RE: [PATCH v4 16/17] remoteproc: st: add reserved memory support

[Loic PALLARDY]

Hi Suman,

> -----Original Message-----
> From: Suman Anna <s-anna@xxxxxx>
> Sent: mercredi 24 octobre 2018 05:02
> To: Loic PALLARDY <loic.pallardy@xxxxxx>; bjorn.andersson@xxxxxxxxxx;
> ohad@xxxxxxxxxx
> Cc: linux-remoteproc@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx;
> Arnaud POULIQUEN <arnaud.pouliquen@xxxxxx>;
> benjamin.gaignard@xxxxxxxxxx
> Subject: Re: [PATCH v4 16/17] remoteproc: st: add reserved memory support
> 
> Hi Loic,
> 
> On 7/27/18 8:14 AM, Loic Pallardy wrote:
> > ST remote processor needs some specified memory regions for
> > firmware and IPC.
> > Memory regions are defined as reserved memory and should
> > be registered in remoteproc core thanks to rproc_add_carveout
> > function before rproc_start. For this, st rproc driver implements
> > prepare ops.
> >
> > Signed-off-by: Loic Pallardy <loic.pallardy@xxxxxx>
> > ---
> >  drivers/remoteproc/st_remoteproc.c | 96
> +++++++++++++++++++++++++++++++++-----
> >  1 file changed, 85 insertions(+), 11 deletions(-)
> >
> > diff --git a/drivers/remoteproc/st_remoteproc.c
> b/drivers/remoteproc/st_remoteproc.c
> > index aacef0e..45958d5 100644
> > --- a/drivers/remoteproc/st_remoteproc.c
> > +++ b/drivers/remoteproc/st_remoteproc.c
> > @@ -19,6 +19,7 @@
> >  #include <linux/mfd/syscon.h>
> >  #include <linux/module.h>
> >  #include <linux/of.h>
> > +#include <linux/of_address.h>
> >  #include <linux/of_device.h>
> >  #include <linux/of_reserved_mem.h>
> >  #include <linux/platform_device.h>
> > @@ -91,6 +92,82 @@ static void st_rproc_kick(struct rproc *rproc, int vqid)
> >  		dev_err(dev, "failed to send message via mbox: %d\n", ret);
> >  }
> >
> > +static int st_rproc_mem_alloc(struct rproc *rproc,
> > +			      struct rproc_mem_entry *mem)
> > +{
> > +	struct device *dev = rproc->dev.parent;
> > +	void *va;
> > +
> > +	va = ioremap_wc(mem->dma, mem->len);
> > +	if (!va) {
> > +		dev_err(dev, "Unable to map memory region: %pa+%zx\n",
> > +			&mem->dma, mem->len);
> > +		return -ENOMEM;
> > +	}
> > +
> > +	/* Update memory entry va */
> > +	mem->va = va;
> > +
> > +	return 0;
> > +}
> > +
> > +static int st_rproc_mem_release(struct rproc *rproc,
> > +				struct rproc_mem_entry *mem)
> > +{
> > +	iounmap(mem->va);
> > +
> > +	return 0;
> > +}
> > +
> > +static int st_rproc_parse_fw(struct rproc *rproc, const struct firmware
> *fw)
> > +{
> > +	struct device *dev = rproc->dev.parent;
> > +	struct device_node *np = dev->of_node;
> > +	struct rproc_mem_entry *mem;
> > +	void *va;
> > +	struct reserved_mem *rmem;
> > +	struct of_phandle_iterator it;
> > +	int err, index = 0;
> > +
> > +	of_phandle_iterator_init(&it, np, "memory-region", NULL, 0);
> > +	while ((err = of_phandle_iterator_next(&it)) == 0) {
> > +		va = NULL;
> > +		rmem = of_reserved_mem_lookup(it.node);
> > +
> > +		/*  No need to map vdev buffer */
> > +		if (strcmp(it.node->name, "vdev0buffer")) {
> > +			va = devm_ioremap_wc(dev, rmem->base, rmem-
> >size);
> > +			if (!va) {
> > +				dev_err(dev, "Unable to map memory
> region: %pa+%zx\n",
> > +					&rmem->base, rmem->size);
> > +				return -ENOMEM;
> > +			}
> > +
> > +			/* Register memory region */
> > +			mem = rproc_mem_entry_init(dev, va,
> > +						   (dma_addr_t)rmem->base,
> > +						   rmem->size, rmem->base,
> > +						   st_rproc_mem_alloc,
> > +						   st_rproc_mem_release,
> 
> You seem to be double-mapping, first just above to supply the va to
> mem_entry_init and then through the alloc function.
> 
> This is DT parsing and is fixed irrespective of firmware and only needs
> to be done once really in the platform driver probe. I think this whole
> logic is unnecessarily complicated in the name of letting the remoteproc
> core handle the alloc and free for fixed memory carveouts during every
> boot and shutdown, and having to redo the mapping everytime during the
> firmware parse. I am not a big fan of overloading the parse_fw to do
> this runtime remapping everytime for something that should have been
> done once. I think you have done this in your v2, and somewhere along in
> v3 got modified into this.
 
Double mapping is definitively an error. Forget it.
Being able to allocate all carveouts at coprocessor start was a remark from Bjorn.
That's why I introduced alloc and free ops to do the allocation at each coprocessor start and so st_rproc_mem_alloc() in this driver.

Regards,
Loic
> 
> regards
> Suman
> 
> > +						   it.node->name);
> > +		} else {
> > +			/* Register reserved memory for vdev buffer
> allocation */
> > +			mem = rproc_of_resm_mem_entry_init(dev, index,
> > +							   rmem->size,
> > +							   rmem->base,
> > +							   it.node->name);
> > +		}
> > +
> > +		if (!mem)
> > +			return -ENOMEM;
> > +
> > +		rproc_add_carveout(rproc, mem);
> > +		index++;
> > +	}
> > +
> > +	return rproc_elf_load_rsc_table(rproc, fw);
> > +}
> > +
> >  static int st_rproc_start(struct rproc *rproc)
> >  {
> >  	struct st_rproc *ddata = rproc->priv;
> > @@ -158,9 +235,14 @@ static int st_rproc_stop(struct rproc *rproc)
> >  }
> >
> >  static const struct rproc_ops st_rproc_ops = {
> > -	.kick		= st_rproc_kick,
> > -	.start		= st_rproc_start,
> > -	.stop		= st_rproc_stop,
> > +	.kick			= st_rproc_kick,
> > +	.start			= st_rproc_start,
> > +	.stop			= st_rproc_stop,
> > +	.parse_fw		= st_rproc_parse_fw,
> > +	.load			= rproc_elf_load_segments,
> > +	.find_loaded_rsc_table	= rproc_elf_find_loaded_rsc_table,
> > +	.sanity_check		= rproc_elf_sanity_check,
> > +	.get_boot_addr		= rproc_elf_get_boot_addr,
> >  };
> >
> >  /*
> > @@ -254,12 +336,6 @@ static int st_rproc_parse_dt(struct
> platform_device *pdev)
> >  		return -EINVAL;
> >  	}
> >
> > -	err = of_reserved_mem_device_init(dev);
> > -	if (err) {
> > -		dev_err(dev, "Failed to obtain shared memory\n");
> > -		return err;
> > -	}
> > -
> >  	err = clk_prepare(ddata->clk);
> >  	if (err)
> >  		dev_err(dev, "failed to get clock\n");
> > @@ -387,8 +463,6 @@ static int st_rproc_remove(struct platform_device
> *pdev)
> >
> >  	clk_disable_unprepare(ddata->clk);
> >
> > -	of_reserved_mem_device_release(&pdev->dev);
> > -
> >  	for (i = 0; i < ST_RPROC_MAX_VRING * MBOX_MAX; i++)
> >  		mbox_free_channel(ddata->mbox_chan[i]);
> >
> >