[PATCH] soc/rockchip: add handler for usb-uart functionality
Heiko Stübner
heiko at sntech.de
Wed Jul 8 12:00:06 PDT 2015
Most newer Rockchip SoCs provide the possibility to use a usb-phy
as passthrough for the debug uart (uart2), making it possible to
get console output without needing to open the device.
This patch adds an early_initcall to enable this functionality
conditionally via the commandline and also disables the corresponding
usb controller in the devicetree.
Currently only data for the rk3288 is provided, but at least the
rk3188 and arm64 rk3368 also provide this functionality and will be
enabled later.
On a spliced usb cable the signals are tx on white wire(D+) and
rx on green wire(D-).
Signed-off-by: Heiko Stuebner <heiko at sntech.de>
---
changes from the version in chromium-review:
- enable siddq (probably saves a little power to power down plls)
- cosmetics to make checkpatch happy
Yunzhi Li already gave a Code-Review+1 in the chromium gerrit
but I'd guess a public Reviewed-by would be better ;-)
Documentation/kernel-parameters.txt | 6 +
drivers/soc/Kconfig | 1 +
drivers/soc/Makefile | 1 +
drivers/soc/rockchip/Kconfig | 13 ++
drivers/soc/rockchip/Makefile | 1 +
drivers/soc/rockchip/rockchip_usb_uart.c | 226 +++++++++++++++++++++++++++++++
6 files changed, 248 insertions(+)
create mode 100644 drivers/soc/rockchip/Kconfig
create mode 100644 drivers/soc/rockchip/Makefile
create mode 100644 drivers/soc/rockchip/rockchip_usb_uart.c
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index 1d6f045..156911b 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -3339,6 +3339,12 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
ro [KNL] Mount root device read-only on boot
+ rockchip.usb_uart
+ Enable the uart passthrough on the designated usb port
+ on Rockchip SoCs. When active, the signals of the
+ debug-uart get routed to the D+ and D- pins of the usb
+ port and the regular usb controller gets disabled.
+
root= [KNL] Root filesystem
See name_to_dev_t comment in init/do_mounts.c.
diff --git a/drivers/soc/Kconfig b/drivers/soc/Kconfig
index 96ddecb..ecb1a6c 100644
--- a/drivers/soc/Kconfig
+++ b/drivers/soc/Kconfig
@@ -2,6 +2,7 @@ menu "SOC (System On Chip) specific Drivers"
source "drivers/soc/mediatek/Kconfig"
source "drivers/soc/qcom/Kconfig"
+source "drivers/soc/rockchip/Kconfig"
source "drivers/soc/sunxi/Kconfig"
source "drivers/soc/ti/Kconfig"
source "drivers/soc/versatile/Kconfig"
diff --git a/drivers/soc/Makefile b/drivers/soc/Makefile
index 7dc7c0d..6c0b677 100644
--- a/drivers/soc/Makefile
+++ b/drivers/soc/Makefile
@@ -4,6 +4,7 @@
obj-$(CONFIG_ARCH_MEDIATEK) += mediatek/
obj-$(CONFIG_ARCH_QCOM) += qcom/
+obj-$(CONFIG_ARCH_ROCKCHIP) += rockchip/
obj-$(CONFIG_ARCH_SUNXI) += sunxi/
obj-$(CONFIG_ARCH_TEGRA) += tegra/
obj-$(CONFIG_SOC_TI) += ti/
diff --git a/drivers/soc/rockchip/Kconfig b/drivers/soc/rockchip/Kconfig
new file mode 100644
index 0000000..24d4e05
--- /dev/null
+++ b/drivers/soc/rockchip/Kconfig
@@ -0,0 +1,13 @@
+#
+# Rockchip Soc drivers
+#
+config ROCKCHIP_USB_UART
+ bool "Rockchip usb-uart override"
+ depends on ARCH_ROCKCHIP
+ select MFD_SYSCON
+ help
+ Say y here to enable usb-uart functionality. Newer Rockchip SoCs
+ provide means to repurpose one usb phy as uart2 output, making it
+ possible to get debug output without needing to open a device.
+ To enable this function on boot, add a rockchip.usb_uart option
+ to the kernel commandline.
diff --git a/drivers/soc/rockchip/Makefile b/drivers/soc/rockchip/Makefile
new file mode 100644
index 0000000..b5dd6f8
--- /dev/null
+++ b/drivers/soc/rockchip/Makefile
@@ -0,0 +1 @@
+obj-$(CONFIG_ROCKCHIP_USB_UART) += rockchip_usb_uart.o
diff --git a/drivers/soc/rockchip/rockchip_usb_uart.c b/drivers/soc/rockchip/rockchip_usb_uart.c
new file mode 100644
index 0000000..8e96d46
--- /dev/null
+++ b/drivers/soc/rockchip/rockchip_usb_uart.c
@@ -0,0 +1,226 @@
+/*
+ * Copyright (c) 2015 Heiko Stuebner <heiko at sntech.de>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ */
+
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/errno.h>
+#include <linux/mfd/syscon.h>
+#include <linux/of_address.h>
+#include <linux/of_platform.h>
+#include <linux/regmap.h>
+#include <linux/slab.h>
+
+#define HIWORD_UPDATE(val, mask) \
+ ((val) | (mask) << 16)
+
+struct rockchip_uart_data {
+ const char *grf_compatible;
+ const char *usb_compatible;
+ phys_addr_t usb_phys_addr;
+ int (*init_uart)(const struct rockchip_uart_data *data,
+ struct regmap *grf);
+};
+
+static int enable_usb_uart;
+
+#define RK3288_UOC0_CON0 0x320
+#define RK3288_UOC0_CON0_COMMON_ON_N BIT(0)
+#define RK3288_UOC0_CON0_DISABLE BIT(4)
+#define RK3288_UOC0_CON0_SIDDQ BIT(13)
+
+#define RK3288_UOC0_CON2 0x328
+#define RK3288_UOC0_CON2_SOFT_CON_SEL BIT(2)
+
+#define RK3288_UOC0_CON3 0x32c
+#define RK3288_UOC0_CON3_UTMI_SUSPENDN BIT(0)
+#define RK3288_UOC0_CON3_UTMI_OPMODE_NODRIVING (1 << 1)
+#define RK3288_UOC0_CON3_UTMI_OPMODE_MASK (3 << 1)
+#define RK3288_UOC0_CON3_UTMI_XCVRSEELCT_FSTRANSC (1 << 3)
+#define RK3288_UOC0_CON3_UTMI_XCVRSEELCT_MASK (3 << 3)
+#define RK3288_UOC0_CON3_UTMI_TERMSEL_FULLSPEED BIT(5)
+#define RK3288_UOC0_CON3_BYPASSDMEN BIT(6)
+#define RK3288_UOC0_CON3_BYPASSSEL BIT(7)
+
+/*
+ * Enable the bypass of uart2 data through the otg usb phy.
+ * Original description in the TRM.
+ * 1. Disable the OTG block by setting OTGDISABLE0 to 1’b1.
+ * 2. Disable the pull-up resistance on the D+ line by setting
+ * OPMODE0[1:0] to 2’b01.
+ * 3. To ensure that the XO, Bias, and PLL blocks are powered down in Suspend
+ * mode, set COMMONONN to 1’b1.
+ * 4. Place the USB PHY in Suspend mode by setting SUSPENDM0 to 1’b0.
+ * 5. Set BYPASSSEL0 to 1’b1.
+ * 6. To transmit data, controls BYPASSDMEN0, and BYPASSDMDATA0.
+ * To receive data, monitor FSVPLUS0.
+ *
+ * The actual code in the vendor kernel does some things differently.
+ */
+static int __init rk3288_init_usb_uart(const struct rockchip_uart_data *data,
+ struct regmap *grf)
+{
+ u32 val;
+ int ret;
+
+ /*
+ * COMMON_ON and DISABLE settings are described in the TRM,
+ * but were not present in the original code.
+ * Also disable the analog phy components to save power.
+ */
+ val = HIWORD_UPDATE(RK3288_UOC0_CON0_COMMON_ON_N
+ | RK3288_UOC0_CON0_DISABLE
+ | RK3288_UOC0_CON0_SIDDQ,
+ RK3288_UOC0_CON0_COMMON_ON_N
+ | RK3288_UOC0_CON0_DISABLE
+ | RK3288_UOC0_CON0_SIDDQ);
+ ret = regmap_write(grf, RK3288_UOC0_CON0, val);
+ if (ret)
+ return ret;
+
+ val = HIWORD_UPDATE(RK3288_UOC0_CON2_SOFT_CON_SEL,
+ RK3288_UOC0_CON2_SOFT_CON_SEL);
+ ret = regmap_write(grf, RK3288_UOC0_CON2, val);
+ if (ret)
+ return ret;
+
+ val = HIWORD_UPDATE(RK3288_UOC0_CON3_UTMI_OPMODE_NODRIVING
+ | RK3288_UOC0_CON3_UTMI_XCVRSEELCT_FSTRANSC
+ | RK3288_UOC0_CON3_UTMI_TERMSEL_FULLSPEED,
+ RK3288_UOC0_CON3_UTMI_SUSPENDN
+ | RK3288_UOC0_CON3_UTMI_OPMODE_MASK
+ | RK3288_UOC0_CON3_UTMI_XCVRSEELCT_MASK
+ | RK3288_UOC0_CON3_UTMI_TERMSEL_FULLSPEED);
+ ret = regmap_write(grf, RK3288_UOC0_CON3, val);
+ if (ret)
+ return ret;
+
+ val = HIWORD_UPDATE(RK3288_UOC0_CON3_BYPASSSEL
+ | RK3288_UOC0_CON3_BYPASSDMEN,
+ RK3288_UOC0_CON3_BYPASSSEL
+ | RK3288_UOC0_CON3_BYPASSDMEN);
+ ret = regmap_write(grf, RK3288_UOC0_CON3, val);
+ if (ret)
+ return ret;
+
+ return 0;
+}
+
+static const struct rockchip_uart_data rk3288_uart_data __initconst = {
+ .grf_compatible = "rockchip,rk3288-grf",
+ .usb_compatible = "rockchip,rk3288-usb",
+ .usb_phys_addr = 0xff580000,
+ .init_uart = rk3288_init_usb_uart,
+};
+
+static const struct of_device_id rockchip_usb_uart_ids[] __initconst = {
+ { .compatible = "rockchip,rk3288", .data = &rk3288_uart_data },
+ { }
+};
+
+/*
+ * Find the usb controller using the shared usb-uart-phy in the dts and
+ * disable it.
+ */
+static int __init
+rockchip_disable_usb_controller(const struct rockchip_uart_data *data)
+{
+ struct device_node *np;
+
+ for_each_compatible_node(np, NULL, data->usb_compatible) {
+ struct property *new_status;
+ struct resource res;
+ int ret;
+
+ ret = of_address_to_resource(np, 0, &res);
+ if (ret) {
+ pr_err("%s: could not get address of usb controller %s\n",
+ __func__, np->full_name);
+ continue;
+ }
+
+ /* not the controller we're looking for */
+ if (res.start != data->usb_phys_addr)
+ continue;
+
+ pr_debug("%s: disabling usb controller %s\n",
+ __func__, np->full_name);
+
+ new_status = kzalloc(sizeof(*new_status), GFP_KERNEL);
+ if (!new_status)
+ return -ENOMEM;
+
+ new_status->name = kstrdup("status", GFP_KERNEL);
+ new_status->length = sizeof("disabled");
+ new_status->value = kstrdup("disabled", GFP_KERNEL);
+
+ return of_update_property(np, new_status);
+ }
+
+ return 0;
+}
+
+static const struct of_device_id __init *rockchip_usb_uart_data_lookup(void)
+{
+ struct device_node *root;
+ const struct of_device_id *id;
+
+ root = of_find_node_by_path("/");
+ if (!root)
+ return NULL;
+
+ id = of_match_node(rockchip_usb_uart_ids, root);
+ of_node_put(root);
+
+ return id;
+}
+
+static int __init rockchip_init_usb_uart(void)
+{
+ const struct of_device_id *match;
+ const struct rockchip_uart_data *data;
+ struct regmap *grf;
+ int ret;
+
+ if (!enable_usb_uart)
+ return 0;
+
+ match = rockchip_usb_uart_data_lookup();
+ if (!match)
+ return -ENOTSUPP;
+
+ pr_debug("%s: using settings for %s\n", __func__, match->compatible);
+ data = match->data;
+
+ grf = syscon_regmap_lookup_by_compatible(data->grf_compatible);
+ if (IS_ERR(grf)) {
+ pr_err("%s: could not find GRF syscon\n", __func__);
+ return PTR_ERR(grf);
+ }
+
+ ret = data->init_uart(data, grf);
+ if (ret) {
+ pr_err("%s: could not init usb_uart\n", __func__);
+ return ret;
+ }
+
+ return rockchip_disable_usb_controller(data);
+}
+early_initcall(rockchip_init_usb_uart);
+
+static int __init rockchip_usb_uart(char *buf)
+{
+ enable_usb_uart = true;
+ return 0;
+}
+early_param("rockchip.usb_uart", rockchip_usb_uart);
--
2.1.4
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