On 12/26/19 6:25 PM, Sughosh Ganu wrote:
Add a uclass for reading a random number seed from a random number generator device.Signed-off-by: Sughosh Ganu <sughosh.g...@linaro.org> Reviewed-by: Patrice Chotard <patrice.chot...@st.com> --- Changes since V4: * Use Sphinx syntax for Return value in the read function * Return number of bytes read on a successful read, and a -ve value on error. drivers/Kconfig | 2 ++ drivers/Makefile | 1 + drivers/rng/Kconfig | 7 +++++++ drivers/rng/Makefile | 6 ++++++ drivers/rng/rng-uclass.c | 23 +++++++++++++++++++++++ include/dm/uclass-id.h | 1 + include/rng.h | 33 +++++++++++++++++++++++++++++++++ 7 files changed, 73 insertions(+) create mode 100644 drivers/rng/Kconfig create mode 100644 drivers/rng/Makefile create mode 100644 drivers/rng/rng-uclass.c create mode 100644 include/rng.h diff --git a/drivers/Kconfig b/drivers/Kconfig index 9d99ce0..e34a227 100644 --- a/drivers/Kconfig +++ b/drivers/Kconfig @@ -90,6 +90,8 @@ source "drivers/remoteproc/Kconfig" source "drivers/reset/Kconfig" +source "drivers/rng/Kconfig" + source "drivers/rtc/Kconfig" source "drivers/scsi/Kconfig" diff --git a/drivers/Makefile b/drivers/Makefile index e977f19..6c619b1 100644 --- a/drivers/Makefile +++ b/drivers/Makefile @@ -115,4 +115,5 @@ obj-$(CONFIG_W1_EEPROM) += w1-eeprom/ obj-$(CONFIG_MACH_PIC32) += ddr/microchip/ obj-$(CONFIG_DM_HWSPINLOCK) += hwspinlock/ +obj-$(CONFIG_DM_RNG) += rng/ endif diff --git a/drivers/rng/Kconfig b/drivers/rng/Kconfig new file mode 100644 index 0000000..dd44cc0 --- /dev/null +++ b/drivers/rng/Kconfig @@ -0,0 +1,7 @@ +config DM_RNG + bool "Driver support for Random Number Generator devices" + depends on DM + help + Enable driver model for random number generator(rng) devices. + This interface is used to initialise the rng device and to + read the random seed from the device. diff --git a/drivers/rng/Makefile b/drivers/rng/Makefile new file mode 100644 index 0000000..311705b --- /dev/null +++ b/drivers/rng/Makefile @@ -0,0 +1,6 @@ +# SPDX-License-Identifier: GPL-2.0+ +# +# Copyright (c) 2019, Linaro Limited +# + +obj-$(CONFIG_DM_RNG) += rng-uclass.o diff --git a/drivers/rng/rng-uclass.c b/drivers/rng/rng-uclass.c new file mode 100644 index 0000000..b6af3b8 --- /dev/null +++ b/drivers/rng/rng-uclass.c @@ -0,0 +1,23 @@ +// SPDX-License-Identifier: GPL-2.0+ +/* + * Copyright (c) 2019, Linaro Limited + */ + +#include <common.h> +#include <dm.h> +#include <rng.h> + +int dm_rng_read(struct udevice *dev, void *buffer, size_t size) +{ + const struct dm_rng_ops *ops = device_get_ops(dev); + + if (!ops->read) + return -ENOSYS; + + return ops->read(dev, buffer, size); +} + +UCLASS_DRIVER(rng) = { + .name = "rng", + .id = UCLASS_RNG, +}; diff --git a/include/dm/uclass-id.h b/include/dm/uclass-id.h index 0c563d8..192202d 100644 --- a/include/dm/uclass-id.h +++ b/include/dm/uclass-id.h @@ -86,6 +86,7 @@ enum uclass_id { UCLASS_REGULATOR, /* Regulator device */ UCLASS_REMOTEPROC, /* Remote Processor device */ UCLASS_RESET, /* Reset controller device */ + UCLASS_RNG, /* Random Number Generator */ UCLASS_RTC, /* Real time clock device */ UCLASS_SCSI, /* SCSI device */ UCLASS_SERIAL, /* Serial UART */ diff --git a/include/rng.h b/include/rng.h new file mode 100644 index 0000000..9a71e81 --- /dev/null +++ b/include/rng.h @@ -0,0 +1,33 @@ +// SPDX-License-Identifier: GPL-2.0+ +/* + * Copyright (c) 2019, Linaro Limited + */ + +#if !defined _RNG_H_ +#define _RNG_H_ + +#include <dm.h> + +/** + * dm_rng_read() - read a random number seed from the rng device + * @buffer: input buffer to put the read random seed into + * @size: number of bytes of random seed read + * + * Return: number of bytes read if OK, -ve on error + */ +int dm_rng_read(struct udevice *dev, void *buffer, size_t size); + +/* struct dm_rng_ops - Operations for the hwrng uclass */ +struct dm_rng_ops { + /** + * @read() - read a random number seed + * + * @data: input buffer to read the random seed + * @max: total number of bytes to read + * + * Return: number of bytes read if OK, -ve on error + */ + int (*read)(struct udevice *dev, void *data, size_t max);
With this interface definition the caller has to check the return value and to call read() again and again until all bytes needed are requested. The EFI_RNG_PROTOCOL will not be the only consumer of the hardware RNG so we will have to rewrite that logic in multiple places. In U-Boot we are very tight on the binary size. So I would really appreciate to avoid such code duplication by making it the drivers duty to return exactly the number of bytes requested. Best regards Heinrich
+}; + +#endi.f /* _RNG_H_ */
