On 10/06/19 11:27 PM, Sergei Shtylyov wrote: > On 06/09/2019 01:32 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/hyperbus-core.c b/drivers/mtd/hyperbus/hyperbus-core.c >> new file mode 100644 >> index 000000000000..df1f75e10b1a >> --- /dev/null >> +++ b/drivers/mtd/hyperbus/hyperbus-core.c >> @@ -0,0 +1,191 @@ >> +// SPDX-License-Identifier: GPL-2.0 >> +// >> +// Copyright (C) 2019 Texas Instruments Incorporated - http://www.ti.com/ >> +// Author: Vignesh Raghavendra <vigneshr@xxxxxx> >> + >> +#include <linux/err.h> >> +#include <linux/kernel.h> >> +#include <linux/module.h> >> +#include <linux/mtd/hyperbus.h> >> +#include <linux/mtd/map.h> >> +#include <linux/mtd/mtd.h> >> +#include <linux/mtd/cfi.h> >> +#include <linux/of.h> >> +#include <linux/of_address.h> >> +#include <linux/types.h> >> + >> +#define HYPERBUS_CALIB_COUNT 25 > > Mhm, I think I've already protested about this being #define'd here... > I thought you had agreed that default optional calibration routine can be part of core code and thus this #define. Anyways, what is your preference here? Drop the constant and use a local variable in hyperbus_calibrate()? Or are you suggesting to move hyperbus_calibrate() TI's specific driver? > [...] >> +int hyperbus_register_device(struct hyperbus_device *hbdev) >> +{ >> + const struct hyperbus_ops *ops; >> + struct hyperbus_ctlr *ctlr; >> + struct device_node *np; >> + struct map_info *map; >> + struct resource res; >> + struct device *dev; >> + int ret; >> + >> + if (!hbdev || !hbdev->np || !hbdev->ctlr || !hbdev->ctlr->dev) { >> + pr_err("hyperbus: please fill all the necessary fields!\n"); >> + return -EINVAL; >> + } >> + >> + np = hbdev->np; >> + ctlr = hbdev->ctlr; >> + if (!of_device_is_compatible(np, "cypress,hyperflash")) >> + return -ENODEV; >> + >> + hbdev->memtype = HYPERFLASH; >> + >> + if (of_address_to_resource(np, 0, &res)) >> + return -EINVAL; > > Why not just propagate the error upstream (yeah, I've noticed that > it only can be -EINVAL)? > Ok. > [...] >> diff --git a/include/linux/mtd/hyperbus.h b/include/linux/mtd/hyperbus.h >> new file mode 100644 >> index 000000000000..ee2eefd822c9 >> --- /dev/null >> +++ b/include/linux/mtd/hyperbus.h >> @@ -0,0 +1,91 @@ >> +/* SPDX-License-Identifier: GPL-2.0 >> + * >> + * Copyright (C) 2019 Texas Instruments Incorporated - http://www.ti.com/ >> + */ >> + >> +#ifndef __LINUX_MTD_HYPERBUS_H__ >> +#define __LINUX_MTD_HYPERBUS_H__ >> + >> +#include <linux/mtd/map.h> >> + >> +enum hyperbus_memtype { >> + HYPERFLASH, >> + HYPERRAM, >> +}; >> + >> +/** >> + * struct hyperbus_device - struct representing HyperBus slave device >> + * @map: map_info struct for accessing MMIO HyperBus flash memory >> + * @np: pointer to HyperBus slave device node > ^ > Space needed here, not tab. > Ok >> + * @mtd: pointer to MTD struct >> + * @ctlr: pointer to HyperBus controller struct >> + * @memtype: type of memory device: HyperFlash or HyperRAM >> + * @registered: flag to indicate whether device is registered with MTD core >> + */ >> + >> +struct hyperbus_device { >> + struct map_info map; >> + struct device_node *np; >> + struct mtd_info *mtd; >> + struct hyperbus_ctlr *ctlr; >> + enum hyperbus_memtype memtype; >> + bool registered; >> +}; >> + >> +/** >> + * struct hyperbus_ops - struct representing custom HyperBus operations >> + * @read16: read 16 bit of data, usually from register/ID-CFI space >> + * @write16: write 16 bit of data, usually to register/ID-CFI space > > Usually? How to differ the register/memory transfers if both are possible? > CFI + map framework does not provide a way to differentiate b/w reg access vs memory access. read16()/write16() is used to either access registers or for sending various cmds like lock/unlock etc or for programming a single word. For regular read/writes copy_from() and copy_to() are used. Looking at HyperBus protocol, controllers would not need to differentiate b/w registers vs memory transfers for HyperFlash devices. So, I think I can drop read16/write16 and redirect these calls to copy_from()/copy_to() I mainly added these functions keeping HyperRAM in mind. Idea was drivers would look at hyperbus_device->memtype and set to register access mode for HyperRAM in case of write16()/read16(). Looks like the interface is not intuitive enough So, will drop these and add it back when adding HyperRAM support. Does that work for your HW as well? >> + * @copy_from: copy data from flash memory >> + * @copy_to: copy data to flash memory >> + * @calibrate: calibrate HyperBus controller >> + */ >> + >> +struct hyperbus_ops { >> + u16 (*read16)(struct hyperbus_device *hbdev, unsigned long addr); >> + void (*write16)(struct hyperbus_device *hbdev, >> + unsigned long addr, u16 val); >> + void (*copy_from)(struct hyperbus_device *hbdev, void *to, >> + unsigned long from, ssize_t len); >> + void (*copy_to)(struct hyperbus_device *dev, unsigned long to, >> + const void *from, ssize_t len); >> + int (*calibrate)(struct hyperbus_device *dev); >> +}; >> + >> +/** >> + * struct hyperbus_ctlr - struct representing HyperBus controller >> + * @calibrated: flag to indicate ctlr calibration sequence is complete >> + * @ops: HyperBus controller ops > > What about @dev? > Will add. >> + */ >> +struct hyperbus_ctlr { >> + struct device *dev; >> + bool calibrated; >> + >> + const struct hyperbus_ops *ops; >> +}; > [...] > > MBR, Sergei > -- Regards Vignesh
