| Message ID | 20190809173321.19944-1-marek.vasut@gmail.com (mailing list archive) |
|---|---|
| State | Superseded |
| Delegated to: | Geert Uytterhoeven |
| Headers | show |
| Series | of: Fix of_empty_ranges_quirk() | expand |
On Fri, Aug 09, 2019 at 07:33:21PM +0200, marek.vasut@gmail.com wrote: > From: Marek Vasut <marek.vasut+renesas@gmail.com> > > The of_empty_ranges_quirk() returns a mix of boolean and signed integer > types, which cannot work well. Replace that with boolean only and fix > usage logic in of_translate_one() -- the check should trigger when the > ranges are NULL and the quirk is applicable on the hardware. > > Signed-off-by: Marek Vasut <marek.vasut+renesas@gmail.com> > Cc: Rob Herring <robh+dt@kernel.org> > Cc: Frank Rowand <frowand.list@gmail.com> > Cc: linux-renesas-soc@vger.kernel.org > To: devicetree@vger.kernel.org Reviewed-by: Simon Horman <horms+renesas@verge.net.au> > --- > drivers/of/address.c | 9 +++++---- > 1 file changed, 5 insertions(+), 4 deletions(-) > > diff --git a/drivers/of/address.c b/drivers/of/address.c > index b492176c0572..ae2819e148b8 100644 > --- a/drivers/of/address.c > +++ b/drivers/of/address.c > @@ -616,7 +616,7 @@ static struct of_bus *of_match_bus(struct device_node *np) > return NULL; > } > > -static int of_empty_ranges_quirk(struct device_node *np) > +static bool of_empty_ranges_quirk(struct device_node *np) > { > if (IS_ENABLED(CONFIG_PPC)) { > /* To save cycles, we cache the result for global "Mac" setting */ > @@ -631,7 +631,8 @@ static int of_empty_ranges_quirk(struct device_node *np) > quirk_state = > of_machine_is_compatible("Power Macintosh") || > of_machine_is_compatible("MacRISC"); > - return quirk_state; > + if (quirk_state > 0) > + return true; > } > return false; > } > @@ -662,8 +663,8 @@ static int of_translate_one(struct device_node *parent, struct of_bus *bus, > * This code is only enabled on powerpc. --gcl > */ > ranges = of_get_property(parent, rprop, &rlen); > - if (ranges == NULL && !of_empty_ranges_quirk(parent)) { > - pr_debug("no ranges; cannot translate\n"); > + if (ranges == NULL && of_empty_ranges_quirk(parent)) { > + pr_err("no ranges; cannot translate\n"); > return 1; > } > if (ranges == NULL || rlen == 0) { > -- > 2.20.1 >
On Fri, Aug 9, 2019 at 11:33 AM <marek.vasut@gmail.com> wrote: > > From: Marek Vasut <marek.vasut+renesas@gmail.com> > > The of_empty_ranges_quirk() returns a mix of boolean and signed integer > types, which cannot work well. It never returns a negative. The negative is used as an uninitialized flag. Note quirk_state is static. > Replace that with boolean only and fix > usage logic in of_translate_one() -- the check should trigger when the > ranges are NULL and the quirk is applicable on the hardware. > > Signed-off-by: Marek Vasut <marek.vasut+renesas@gmail.com> > Cc: Rob Herring <robh+dt@kernel.org> > Cc: Frank Rowand <frowand.list@gmail.com> > Cc: linux-renesas-soc@vger.kernel.org > To: devicetree@vger.kernel.org > --- > drivers/of/address.c | 9 +++++---- > 1 file changed, 5 insertions(+), 4 deletions(-) > > diff --git a/drivers/of/address.c b/drivers/of/address.c > index b492176c0572..ae2819e148b8 100644 > --- a/drivers/of/address.c > +++ b/drivers/of/address.c > @@ -616,7 +616,7 @@ static struct of_bus *of_match_bus(struct device_node *np) > return NULL; > } > > -static int of_empty_ranges_quirk(struct device_node *np) > +static bool of_empty_ranges_quirk(struct device_node *np) > { > if (IS_ENABLED(CONFIG_PPC)) { > /* To save cycles, we cache the result for global "Mac" setting */ > @@ -631,7 +631,8 @@ static int of_empty_ranges_quirk(struct device_node *np) > quirk_state = > of_machine_is_compatible("Power Macintosh") || > of_machine_is_compatible("MacRISC"); > - return quirk_state; > + if (quirk_state > 0) > + return true; > } > return false; > } > @@ -662,8 +663,8 @@ static int of_translate_one(struct device_node *parent, struct of_bus *bus, > * This code is only enabled on powerpc. --gcl > */ > ranges = of_get_property(parent, rprop, &rlen); > - if (ranges == NULL && !of_empty_ranges_quirk(parent)) { > - pr_debug("no ranges; cannot translate\n"); > + if (ranges == NULL && of_empty_ranges_quirk(parent)) { > + pr_err("no ranges; cannot translate\n"); This is wrong. If you have NULL ranges and not the quirk, then no ranges is an error. IOW, if you are getting an error here, you have an error in your DT (because I assume you are not working on a PASemi or Apple system). Rob
On 8/10/19 12:34 AM, Rob Herring wrote: > On Fri, Aug 9, 2019 at 11:33 AM <marek.vasut@gmail.com> wrote: >> >> From: Marek Vasut <marek.vasut+renesas@gmail.com> >> >> The of_empty_ranges_quirk() returns a mix of boolean and signed integer >> types, which cannot work well. > > It never returns a negative. The negative is used as an uninitialized > flag. Note quirk_state is static. It's still mixing boolean and signed int types though, which isn't right. >> Replace that with boolean only and fix >> usage logic in of_translate_one() -- the check should trigger when the >> ranges are NULL and the quirk is applicable on the hardware. >> >> Signed-off-by: Marek Vasut <marek.vasut+renesas@gmail.com> >> Cc: Rob Herring <robh+dt@kernel.org> >> Cc: Frank Rowand <frowand.list@gmail.com> >> Cc: linux-renesas-soc@vger.kernel.org >> To: devicetree@vger.kernel.org >> --- >> drivers/of/address.c | 9 +++++---- >> 1 file changed, 5 insertions(+), 4 deletions(-) >> >> diff --git a/drivers/of/address.c b/drivers/of/address.c >> index b492176c0572..ae2819e148b8 100644 >> --- a/drivers/of/address.c >> +++ b/drivers/of/address.c >> @@ -616,7 +616,7 @@ static struct of_bus *of_match_bus(struct device_node *np) >> return NULL; >> } >> >> -static int of_empty_ranges_quirk(struct device_node *np) >> +static bool of_empty_ranges_quirk(struct device_node *np) >> { >> if (IS_ENABLED(CONFIG_PPC)) { >> /* To save cycles, we cache the result for global "Mac" setting */ >> @@ -631,7 +631,8 @@ static int of_empty_ranges_quirk(struct device_node *np) >> quirk_state = >> of_machine_is_compatible("Power Macintosh") || >> of_machine_is_compatible("MacRISC"); >> - return quirk_state; >> + if (quirk_state > 0) >> + return true; >> } >> return false; >> } >> @@ -662,8 +663,8 @@ static int of_translate_one(struct device_node *parent, struct of_bus *bus, >> * This code is only enabled on powerpc. --gcl >> */ >> ranges = of_get_property(parent, rprop, &rlen); >> - if (ranges == NULL && !of_empty_ranges_quirk(parent)) { >> - pr_debug("no ranges; cannot translate\n"); >> + if (ranges == NULL && of_empty_ranges_quirk(parent)) { >> + pr_err("no ranges; cannot translate\n"); > > This is wrong. If you have NULL ranges and not the quirk, then no > ranges is an error. IOW, if you are getting an error here, you have an > error in your DT (because I assume you are not working on a PASemi or > Apple system). The way I understand the code is that if (you have no ranges in the DT) AND (the quirk is applicable) then print the message. Which is what this patch does. Am I missing something ?
On 8/10/19 6:39 AM, Marek Vasut wrote: > On 8/10/19 12:34 AM, Rob Herring wrote: >> On Fri, Aug 9, 2019 at 11:33 AM <marek.vasut@gmail.com> wrote: >>> >>> From: Marek Vasut <marek.vasut+renesas@gmail.com> >>> >>> The of_empty_ranges_quirk() returns a mix of boolean and signed integer >>> types, which cannot work well. >> >> It never returns a negative. The negative is used as an uninitialized >> flag. Note quirk_state is static. > > It's still mixing boolean and signed int types though, which isn't right. From a code readability aspect, Marek is correct. The code author used "stupid (or clever) coding tricks" (tm) to save a little bit of memory. A more readable implementation would be: static bool of_empty_ranges_quirk(struct device_node *np) { /* * As far as we know, the missing "ranges" problem only exists on Apple * machines, so only enable the exception on powerpc. --gcl */ if (IS_ENABLED(CONFIG_PPC)) { /* Cache the result for global "Mac" setting */ static int quirk_state_initialized = 0; static bool quirk_state; /* PA-SEMI sdc DT bug */ if (of_device_is_compatible(np, "1682m-sdc")) return true; if (!quirk_state_initialized) quirk_state_initialized = 1; quirk_state = of_machine_is_compatible("Power Macintosh") || of_machine_is_compatible("MacRISC"); return quirk_state; } return false; } I would also rename of_empty_ranges_quirk() to something like of_missing_ranges_is_ok() or of_missing_ranges_allowed(). "quirk" does not convey any useful information while my proposed rename describes what the function is actually checking for. The comment that I added is currently in the caller of of_empty_ranges_quirk(), but instead belongs in of_empty_ranges_quirk(). When I read that comment in of_translate_one(), my reaction was to look for the check for powerpc in of_translate_one() and to be puzzled when I could not find it. I also modified the comment for the changed context. Thus the "--gcl" portion of the comment should also be removed from of_translate_one(). The more readable implementation (IMNSHO) uses slightly more memory and slightly more code, but it is more direct about what it is doing and thus more readable. -Frank > >>> Replace that with boolean only and fix >>> usage logic in of_translate_one() -- the check should trigger when the >>> ranges are NULL and the quirk is applicable on the hardware. >>> >>> Signed-off-by: Marek Vasut <marek.vasut+renesas@gmail.com> >>> Cc: Rob Herring <robh+dt@kernel.org> >>> Cc: Frank Rowand <frowand.list@gmail.com> >>> Cc: linux-renesas-soc@vger.kernel.org >>> To: devicetree@vger.kernel.org >>> --- >>> drivers/of/address.c | 9 +++++---- >>> 1 file changed, 5 insertions(+), 4 deletions(-) >>> >>> diff --git a/drivers/of/address.c b/drivers/of/address.c >>> index b492176c0572..ae2819e148b8 100644 >>> --- a/drivers/of/address.c >>> +++ b/drivers/of/address.c >>> @@ -616,7 +616,7 @@ static struct of_bus *of_match_bus(struct device_node *np) >>> return NULL; >>> } >>> >>> -static int of_empty_ranges_quirk(struct device_node *np) >>> +static bool of_empty_ranges_quirk(struct device_node *np) >>> { >>> if (IS_ENABLED(CONFIG_PPC)) { >>> /* To save cycles, we cache the result for global "Mac" setting */ >>> @@ -631,7 +631,8 @@ static int of_empty_ranges_quirk(struct device_node *np) >>> quirk_state = >>> of_machine_is_compatible("Power Macintosh") || >>> of_machine_is_compatible("MacRISC"); >>> - return quirk_state; >>> + if (quirk_state > 0) >>> + return true; >>> } >>> return false; >>> } >>> @@ -662,8 +663,8 @@ static int of_translate_one(struct device_node *parent, struct of_bus *bus, >>> * This code is only enabled on powerpc. --gcl >>> */ >>> ranges = of_get_property(parent, rprop, &rlen); >>> - if (ranges == NULL && !of_empty_ranges_quirk(parent)) { >>> - pr_debug("no ranges; cannot translate\n"); >>> + if (ranges == NULL && of_empty_ranges_quirk(parent)) { >>> + pr_err("no ranges; cannot translate\n"); >> >> This is wrong. If you have NULL ranges and not the quirk, then no >> ranges is an error. IOW, if you are getting an error here, you have an >> error in your DT (because I assume you are not working on a PASemi or >> Apple system). > > The way I understand the code is that > if (you have no ranges in the DT) AND (the quirk is applicable) then > print the message. Which is what this patch does. > > Am I missing something ? >
On Sat, Aug 10, 2019 at 7:39 AM Marek Vasut <marek.vasut@gmail.com> wrote: > > On 8/10/19 12:34 AM, Rob Herring wrote: > > On Fri, Aug 9, 2019 at 11:33 AM <marek.vasut@gmail.com> wrote: > >> > >> From: Marek Vasut <marek.vasut+renesas@gmail.com> > >> > >> The of_empty_ranges_quirk() returns a mix of boolean and signed integer > >> types, which cannot work well. > > > > It never returns a negative. The negative is used as an uninitialized > > flag. Note quirk_state is static. > > It's still mixing boolean and signed int types though, which isn't right. I'm really only interested in touching this code if it is too remove it. But some reason people still run 1990s Macs. > >> Replace that with boolean only and fix > >> usage logic in of_translate_one() -- the check should trigger when the > >> ranges are NULL and the quirk is applicable on the hardware. > >> > >> Signed-off-by: Marek Vasut <marek.vasut+renesas@gmail.com> > >> Cc: Rob Herring <robh+dt@kernel.org> > >> Cc: Frank Rowand <frowand.list@gmail.com> > >> Cc: linux-renesas-soc@vger.kernel.org > >> To: devicetree@vger.kernel.org > >> --- > >> drivers/of/address.c | 9 +++++---- > >> 1 file changed, 5 insertions(+), 4 deletions(-) > >> > >> diff --git a/drivers/of/address.c b/drivers/of/address.c > >> index b492176c0572..ae2819e148b8 100644 > >> --- a/drivers/of/address.c > >> +++ b/drivers/of/address.c > >> @@ -616,7 +616,7 @@ static struct of_bus *of_match_bus(struct device_node *np) > >> return NULL; > >> } > >> > >> -static int of_empty_ranges_quirk(struct device_node *np) > >> +static bool of_empty_ranges_quirk(struct device_node *np) > >> { > >> if (IS_ENABLED(CONFIG_PPC)) { > >> /* To save cycles, we cache the result for global "Mac" setting */ > >> @@ -631,7 +631,8 @@ static int of_empty_ranges_quirk(struct device_node *np) > >> quirk_state = > >> of_machine_is_compatible("Power Macintosh") || > >> of_machine_is_compatible("MacRISC"); > >> - return quirk_state; > >> + if (quirk_state > 0) > >> + return true; > >> } > >> return false; > >> } > >> @@ -662,8 +663,8 @@ static int of_translate_one(struct device_node *parent, struct of_bus *bus, > >> * This code is only enabled on powerpc. --gcl > >> */ > >> ranges = of_get_property(parent, rprop, &rlen); > >> - if (ranges == NULL && !of_empty_ranges_quirk(parent)) { > >> - pr_debug("no ranges; cannot translate\n"); > >> + if (ranges == NULL && of_empty_ranges_quirk(parent)) { > >> + pr_err("no ranges; cannot translate\n"); > > > > This is wrong. If you have NULL ranges and not the quirk, then no > > ranges is an error. IOW, if you are getting an error here, you have an > > error in your DT (because I assume you are not working on a PASemi or > > Apple system). > > The way I understand the code is that > if (you have no ranges in the DT) AND (the quirk is applicable) then > print the message. Which is what this patch does. Your understanding is wrong. > Am I missing something ? The normal case is you must have ranges to translate addresses. If you don't have ranges (say for I2C addresses), then you shouldn't be in this code. The quirk is for when there is not a ranges property but should be. IOW, if the quirk is true, then pretend there is an empty ranges (1:1 translation) property and continue to translate the address. Rob
On 8/10/19 9:47 PM, Frank Rowand wrote: > On 8/10/19 6:39 AM, Marek Vasut wrote: >> On 8/10/19 12:34 AM, Rob Herring wrote: >>> On Fri, Aug 9, 2019 at 11:33 AM <marek.vasut@gmail.com> wrote: >>>> >>>> From: Marek Vasut <marek.vasut+renesas@gmail.com> >>>> >>>> The of_empty_ranges_quirk() returns a mix of boolean and signed integer >>>> types, which cannot work well. >>> >>> It never returns a negative. The negative is used as an uninitialized >>> flag. Note quirk_state is static. >> >> It's still mixing boolean and signed int types though, which isn't right. > > From a code readability aspect, Marek is correct. > > The code author used "stupid (or clever) coding tricks" (tm) to save a > little bit of memory. A more readable implementation would be: > > > static bool of_empty_ranges_quirk(struct device_node *np) > { > /* > * As far as we know, the missing "ranges" problem only exists on Apple > * machines, so only enable the exception on powerpc. --gcl > */ > > if (IS_ENABLED(CONFIG_PPC)) { > /* Cache the result for global "Mac" setting */ > static int quirk_state_initialized = 0; > static bool quirk_state; > > /* PA-SEMI sdc DT bug */ > if (of_device_is_compatible(np, "1682m-sdc")) > return true; > > if (!quirk_state_initialized) > quirk_state_initialized = 1; > quirk_state = > of_machine_is_compatible("Power Macintosh") || > of_machine_is_compatible("MacRISC"); > return quirk_state; > } > return false; > } > > > I would also rename of_empty_ranges_quirk() to something like > of_missing_ranges_is_ok() or of_missing_ranges_allowed(). > "quirk" does not convey any useful information while my proposed rename > describes what the function is actually checking for. > > The comment that I added is currently in the caller of of_empty_ranges_quirk(), > but instead belongs in of_empty_ranges_quirk(). When I read that comment in > of_translate_one(), my reaction was to look for the check for powerpc in > of_translate_one() and to be puzzled when I could not find it. I also > modified the comment for the changed context. Thus the "--gcl" portion > of the comment should also be removed from of_translate_one(). > > The more readable implementation (IMNSHO) uses slightly more memory and > slightly more code, but it is more direct about what it is doing and thus > more readable. Thanks for the input, sorry for the delay, let me send a V2.
diff --git a/drivers/of/address.c b/drivers/of/address.c index b492176c0572..ae2819e148b8 100644 --- a/drivers/of/address.c +++ b/drivers/of/address.c @@ -616,7 +616,7 @@ static struct of_bus *of_match_bus(struct device_node *np) return NULL; } -static int of_empty_ranges_quirk(struct device_node *np) +static bool of_empty_ranges_quirk(struct device_node *np) { if (IS_ENABLED(CONFIG_PPC)) { /* To save cycles, we cache the result for global "Mac" setting */ @@ -631,7 +631,8 @@ static int of_empty_ranges_quirk(struct device_node *np) quirk_state = of_machine_is_compatible("Power Macintosh") || of_machine_is_compatible("MacRISC"); - return quirk_state; + if (quirk_state > 0) + return true; } return false; } @@ -662,8 +663,8 @@ static int of_translate_one(struct device_node *parent, struct of_bus *bus, * This code is only enabled on powerpc. --gcl */ ranges = of_get_property(parent, rprop, &rlen); - if (ranges == NULL && !of_empty_ranges_quirk(parent)) { - pr_debug("no ranges; cannot translate\n"); + if (ranges == NULL && of_empty_ranges_quirk(parent)) { + pr_err("no ranges; cannot translate\n"); return 1; } if (ranges == NULL || rlen == 0) {