55adc61c56
Both earlycon and eralyprintk depend on the bootloader setup UART clocks being retained. This patch adds the common logic to detect such situations and make the information available to the clock drivers, as well as adding the facilities to disable those clocks at the end of the kernel init. Signed-off-by: Lucas Stach <l.stach@pengutronix.de> Signed-off-by: Shawn Guo <shawnguo@kernel.org>
114 lines
2.6 KiB
C
114 lines
2.6 KiB
C
#include <linux/clk.h>
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#include <linux/err.h>
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#include <linux/of.h>
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#include <linux/slab.h>
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#include <linux/spinlock.h>
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#include "clk.h"
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DEFINE_SPINLOCK(imx_ccm_lock);
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void __init imx_check_clocks(struct clk *clks[], unsigned int count)
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{
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unsigned i;
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for (i = 0; i < count; i++)
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if (IS_ERR(clks[i]))
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pr_err("i.MX clk %u: register failed with %ld\n",
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i, PTR_ERR(clks[i]));
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}
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static struct clk * __init imx_obtain_fixed_clock_from_dt(const char *name)
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{
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struct of_phandle_args phandle;
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struct clk *clk = ERR_PTR(-ENODEV);
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char *path;
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path = kasprintf(GFP_KERNEL, "/clocks/%s", name);
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if (!path)
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return ERR_PTR(-ENOMEM);
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phandle.np = of_find_node_by_path(path);
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kfree(path);
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if (phandle.np) {
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clk = of_clk_get_from_provider(&phandle);
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of_node_put(phandle.np);
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}
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return clk;
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}
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struct clk * __init imx_obtain_fixed_clock(
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const char *name, unsigned long rate)
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{
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struct clk *clk;
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clk = imx_obtain_fixed_clock_from_dt(name);
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if (IS_ERR(clk))
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clk = imx_clk_fixed(name, rate);
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return clk;
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}
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/*
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* This fixups the register CCM_CSCMR1 write value.
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* The write/read/divider values of the aclk_podf field
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* of that register have the relationship described by
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* the following table:
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*
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* write value read value divider
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* 3b'000 3b'110 7
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* 3b'001 3b'111 8
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* 3b'010 3b'100 5
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* 3b'011 3b'101 6
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* 3b'100 3b'010 3
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* 3b'101 3b'011 4
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* 3b'110 3b'000 1
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* 3b'111 3b'001 2(default)
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*
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* That's why we do the xor operation below.
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*/
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#define CSCMR1_FIXUP 0x00600000
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void imx_cscmr1_fixup(u32 *val)
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{
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*val ^= CSCMR1_FIXUP;
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return;
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}
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static int imx_keep_uart_clocks __initdata;
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static struct clk ** const *imx_uart_clocks __initdata;
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static int __init imx_keep_uart_clocks_param(char *str)
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{
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imx_keep_uart_clocks = 1;
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return 0;
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}
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__setup_param("earlycon", imx_keep_uart_earlycon,
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imx_keep_uart_clocks_param, 0);
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__setup_param("earlyprintk", imx_keep_uart_earlyprintk,
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imx_keep_uart_clocks_param, 0);
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void __init imx_register_uart_clocks(struct clk ** const clks[])
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{
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if (imx_keep_uart_clocks) {
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int i;
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imx_uart_clocks = clks;
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for (i = 0; imx_uart_clocks[i]; i++)
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clk_prepare_enable(*imx_uart_clocks[i]);
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}
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}
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static int __init imx_clk_disable_uart(void)
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{
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if (imx_keep_uart_clocks && imx_uart_clocks) {
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int i;
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for (i = 0; imx_uart_clocks[i]; i++)
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clk_disable_unprepare(*imx_uart_clocks[i]);
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}
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return 0;
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}
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late_initcall_sync(imx_clk_disable_uart);
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