[Pdbg] [PATCH v2 1/7] libpdbg: Store fsi_fd state information in fsi structure

Amitay Isaacs amitay at ozlabs.org
Mon Jun 15 17:37:44 AEST 2020


On Mon, 2020-06-15 at 17:22 +1000, Alistair Popple wrote:
> On Wednesday, 10 June 2020 3:24:20 PM AEST Amitay Isaacs wrote:
> > This allows to have different fd for different fsi targets.  Also,
> > we
> > can close the fd cleanly in release procedure.
> > 
> > Signed-off-by: Amitay Isaacs <amitay at ozlabs.org>
> > ---
> >  libpdbg/hwunit.h |  1 +
> >  libpdbg/kernel.c | 87 +++++++++++++++++++++++---------------------
> > ----
> >  2 files changed, 43 insertions(+), 45 deletions(-)
> > 
> > diff --git a/libpdbg/hwunit.h b/libpdbg/hwunit.h
> > index 61aea0f..e3a8426 100644
> > --- a/libpdbg/hwunit.h
> > +++ b/libpdbg/hwunit.h
> > @@ -112,6 +112,7 @@ struct fsi {
> >  	int (*read)(struct fsi *, uint32_t, uint32_t *);
> >  	int (*write)(struct fsi *, uint32_t, uint32_t);
> >  	enum chip_type chip_type;
> > +	int fd;
> >  };
> >  #define target_to_fsi(x) container_of(x, struct fsi, target)
> >  
> > diff --git a/libpdbg/kernel.c b/libpdbg/kernel.c
> > index c4637a7..7914e50 100644
> > --- a/libpdbg/kernel.c
> > +++ b/libpdbg/kernel.c
> > @@ -33,7 +33,6 @@
> >  #define OPENFSI_LEGACY_PATH "/sys/bus/platform/devices/gpio-fsi/"
> >  #define OPENFSI_PATH "/sys/class/fsi-master/"
> >  
> > -int fsi_fd;
> >  const char *fsi_base;
> >  
> >  const char *kernel_get_fsi_path(void)
> > @@ -66,14 +65,14 @@ static int kernel_fsi_getcfam(struct fsi *fsi,
> > uint32_t 
> addr64, uint32_t *value)
> >  	int rc;
> >  	uint32_t tmp, addr = (addr64 & 0x7ffc00) | ((addr64 & 0x3ff) <<
> > 2);
> >  
> > -	rc = lseek(fsi_fd, addr, SEEK_SET);
> > +	rc = lseek(fsi->fd, addr, SEEK_SET);
> >  	if (rc < 0) {
> >  		rc = errno;
> >  		PR_WARNING("seek failed: %s\n", strerror(errno));
> >  		return rc;
> >  	}
> >  
> > -	rc = read(fsi_fd, &tmp, 4);
> > +	rc = read(fsi->fd, &tmp, 4);
> >  	if (rc < 0) {
> >  		rc = errno;
> >  		if ((addr64 & 0xfff) != 0xc09)
> > @@ -93,7 +92,7 @@ static int kernel_fsi_putcfam(struct fsi *fsi,
> > uint32_t 
> addr64, uint32_t data)
> >  	int rc;
> >  	uint32_t tmp, addr = (addr64 & 0x7ffc00) | ((addr64 & 0x3ff) <<
> > 2);
> >  
> > -	rc = lseek(fsi_fd, addr, SEEK_SET);
> > +	rc = lseek(fsi->fd, addr, SEEK_SET);
> >  	if (rc < 0) {
> >  		rc = errno;
> >  		PR_WARNING("seek failed: %s\n", strerror(errno));
> > @@ -101,7 +100,7 @@ static int kernel_fsi_putcfam(struct fsi *fsi,
> > uint32_t 
> addr64, uint32_t data)
> >  	}
> >  
> >  	tmp = htobe32(data);
> > -	rc = write(fsi_fd, &tmp, 4);
> > +	rc = write(fsi->fd, &tmp, 4);
> >  	if (rc < 0) {
> >  		rc = errno;
> >  		PR_ERROR("Failed to write to 0x%08" PRIx32 " (%016"
> > PRIx32 ")\n", 
> addr, addr64);
> > @@ -111,16 +110,6 @@ static int kernel_fsi_putcfam(struct fsi *fsi,
> > uint32_t 
> addr64, uint32_t data)
> >  	return 0;
> >  }
> >  
> > -#if 0
> > -/* TODO: At present we don't have a generic destroy method as
> > there aren't 
> many
> > - * use cases for it. So for the moment we can just let the OS
> > close the file
> > - * descriptor on exit. */
> > -static void kernel_fsi_destroy(struct pdbg_target *target)
> > -{
> > -	close(fsi_fd);
> > -}
> > -#endif
> > -
> >  static void kernel_fsi_scan_devices(void)
> >  {
> >  	const char one = '1';
> > @@ -154,51 +143,59 @@ static void kernel_fsi_scan_devices(void)
> >  
> >  int kernel_fsi_probe(struct pdbg_target *target)
> >  {
> > -	if (!fsi_fd) {
> > -		int tries = 5;
> > -		int rc;
> > -		const char *kernel_path = kernel_get_fsi_path();
> > -		char *path;
> > -
> > -		if (!kernel_path)
> > -			return -1;
> > -
> > -		rc = asprintf(&path, "%s/fsi0/slave at 00:00/raw", 
> kernel_get_fsi_path());
> > -		if (rc < 0) {
> > -			PR_ERROR("Unable create fsi path\n");
> > -			return rc;
> > -		}
> > +	struct fsi *fsi = target_to_fsi(target);
> > +	int tries = 5;
> > +	int rc;
> > +	const char *kernel_path = kernel_get_fsi_path();
> > +	char *path;
> >  
> > -		while (tries) {
> > -			/* Open first raw device */
> > -			fsi_fd = open(path, O_RDWR | O_SYNC);
> > -			if (fsi_fd >= 0) {
> > -				free(path);
> > -				return 0;
> > -			}
> > -			tries--;
> > -
> > -			/* Scan */
> > -			kernel_fsi_scan_devices();
> > -			sleep(1);
> > -		}
> > -		if (fsi_fd < 0) {
> > -			PR_ERROR("Unable to open %s\n", path);
> > +	if (!kernel_path)
> > +		return -1;
> > +
> > +	rc = asprintf(&path, "%s/fsi0/slave at 00:00/raw",
> > kernel_get_fsi_path());
> > +	if (rc < 0) {
> > +		PR_ERROR("Unable create fsi path\n");
> > +		return rc;
> > +	}
> > +
> > +	while (tries) {
> > +		/* Open first raw device */
> > +		fsi->fd = open(path, O_RDWR | O_SYNC);
> > +		if (fsi->fd >= 0) {
> >  			free(path);
> > -			return -1;
> > +			return 0;
> 
> Minor nit that doesn't need fixing but IMHO it would probably have
> been clearer 
> to make this a for loop and break out rather than return.

I can still do that, if that'll make things clearer.

> 
> >  		}
> > +		tries--;
> >  
> > +		/* Scan */
> > +		kernel_fsi_scan_devices();
> > +		sleep(1);
> > +	}
> > +	if (fsi->fd < 0) {
> > +		PR_ERROR("Unable to open %s\n", path);
> > +		free(path);
> >  	}
> >  
> >  	return -1;
> >  }
> >  
> > +static void kernel_fsi_release(struct pdbg_target *target)
> > +{
> > +	struct fsi *fsi = target_to_fsi(target);
> > +
> > +	if (fsi->fd != -1) {
> 
> In theory I think generic pdbg logic should prevent this from ever
> being false 
> as release should only get called on a successful probe.

Yes, we can definitely drop the check.  I was going nuts trying to
figure out what will happen with releasing virtual targets.  I am
convinced now that each target will be released only once.

> 
> Reviewed-by: Alistair Popple <alistair at popple.id.au>
> 
> > +		close(fsi->fd);
> > +		fsi->fd = -1;
> > +	}
> > +}
> > +
> >  static struct fsi kernel_fsi = {
> >  	.target = {
> >  		.name = "Kernel based FSI master",
> >  		.compatible = "ibm,kernel-fsi",
> >  		.class = "fsi",
> >  		.probe = kernel_fsi_probe,
> > +		.release = kernel_fsi_release,
> >  	},
> >  	.read = kernel_fsi_getcfam,
> >  	.write = kernel_fsi_putcfam,
> > 
> 
> 
> 

Amitay.
-- 

Treasure the love you receive above all. It will survive long after your gold
and good health have vanished. - Og Mandino



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