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path: root/drivers/clk/baikal-t1/ccu-rst.c
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-rw-r--r--drivers/clk/baikal-t1/ccu-rst.c217
1 files changed, 217 insertions, 0 deletions
diff --git a/drivers/clk/baikal-t1/ccu-rst.c b/drivers/clk/baikal-t1/ccu-rst.c
new file mode 100644
index 000000000..40023ea67
--- /dev/null
+++ b/drivers/clk/baikal-t1/ccu-rst.c
@@ -0,0 +1,217 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2021 BAIKAL ELECTRONICS, JSC
+ *
+ * Authors:
+ * Serge Semin <Sergey.Semin@baikalelectronics.ru>
+ *
+ * Baikal-T1 CCU Resets interface driver
+ */
+
+#define pr_fmt(fmt) "bt1-ccu-rst: " fmt
+
+#include <linux/bits.h>
+#include <linux/delay.h>
+#include <linux/kernel.h>
+#include <linux/of.h>
+#include <linux/printk.h>
+#include <linux/regmap.h>
+#include <linux/reset-controller.h>
+#include <linux/slab.h>
+
+#include <dt-bindings/reset/bt1-ccu.h>
+
+#include "ccu-rst.h"
+
+#define CCU_AXI_MAIN_BASE 0x030
+#define CCU_AXI_DDR_BASE 0x034
+#define CCU_AXI_SATA_BASE 0x038
+#define CCU_AXI_GMAC0_BASE 0x03C
+#define CCU_AXI_GMAC1_BASE 0x040
+#define CCU_AXI_XGMAC_BASE 0x044
+#define CCU_AXI_PCIE_M_BASE 0x048
+#define CCU_AXI_PCIE_S_BASE 0x04C
+#define CCU_AXI_USB_BASE 0x050
+#define CCU_AXI_HWA_BASE 0x054
+#define CCU_AXI_SRAM_BASE 0x058
+
+#define CCU_SYS_DDR_BASE 0x02c
+#define CCU_SYS_SATA_REF_BASE 0x060
+#define CCU_SYS_APB_BASE 0x064
+#define CCU_SYS_PCIE_BASE 0x144
+
+#define CCU_RST_DELAY_US 1
+
+#define CCU_RST_TRIG(_base, _ofs) \
+ { \
+ .type = CCU_RST_TRIG, \
+ .base = _base, \
+ .mask = BIT(_ofs), \
+ }
+
+#define CCU_RST_DIR(_base, _ofs) \
+ { \
+ .type = CCU_RST_DIR, \
+ .base = _base, \
+ .mask = BIT(_ofs), \
+ }
+
+struct ccu_rst_info {
+ enum ccu_rst_type type;
+ unsigned int base;
+ unsigned int mask;
+};
+
+/*
+ * Each AXI-bus clock divider is equipped with the corresponding clock-consumer
+ * domain reset (it's self-deasserted reset control).
+ */
+static const struct ccu_rst_info axi_rst_info[] = {
+ [CCU_AXI_MAIN_RST] = CCU_RST_TRIG(CCU_AXI_MAIN_BASE, 1),
+ [CCU_AXI_DDR_RST] = CCU_RST_TRIG(CCU_AXI_DDR_BASE, 1),
+ [CCU_AXI_SATA_RST] = CCU_RST_TRIG(CCU_AXI_SATA_BASE, 1),
+ [CCU_AXI_GMAC0_RST] = CCU_RST_TRIG(CCU_AXI_GMAC0_BASE, 1),
+ [CCU_AXI_GMAC1_RST] = CCU_RST_TRIG(CCU_AXI_GMAC1_BASE, 1),
+ [CCU_AXI_XGMAC_RST] = CCU_RST_TRIG(CCU_AXI_XGMAC_BASE, 1),
+ [CCU_AXI_PCIE_M_RST] = CCU_RST_TRIG(CCU_AXI_PCIE_M_BASE, 1),
+ [CCU_AXI_PCIE_S_RST] = CCU_RST_TRIG(CCU_AXI_PCIE_S_BASE, 1),
+ [CCU_AXI_USB_RST] = CCU_RST_TRIG(CCU_AXI_USB_BASE, 1),
+ [CCU_AXI_HWA_RST] = CCU_RST_TRIG(CCU_AXI_HWA_BASE, 1),
+ [CCU_AXI_SRAM_RST] = CCU_RST_TRIG(CCU_AXI_SRAM_BASE, 1),
+};
+
+/*
+ * SATA reference clock domain and APB-bus domain are connected with the
+ * sefl-deasserted reset control, which can be activated via the corresponding
+ * clock divider register. DDR and PCIe sub-domains can be reset with directly
+ * controlled reset signals. Resetting the DDR controller though won't end up
+ * well while the Linux kernel is working.
+ */
+static const struct ccu_rst_info sys_rst_info[] = {
+ [CCU_SYS_SATA_REF_RST] = CCU_RST_TRIG(CCU_SYS_SATA_REF_BASE, 1),
+ [CCU_SYS_APB_RST] = CCU_RST_TRIG(CCU_SYS_APB_BASE, 1),
+ [CCU_SYS_DDR_FULL_RST] = CCU_RST_DIR(CCU_SYS_DDR_BASE, 1),
+ [CCU_SYS_DDR_INIT_RST] = CCU_RST_DIR(CCU_SYS_DDR_BASE, 2),
+ [CCU_SYS_PCIE_PCS_PHY_RST] = CCU_RST_DIR(CCU_SYS_PCIE_BASE, 0),
+ [CCU_SYS_PCIE_PIPE0_RST] = CCU_RST_DIR(CCU_SYS_PCIE_BASE, 4),
+ [CCU_SYS_PCIE_CORE_RST] = CCU_RST_DIR(CCU_SYS_PCIE_BASE, 8),
+ [CCU_SYS_PCIE_PWR_RST] = CCU_RST_DIR(CCU_SYS_PCIE_BASE, 9),
+ [CCU_SYS_PCIE_STICKY_RST] = CCU_RST_DIR(CCU_SYS_PCIE_BASE, 10),
+ [CCU_SYS_PCIE_NSTICKY_RST] = CCU_RST_DIR(CCU_SYS_PCIE_BASE, 11),
+ [CCU_SYS_PCIE_HOT_RST] = CCU_RST_DIR(CCU_SYS_PCIE_BASE, 12),
+};
+
+static int ccu_rst_reset(struct reset_controller_dev *rcdev, unsigned long idx)
+{
+ struct ccu_rst *rst = to_ccu_rst(rcdev);
+ const struct ccu_rst_info *info = &rst->rsts_info[idx];
+
+ if (info->type != CCU_RST_TRIG)
+ return -EOPNOTSUPP;
+
+ regmap_update_bits(rst->sys_regs, info->base, info->mask, info->mask);
+
+ /* The next delay must be enough to cover all the resets. */
+ udelay(CCU_RST_DELAY_US);
+
+ return 0;
+}
+
+static int ccu_rst_set(struct reset_controller_dev *rcdev,
+ unsigned long idx, bool high)
+{
+ struct ccu_rst *rst = to_ccu_rst(rcdev);
+ const struct ccu_rst_info *info = &rst->rsts_info[idx];
+
+ if (info->type != CCU_RST_DIR)
+ return high ? -EOPNOTSUPP : 0;
+
+ return regmap_update_bits(rst->sys_regs, info->base,
+ info->mask, high ? info->mask : 0);
+}
+
+static int ccu_rst_assert(struct reset_controller_dev *rcdev,
+ unsigned long idx)
+{
+ return ccu_rst_set(rcdev, idx, true);
+}
+
+static int ccu_rst_deassert(struct reset_controller_dev *rcdev,
+ unsigned long idx)
+{
+ return ccu_rst_set(rcdev, idx, false);
+}
+
+static int ccu_rst_status(struct reset_controller_dev *rcdev,
+ unsigned long idx)
+{
+ struct ccu_rst *rst = to_ccu_rst(rcdev);
+ const struct ccu_rst_info *info = &rst->rsts_info[idx];
+ u32 val;
+
+ if (info->type != CCU_RST_DIR)
+ return -EOPNOTSUPP;
+
+ regmap_read(rst->sys_regs, info->base, &val);
+
+ return !!(val & info->mask);
+}
+
+static const struct reset_control_ops ccu_rst_ops = {
+ .reset = ccu_rst_reset,
+ .assert = ccu_rst_assert,
+ .deassert = ccu_rst_deassert,
+ .status = ccu_rst_status,
+};
+
+struct ccu_rst *ccu_rst_hw_register(const struct ccu_rst_init_data *rst_init)
+{
+ struct ccu_rst *rst;
+ int ret;
+
+ if (!rst_init)
+ return ERR_PTR(-EINVAL);
+
+ rst = kzalloc(sizeof(*rst), GFP_KERNEL);
+ if (!rst)
+ return ERR_PTR(-ENOMEM);
+
+ rst->sys_regs = rst_init->sys_regs;
+ if (of_device_is_compatible(rst_init->np, "baikal,bt1-ccu-axi")) {
+ rst->rcdev.nr_resets = ARRAY_SIZE(axi_rst_info);
+ rst->rsts_info = axi_rst_info;
+ } else if (of_device_is_compatible(rst_init->np, "baikal,bt1-ccu-sys")) {
+ rst->rcdev.nr_resets = ARRAY_SIZE(sys_rst_info);
+ rst->rsts_info = sys_rst_info;
+ } else {
+ pr_err("Incompatible DT node '%s' specified\n",
+ of_node_full_name(rst_init->np));
+ ret = -EINVAL;
+ goto err_kfree_rst;
+ }
+
+ rst->rcdev.owner = THIS_MODULE;
+ rst->rcdev.ops = &ccu_rst_ops;
+ rst->rcdev.of_node = rst_init->np;
+
+ ret = reset_controller_register(&rst->rcdev);
+ if (ret) {
+ pr_err("Couldn't register '%s' reset controller\n",
+ of_node_full_name(rst_init->np));
+ goto err_kfree_rst;
+ }
+
+ return rst;
+
+err_kfree_rst:
+ kfree(rst);
+
+ return ERR_PTR(ret);
+}
+
+void ccu_rst_hw_unregister(struct ccu_rst *rst)
+{
+ reset_controller_unregister(&rst->rcdev);
+
+ kfree(rst);
+}