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authorRam Chandra Jangir <rjangi@codeaurora.org>2016-05-21 14:48:31 +0530
committerJohn Crispin <john@phrozen.org>2016-05-27 15:50:17 +0200
commit5e49c5795697868f6317f17fda5a2b04f299e116 (patch)
treebf6ebcc54ae88fa08f268f02a8f118939fe6bf6a /target/linux/ipq806x/patches-4.4/135-clk-Avoid-sending-high-rates-to-downstream-clocks-du.patch
parent955c341d3bec0eb4971a03924e99156367255d7b (diff)
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ipq806x: Add support for linux-4.4
1)Changes - Rebased the patches for linux-4.4.7 - Added patch to fix spi nor fifo and dma support - Added patch to configure watchdog barktime 2)Testing Tested on IPQ AP148 Board: a. NOR boot and NAND boot b. ethernet network and ath10k wifi c. ubi sysupgrade UnTested dwc3 usb has not been validated on IPQ board(AP148) 3)Known Issues: Once we flash ubi image on AP148, and if we reset the board, uboot on first boot creates PEB and LEB for dynamic sized partitions, which is incorrect and not what linux expects which causes errors when trying to mount rootfs. In order to test this, we can use the below steps: a. Flash the ubi image on board and don't reset the board b. load the kernel fit image in RAM and boot from there. Signed-off-by: Ram Chandra Jangir <rjangi@codeaurora.org>
Diffstat (limited to 'target/linux/ipq806x/patches-4.4/135-clk-Avoid-sending-high-rates-to-downstream-clocks-du.patch')
-rw-r--r--target/linux/ipq806x/patches-4.4/135-clk-Avoid-sending-high-rates-to-downstream-clocks-du.patch127
1 files changed, 127 insertions, 0 deletions
diff --git a/target/linux/ipq806x/patches-4.4/135-clk-Avoid-sending-high-rates-to-downstream-clocks-du.patch b/target/linux/ipq806x/patches-4.4/135-clk-Avoid-sending-high-rates-to-downstream-clocks-du.patch
new file mode 100644
index 0000000000..5df0a5613e
--- /dev/null
+++ b/target/linux/ipq806x/patches-4.4/135-clk-Avoid-sending-high-rates-to-downstream-clocks-du.patch
@@ -0,0 +1,127 @@
+From 39d42ce5031d2a4f92fa203b87acfbab340b15a2 Mon Sep 17 00:00:00 2001
+From: Stephen Boyd <sboyd@codeaurora.org>
+Date: Fri, 20 Mar 2015 23:45:22 -0700
+Subject: [PATCH 2/2] clk: Avoid sending high rates to downstream clocks during
+ set_rate
+
+If a clock is on and we call clk_set_rate() on it we may get into
+a situation where the clock temporarily increases in rate
+dramatically while we walk the tree and call .set_rate() ops. For
+example, consider a case where a PLL feeds into a divider.
+Initially the divider is set to divide by 1 and the PLL is
+running fairly slow (100MHz). The downstream consumer of the
+divider output can only handle rates =< 400 MHz, but the divider
+can only choose between divisors of 1 and 4.
+
+ +-----+ +----------------+
+ | PLL |-->| div 1 or div 4 |---> consumer device
+ +-----+ +----------------+
+
+To achieve a rate of 400MHz on the output of the divider, we
+would have to set the rate of the PLL to 1.6 GHz and then divide
+it by 4. The current code would set the PLL to 1.6GHz first while
+the divider is still set to 1, thus causing the downstream
+consumer of the clock to receive a few clock cycles of 1.6GHz
+clock (far beyond it's maximum acceptable rate). We should be
+changing the divider first before increasing the PLL rate to
+avoid this problem.
+
+Therefore, set the rate of any child clocks that are increasing
+in rate from their current rate so that they can increase their
+dividers if necessary. We assume that there isn't such a thing as
+minimum rate requirements.
+
+Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
+Signed-off-by: Ram Chandra Jangir <rjangi@codeaurora.org>
+---
+ drivers/clk/clk.c | 34 ++++++++++++++++++++++------------
+ 1 file changed, 22 insertions(+), 12 deletions(-)
+
+diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
+index f13c3f4..8404c3c 100644
+--- a/drivers/clk/clk.c
++++ b/drivers/clk/clk.c
+@@ -1427,21 +1427,24 @@ static struct clk_core *clk_propagate_rate_change(struct clk_core *core,
+ * walk down a subtree and set the new rates notifying the rate
+ * change on the way
+ */
+-static void clk_change_rate(struct clk_core *core)
++static void
++clk_change_rate(struct clk_core *core, unsigned long best_parent_rate)
+ {
+ struct clk_core *child;
+ struct hlist_node *tmp;
+ unsigned long old_rate;
+- unsigned long best_parent_rate = 0;
+ bool skip_set_rate = false;
+ struct clk_core *old_parent;
+
+- old_rate = core->rate;
++ hlist_for_each_entry(child, &core->children, child_node) {
++ /* Skip children who will be reparented to another clock */
++ if (child->new_parent && child->new_parent != core)
++ continue;
++ if (child->new_rate > child->rate)
++ clk_change_rate(child, core->new_rate);
++ }
+
+- if (core->new_parent)
+- best_parent_rate = core->new_parent->rate;
+- else if (core->parent)
+- best_parent_rate = core->parent->rate;
++ old_rate = core->rate;
+
+ if (core->new_parent && core->new_parent != core->parent) {
+ old_parent = __clk_set_parent_before(core, core->new_parent);
+@@ -1467,7 +1470,7 @@ static void clk_change_rate(struct clk_core *core)
+
+ trace_clk_set_rate_complete(core, core->new_rate);
+
+- core->rate = clk_recalc(core, best_parent_rate);
++ core->rate = core->new_rate;
+
+ if (core->notifier_count && old_rate != core->rate)
+ __clk_notify(core, POST_RATE_CHANGE, old_rate, core->rate);
+@@ -1483,12 +1486,13 @@ static void clk_change_rate(struct clk_core *core)
+ /* Skip children who will be reparented to another clock */
+ if (child->new_parent && child->new_parent != core)
+ continue;
+- clk_change_rate(child);
++ if (child->new_rate != child->rate)
++ clk_change_rate(child, core->new_rate);
+ }
+
+ /* handle the new child who might not be in core->children yet */
+- if (core->new_child)
+- clk_change_rate(core->new_child);
++ if (core->new_child && core->new_child->new_rate != core->new_child->rate)
++ clk_change_rate(core->new_child, core->new_rate);
+ }
+
+ static int clk_core_set_rate_nolock(struct clk_core *core,
+@@ -1497,6 +1501,7 @@ static int clk_core_set_rate_nolock(struct clk_core *core,
+ struct clk_core *top, *fail_clk;
+ unsigned long rate = req_rate;
+ int ret = 0;
++ unsigned long parent_rate;
+
+ if (!core)
+ return 0;
+@@ -1522,8 +1527,13 @@ static int clk_core_set_rate_nolock(struct clk_core *core,
+ return -EBUSY;
+ }
+
++ if (top->parent)
++ parent_rate = top->parent->rate;
++ else
++ parent_rate = 0;
++
+ /* change the rates */
+- clk_change_rate(top);
++ clk_change_rate(top, parent_rate);
+
+ core->req_rate = req_rate;
+
+--
+2.7.2
+