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clk: at91: usb: propagate rate modification to the parent clk
The at91sam9n12 and at91sam9x5 usb clocks do not propagate rate modification requests to their parents. This causes a bug when the PLLB is left uninitialized by the bootloader (PLL multiplier set to 0, or in other words, PLL rate = 0 Hz). Implement the determinate_rate method and propagate the change rate request to the parent clk. Cc: <stable@vger.kernel.org> # v3.14+ Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com> Reported-by: Bo Shen <voice.shen@atmel.com> Tested-by: Bo Shen <voice.shen@atmel.com> Signed-off-by: Michael Turquette <mturquette@linaro.org>
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3a9e9cb65b
commit
4591243102
1 changed files with 49 additions and 15 deletions
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@ -56,22 +56,55 @@ static unsigned long at91sam9x5_clk_usb_recalc_rate(struct clk_hw *hw,
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return DIV_ROUND_CLOSEST(parent_rate, (usbdiv + 1));
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}
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static long at91sam9x5_clk_usb_round_rate(struct clk_hw *hw, unsigned long rate,
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unsigned long *parent_rate)
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static long at91sam9x5_clk_usb_determine_rate(struct clk_hw *hw,
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unsigned long rate,
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unsigned long min_rate,
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unsigned long max_rate,
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unsigned long *best_parent_rate,
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struct clk_hw **best_parent_hw)
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{
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unsigned long div;
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struct clk *parent = NULL;
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long best_rate = -EINVAL;
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unsigned long tmp_rate;
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int best_diff = -1;
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int tmp_diff;
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int i;
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if (!rate)
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return -EINVAL;
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for (i = 0; i < __clk_get_num_parents(hw->clk); i++) {
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int div;
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if (rate >= *parent_rate)
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return *parent_rate;
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parent = clk_get_parent_by_index(hw->clk, i);
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if (!parent)
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continue;
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div = DIV_ROUND_CLOSEST(*parent_rate, rate);
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if (div > SAM9X5_USB_MAX_DIV + 1)
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div = SAM9X5_USB_MAX_DIV + 1;
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for (div = 1; div < SAM9X5_USB_MAX_DIV + 2; div++) {
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unsigned long tmp_parent_rate;
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return DIV_ROUND_CLOSEST(*parent_rate, div);
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tmp_parent_rate = rate * div;
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tmp_parent_rate = __clk_round_rate(parent,
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tmp_parent_rate);
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tmp_rate = DIV_ROUND_CLOSEST(tmp_parent_rate, div);
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if (tmp_rate < rate)
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tmp_diff = rate - tmp_rate;
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else
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tmp_diff = tmp_rate - rate;
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if (best_diff < 0 || best_diff > tmp_diff) {
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best_rate = tmp_rate;
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best_diff = tmp_diff;
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*best_parent_rate = tmp_parent_rate;
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*best_parent_hw = __clk_get_hw(parent);
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}
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if (!best_diff || tmp_rate < rate)
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break;
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}
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if (!best_diff)
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break;
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}
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return best_rate;
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}
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static int at91sam9x5_clk_usb_set_parent(struct clk_hw *hw, u8 index)
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@ -121,7 +154,7 @@ static int at91sam9x5_clk_usb_set_rate(struct clk_hw *hw, unsigned long rate,
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static const struct clk_ops at91sam9x5_usb_ops = {
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.recalc_rate = at91sam9x5_clk_usb_recalc_rate,
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.round_rate = at91sam9x5_clk_usb_round_rate,
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.determine_rate = at91sam9x5_clk_usb_determine_rate,
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.get_parent = at91sam9x5_clk_usb_get_parent,
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.set_parent = at91sam9x5_clk_usb_set_parent,
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.set_rate = at91sam9x5_clk_usb_set_rate,
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@ -159,7 +192,7 @@ static const struct clk_ops at91sam9n12_usb_ops = {
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.disable = at91sam9n12_clk_usb_disable,
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.is_enabled = at91sam9n12_clk_usb_is_enabled,
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.recalc_rate = at91sam9x5_clk_usb_recalc_rate,
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.round_rate = at91sam9x5_clk_usb_round_rate,
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.determine_rate = at91sam9x5_clk_usb_determine_rate,
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.set_rate = at91sam9x5_clk_usb_set_rate,
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};
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@ -179,7 +212,8 @@ at91sam9x5_clk_register_usb(struct at91_pmc *pmc, const char *name,
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init.ops = &at91sam9x5_usb_ops;
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init.parent_names = parent_names;
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init.num_parents = num_parents;
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init.flags = CLK_SET_RATE_GATE | CLK_SET_PARENT_GATE;
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init.flags = CLK_SET_RATE_GATE | CLK_SET_PARENT_GATE |
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CLK_SET_RATE_PARENT;
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usb->hw.init = &init;
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usb->pmc = pmc;
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@ -207,7 +241,7 @@ at91sam9n12_clk_register_usb(struct at91_pmc *pmc, const char *name,
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init.ops = &at91sam9n12_usb_ops;
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init.parent_names = &parent_name;
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init.num_parents = 1;
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init.flags = CLK_SET_RATE_GATE;
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init.flags = CLK_SET_RATE_GATE | CLK_SET_RATE_PARENT;
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usb->hw.init = &init;
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usb->pmc = pmc;
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