX-License-Identifier: GPL-2.0 > +// > +// Copyright (C) 2019 Texas Instruments Incorporated - http://www.ti.com/ > +// Author: Vignesh Raghavendra <vigneshr@xxxxxx> [...] > +/* Default calibration routine for use by HyperBus controller. > + * Controller is calibrated by repeatedly reading known pattern ("QRY" > + * string from CFI space) > + * Lets ensure "QRY" string is read correctly at least 5 times to ensure > + * stability of the DLL lock. > + */ > +int hyperbus_calibrate(struct hyperbus_device *hbdev) > +{ > + struct map_info *map = &hbdev->map; > + struct cfi_private cfi; > + int count = HYPERBUS_CALIB_COUNT; > + int pass_count = 0; > + int ret; > + > + cfi.interleave = 1; > + cfi.device_type = CFI_DEVICETYPE_X16; > + cfi_send_gen_cmd(0xF0, 0, 0, map, &cfi, cfi.device_type, NULL); > + cfi_send_gen_cmd(0x98, 0x55, 0, map, &cfi, cfi.device_type, NULL); > + > + while (count--) { > + cfi_qry_present(map, 0, &cfi); > + ret = cfi_qry_present(map, 0, &cfi); Why call it twice in a row? > + if (ret) > + pass_count++; > + else > + pass_count = 0; > + if (pass_count == 5) > + break; > + } > + > + cfi_qry_mode_off(0, map, &cfi); > + > + return ret; > +} > +EXPORT_SYMBOL_GPL(hyperbus_calibrate); [...] > diff --git a/include/linux/mtd/hyperbus.h b/include/linux/mtd/hyperbus.h > new file mode 100644 > index 000000000000..19340cc56aa4 > --- /dev/null > +++ b/include/linux/mtd/hyperbus.h > @@ -0,0 +1,91 @@ [...] > +/** > + * hb_unregister_device - deregister HyperBus slave memory device You forgot to update the function name in the kernel-doc. :-) > + * @hbdev: hyperbus_device to be unregistered > + * > + * Return: 0 for success, others for failure. > + */ > +int hyperbus_unregister_device(struct hyperbus_device *hbdev); > + > +#endif /* __LINUX_MTD_HYPERBUS_H__ */ MBR, Sergei
