Hi, On 14/04/19 11:21 PM, Sergei Shtylyov wrote: > 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? > Oops, will fix in v2 >> + 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. :-) > Indeed, thanks for catching this! >> + * @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 > -- Regards Vignesh
