clk: imx: Fix reparenting of UARTs not associated with stdout

Most if not all i.MX SoC's call a function which enables all UARTS.
This is a problem for users who need to re-parent the clock source,
because any attempt to change the parent results in an busy error
due to the fact that the clocks have been enabled already.

clk: failed to reparent uart1 to sys_pll1_80m: -16

Instead of pre-initializing all UARTS, scan the device tree to see
which UART clocks are associated to stdout, and only enable those
UART clocks if it's needed early. This will move initialization of
the remaining clocks until after the parenting of the clocks.

When the clocks are shutdown, this mechanism will also disable any
clocks that were pre-initialized.

Fixes: 9461f7b33d11c ("clk: fix CLK_SET_RATE_GATE with clock rate protection")
Suggested-by: Aisheng Dong <[e-mail]>
Signed-off-by: Adam Ford <[e-mail]>
Reviewed-by: Abel Vesa <[e-mail]>
Tested-by: Ahmad Fatoum <[e-mail]>
Signed-off-by: Abel Vesa <[e-mail]>

drivers/clk/imx/clk-imx25.c

···
 
 static struct clk *clk[clk_max];
 
-static struct clk ** const uart_clks[] __initconst = {
-	&clk[uart_ipg_per],
-	&clk[uart1_ipg],
-	&clk[uart2_ipg],
-	&clk[uart3_ipg],
-	&clk[uart4_ipg],
-	&clk[uart5_ipg],
-	NULL
-};
-
 static int __init __mx25_clocks_init(void __iomem *ccm_base)
 {
 	BUG_ON(!ccm_base);
···
 	 */
 	clk_set_parent(clk[cko_sel], clk[ipg]);
 
-	imx_register_uart_clocks(uart_clks);
+	imx_register_uart_clocks(6);
 
 	return 0;
 }

drivers/clk/imx/clk-imx27.c

···
 static struct clk *clk[IMX27_CLK_MAX];
 static struct clk_onecell_data clk_data;
 
-static struct clk ** const uart_clks[] __initconst = {
-	&clk[IMX27_CLK_PER1_GATE],
-	&clk[IMX27_CLK_UART1_IPG_GATE],
-	&clk[IMX27_CLK_UART2_IPG_GATE],
-	&clk[IMX27_CLK_UART3_IPG_GATE],
-	&clk[IMX27_CLK_UART4_IPG_GATE],
-	&clk[IMX27_CLK_UART5_IPG_GATE],
-	&clk[IMX27_CLK_UART6_IPG_GATE],
-	NULL
-};
-
 static void __init _mx27_clocks_init(unsigned long fref)
 {
 	BUG_ON(!ccm);
···
 
 	clk_prepare_enable(clk[IMX27_CLK_EMI_AHB_GATE]);
 
-	imx_register_uart_clocks(uart_clks);
+	imx_register_uart_clocks(7);
 
 	imx_print_silicon_rev("i.MX27", mx27_revision());
 }

drivers/clk/imx/clk-imx35.c

···
 
 static struct clk *clk[clk_max];
 
-static struct clk ** const uart_clks[] __initconst = {
-	&clk[ipg],
-	&clk[uart1_gate],
-	&clk[uart2_gate],
-	&clk[uart3_gate],
-	NULL
-};
-
 static void __init _mx35_clocks_init(void)
 {
 	void __iomem *base;
···
 	 */
 	clk_prepare_enable(clk[scc_gate]);
 
-	imx_register_uart_clocks(uart_clks);
+	imx_register_uart_clocks(4);
 
 	imx_print_silicon_rev("i.MX35", mx35_revision());
 }

drivers/clk/imx/clk-imx5.c

···
 static struct clk *clk[IMX5_CLK_END];
 static struct clk_onecell_data clk_data;
 
-static struct clk ** const uart_clks_mx51[] __initconst = {
-	&clk[IMX5_CLK_UART1_IPG_GATE],
-	&clk[IMX5_CLK_UART1_PER_GATE],
-	&clk[IMX5_CLK_UART2_IPG_GATE],
-	&clk[IMX5_CLK_UART2_PER_GATE],
-	&clk[IMX5_CLK_UART3_IPG_GATE],
-	&clk[IMX5_CLK_UART3_PER_GATE],
-	NULL
-};
-
-static struct clk ** const uart_clks_mx50_mx53[] __initconst = {
-	&clk[IMX5_CLK_UART1_IPG_GATE],
-	&clk[IMX5_CLK_UART1_PER_GATE],
-	&clk[IMX5_CLK_UART2_IPG_GATE],
-	&clk[IMX5_CLK_UART2_PER_GATE],
-	&clk[IMX5_CLK_UART3_IPG_GATE],
-	&clk[IMX5_CLK_UART3_PER_GATE],
-	&clk[IMX5_CLK_UART4_IPG_GATE],
-	&clk[IMX5_CLK_UART4_PER_GATE],
-	&clk[IMX5_CLK_UART5_IPG_GATE],
-	&clk[IMX5_CLK_UART5_PER_GATE],
-	NULL
-};
-
 static void __init mx5_clocks_common_init(void __iomem *ccm_base)
 {
 	clk[IMX5_CLK_DUMMY]		= imx_clk_fixed("dummy", 0);
···
 	r = clk_round_rate(clk[IMX5_CLK_USBOH3_PER_GATE], 54000000);
 	clk_set_rate(clk[IMX5_CLK_USBOH3_PER_GATE], r);
 
-	imx_register_uart_clocks(uart_clks_mx50_mx53);
+	imx_register_uart_clocks(5);
 }
 CLK_OF_DECLARE(imx50_ccm, "fsl,imx50-ccm", mx50_clocks_init);
 
···
 	val |= 1 << 23;
 	writel(val, MXC_CCM_CLPCR);
 
-	imx_register_uart_clocks(uart_clks_mx51);
+	imx_register_uart_clocks(3);
 }
 CLK_OF_DECLARE(imx51_ccm, "fsl,imx51-ccm", mx51_clocks_init);
 
···
 	r = clk_round_rate(clk[IMX5_CLK_USBOH3_PER_GATE], 54000000);
 	clk_set_rate(clk[IMX5_CLK_USBOH3_PER_GATE], r);
 
-	imx_register_uart_clocks(uart_clks_mx50_mx53);
+	imx_register_uart_clocks(5);
 }
 CLK_OF_DECLARE(imx53_ccm, "fsl,imx53-ccm", mx53_clocks_init);

drivers/clk/imx/clk-imx6q.c

···
 	return of_machine_is_compatible("fsl,imx6dl");
 }
 
-static const int uart_clk_ids[] __initconst = {
-	IMX6QDL_CLK_UART_IPG,
-	IMX6QDL_CLK_UART_SERIAL,
-};
-
-static struct clk **uart_clks[ARRAY_SIZE(uart_clk_ids) + 1] __initdata;
-
 static int ldb_di_sel_by_clock_id(int clock_id)
 {
 	switch (clock_id) {
···
 	struct device_node *np;
 	void __iomem *anatop_base, *base;
 	int ret;
-	int i;
 
 	clk_hw_data = kzalloc(struct_size(clk_hw_data, hws,
 					  IMX6QDL_CLK_END), GFP_KERNEL);
···
 			       hws[IMX6QDL_CLK_PLL3_USB_OTG]->clk);
 	}
 
-	for (i = 0; i < ARRAY_SIZE(uart_clk_ids); i++) {
-		int index = uart_clk_ids[i];
-
-		uart_clks[i] = &hws[index]->clk;
-	}
-
-	imx_register_uart_clocks(uart_clks);
+	imx_register_uart_clocks(1);
 }
 CLK_OF_DECLARE(imx6q, "fsl,imx6q-ccm", imx6q_clocks_init);

drivers/clk/imx/clk-imx6sl.c

···
 		imx6sl_enable_pll_arm(false);
 }
 
-static const int uart_clk_ids[] __initconst = {
-	IMX6SL_CLK_UART,
-	IMX6SL_CLK_UART_SERIAL,
-};
-
-static struct clk **uart_clks[ARRAY_SIZE(uart_clk_ids) + 1] __initdata;
-
 static void __init imx6sl_clocks_init(struct device_node *ccm_node)
 {
 	struct device_node *np;
 	void __iomem *base;
 	int ret;
-	int i;
 
 	clk_hw_data = kzalloc(struct_size(clk_hw_data, hws,
 					  IMX6SL_CLK_END), GFP_KERNEL);
···
 	clk_set_parent(hws[IMX6SL_CLK_LCDIF_AXI_SEL]->clk,
 		       hws[IMX6SL_CLK_PLL2_PFD2]->clk);
 
-	for (i = 0; i < ARRAY_SIZE(uart_clk_ids); i++) {
-		int index = uart_clk_ids[i];
-
-		uart_clks[i] = &hws[index]->clk;
-	}
-
-	imx_register_uart_clocks(uart_clks);
+	imx_register_uart_clocks(2);
 }
 CLK_OF_DECLARE(imx6sl, "fsl,imx6sl-ccm", imx6sl_clocks_init);

drivers/clk/imx/clk-imx6sll.c

···
 static u32 share_count_ssi2;
 static u32 share_count_ssi3;
 
-static const int uart_clk_ids[] __initconst = {
-	IMX6SLL_CLK_UART1_IPG,
-	IMX6SLL_CLK_UART1_SERIAL,
-	IMX6SLL_CLK_UART2_IPG,
-	IMX6SLL_CLK_UART2_SERIAL,
-	IMX6SLL_CLK_UART3_IPG,
-	IMX6SLL_CLK_UART3_SERIAL,
-	IMX6SLL_CLK_UART4_IPG,
-	IMX6SLL_CLK_UART4_SERIAL,
-	IMX6SLL_CLK_UART5_IPG,
-	IMX6SLL_CLK_UART5_SERIAL,
-};
-
-static struct clk **uart_clks[ARRAY_SIZE(uart_clk_ids) + 1] __initdata;
-
 static void __init imx6sll_clocks_init(struct device_node *ccm_node)
 {
 	struct device_node *np;
 	void __iomem *base;
-	int i;
 
 	clk_hw_data = kzalloc(struct_size(clk_hw_data, hws,
 					  IMX6SLL_CLK_END), GFP_KERNEL);
···
 
 	of_clk_add_hw_provider(np, of_clk_hw_onecell_get, clk_hw_data);
 
-	for (i = 0; i < ARRAY_SIZE(uart_clk_ids); i++) {
-		int index = uart_clk_ids[i];
-
-		uart_clks[i] = &hws[index]->clk;
-	}
-
-	imx_register_uart_clocks(uart_clks);
+	imx_register_uart_clocks(5);
 
 	/* Lower the AHB clock rate before changing the clock source. */
 	clk_set_rate(hws[IMX6SLL_CLK_AHB]->clk, 99000000);

drivers/clk/imx/clk-imx6sx.c

···
 static u32 share_count_sai1;
 static u32 share_count_sai2;
 
-static const int uart_clk_ids[] __initconst = {
-	IMX6SX_CLK_UART_IPG,
-	IMX6SX_CLK_UART_SERIAL,
-};
-
-static struct clk **uart_clks[ARRAY_SIZE(uart_clk_ids) + 1] __initdata;
-
 static void __init imx6sx_clocks_init(struct device_node *ccm_node)
 {
 	struct device_node *np;
 	void __iomem *base;
-	int i;
 
 	clk_hw_data = kzalloc(struct_size(clk_hw_data, hws,
 					  IMX6SX_CLK_CLK_END), GFP_KERNEL);
···
 	clk_set_parent(hws[IMX6SX_CLK_QSPI1_SEL]->clk, hws[IMX6SX_CLK_PLL2_BUS]->clk);
 	clk_set_parent(hws[IMX6SX_CLK_QSPI2_SEL]->clk, hws[IMX6SX_CLK_PLL2_BUS]->clk);
 
-	for (i = 0; i < ARRAY_SIZE(uart_clk_ids); i++) {
-		int index = uart_clk_ids[i];
-
-		uart_clks[i] = &hws[index]->clk;
-	}
-
-	imx_register_uart_clocks(uart_clks);
+	imx_register_uart_clocks(2);
 }
 CLK_OF_DECLARE(imx6sx, "fsl,imx6sx-ccm", imx6sx_clocks_init);

drivers/clk/imx/clk-imx7d.c

···
 static struct clk_hw **hws;
 static struct clk_hw_onecell_data *clk_hw_data;
 
-static const int uart_clk_ids[] __initconst = {
-	IMX7D_UART1_ROOT_CLK,
-	IMX7D_UART2_ROOT_CLK,
-	IMX7D_UART3_ROOT_CLK,
-	IMX7D_UART4_ROOT_CLK,
-	IMX7D_UART5_ROOT_CLK,
-	IMX7D_UART6_ROOT_CLK,
-	IMX7D_UART7_ROOT_CLK,
-};
-
-static struct clk **uart_clks[ARRAY_SIZE(uart_clk_ids) + 1] __initdata;
-
 static void __init imx7d_clocks_init(struct device_node *ccm_node)
 {
 	struct device_node *np;
 	void __iomem *base;
-	int i;
 
 	clk_hw_data = kzalloc(struct_size(clk_hw_data, hws,
 					  IMX7D_CLK_END), GFP_KERNEL);
···
 	hws[IMX7D_USB1_MAIN_480M_CLK] = imx_clk_hw_fixed_factor("pll_usb1_main_clk", "osc", 20, 1);
 	hws[IMX7D_USB_MAIN_480M_CLK] = imx_clk_hw_fixed_factor("pll_usb_main_clk", "osc", 20, 1);
 
-	for (i = 0; i < ARRAY_SIZE(uart_clk_ids); i++) {
-		int index = uart_clk_ids[i];
-
-		uart_clks[i] = &hws[index]->clk;
-	}
-
-
-	imx_register_uart_clocks(uart_clks);
+	imx_register_uart_clocks(7);
 
 }
 CLK_OF_DECLARE(imx7d, "fsl,imx7d-ccm", imx7d_clocks_init);

drivers/clk/imx/clk-imx7ulp.c

···
 	{ /* sentinel */ },
 };
 
-static const int pcc2_uart_clk_ids[] __initconst = {
-	IMX7ULP_CLK_LPUART4,
-	IMX7ULP_CLK_LPUART5,
-};
-
-static const int pcc3_uart_clk_ids[] __initconst = {
-	IMX7ULP_CLK_LPUART6,
-	IMX7ULP_CLK_LPUART7,
-};
-
-static struct clk **pcc2_uart_clks[ARRAY_SIZE(pcc2_uart_clk_ids) + 1] __initdata;
-static struct clk **pcc3_uart_clks[ARRAY_SIZE(pcc3_uart_clk_ids) + 1] __initdata;
-
 static void __init imx7ulp_clk_scg1_init(struct device_node *np)
 {
 	struct clk_hw_onecell_data *clk_data;
···
 	struct clk_hw_onecell_data *clk_data;
 	struct clk_hw **hws;
 	void __iomem *base;
-	int i;
 
 	clk_data = kzalloc(struct_size(clk_data, hws, IMX7ULP_CLK_PCC2_END),
 			   GFP_KERNEL);
···
 
 	of_clk_add_hw_provider(np, of_clk_hw_onecell_get, clk_data);
 
-	for (i = 0; i < ARRAY_SIZE(pcc2_uart_clk_ids); i++) {
-		int index = pcc2_uart_clk_ids[i];
-
-		pcc2_uart_clks[i] = &hws[index]->clk;
-	}
-
-	imx_register_uart_clocks(pcc2_uart_clks);
+	imx_register_uart_clocks(2);
 }
 CLK_OF_DECLARE(imx7ulp_clk_pcc2, "fsl,imx7ulp-pcc2", imx7ulp_clk_pcc2_init);
 
···
 	struct clk_hw_onecell_data *clk_data;
 	struct clk_hw **hws;
 	void __iomem *base;
-	int i;
 
 	clk_data = kzalloc(struct_size(clk_data, hws, IMX7ULP_CLK_PCC3_END),
 			   GFP_KERNEL);
···
 
 	of_clk_add_hw_provider(np, of_clk_hw_onecell_get, clk_data);
 
-	for (i = 0; i < ARRAY_SIZE(pcc3_uart_clk_ids); i++) {
-		int index = pcc3_uart_clk_ids[i];
-
-		pcc3_uart_clks[i] = &hws[index]->clk;
-	}
-
-	imx_register_uart_clocks(pcc3_uart_clks);
+	imx_register_uart_clocks(7);
 }
 CLK_OF_DECLARE(imx7ulp_clk_pcc3, "fsl,imx7ulp-pcc3", imx7ulp_clk_pcc3_init);
 

drivers/clk/imx/clk-imx8mm.c

···
 static struct clk_hw_onecell_data *clk_hw_data;
 static struct clk_hw **hws;
 
-static const int uart_clk_ids[] = {
-	IMX8MM_CLK_UART1_ROOT,
-	IMX8MM_CLK_UART2_ROOT,
-	IMX8MM_CLK_UART3_ROOT,
-	IMX8MM_CLK_UART4_ROOT,
-};
-static struct clk **uart_hws[ARRAY_SIZE(uart_clk_ids) + 1];
-
 static int imx8mm_clocks_probe(struct platform_device *pdev)
 {
 	struct device *dev = &pdev->dev;
 	struct device_node *np = dev->of_node;
 	void __iomem *base;
-	int ret, i;
+	int ret;
 
 	clk_hw_data = kzalloc(struct_size(clk_hw_data, hws,
 					  IMX8MM_CLK_END), GFP_KERNEL);
···
 		goto unregister_hws;
 	}
 
-	for (i = 0; i < ARRAY_SIZE(uart_clk_ids); i++) {
-		int index = uart_clk_ids[i];
-
-		uart_hws[i] = &hws[index]->clk;
-	}
-
-	imx_register_uart_clocks(uart_hws);
+	imx_register_uart_clocks(4);
 
 	return 0;
 

drivers/clk/imx/clk-imx8mn.c

···
 static struct clk_hw_onecell_data *clk_hw_data;
 static struct clk_hw **hws;
 
-static const int uart_clk_ids[] = {
-	IMX8MN_CLK_UART1_ROOT,
-	IMX8MN_CLK_UART2_ROOT,
-	IMX8MN_CLK_UART3_ROOT,
-	IMX8MN_CLK_UART4_ROOT,
-};
-static struct clk **uart_hws[ARRAY_SIZE(uart_clk_ids) + 1];
-
 static int imx8mn_clocks_probe(struct platform_device *pdev)
 {
 	struct device *dev = &pdev->dev;
 	struct device_node *np = dev->of_node;
 	void __iomem *base;
-	int ret, i;
+	int ret;
 
 	clk_hw_data = kzalloc(struct_size(clk_hw_data, hws,
 					  IMX8MN_CLK_END), GFP_KERNEL);
···
 		goto unregister_hws;
 	}
 
-	for (i = 0; i < ARRAY_SIZE(uart_clk_ids); i++) {
-		int index = uart_clk_ids[i];
-
-		uart_hws[i] = &hws[index]->clk;
-	}
-
-	imx_register_uart_clocks(uart_hws);
+	imx_register_uart_clocks(4);
 
 	return 0;
 

drivers/clk/imx/clk-imx8mp.c

···
 static struct clk_hw **hws;
 static struct clk_hw_onecell_data *clk_hw_data;
 
-static const int uart_clk_ids[] = {
-	IMX8MP_CLK_UART1_ROOT,
-	IMX8MP_CLK_UART2_ROOT,
-	IMX8MP_CLK_UART3_ROOT,
-	IMX8MP_CLK_UART4_ROOT,
-};
-static struct clk **uart_clks[ARRAY_SIZE(uart_clk_ids) + 1];
-
 static int imx8mp_clocks_probe(struct platform_device *pdev)
 {
 	struct device *dev = &pdev->dev;
 	struct device_node *np;
 	void __iomem *anatop_base, *ccm_base;
-	int i;
 
 	np = of_find_compatible_node(NULL, NULL, "fsl,imx8mp-anatop");
 	anatop_base = of_iomap(np, 0);
···
 
 	of_clk_add_hw_provider(np, of_clk_hw_onecell_get, clk_hw_data);
 
-	for (i = 0; i < ARRAY_SIZE(uart_clk_ids); i++) {
-		int index = uart_clk_ids[i];
-
-		uart_clks[i] = &hws[index]->clk;
-	}
-
-	imx_register_uart_clocks(uart_clks);
+	imx_register_uart_clocks(4);
 
 	return 0;
 }

drivers/clk/imx/clk-imx8mq.c

···
 static struct clk_hw_onecell_data *clk_hw_data;
 static struct clk_hw **hws;
 
-static const int uart_clk_ids[] = {
-	IMX8MQ_CLK_UART1_ROOT,
-	IMX8MQ_CLK_UART2_ROOT,
-	IMX8MQ_CLK_UART3_ROOT,
-	IMX8MQ_CLK_UART4_ROOT,
-};
-static struct clk **uart_hws[ARRAY_SIZE(uart_clk_ids) + 1];
-
 static int imx8mq_clocks_probe(struct platform_device *pdev)
 {
 	struct device *dev = &pdev->dev;
 	struct device_node *np = dev->of_node;
 	void __iomem *base;
-	int err, i;
+	int err;
 
 	clk_hw_data = kzalloc(struct_size(clk_hw_data, hws,
 					  IMX8MQ_CLK_END), GFP_KERNEL);
···
 		goto unregister_hws;
 	}
 
-	for (i = 0; i < ARRAY_SIZE(uart_clk_ids); i++) {
-		int index = uart_clk_ids[i];
-
-		uart_hws[i] = &hws[index]->clk;
-	}
-
-	imx_register_uart_clocks(uart_hws);
+	imx_register_uart_clocks(4);
 
 	return 0;
 

drivers/clk/imx/clk.c

···
 }
 
 #ifndef MODULE
-static int imx_keep_uart_clocks;
-static struct clk ** const *imx_uart_clocks;
+
+static bool imx_keep_uart_clocks;
+static int imx_enabled_uart_clocks;
+static struct clk **imx_uart_clocks;
 
 static int __init imx_keep_uart_clocks_param(char *str)
 {
···
 __setup_param("earlyprintk", imx_keep_uart_earlyprintk,
 	      imx_keep_uart_clocks_param, 0);
 
-void imx_register_uart_clocks(struct clk ** const clks[])
+void imx_register_uart_clocks(unsigned int clk_count)
 {
+	imx_enabled_uart_clocks = 0;
+
+/* i.MX boards use device trees now.  For build tests without CONFIG_OF, do nothing */
+#ifdef CONFIG_OF
 	if (imx_keep_uart_clocks) {
 		int i;
 
-		imx_uart_clocks = clks;
-		for (i = 0; imx_uart_clocks[i]; i++)
-			clk_prepare_enable(*imx_uart_clocks[i]);
+		imx_uart_clocks = kcalloc(clk_count, sizeof(struct clk *), GFP_KERNEL);
+
+		if (!of_stdout)
+			return;
+
+		for (i = 0; i < clk_count; i++) {
+			imx_uart_clocks[imx_enabled_uart_clocks] = of_clk_get(of_stdout, i);
+
+			/* Stop if there are no more of_stdout references */
+			if (IS_ERR(imx_uart_clocks[imx_enabled_uart_clocks]))
+				return;
+
+			/* Only enable the clock if it's not NULL */
+			if (imx_uart_clocks[imx_enabled_uart_clocks])
+				clk_prepare_enable(imx_uart_clocks[imx_enabled_uart_clocks++]);
+		}
 	}
+#endif
 }
 
 static int __init imx_clk_disable_uart(void)
 {
-	if (imx_keep_uart_clocks && imx_uart_clocks) {
+	if (imx_keep_uart_clocks && imx_enabled_uart_clocks) {
 		int i;
 
-		for (i = 0; imx_uart_clocks[i]; i++)
-			clk_disable_unprepare(*imx_uart_clocks[i]);
+		for (i = 0; i < imx_enabled_uart_clocks; i++) {
+			clk_disable_unprepare(imx_uart_clocks[i]);
+			clk_put(imx_uart_clocks[i]);
+		}
+		kfree(imx_uart_clocks);
 	}
 
 	return 0;

drivers/clk/imx/clk.h

···
 void imx_check_clocks(struct clk *clks[], unsigned int count);
 void imx_check_clk_hws(struct clk_hw *clks[], unsigned int count);
 #ifndef MODULE
-void imx_register_uart_clocks(struct clk ** const clks[]);
+void imx_register_uart_clocks(unsigned int clk_count);
 #else
-static inline void imx_register_uart_clocks(struct clk ** const clks[])
+static inline void imx_register_uart_clocks(unsigned int clk_count)
 {
 }
 #endif