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SubjectRe: [PATCH v5 2/3] remoteproc: stm32: add support for co-processor booted before kernel
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Hi Mathieu,

On 2/13/20 9:34 PM, Mathieu Poirier wrote:
> On Tue, Feb 11, 2020 at 06:42:04PM +0100, Arnaud Pouliquen wrote:
>> From: Fabien Dessenne <fabien.dessenne@st.com>
>>
>> Add support of a remote firmware, preloaded by the boot loader.
>> Two backup registers are used to retrieve the state of the remote
>> firmware and to get the optional resource table address.
>>
>> Signed-off-by: Fabien Dessenne <fabien.dessenne@st.com>
>> Signed-off-by: Arnaud Pouliquen <arnaud.pouliquen@st.com>
>> ---
>> drivers/remoteproc/stm32_rproc.c | 205 ++++++++++++++++++++++++++++---
>> 1 file changed, 191 insertions(+), 14 deletions(-)
>>
>> diff --git a/drivers/remoteproc/stm32_rproc.c b/drivers/remoteproc/stm32_rproc.c
>> index a18f88044111..3d1e0774318c 100644
>> --- a/drivers/remoteproc/stm32_rproc.c
>> +++ b/drivers/remoteproc/stm32_rproc.c
>> @@ -38,6 +38,15 @@
>> #define STM32_MBX_VQ1_ID 1
>> #define STM32_MBX_SHUTDOWN "shutdown"
>>
>> +#define RSC_TBL_SIZE (1024)
>> +
>> +#define COPRO_STATE_OFF 0
>> +#define COPRO_STATE_INIT 1
>> +#define COPRO_STATE_CRUN 2
>> +#define COPRO_STATE_CSTOP 3
>> +#define COPRO_STATE_STANDBY 4
>> +#define COPRO_STATE_CRASH 5
>> +
>
> At this time only COPRO_STATE_OFF and COPRO_STATE_CRUN are used. I also looked
> on github[1] but couldn't find where the rest of the defines come in.
>
> [1]. https://github.com/STMicroelectronics/linux/blob/v4.19-stm32mp/drivers/remoteproc/stm32_rproc.c

This comes from stm32 code that has been upstreamed in U-boot
These definition match with the u-boot definitions available here:
https://gitlab.denx.de/u-boot/u-boot/blob/master/arch/arm/mach-stm32mp/include/mach/stm32.h
the U-boot source code related to the preloaded is available here:
https://gitlab.denx.de/u-boot/u-boot/blob/master/drivers/remoteproc/stm32_copro.c
to add reference at least in commit message.

>
>> struct stm32_syscon {
>> struct regmap *map;
>> u32 reg;
>> @@ -70,12 +79,14 @@ struct stm32_rproc {
>> struct reset_control *rst;
>> struct stm32_syscon hold_boot;
>> struct stm32_syscon pdds;
>> + struct stm32_syscon copro_state;
>> int wdg_irq;
>> u32 nb_rmems;
>> struct stm32_rproc_mem *rmems;
>> struct stm32_mbox mb[MBOX_NB_MBX];
>> struct workqueue_struct *workqueue;
>> bool secured_soc;
>> + void __iomem *rsc_va;
>> };
>>
>> static int stm32_rproc_pa_to_da(struct rproc *rproc, phys_addr_t pa, u64 *da)
>> @@ -98,6 +109,28 @@ static int stm32_rproc_pa_to_da(struct rproc *rproc, phys_addr_t pa, u64 *da)
>> return -EINVAL;
>> }
>>
>> +static int stm32_rproc_da_to_pa(struct rproc *rproc, u64 da, phys_addr_t *pa)
>> +{
>> + unsigned int i;
>> + struct stm32_rproc *ddata = rproc->priv;
>> + struct stm32_rproc_mem *p_mem;
>> +
>> + for (i = 0; i < ddata->nb_rmems; i++) {
>> + p_mem = &ddata->rmems[i];
>> +
>> + if (da < p_mem->dev_addr ||
>> + da >= p_mem->dev_addr + p_mem->size)
>> + continue;
>> + *pa = da - p_mem->dev_addr + p_mem->bus_addr;
>> + dev_dbg(rproc->dev.parent, "da %llx to pa %#x\n", da, *pa);
>> + return 0;
>> + }
>> +
>> + dev_err(rproc->dev.parent, "can't translate da %llx\n", da);
>> +
>> + return -EINVAL;
>> +}
>> +
>> static int stm32_rproc_mem_alloc(struct rproc *rproc,
>> struct rproc_mem_entry *mem)
>> {
>> @@ -127,6 +160,15 @@ static int stm32_rproc_mem_release(struct rproc *rproc,
>> return 0;
>> }
>>
>> +static int stm32_rproc_elf_load_segments(struct rproc *rproc,
>> + const struct firmware *fw)
>> +{
>> + if (!rproc->skip_fw_load)
>> + return rproc_elf_load_segments(rproc, fw);
>
> Is it possible that the image loaded by the boot loader be also present in
> lib/firmware? If so the segment from the image could be added to the
> ->dump_segments so that if a crash occurs before the MCU is rebooted, some
> information is available. But that is just a thought... Nothing specific to
> change if you don't feel the need to.

It could be possible. But i think there are several constraints to take into account such as file matching with the remote FW that is running, memory accesses right...
I would prefer to address this in a separate thread if needed.

>
>> +
>> + return 0;
>> +}
>> +
>> static int stm32_rproc_of_memory_translations(struct rproc *rproc)
>> {
>> struct device *parent, *dev = rproc->dev.parent;
>> @@ -197,9 +239,34 @@ static int stm32_rproc_mbox_idx(struct rproc *rproc, const unsigned char *name)
>> static int stm32_rproc_elf_load_rsc_table(struct rproc *rproc,
>> const struct firmware *fw)
>> {
>> - if (rproc_elf_load_rsc_table(rproc, fw))
>> - dev_warn(&rproc->dev, "no resource table found for this firmware\n");
>> + struct resource_table *table = NULL;
>> + struct stm32_rproc *ddata = rproc->priv;
>> +
>> + if (!rproc->skip_fw_load) {
>> + if (rproc_elf_load_rsc_table(rproc, fw))
>> + goto no_rsc_table;
>> +
>> + return 0;
>> + }
>> +
>> + if (ddata->rsc_va) {
>> + table = (struct resource_table *)ddata->rsc_va;
>> + /* Assuming that the resource table fits in 1kB is fair */
>> + rproc->cached_table = kmemdup(table, RSC_TBL_SIZE, GFP_KERNEL);
>> + if (!rproc->cached_table)
>> + return -ENOMEM;
>> +
>> + rproc->table_ptr = rproc->cached_table;
>> + rproc->table_sz = RSC_TBL_SIZE;
>> + return 0;
>> + }
>>
>> + rproc->cached_table = NULL;
>> + rproc->table_ptr = NULL;
>> + rproc->table_sz = 0;
>> +
>> +no_rsc_table:
>> + dev_warn(&rproc->dev, "no resource table found for this firmware\n");
>> return 0;
>> }
>>
>> @@ -259,6 +326,36 @@ static int stm32_rproc_parse_fw(struct rproc *rproc, const struct firmware *fw)
>> return stm32_rproc_elf_load_rsc_table(rproc, fw);
>> }
>>
>> +static struct resource_table *
>> +stm32_rproc_elf_find_loaded_rsc_table(struct rproc *rproc,
>> + const struct firmware *fw)
>> +{
>> + struct stm32_rproc *ddata = rproc->priv;
>> +
>> + if (!rproc->skip_fw_load)
>> + return rproc_elf_find_loaded_rsc_table(rproc, fw);
>> +
>> + return (struct resource_table *)ddata->rsc_va;
>> +}
>> +
>> +static int stm32_rproc_elf_sanity_check(struct rproc *rproc,
>> + const struct firmware *fw)
>> +{
>> + if (!rproc->skip_fw_load)
>> + return rproc_elf_sanity_check(rproc, fw);
>> +
>> + return 0;
>> +}
>> +
>> +static u32 stm32_rproc_elf_get_boot_addr(struct rproc *rproc,
>> + const struct firmware *fw)
>> +{
>> + if (!rproc->skip_fw_load)
>> + return rproc_elf_get_boot_addr(rproc, fw);
>> +
>> + return 0;
>> +}
>> +
>> static irqreturn_t stm32_rproc_wdg(int irq, void *data)
>> {
>> struct rproc *rproc = data;
>> @@ -420,7 +517,7 @@ static int stm32_rproc_start(struct rproc *rproc)
>> stm32_rproc_add_coredump_trace(rproc);
>>
>> /* clear remote proc Deep Sleep */
>> - if (ddata->pdds.map) {
>> + if (ddata->pdds.map && !rproc->skip_fw_load) {
>> err = regmap_update_bits(ddata->pdds.map, ddata->pdds.reg,
>> ddata->pdds.mask, 0);
>
> Because this is platform code it is really hard to understand what is going on
> and why this change is needed. As such it is hard to do a meticulous review of
> the code and find problems. Ideally reviewers should only have to look at the
> code and read the comments to understand the logic.
>
> There is probably nothing wrong with the above, I just don't have enough
> information to understand it.

You are right, this requests more comment to be readable. PDDS prevents to put platform in standby
when Linux starts a remoteproc firmware. In case of preloaded firmware, decision is taken by U-boot.
i will add comments in next version.

>
>> if (err) {
>> @@ -429,9 +526,15 @@ static int stm32_rproc_start(struct rproc *rproc)
>> }
>> }
>>
>> - err = stm32_rproc_set_hold_boot(rproc, false);
>> - if (err)
>> - return err;
>> + /*
>> + * If M4 previously started by bootloader, just guarantee holdboot
>> + * is set to catch any crash.
>> + */
>> + if (!rproc->skip_fw_load) {
>> + err = stm32_rproc_set_hold_boot(rproc, false);
>> + if (err)
>> + return err;
>> + }
>
> Same here.
>
>>
>> return stm32_rproc_set_hold_boot(rproc, true);
>> }
>> @@ -473,6 +576,21 @@ static int stm32_rproc_stop(struct rproc *rproc)
>> }
>> }
>>
>> + /* update copro state to OFF */
>> + if (ddata->copro_state.map) {
>> + err = regmap_update_bits(ddata->copro_state.map,
>> + ddata->copro_state.reg,
>> + ddata->copro_state.mask,
>> + COPRO_STATE_OFF);
>> + if (err) {
>> + dev_err(&rproc->dev, "failed to set copro state\n");
>> + return err;
>> + }
>> + }
>> +
>> + /* Reset skip_fw_load state as we stop the co-processor */
>> + rproc->skip_fw_load = false;
>> +
>> return 0;
>> }
>>
>> @@ -502,11 +620,11 @@ static struct rproc_ops st_rproc_ops = {
>> .start = stm32_rproc_start,
>> .stop = stm32_rproc_stop,
>> .kick = stm32_rproc_kick,
>> - .load = rproc_elf_load_segments,
>> + .load = stm32_rproc_elf_load_segments,
>> .parse_fw = stm32_rproc_parse_fw,
>> - .find_loaded_rsc_table = rproc_elf_find_loaded_rsc_table,
>> - .sanity_check = rproc_elf_sanity_check,
>> - .get_boot_addr = rproc_elf_get_boot_addr,
>> + .find_loaded_rsc_table = stm32_rproc_elf_find_loaded_rsc_table,
>> + .sanity_check = stm32_rproc_elf_sanity_check,
>> + .get_boot_addr = stm32_rproc_elf_get_boot_addr,
>> };
>>
>> static const struct of_device_id stm32_rproc_match[] = {
>> @@ -543,8 +661,10 @@ static int stm32_rproc_parse_dt(struct platform_device *pdev)
>> struct device_node *np = dev->of_node;
>> struct rproc *rproc = platform_get_drvdata(pdev);
>> struct stm32_rproc *ddata = rproc->priv;
>> - struct stm32_syscon tz;
>> - unsigned int tzen;
>> + struct stm32_syscon tz, rsctbl;
>> + phys_addr_t rsc_pa;
>> + u32 rsc_da;
>> + unsigned int tzen, state;
>> int err, irq;
>>
>> irq = platform_get_irq(pdev, 0);
>> @@ -602,11 +722,62 @@ static int stm32_rproc_parse_dt(struct platform_device *pdev)
>>
>> err = stm32_rproc_get_syscon(np, "st,syscfg-pdds", &ddata->pdds);
>> if (err)
>> - dev_warn(dev, "failed to get pdds\n");
>> + dev_warn(dev, "pdds not supported\n");
>>
>> rproc->auto_boot = of_property_read_bool(np, "st,auto-boot");
>>
>> - return stm32_rproc_of_memory_translations(rproc);
>> + err = stm32_rproc_of_memory_translations(rproc);
>> + if (err)
>> + return err;
>> +
>> + /* check if the coprocessor has been started from the bootloader */
>> + err = stm32_rproc_get_syscon(np, "st,syscfg-copro-state",
>> + &ddata->copro_state);
>> + if (err) {
>> + /* no copro_state syscon (optional) */
>> + dev_warn(dev, "copro_state not supported\n");
>> + goto bail;
>> + }
>> +
>> + err = regmap_read(ddata->copro_state.map, ddata->copro_state.reg,
>> + &state);
>> + if (err) {
>> + dev_err(&rproc->dev, "failed to read copro state\n");
>> + return err;
>> + }
>> +
>
> if (state != COPRO_STATE_CRUN)
> goto bail;

yes and as mentioned by Bjorn return 0 instead of goto

>>> + if (state == COPRO_STATE_CRUN) {
>> + rproc->skip_fw_load = true;
>> +
>> + if (stm32_rproc_get_syscon(np, "st,syscfg-rsc-tbl", &rsctbl)) {
>> + /* no rsc table syscon (optional) */
>> + dev_warn(dev, "rsc tbl syscon not supported\n");
>> + goto bail;
>> + }
>> +
>> + err = regmap_read(rsctbl.map, rsctbl.reg, &rsc_da);
>> + if (err) {
>> + dev_err(&rproc->dev, "failed to read rsc tbl addr\n");
>> + return err;
>> + }
>> + if (!rsc_da)
>> + /* no rsc table */
>> + goto bail;
>> +
>> + err = stm32_rproc_da_to_pa(rproc, rsc_da, &rsc_pa);
>> + if (err)
>> + return err;
>> +
>> + ddata->rsc_va = devm_ioremap_wc(dev, rsc_pa, RSC_TBL_SIZE);
>> + if (IS_ERR_OR_NULL(ddata->rsc_va)) {
>> + dev_err(dev, "Unable to map memory region: %pa+%zx\n",
>> + &rsc_pa, RSC_TBL_SIZE);
>> + ddata->rsc_va = NULL;
>> + return -ENOMEM;
>> + }
>> + }
>> +bail:
>> + return 0;
>> }
>>
>> static int stm32_rproc_probe(struct platform_device *pdev)
>> @@ -640,6 +811,12 @@ static int stm32_rproc_probe(struct platform_device *pdev)
>> if (ret)
>> goto free_wkq;
>>
>> + if (!rproc->skip_fw_load) {
>> + ret = stm32_rproc_stop(rproc);
>> + if (ret)
>> + goto free_rproc;
>> + }
>> +
>
> I'm very puzzled here, especially since it deals with the case where FW is
> loaded by the framework. Do you think you could add a (lengthy) comment to
> explain what is going on?

Sure, i will improve comments in code, and commit message.

Thanks,
Arnaud

>
> Thanks,
> Mathieu
>
>> ret = stm32_rproc_request_mbox(rproc);
>> if (ret)
>> goto free_rproc;
>> --
>> 2.17.1
>>

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