From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: kernel@martin.sperl.org To: Michael Turquette , Stephen Boyd , Stephen Warren , Lee Jones , Eric Anholt , linux-clk@vger.kernel.org, linux-rpi-kernel@lists.infradead.org, linux-arm-kernel@lists.infradead.org Cc: Martin Sperl Subject: [PATCH V5] clk: bcm2835: mark enabled clocks and pll with CLK_ENABLE_HAND_OFF Date: Wed, 4 May 2016 07:53:05 +0000 Message-Id: <1462348385-16167-1-git-send-email-kernel@martin.sperl.org> List-ID: From: Martin Sperl The bcm2835 firmware enables several clocks and plls before booting the linux kernel. These plls should never get disabled as it may result in a stopped system clock and more. So during probing we check if the clock and plls are enabled and if it is then mark that clock/pll with CLK_ENABLE_HAND_OFF. Signed-off-by: Martin Sperl --- drivers/clk/bcm/clk-bcm2835.c | 17 +++++++++++++++++ 1 file changed, 17 insertions(+) Note: This requires the CLK_ENABLE_HAND_OFF patch to be applied. diff --git a/drivers/clk/bcm/clk-bcm2835.c b/drivers/clk/bcm/clk-bcm2835.c index 0fc71cb..0663b6c 100644 --- a/drivers/clk/bcm/clk-bcm2835.c +++ b/drivers/clk/bcm/clk-bcm2835.c @@ -1211,6 +1211,15 @@ bcm2835_register_pll_divider(struct bcm2835_cprman *cprman, divider->cprman = cprman; divider->data = data; + /* if the pll-divider is running, then enable CLK_ENABLE_HAND_OFF */ + if ((cprman_read(cprman, data->a2w_reg) & + A2W_PLL_CHANNEL_DISABLE) == 0) { + dev_dbg(cprman->dev, + "found firmware enabled pll_div %s - enabling hand off\n", + data->name); + init.flags |= CLK_ENABLE_HAND_OFF; + } + clk = devm_clk_register(cprman->dev, ÷r->div.hw); if (IS_ERR(clk)) return clk; @@ -1262,6 +1271,14 @@ static struct clk *bcm2835_register_clock(struct bcm2835_cprman *cprman, init.flags |= CLK_SET_RATE_GATE | CLK_SET_PARENT_GATE; } + /* if the clock is running, then enable CLK_ENABLE_HAND_OFF */ + if (cprman_read(cprman, data->ctl_reg) & CM_ENABLE) { + dev_dbg(cprman->dev, + "found firmware enabled clock %s - enabling hand off\n", + data->name); + init.flags |= CLK_ENABLE_HAND_OFF; + } + clock = devm_kzalloc(cprman->dev, sizeof(*clock), GFP_KERNEL); if (!clock) return NULL; -- 2.1.4 From mboxrd@z Thu Jan 1 00:00:00 1970 From: kernel@martin.sperl.org (kernel at martin.sperl.org) Date: Wed, 4 May 2016 07:53:05 +0000 Subject: [PATCH V5] clk: bcm2835: mark enabled clocks and pll with CLK_ENABLE_HAND_OFF Message-ID: <1462348385-16167-1-git-send-email-kernel@martin.sperl.org> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org From: Martin Sperl The bcm2835 firmware enables several clocks and plls before booting the linux kernel. These plls should never get disabled as it may result in a stopped system clock and more. So during probing we check if the clock and plls are enabled and if it is then mark that clock/pll with CLK_ENABLE_HAND_OFF. Signed-off-by: Martin Sperl --- drivers/clk/bcm/clk-bcm2835.c | 17 +++++++++++++++++ 1 file changed, 17 insertions(+) Note: This requires the CLK_ENABLE_HAND_OFF patch to be applied. diff --git a/drivers/clk/bcm/clk-bcm2835.c b/drivers/clk/bcm/clk-bcm2835.c index 0fc71cb..0663b6c 100644 --- a/drivers/clk/bcm/clk-bcm2835.c +++ b/drivers/clk/bcm/clk-bcm2835.c @@ -1211,6 +1211,15 @@ bcm2835_register_pll_divider(struct bcm2835_cprman *cprman, divider->cprman = cprman; divider->data = data; + /* if the pll-divider is running, then enable CLK_ENABLE_HAND_OFF */ + if ((cprman_read(cprman, data->a2w_reg) & + A2W_PLL_CHANNEL_DISABLE) == 0) { + dev_dbg(cprman->dev, + "found firmware enabled pll_div %s - enabling hand off\n", + data->name); + init.flags |= CLK_ENABLE_HAND_OFF; + } + clk = devm_clk_register(cprman->dev, ÷r->div.hw); if (IS_ERR(clk)) return clk; @@ -1262,6 +1271,14 @@ static struct clk *bcm2835_register_clock(struct bcm2835_cprman *cprman, init.flags |= CLK_SET_RATE_GATE | CLK_SET_PARENT_GATE; } + /* if the clock is running, then enable CLK_ENABLE_HAND_OFF */ + if (cprman_read(cprman, data->ctl_reg) & CM_ENABLE) { + dev_dbg(cprman->dev, + "found firmware enabled clock %s - enabling hand off\n", + data->name); + init.flags |= CLK_ENABLE_HAND_OFF; + } + clock = devm_kzalloc(cprman->dev, sizeof(*clock), GFP_KERNEL); if (!clock) return NULL; -- 2.1.4