[U-Boot] [RFC v2 2/2] arm64: zynqmp: spl: install a PMU firmware config object at runtime

Luca Ceresoli luca at lucaceresoli.net
Wed Apr 3 21:18:14 UTC 2019 

Hi Mike,

On 03/04/19 13:24, Mike Looijmans wrote:
> On 29-03-19 13:22, Luca Ceresoli wrote:
>> Hi Michal,
>>
>> thanks for the feedback.
>>
>> On 27/03/19 16:03, Michal Simek wrote:
>>> On 21. 03. 19 16:48, Luca Ceresoli wrote:
>>>> Optionally allow U-Boot to load at the PMU firmware configuration object
>>>> into the Power Management Unit (PMU) on Xilinx ZynqMP.
>>>>
>>>> The configuration object is required by the PMU FW to enable most SoC
>>>> peripherals. So far the only way to boot using U-Boot SPL was to hard-code
>>>> the configuration object in the PMU firmware. Allow a different boot
>>>> process, where the PMU FW is equal for any ZynqMP chip and its
>>>> configuration is passed at runtime by U-Boot SPL.
>>>>
>>>> All the code for Inter-processor communication with the PMU is isolated in
>>>> a new file (pmu_ipc.c). The code is inspired by the same feature as
>>>> implemented in the Xilinx First Stage Bootloader (FSBL) and Arm Trusted
>>>> Firmware:
>>>>
>>>>   * https://github.com/Xilinx/embeddedsw/blob/fb647e6b4c00f5154eba52a88b948195b6f1dc2b/lib/sw_apps/zynqmp_fsbl/src/xfsbl_misc_drivers.c#L295
>>>>   * https://github.com/ARM-software/arm-trusted-firmware/blob/c48d02bade88b07fa7f43aa44e5217f68e5d047f/plat/xilinx/zynqmp/pm_service/pm_api_sys.c#L357
>>>>
>>>> The load is logged on the console during boot:
>>>>
>>>>    U-Boot SPL 2018.01 (Mar 20 2019 - 08:12:21)
>>>>    Loading PMUFW cfg obj (2008 bytes)
>>>>    EL Level:	EL3
>>>>    ...
>>>>
>>>> Signed-off-by: Luca Ceresoli <luca at lucaceresoli.net>
>> [...]
>>>> diff --git a/board/xilinx/zynqmp/pmu_ipc.c b/board/xilinx/zynqmp/pmu_ipc.c
>>>> new file mode 100644
>>>> index 000000000000..6306d33d6f17
>>>> --- /dev/null
>>>> +++ b/board/xilinx/zynqmp/pmu_ipc.c
>>>> @@ -0,0 +1,116 @@
>>>> +// SPDX-License-Identifier: GPL-2.0+
>>>> +/*
>>>> + * Inter-Processor Communication with the Platform Management Unit (PMU)
>>>> + * firmware.
>> [...]
>>>> +static int pmu_ipc_request(const u32 *req, size_t req_len,
>>>> +			   u32 *res, size_t res_maxlen)
>>>> +{
>>>> +	u32 status;
>>>> +
>>>> +	if (req_len > PMUFW_PAYLOAD_ARG_CNT ||
>>>> +	    res_maxlen > PMUFW_PAYLOAD_ARG_CNT)
>>>> +		return -EINVAL;
>>>> +
>>>> +	pmu_ipc_send_request(req, req_len);
>>>> +
>>>> +	/* Raise Inter-Processor Interrupt to PMU and wait for response */
>>>> +	writel(IPI_BIT_MASK_PMU0, IPI_REG_BASE_APU + IPI_REG_OFFSET_TRIG);
>>>> +	do {
>>>> +		status = readl(IPI_REG_BASE_APU + IPI_REG_OFFSET_OBR);
>>>> +	} while (status & IPI_BIT_MASK_PMU0);
>>>> +
>>>> +	pmu_ipc_read_response(res, res_maxlen);
>>>> +
>>>> +	return 0;
>>>> +}
>>>
>>> All above should be mailbox driver. It means this should go to
>>> drivers/mailbox and be split to mbox send/recv functions.
>>
>> Oh, wow, there's a mailbox uclass! I'll have a look into it.
>>
>>> But I have no problem to use this configuration in the first patch and
>>> move to mbox driver in separate patch.
>>
>> Good to know, I'll use this option in case it takes too long to make it
>> a proper mailbox driver.
>>
>>>> +/**
>>>> + * Send a configuration object to the PMU firmware.
>>>> + *
>>>> + * @cfg_obj Pointer to the configuration object
>>>> + * @size    Size of @cfg_obj in bytes
>>>> + */
>>>> +void zynqmp_pmufw_load_config_object(const void *cfg_obj, size_t size)
>>>> +{
>>>> +	const u32 *ocm = (u32 *)CONFIG_SPL_TEXT_BASE;
>>>> +	const u32 request[] = {
>>>> +		PMUFW_CMD_SET_CONFIGURATION,
>>>> +		CONFIG_SPL_TEXT_BASE
>>>> +	};
>>>> +	u32 response;
>>>> +	int err;
>>>> +
>>>> +	printf("Loading PMUFW cfg obj (%ld bytes)\n", size);
>>>> +
>>>> +	memcpy(ocm, cfg_obj, size);
>>>> +
>>>> +	err = pmu_ipc_request(request,  ARRAY_SIZE(request), &response, 1);
>>>> +	if (err)
>>>> +		panic("Cannot load PMUFW configuration object (%d)\n", err);
>>>> +	if (response != 0)
>>>> +		panic("PMUFW returned 0x%08x status!\n", response);
>>>> +}
>>>
>>> And this can stay here or go to arch/arm/mach-zynq/
>>
>> Ok, I'll move it to arch/arm/mach-zynq/pmu.c or so.
>>
>> I assume "zynq" here means the whole zynq family, including zynqmp.
>>
>>>> diff --git a/board/xilinx/zynqmp/pmu_ipc.h b/board/xilinx/zynqmp/pmu_ipc.h
>>>> new file mode 100644
>>>> index 000000000000..37bb72c1b20a
>>>> --- /dev/null
>>>> +++ b/board/xilinx/zynqmp/pmu_ipc.h
>>>> @@ -0,0 +1,14 @@
>>>> +/* SPDX-License-Identifier: GPL-2.0+ */
>>>> +/*
>>>> + * (C) Copyright 2019 Luca Ceresoli
>>>> + * Luca Ceresoli <luca at lucaceresoli.net>
>>>> + */
>>>> +
>>>> +#ifndef __ZYNQMP_PMU_IPC_H__
>>>> +#define __ZYNQMP_PMU_IPC_H__
>>>> +
>>>> +#include <linux/types.h>
>>>> +
>>>> +void zynqmp_pmufw_load_config_object(const void *cfg_obj, size_t size);
>>>> +
>>>
>>>
>>> arch/arm/mach-zynqmp/include/mach/sys_proto.h should be fine.
>>
>> Ok, but I guess you mean s/zynqmp/zynq/, as above.
>>
>>>> +#endif /* __ZYNQMP_PMU_IPC_H__ */
>>>> diff --git a/board/xilinx/zynqmp/zynqmp.c b/board/xilinx/zynqmp/zynqmp.c
>>>> index 5e1d2116bc32..1d5e25961863 100644
>>>> --- a/board/xilinx/zynqmp/zynqmp.c
>>>> +++ b/board/xilinx/zynqmp/zynqmp.c
>>>> @@ -4,6 +4,8 @@
>>>>    * Michal Simek <michal.simek at xilinx.com>
>>>>    */
>>>>   
>>>> +#include "pmu_ipc.h"
>>>> +
>>>>   #include <common.h>
>>>>   #include <sata.h>
>>>>   #include <ahci.h>
>>>> @@ -302,6 +304,10 @@ static char *zynqmp_get_silicon_idcode_name(void)
>>>>   }
>>>>   #endif
>>>>   
>>>> +#ifdef ZYNQMP_LOAD_PM_CFG_OBJ
>>>> +#include CONFIG_ZYNQMP_LOAD_PM_CFG_OBJ_FILE
>>>> +#endif
>>>> +
>>>>   int board_early_init_f(void)
>>>>   {
>>>>   	int ret = 0;
>>>> @@ -332,6 +338,11 @@ int board_early_init_f(void)
>>>>   
>>>>   int board_init(void)
>>>>   {
>>>> +#if defined(CONFIG_SPL_BUILD) && defined(ZYNQMP_LOAD_PM_CFG_OBJ)
>>>> +	zynqmp_pmufw_load_config_object(XPm_ConfigObject,
>>>> +					sizeof(XPm_ConfigObject));
>>>> +#endif
>>>
>>> As we discussed over IRC. I think that this should be simply bin
>>> firmware file compare to C built by u-boot.
>>
>> Sure. I have a working prototype that uses a binary blob. It still needs
>> a decent way to produce a blob and to be updated according to your review.
> 
> It should be doable to write a Python script to parse the C file and create an 
> equivalent binary (using "struct" module) which is just an array of integers 
> in the end. That avoids the need for a microblaze C compiler...

There's no need for a microblaze compiler. pm_cfg_obj.c is simply
declaring a u32 array and some #defines, any C compiler is enough.

That said, my current solution (a trivial main.c that compiles the u32
array and outputs it to a binary file) is not nice at all, and it
requires a pm_defs.h file.

The python script you mention looks way better from a user perspective,
although the parsing might be a bit fragile. I'll consider it, thanks
for the suggestion.

In the past I even prototyped a python script that parses the Vivado
.xpr project file and produces a pm_cfg_obj.c. It avoided the need to
run the Xilinx XSDK just to generate pm_cfg_obj.c. It might also be
extended to produce a .bin directly, or a self-standing .c file that
doesn't need pm_defs.h, thus removing any licensing issue. But it never
grew complete to handle all cases. Obvious, since *I* don't even know
all of the cases. :)

-- 
Luca

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