diff mbox series

clk: qcom: ipq4019: fix apss cpu overclocking

Message ID 20200604120905.1344074-1-robert.marko@sartura.hr
State New
Headers show
Series clk: qcom: ipq4019: fix apss cpu overclocking | expand

Commit Message

Robert Marko June 4, 2020, 12:09 p.m. UTC 
From: Christian Lamparter <chunkeey@gmail.com>

There's an interaction issue between the clk changes:"
clk: qcom: ipq4019: Add the apss cpu pll divider clock node
clk: qcom: ipq4019: remove fixed clocks and add pll clocks
" and the cpufreq-dt.

cpufreq-dt is now spamming the kernel-log with the following:

[ 1099.190658] cpu cpu0: dev_pm_opp_set_rate: failed to find current OPP
for freq 761142857 (-34)

This only happens on certain devices like the Compex WPJ428
and AVM FritzBox!4040. However, other devices like the Asus
RT-AC58U and Meraki MR33 work just fine.

The issue stem from the fact that all higher CPU-Clocks
are achieved by switching the clock-parent to the P_DDRPLLAPSS
(ddrpllapss). Which is set by Qualcomm's proprietary bootcode
as part of the DDR calibration.

For example, the FB4040 uses 256 MiB Nanya NT5CC128M16IP clocked
at round 533 MHz (ddrpllsdcc = 190285714 Hz).

whereas the 128 MiB Nanya NT5CC64M16GP-DI in the ASUS RT-AC58U is
clocked at a slightly higher 537 MHz ( ddrpllsdcc = 192000000 Hz).

This patch attempts to fix the issue by modifying
clk_cpu_div_round_rate(), clk_cpu_div_set_rate(), clk_cpu_div_recalc_rate()
to use a new qcom_find_freq_close() function, which returns the closest
matching frequency, instead of the next higher. This way, the SoC in
the FB4040 (with its max clock speed of 710.4 MHz) will no longer
try to overclock to 761 MHz.

Fixes: d83dcacea18 ("clk: qcom: ipq4019: Add the apss cpu pll divider clock node")
Signed-off-by: Christian Lamparter <chunkeey@gmail.com>
Signed-off-by: John Crispin <john@phrozen.org>
Tested-by: Robert Marko <robert.marko@sartura.hr>
Cc: Luka Perkov <luka.perkov@sartura.hr>
---
 drivers/clk/qcom/gcc-ipq4019.c | 34 +++++++++++++++++++++++++++++++---
 1 file changed, 31 insertions(+), 3 deletions(-)

Comments

Nathan Chancellor June 8, 2020, 9:07 a.m. UTC | #1 
On Mon, Jun 08, 2020 at 10:54:34AM +0200, Robert Marko wrote:
> On Thu, Jun 4, 2020 at 10:25 PM kernel test robot <lkp@intel.com> wrote:
> >
> > Hi Robert,
> >
> > I love your patch! Perhaps something to improve:
> >
> > [auto build test WARNING on clk/clk-next]
> > [also build test WARNING on v5.7 next-20200604]
> > [if your patch is applied to the wrong git tree, please drop us a note to help
> > improve the system. BTW, we also suggest to use '--base' option to specify the
> > base tree in git format-patch, please see https://stackoverflow.com/a/37406982]
> >
> > url:    https://github.com/0day-ci/linux/commits/Robert-Marko/clk-qcom-ipq4019-fix-apss-cpu-overclocking/20200605-002859
> > base:   https://git.kernel.org/pub/scm/linux/kernel/git/clk/linux.git clk-next
> > config: x86_64-allyesconfig (attached as .config)
> > compiler: clang version 11.0.0 (https://github.com/llvm/llvm-project ac47588bc4ff5927a01ed6fcd269ce86aba52a7c)
> > reproduce (this is a W=1 build):
> >         wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
> >         chmod +x ~/bin/make.cross
> >         # install x86_64 cross compiling tool for clang build
> >         # apt-get install binutils-x86-64-linux-gnu
> >         # save the attached .config to linux build tree
> >         COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross ARCH=x86_64
> >
> > If you fix the issue, kindly add following tag as appropriate
> > Reported-by: kernel test robot <lkp@intel.com>
> >
> > All warnings (new ones prefixed by >>, old ones prefixed by <<):
> >
> > >> drivers/clk/qcom/gcc-ipq4019.c:1247:24: warning: no previous prototype for function 'qcom_find_freq_close' [-Wmissing-prototypes]
> > const struct freq_tbl *qcom_find_freq_close(const struct freq_tbl *f,
> > ^
> > drivers/clk/qcom/gcc-ipq4019.c:1247:7: note: declare 'static' if the function is not intended to be used outside of this translation unit
> > const struct freq_tbl *qcom_find_freq_close(const struct freq_tbl *f,
> > ^
> > static
> > 1 warning generated.
> >
> > vim +/qcom_find_freq_close +1247 drivers/clk/qcom/gcc-ipq4019.c
> >
> >   1245
> >   1246
> > > 1247  const struct freq_tbl *qcom_find_freq_close(const struct freq_tbl *f,
> >   1248                                               unsigned long rate)
> >   1249  {
> >   1250          const struct freq_tbl *last = NULL;
> >   1251
> >   1252          for ( ; f->freq; f++) {
> >   1253                  if (rate == f->freq)
> >   1254                          return f;
> >   1255
> >   1256                  if (f->freq > rate) {
> >   1257                          if (!last ||
> >   1258                             (f->freq - rate) < (rate - last->freq))
> >   1259                                  return f;
> >   1260                          else
> >   1261                                  return last;
> >   1262                  }
> >   1263                  last = f;
> >   1264          }
> >   1265
> >   1266          return last;
> >   1267  }
> >   1268
> >
> > ---
> > 0-DAY CI Kernel Test Service, Intel Corporation
> > https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org
> 

<moved post to the bottom>

> Sorry for asking, but are these warnings relevant?
> GCC9.3 does not throw them
> 
> Regards
> Robert
> 

It should if you are using make W=1, this is not a clang specific
warning (it just happens that clang was the compiler for this report).

It looks like qcom_find_freq_close is only used in
drivers/clk/qcom/gcc-ipq4019.c, in which case it should be marked
static.

Cheers,
Nathan
Robert Marko June 8, 2020, 9:43 a.m. UTC | #2 
On Mon, Jun 8, 2020 at 11:07 AM Nathan Chancellor
<natechancellor@gmail.com> wrote:
>
> On Mon, Jun 08, 2020 at 10:54:34AM +0200, Robert Marko wrote:
> > On Thu, Jun 4, 2020 at 10:25 PM kernel test robot <lkp@intel.com> wrote:
> > >
> > > Hi Robert,
> > >
> > > I love your patch! Perhaps something to improve:
> > >
> > > [auto build test WARNING on clk/clk-next]
> > > [also build test WARNING on v5.7 next-20200604]
> > > [if your patch is applied to the wrong git tree, please drop us a note to help
> > > improve the system. BTW, we also suggest to use '--base' option to specify the
> > > base tree in git format-patch, please see https://stackoverflow.com/a/37406982]
> > >
> > > url:    https://github.com/0day-ci/linux/commits/Robert-Marko/clk-qcom-ipq4019-fix-apss-cpu-overclocking/20200605-002859
> > > base:   https://git.kernel.org/pub/scm/linux/kernel/git/clk/linux.git clk-next
> > > config: x86_64-allyesconfig (attached as .config)
> > > compiler: clang version 11.0.0 (https://github.com/llvm/llvm-project ac47588bc4ff5927a01ed6fcd269ce86aba52a7c)
> > > reproduce (this is a W=1 build):
> > >         wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
> > >         chmod +x ~/bin/make.cross
> > >         # install x86_64 cross compiling tool for clang build
> > >         # apt-get install binutils-x86-64-linux-gnu
> > >         # save the attached .config to linux build tree
> > >         COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross ARCH=x86_64
> > >
> > > If you fix the issue, kindly add following tag as appropriate
> > > Reported-by: kernel test robot <lkp@intel.com>
> > >
> > > All warnings (new ones prefixed by >>, old ones prefixed by <<):
> > >
> > > >> drivers/clk/qcom/gcc-ipq4019.c:1247:24: warning: no previous prototype for function 'qcom_find_freq_close' [-Wmissing-prototypes]
> > > const struct freq_tbl *qcom_find_freq_close(const struct freq_tbl *f,
> > > ^
> > > drivers/clk/qcom/gcc-ipq4019.c:1247:7: note: declare 'static' if the function is not intended to be used outside of this translation unit
> > > const struct freq_tbl *qcom_find_freq_close(const struct freq_tbl *f,
> > > ^
> > > static
> > > 1 warning generated.
> > >
> > > vim +/qcom_find_freq_close +1247 drivers/clk/qcom/gcc-ipq4019.c
> > >
> > >   1245
> > >   1246
> > > > 1247  const struct freq_tbl *qcom_find_freq_close(const struct freq_tbl *f,
> > >   1248                                               unsigned long rate)
> > >   1249  {
> > >   1250          const struct freq_tbl *last = NULL;
> > >   1251
> > >   1252          for ( ; f->freq; f++) {
> > >   1253                  if (rate == f->freq)
> > >   1254                          return f;
> > >   1255
> > >   1256                  if (f->freq > rate) {
> > >   1257                          if (!last ||
> > >   1258                             (f->freq - rate) < (rate - last->freq))
> > >   1259                                  return f;
> > >   1260                          else
> > >   1261                                  return last;
> > >   1262                  }
> > >   1263                  last = f;
> > >   1264          }
> > >   1265
> > >   1266          return last;
> > >   1267  }
> > >   1268
> > >
> > > ---
> > > 0-DAY CI Kernel Test Service, Intel Corporation
> > > https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org
> >
>
> <moved post to the bottom>
>
> > Sorry for asking, but are these warnings relevant?
> > GCC9.3 does not throw them
> >
> > Regards
> > Robert
> >
>
> It should if you are using make W=1, this is not a clang specific
> warning (it just happens that clang was the compiler for this report).

Thanks, W=1 does indeed show the warning along with a not evaluated return.
>
> It looks like qcom_find_freq_close is only used in
> drivers/clk/qcom/gcc-ipq4019.c, in which case it should be marked
> static.
Thanks, it does indeed solve the warning.
I will send a v2 today.

Regards,
Robert
>
> Cheers,
> Nathan
diff mbox series

Patch

diff --git a/drivers/clk/qcom/gcc-ipq4019.c b/drivers/clk/qcom/gcc-ipq4019.c
index ef5137fd50f3..eeed50573752 100644
--- a/drivers/clk/qcom/gcc-ipq4019.c
+++ b/drivers/clk/qcom/gcc-ipq4019.c
@@ -1243,6 +1243,29 @@  static const struct clk_fepll_vco gcc_fepll_vco = {
 	.reg = 0x2f020,
 };
 
+
+const struct freq_tbl *qcom_find_freq_close(const struct freq_tbl *f,
+					     unsigned long rate)
+{
+	const struct freq_tbl *last = NULL;
+
+	for ( ; f->freq; f++) {
+		if (rate == f->freq)
+			return f;
+
+		if (f->freq > rate) {
+			if (!last ||
+			   (f->freq - rate) < (rate - last->freq))
+				return f;
+			else
+				return last;
+		}
+		last = f;
+	}
+
+	return last;
+}
+
 /*
  * Round rate function for APSS CPU PLL Clock divider.
  * It looks up the frequency table and returns the next higher frequency
@@ -1255,7 +1278,7 @@  static long clk_cpu_div_round_rate(struct clk_hw *hw, unsigned long rate,
 	struct clk_hw *p_hw;
 	const struct freq_tbl *f;
 
-	f = qcom_find_freq(pll->freq_tbl, rate);
+	f = qcom_find_freq_close(pll->freq_tbl, rate);
 	if (!f)
 		return -EINVAL;
 
@@ -1278,7 +1301,7 @@  static int clk_cpu_div_set_rate(struct clk_hw *hw, unsigned long rate,
 	u32 mask;
 	int ret;
 
-	f = qcom_find_freq(pll->freq_tbl, rate);
+	f = qcom_find_freq_close(pll->freq_tbl, rate);
 	if (!f)
 		return -EINVAL;
 
@@ -1305,6 +1328,7 @@  static unsigned long
 clk_cpu_div_recalc_rate(struct clk_hw *hw,
 			unsigned long parent_rate)
 {
+	const struct freq_tbl *f;
 	struct clk_fepll *pll = to_clk_fepll(hw);
 	u32 cdiv, pre_div;
 	u64 rate;
@@ -1325,7 +1349,11 @@  clk_cpu_div_recalc_rate(struct clk_hw *hw,
 	rate = clk_fepll_vco_calc_rate(pll, parent_rate) * 2;
 	do_div(rate, pre_div);
 
-	return rate;
+	f = qcom_find_freq_close(pll->freq_tbl, rate);
+	if (!f)
+		return rate;
+
+	return f->freq;
 };
 
 static const struct clk_ops clk_regmap_cpu_div_ops = {