From 7001ec560a82d1cc2ba5c0c9ac1f7fcca820b27e Mon Sep 17 00:00:00 2001 From: Arnd Bergmann Date: Mon, 1 Feb 2016 11:19:10 +0100 Subject: [PATCH] clk: vt8500: don't return possibly uninitialized data The clk-vt8500.c driver would previously enter an endless loop when invalid settings got requested, this was now fixed. However, the driver will now return uninitialized data for a subset of those cases instead, as the gcc correctly warns: clk/clk-vt8500.c: In function 'wm8650_find_pll_bits': clk/clk-vt8500.c:423:12: error: 'best_div2' may be used uninitialized in this function [-Werror=maybe-uninitialized] *divisor2 = best_div2; ^ clk/clk-vt8500.c:422:12: error: 'best_div1' may be used uninitialized in this function [-Werror=maybe-uninitialized] *divisor1 = best_div1; ^ clk/clk-vt8500.c:421:14: error: 'best_mul' may be used uninitialized in this function [-Werror=maybe-uninitialized] *multiplier = best_mul; This reworks the error handling in the driver so we now return -EINVAL from clk_round_rate() and clk_set_rate() when we get impossible inputs. Signed-off-by: Arnd Bergmann Fixes: 090341b0a95d ("clk: vt8500: fix sign of possible PLL values") Signed-off-by: Stephen Boyd --- drivers/clk/clk-vt8500.c | 91 ++++++++++++++++++++++++++++------------ 1 file changed, 65 insertions(+), 26 deletions(-) diff --git a/drivers/clk/clk-vt8500.c b/drivers/clk/clk-vt8500.c index 98c4492d2c0d..b0f76a84f1e9 100644 --- a/drivers/clk/clk-vt8500.c +++ b/drivers/clk/clk-vt8500.c @@ -355,7 +355,7 @@ CLK_OF_DECLARE(vt8500_device, "via,vt8500-device-clock", vtwm_device_clk_init); #define WM8850_BITS_TO_VAL(m, d1, d2) \ ((((m / 2) - 1) << 16) | ((d1 - 1) << 8) | d2) -static void vt8500_find_pll_bits(unsigned long rate, unsigned long parent_rate, +static int vt8500_find_pll_bits(unsigned long rate, unsigned long parent_rate, u32 *multiplier, u32 *prediv) { unsigned long tclk; @@ -365,7 +365,7 @@ static void vt8500_find_pll_bits(unsigned long rate, unsigned long parent_rate, pr_err("%s: requested rate out of range\n", __func__); *multiplier = 0; *prediv = 1; - return; + return -EINVAL; } if (rate <= parent_rate * 31) /* use the prediv to double the resolution */ @@ -379,9 +379,11 @@ static void vt8500_find_pll_bits(unsigned long rate, unsigned long parent_rate, if (tclk != rate) pr_warn("%s: requested rate %lu, found rate %lu\n", __func__, rate, tclk); + + return 0; } -static void wm8650_find_pll_bits(unsigned long rate, unsigned long parent_rate, +static int wm8650_find_pll_bits(unsigned long rate, unsigned long parent_rate, u32 *multiplier, u32 *divisor1, u32 *divisor2) { u32 mul, div1; @@ -404,7 +406,7 @@ static void wm8650_find_pll_bits(unsigned long rate, unsigned long parent_rate, *multiplier = mul; *divisor1 = div1; *divisor2 = div2; - return; + return 0; } if (rate_err < best_err) { @@ -415,12 +417,19 @@ static void wm8650_find_pll_bits(unsigned long rate, unsigned long parent_rate, } } + if (best_err == (unsigned long)-1) { + pr_warn("%s: impossible rate %lu\n", __func__, rate); + return -EINVAL; + } + /* if we got here, it wasn't an exact match */ pr_warn("%s: requested rate %lu, found rate %lu\n", __func__, rate, rate - best_err); *multiplier = best_mul; *divisor1 = best_div1; *divisor2 = best_div2; + + return 0; } static u32 wm8750_get_filter(u32 parent_rate, u32 divisor1) @@ -450,7 +459,7 @@ static u32 wm8750_get_filter(u32 parent_rate, u32 divisor1) return 0; } -static void wm8750_find_pll_bits(unsigned long rate, unsigned long parent_rate, +static int wm8750_find_pll_bits(unsigned long rate, unsigned long parent_rate, u32 *filter, u32 *multiplier, u32 *divisor1, u32 *divisor2) { u32 mul; @@ -474,7 +483,7 @@ static void wm8750_find_pll_bits(unsigned long rate, unsigned long parent_rate, *multiplier = mul; *divisor1 = div1; *divisor2 = div2; - return; + return 0; } if (rate_err < best_err) { @@ -485,6 +494,11 @@ static void wm8750_find_pll_bits(unsigned long rate, unsigned long parent_rate, } } + if (best_err == (unsigned long)-1) { + pr_warn("%s: impossible rate %lu\n", __func__, rate); + return -EINVAL; + } + /* if we got here, it wasn't an exact match */ pr_warn("%s: requested rate %lu, found rate %lu\n", __func__, rate, rate - best_err); @@ -493,9 +507,11 @@ static void wm8750_find_pll_bits(unsigned long rate, unsigned long parent_rate, *multiplier = best_mul; *divisor1 = best_div1; *divisor2 = best_div2; + + return 0; } -static void wm8850_find_pll_bits(unsigned long rate, unsigned long parent_rate, +static int wm8850_find_pll_bits(unsigned long rate, unsigned long parent_rate, u32 *multiplier, u32 *divisor1, u32 *divisor2) { u32 mul; @@ -519,7 +535,7 @@ static void wm8850_find_pll_bits(unsigned long rate, unsigned long parent_rate, *multiplier = mul; *divisor1 = div1; *divisor2 = div2; - return; + return 0; } if (rate_err < best_err) { @@ -530,6 +546,11 @@ static void wm8850_find_pll_bits(unsigned long rate, unsigned long parent_rate, } } + if (best_err == (unsigned long)-1) { + pr_warn("%s: impossible rate %lu\n", __func__, rate); + return -EINVAL; + } + /* if we got here, it wasn't an exact match */ pr_warn("%s: requested rate %lu, found rate %lu\n", __func__, rate, rate - best_err); @@ -537,6 +558,8 @@ static void wm8850_find_pll_bits(unsigned long rate, unsigned long parent_rate, *multiplier = best_mul; *divisor1 = best_div1; *divisor2 = best_div2; + + return 0; } static int vtwm_pll_set_rate(struct clk_hw *hw, unsigned long rate, @@ -546,31 +569,39 @@ static int vtwm_pll_set_rate(struct clk_hw *hw, unsigned long rate, u32 filter, mul, div1, div2; u32 pll_val; unsigned long flags = 0; + int ret; /* sanity check */ switch (pll->type) { case PLL_TYPE_VT8500: - vt8500_find_pll_bits(rate, parent_rate, &mul, &div1); - pll_val = VT8500_BITS_TO_VAL(mul, div1); + ret = vt8500_find_pll_bits(rate, parent_rate, &mul, &div1); + if (!ret) + pll_val = VT8500_BITS_TO_VAL(mul, div1); break; case PLL_TYPE_WM8650: - wm8650_find_pll_bits(rate, parent_rate, &mul, &div1, &div2); - pll_val = WM8650_BITS_TO_VAL(mul, div1, div2); + ret = wm8650_find_pll_bits(rate, parent_rate, &mul, &div1, &div2); + if (!ret) + pll_val = WM8650_BITS_TO_VAL(mul, div1, div2); break; case PLL_TYPE_WM8750: - wm8750_find_pll_bits(rate, parent_rate, &filter, &mul, &div1, &div2); - pll_val = WM8750_BITS_TO_VAL(filter, mul, div1, div2); + ret = wm8750_find_pll_bits(rate, parent_rate, &filter, &mul, &div1, &div2); + if (!ret) + pll_val = WM8750_BITS_TO_VAL(filter, mul, div1, div2); break; case PLL_TYPE_WM8850: - wm8850_find_pll_bits(rate, parent_rate, &mul, &div1, &div2); - pll_val = WM8850_BITS_TO_VAL(mul, div1, div2); + ret = wm8850_find_pll_bits(rate, parent_rate, &mul, &div1, &div2); + if (!ret) + pll_val = WM8850_BITS_TO_VAL(mul, div1, div2); break; default: pr_err("%s: invalid pll type\n", __func__); - return 0; + ret = -EINVAL; } + if (ret) + return ret; + spin_lock_irqsave(pll->lock, flags); vt8500_pmc_wait_busy(); @@ -588,28 +619,36 @@ static long vtwm_pll_round_rate(struct clk_hw *hw, unsigned long rate, struct clk_pll *pll = to_clk_pll(hw); u32 filter, mul, div1, div2; long round_rate; + int ret; switch (pll->type) { case PLL_TYPE_VT8500: - vt8500_find_pll_bits(rate, *prate, &mul, &div1); - round_rate = VT8500_BITS_TO_FREQ(*prate, mul, div1); + ret = vt8500_find_pll_bits(rate, *prate, &mul, &div1); + if (!ret) + round_rate = VT8500_BITS_TO_FREQ(*prate, mul, div1); break; case PLL_TYPE_WM8650: - wm8650_find_pll_bits(rate, *prate, &mul, &div1, &div2); - round_rate = WM8650_BITS_TO_FREQ(*prate, mul, div1, div2); + ret = wm8650_find_pll_bits(rate, *prate, &mul, &div1, &div2); + if (!ret) + round_rate = WM8650_BITS_TO_FREQ(*prate, mul, div1, div2); break; case PLL_TYPE_WM8750: - wm8750_find_pll_bits(rate, *prate, &filter, &mul, &div1, &div2); - round_rate = WM8750_BITS_TO_FREQ(*prate, mul, div1, div2); + ret = wm8750_find_pll_bits(rate, *prate, &filter, &mul, &div1, &div2); + if (!ret) + round_rate = WM8750_BITS_TO_FREQ(*prate, mul, div1, div2); break; case PLL_TYPE_WM8850: - wm8850_find_pll_bits(rate, *prate, &mul, &div1, &div2); - round_rate = WM8850_BITS_TO_FREQ(*prate, mul, div1, div2); + ret = wm8850_find_pll_bits(rate, *prate, &mul, &div1, &div2); + if (!ret) + round_rate = WM8850_BITS_TO_FREQ(*prate, mul, div1, div2); break; default: - round_rate = 0; + ret = -EINVAL; } + if (ret) + return ret; + return round_rate; } -- 2.20.1