On Mon, Dec 05, 2016 at 06:54:34AM -0800, Andrey Smirnov wrote:
> Mask ROM leaves the CPU running at 264Mhz, so configure the clock tree
> to such that CPU runs at maximum supported frequency, based on speed
> grading burned into OCOTP fusebox.
>
> Signed-off-by: Andrey Smirnov <andrew.smirnov@xxxxxxxxx>
> ---
> arch/arm/mach-imx/Kconfig | 13 +++
> drivers/clk/imx/clk-vf610.c | 187 +++++++++++++++++++++++++++++++++++++++++++-
> 2 files changed, 198 insertions(+), 2 deletions(-)
>
> diff --git a/arch/arm/mach-imx/Kconfig b/arch/arm/mach-imx/Kconfig
> index af533ea..1752335 100644
> --- a/arch/arm/mach-imx/Kconfig
> +++ b/arch/arm/mach-imx/Kconfig
> @@ -750,6 +750,19 @@ config HABV3_IMG_CRT_DER
>
> endif
>
> +config ADJUST_CPU_CLOCK
> + bool "Adjust CPU clock based on its speed grading"
> + select IMX_OCOTP
> + depends on ARCH_VF610
> + default y
> + help
> + Some i.MX SoCs (e. g. Vybrid) are manufactured to have
> + several variants of the same chip different only in maxumum
s/maxumum/maximum/
> + CPU frequency supported. MaskROM on such chips plays it safe
> + and uses the lowest possible frequency. This option
> + configures Barebox to read chip's speed grade information
> + and increase CPU clock to it's highest possible value.
Why do we need this configurable?
> +
> endmenu
>
> endif
> diff --git a/drivers/clk/imx/clk-vf610.c b/drivers/clk/imx/clk-vf610.c
> index 04cb02f..1cf2b65 100644
> --- a/drivers/clk/imx/clk-vf610.c
> +++ b/drivers/clk/imx/clk-vf610.c
> @@ -16,7 +16,9 @@
> #include <of_address.h>
> #include <linux/clkdev.h>
> #include <linux/clk.h>
> +#include <notifier.h>
> #include <dt-bindings/clock/vf610-clock.h>
> +#include <mach/vf610-regs.h>
>
> #include "clk.h"
>
> @@ -76,6 +78,7 @@
> #define PLL6_CTRL (anatop_base + 0xa0)
> #define PLL7_CTRL (anatop_base + 0x20)
> #define ANA_MISC1 (anatop_base + 0x160)
> +#define PLL_LOCK (anatop_base + 0x2c0)
>
> static void __iomem *anatop_base;
> static void __iomem *ccm_base;
> @@ -188,8 +191,9 @@ static void __init vf610_clocks_init(struct device_node *ccm_node)
> clk[VF610_CLK_PLL6_BYPASS_SRC] = imx_clk_mux("pll6_bypass_src", PLL6_CTRL, 14, 1, pll_bypass_src_sels, ARRAY_SIZE(pll_bypass_src_sels));
> clk[VF610_CLK_PLL7_BYPASS_SRC] = imx_clk_mux("pll7_bypass_src", PLL7_CTRL, 14, 1, pll_bypass_src_sels, ARRAY_SIZE(pll_bypass_src_sels));
>
> - clk[VF610_CLK_PLL1] = imx_clk_pllv3(IMX_PLLV3_GENERIC, "pll1", "pll1_bypass_src", PLL1_CTRL, 0x1);
> - clk[VF610_CLK_PLL2] = imx_clk_pllv3(IMX_PLLV3_GENERIC, "pll2", "pll2_bypass_src", PLL2_CTRL, 0x1);
> + clk[VF610_CLK_PLL1] = imx_clk_pllv3_locked(IMX_PLLV3_SYS_VF610, "pll1", "pll1_bypass_src", PLL1_CTRL, 0x1, PLL_LOCK, BIT(6));
> + clk[VF610_CLK_PLL2] = imx_clk_pllv3_locked(IMX_PLLV3_SYS_VF610, "pll2", "pll2_bypass_src", PLL2_CTRL, 0x1, PLL_LOCK, BIT(5));
> +
> clk[VF610_CLK_PLL3] = imx_clk_pllv3(IMX_PLLV3_USB_VF610, "pll3", "pll3_bypass_src", PLL3_CTRL, 0x2);
> clk[VF610_CLK_PLL4] = imx_clk_pllv3(IMX_PLLV3_AV, "pll4", "pll4_bypass_src", PLL4_CTRL, 0x7f);
> clk[VF610_CLK_PLL5] = imx_clk_pllv3(IMX_PLLV3_ENET, "pll5", "pll5_bypass_src", PLL5_CTRL, 0x3);
> @@ -441,3 +445,182 @@ static void __init vf610_clocks_init(struct device_node *ccm_node)
> of_clk_add_provider(np, of_clk_src_onecell_get, &clk_data);
> }
> CLK_OF_DECLARE(vf610, "fsl,vf610-ccm", vf610_clocks_init);
> +
> +#ifdef CONFIG_ADJUST_CPU_CLOCK
> +
> +enum {
> + OCOTP_SPEED_GRADING_OFFSET = (0x4 * sizeof(uint32_t)),
> + OCOTP_SPEED_GRADING_SHIFT = 18,
> + OCOTP_SPEED_GRADING_MASK = 0b1111,
> +
> + VF610_SPEED_500 = 0b1110,
> + VF610_SPEED_400 = 0b1001,
> + VF610_SPEED_266 = 0b0001,
> +
> + DDRMC_CR117 = 0x01d4,
> + DDRMC_CR117_AXI0_FITYPEREG_SYNC = 0b01 << 16,
> +};
> +
> +static int vf610_switch_cpu_clock_to_500mhz(void)
> +{
> + int ret;
> +
> + /*
> + * When switching A5 CPU to 500Mhz we expect DDRC to be
> + * clocked by PLL2_PFD2 and the system to be configured in
> + * asynchronous mode.
> + *
> + * We also can't just use default PFD1 output of PLL1 due to
> + * Errata e6235, so we have to re-clock the PLL itself and use
> + * its output to clock the CPU directly.
> + */
> +
> + if (clk_get_parent(clk[VF610_CLK_DDR_SEL]) != clk[VF610_CLK_PLL2_PFD2]) {
> + pr_warn("DDRC is clocked by PLL1, can't switch CPU clock");
> + return -EINVAL;
> + }
> +
> + ret = clk_set_parent(clk[VF610_CLK_SYS_SEL], clk[VF610_CLK_PLL2_BUS]);
> + if (ret < 0) {
> + pr_crit("Unable to re-parent '%s'\n",
> + clk[VF610_CLK_SYS_SEL]->name);
> + return ret;
> + }
> +
> + ret = clk_set_rate(clk[VF610_CLK_PLL1], 500000000);
> + if (ret < 0) {
> + pr_crit("Unable to set %s to 500Mhz %d\n",
> + clk[VF610_CLK_PLL1]->name, ret);
> + return ret;
> + }
> +
> + ret = clk_set_parent(clk[VF610_CLK_PLL1_PFD_SEL], clk[VF610_CLK_PLL1_SYS]);
> + if (ret < 0) {
> + pr_crit("Unable to re-parent '%s'\n",
> + clk[VF610_CLK_PLL1_PFD_SEL]->name);
> + return ret;
> + }
> +
> + ret = clk_set_parent(clk[VF610_CLK_SYS_SEL], clk[VF610_CLK_PLL1_PFD_SEL]);
> + if (ret < 0) {
> + pr_crit("Unable to re-parent '%s'\n",
> + clk[VF610_CLK_SYS_SEL]->name);
> + return ret;
> + }
> +
> + /*
> + * imx_clk_divider has no error path in its set_rate hook
> + */
> + clk_set_rate(clk[VF610_CLK_SYS_BUS], clk_get_rate(clk[VF610_CLK_SYS_SEL]));
> + clk_set_rate(clk[VF610_CLK_PLATFORM_BUS], clk_get_rate(clk[VF610_CLK_SYS_BUS]) / 3);
> +
> + return ret;
> +}
> +
> +static int vf610_switch_cpu_clock_to_400mhz(void)
> +{
> + int ret;
> + uint32_t cr117;
> + void * __iomem ddrmc = IOMEM(VF610_DDR_BASE_ADDR);
> +
> + if (clk_get_parent(clk[VF610_CLK_DDR_SEL]) != clk[VF610_CLK_PLL2_PFD2]) {
> + pr_warn("DDRC is clocked by PLL1, can't switch CPU clock");
> + return -EINVAL;
> + }
> +
> + ret = clk_set_parent(clk[VF610_CLK_PLL2_PFD_SEL], clk[VF610_CLK_PLL2_PFD2]);
> + if (ret < 0) {
> + pr_crit("Unable to re-parent '%s'\n",
> + clk[VF610_CLK_PLL2_PFD_SEL]->name);
> + return ret;
> + }
> +
> + ret = clk_set_parent(clk[VF610_CLK_SYS_SEL], clk[VF610_CLK_PLL2_PFD_SEL]);
> + if (ret < 0) {
> + pr_crit("Unable to re-parent '%s'\n",
> + clk[VF610_CLK_SYS_SEL]->name);
> + return ret;
> + }
> +
> + /*
> + * imx_clk_divider has no error path in its set_rate hook
> + */
> + clk_set_rate(clk[VF610_CLK_SYS_BUS], clk_get_rate(clk[VF610_CLK_SYS_SEL]));
> + clk_set_rate(clk[VF610_CLK_PLATFORM_BUS], clk_get_rate(clk[VF610_CLK_SYS_BUS]) / 3);
> +
> + /*
> + * Now that we are running off of the same clock as DDRMC we
> + * shouldn't need to use clock domain corssing FIFO and
s/corssing/crossing/?
> + * asynchronous mode and instead can swithch to sychronous
> + * mode for AXI0 accesses
> + */
> + cr117 = readl(ddrmc + DDRMC_CR117);
> + cr117 |= DDRMC_CR117_AXI0_FITYPEREG_SYNC;
> + writel(cr117, ddrmc + DDRMC_CR117);
> +
> + return 0;
> +}
> +
> +static int vf610_switch_cpu_clock(void)
> +{
> + int ret;
> + struct device_node *ocotp_node;
> + struct cdev *ocotp;
> + uint32_t speed_grading;
> +
> + if (!of_machine_is_compatible("fsl,vf610"))
> + return 0;
> +
> + ocotp_node = of_find_compatible_node(NULL, NULL, "fsl,vf610-ocotp");
> + if (!ocotp_node) {
> + pr_err("Unable to find OCOTP DT node\n");
> + return -ENODEV;
> + }
> +
> + ocotp = cdev_by_device_node(ocotp_node);
> + if (!ocotp) {
> + pr_err("No OCOTP character device\n");
> + return -ENODEV;
> + }
> +
> + ret = cdev_read(ocotp, &speed_grading, sizeof(speed_grading),
> + OCOTP_SPEED_GRADING_OFFSET, 0);
> + if (ret != sizeof(speed_grading)) {
> + pr_err("Failed to read speed grading data\n");
> + return ret < 0 ? ret : -EIO;
> + }
There's a better way to access ocotp registers. see
imx_ocotp_read_field().
> +
> + speed_grading >>= OCOTP_SPEED_GRADING_SHIFT;
> + speed_grading &= OCOTP_SPEED_GRADING_MASK;
> +
> + switch (speed_grading) {
> + default:
> + pr_err("Unknown CPU speed grading %x\n", speed_grading);
> + return -EINVAL;
> +
> + case VF610_SPEED_266:
> + return 0;
> +
> + case VF610_SPEED_500:
> + ret = vf610_switch_cpu_clock_to_500mhz();
> + break;
> +
> + case VF610_SPEED_400:
> + ret = vf610_switch_cpu_clock_to_400mhz();
> + break;
> + }
> +
> + clock_notifier_call_chain();
> + return ret;
> +}
> +/*
> + * We can probably gain a bit of a boot speed if we switch CPU clock
> + * earlier, but if we do this we'd need to figure out a way how to
> + * re-adjust the baud rate settings of the UART for DEBUG_LL
> + * functionality, or, accept the fact that it will be unavailbe after
s/unavailbe/unavailable/
Sascha
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