--- /dev/null
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * DWC AHCI SATA Platform driver
+ *
+ * Copyright (C) 2021 BAIKAL ELECTRONICS, JSC
+ */
+
+#include <linux/ahci_platform.h>
+#include <linux/bitfield.h>
+#include <linux/bits.h>
+#include <linux/clk.h>
+#include <linux/device.h>
+#include <linux/kernel.h>
+#include <linux/libata.h>
+#include <linux/log2.h>
+#include <linux/module.h>
+#include <linux/of_device.h>
+#include <linux/platform_device.h>
+#include <linux/pm.h>
+
+#include "ahci.h"
+
+#define DRV_NAME "ahci-dwc"
+
+#define AHCI_DWC_FBS_PMPN_MAX          15
+
+/* DWC AHCI SATA controller specific registers */
+#define AHCI_DWC_HOST_OOBR             0xbc
+#define AHCI_DWC_HOST_OOB_WE           BIT(31)
+#define AHCI_DWC_HOST_CWMIN_MASK       GENMASK(30, 24)
+#define AHCI_DWC_HOST_CWMAX_MASK       GENMASK(23, 16)
+#define AHCI_DWC_HOST_CIMIN_MASK       GENMASK(15, 8)
+#define AHCI_DWC_HOST_CIMAX_MASK       GENMASK(7, 0)
+
+#define AHCI_DWC_HOST_GPCR             0xd0
+#define AHCI_DWC_HOST_GPSR             0xd4
+
+#define AHCI_DWC_HOST_TIMER1MS         0xe0
+#define AHCI_DWC_HOST_TIMV_MASK                GENMASK(19, 0)
+
+#define AHCI_DWC_HOST_GPARAM1R         0xe8
+#define AHCI_DWC_HOST_ALIGN_M          BIT(31)
+#define AHCI_DWC_HOST_RX_BUFFER                BIT(30)
+#define AHCI_DWC_HOST_PHY_DATA_MASK    GENMASK(29, 28)
+#define AHCI_DWC_HOST_PHY_RST          BIT(27)
+#define AHCI_DWC_HOST_PHY_CTRL_MASK    GENMASK(26, 21)
+#define AHCI_DWC_HOST_PHY_STAT_MASK    GENMASK(20, 15)
+#define AHCI_DWC_HOST_LATCH_M          BIT(14)
+#define AHCI_DWC_HOST_PHY_TYPE_MASK    GENMASK(13, 11)
+#define AHCI_DWC_HOST_RET_ERR          BIT(10)
+#define AHCI_DWC_HOST_AHB_ENDIAN_MASK  GENMASK(9, 8)
+#define AHCI_DWC_HOST_S_HADDR          BIT(7)
+#define AHCI_DWC_HOST_M_HADDR          BIT(6)
+#define AHCI_DWC_HOST_S_HDATA_MASK     GENMASK(5, 3)
+#define AHCI_DWC_HOST_M_HDATA_MASK     GENMASK(2, 0)
+
+#define AHCI_DWC_HOST_GPARAM2R         0xec
+#define AHCI_DWC_HOST_FBS_MEM_S                BIT(19)
+#define AHCI_DWC_HOST_FBS_PMPN_MASK    GENMASK(17, 16)
+#define AHCI_DWC_HOST_FBS_SUP          BIT(15)
+#define AHCI_DWC_HOST_DEV_CP           BIT(14)
+#define AHCI_DWC_HOST_DEV_MP           BIT(13)
+#define AHCI_DWC_HOST_ENCODE_M         BIT(12)
+#define AHCI_DWC_HOST_RXOOB_CLK_M      BIT(11)
+#define AHCI_DWC_HOST_RXOOB_M          BIT(10)
+#define AHCI_DWC_HOST_TXOOB_M          BIT(9)
+#define AHCI_DWC_HOST_RXOOB_M          BIT(10)
+#define AHCI_DWC_HOST_RXOOB_CLK_MASK   GENMASK(8, 0)
+
+#define AHCI_DWC_HOST_PPARAMR          0xf0
+#define AHCI_DWC_HOST_TX_MEM_M         BIT(11)
+#define AHCI_DWC_HOST_TX_MEM_S         BIT(10)
+#define AHCI_DWC_HOST_RX_MEM_M         BIT(9)
+#define AHCI_DWC_HOST_RX_MEM_S         BIT(8)
+#define AHCI_DWC_HOST_TXFIFO_DEPTH     GENMASK(7, 4)
+#define AHCI_DWC_HOST_RXFIFO_DEPTH     GENMASK(3, 0)
+
+#define AHCI_DWC_HOST_TESTR            0xf4
+#define AHCI_DWC_HOST_PSEL_MASK                GENMASK(18, 16)
+#define AHCI_DWC_HOST_TEST_IF          BIT(0)
+
+#define AHCI_DWC_HOST_VERSIONR         0xf8
+#define AHCI_DWC_HOST_IDR              0xfc
+
+#define AHCI_DWC_PORT_DMACR            0x70
+#define AHCI_DWC_PORT_RXABL_MASK       GENMASK(15, 12)
+#define AHCI_DWC_PORT_TXABL_MASK       GENMASK(11, 8)
+#define AHCI_DWC_PORT_RXTS_MASK                GENMASK(7, 4)
+#define AHCI_DWC_PORT_TXTS_MASK                GENMASK(3, 0)
+#define AHCI_DWC_PORT_PHYCR            0x74
+#define AHCI_DWC_PORT_PHYSR            0x78
+
+struct ahci_dwc_host_priv {
+       struct platform_device *pdev;
+
+       u32 timv;
+       u32 dmacr[AHCI_MAX_PORTS];
+};
+
+static struct ahci_host_priv *ahci_dwc_get_resources(struct platform_device *pdev)
+{
+       struct ahci_dwc_host_priv *dpriv;
+       struct ahci_host_priv *hpriv;
+
+       dpriv = devm_kzalloc(&pdev->dev, sizeof(*dpriv), GFP_KERNEL);
+       if (!dpriv)
+               return ERR_PTR(-ENOMEM);
+
+       dpriv->pdev = pdev;
+
+       hpriv = ahci_platform_get_resources(pdev, AHCI_PLATFORM_GET_RESETS);
+       if (IS_ERR(hpriv))
+               return hpriv;
+
+       hpriv->plat_data = (void *)dpriv;
+
+       return hpriv;
+}
+
+static void ahci_dwc_check_cap(struct ahci_host_priv *hpriv)
+{
+       unsigned long port_map = hpriv->saved_port_map | hpriv->mask_port_map;
+       struct ahci_dwc_host_priv *dpriv = hpriv->plat_data;
+       bool dev_mp, dev_cp, fbs_sup;
+       unsigned int fbs_pmp;
+       u32 param;
+       int i;
+
+       param = readl(hpriv->mmio + AHCI_DWC_HOST_GPARAM2R);
+       dev_mp = !!(param & AHCI_DWC_HOST_DEV_MP);
+       dev_cp = !!(param & AHCI_DWC_HOST_DEV_CP);
+       fbs_sup = !!(param & AHCI_DWC_HOST_FBS_SUP);
+       fbs_pmp = 5 * FIELD_GET(AHCI_DWC_HOST_FBS_PMPN_MASK, param);
+
+       if (!dev_mp && hpriv->saved_cap & HOST_CAP_MPS) {
+               dev_warn(&dpriv->pdev->dev, "MPS is unsupported\n");
+               hpriv->saved_cap &= ~HOST_CAP_MPS;
+       }
+
+
+       if (fbs_sup && fbs_pmp < AHCI_DWC_FBS_PMPN_MAX) {
+               dev_warn(&dpriv->pdev->dev, "PMPn is limited up to %u ports\n",
+                        fbs_pmp);
+       }
+
+       for_each_set_bit(i, &port_map, AHCI_MAX_PORTS) {
+               if (!dev_mp && hpriv->saved_port_cap[i] & PORT_CMD_MPSP) {
+                       dev_warn(&dpriv->pdev->dev, "MPS incapable port %d\n", i);
+                       hpriv->saved_port_cap[i] &= ~PORT_CMD_MPSP;
+               }
+
+               if (!dev_cp && hpriv->saved_port_cap[i] & PORT_CMD_CPD) {
+                       dev_warn(&dpriv->pdev->dev, "CPD incapable port %d\n", i);
+                       hpriv->saved_port_cap[i] &= ~PORT_CMD_CPD;
+               }
+
+               if (!fbs_sup && hpriv->saved_port_cap[i] & PORT_CMD_FBSCP) {
+                       dev_warn(&dpriv->pdev->dev, "FBS incapable port %d\n", i);
+                       hpriv->saved_port_cap[i] &= ~PORT_CMD_FBSCP;
+               }
+       }
+}
+
+static void ahci_dwc_init_timer(struct ahci_host_priv *hpriv)
+{
+       struct ahci_dwc_host_priv *dpriv = hpriv->plat_data;
+       unsigned long rate;
+       struct clk *aclk;
+       u32 cap, cap2;
+
+       /* 1ms tick is generated only for the CCC or DevSleep features */
+       cap = readl(hpriv->mmio + HOST_CAP);
+       cap2 = readl(hpriv->mmio + HOST_CAP2);
+       if (!(cap & HOST_CAP_CCC) && !(cap2 & HOST_CAP2_SDS))
+               return;
+
+       /*
+        * Tick is generated based on the AXI/AHB application clocks signal
+        * so we need to be sure in the clock we are going to use.
+        */
+       aclk = ahci_platform_find_clk(hpriv, "aclk");
+       if (!aclk)
+               return;
+
+       /* 1ms timer interval is set as TIMV = AMBA_FREQ[MHZ] * 1000 */
+       dpriv->timv = readl(hpriv->mmio + AHCI_DWC_HOST_TIMER1MS);
+       dpriv->timv = FIELD_GET(AHCI_DWC_HOST_TIMV_MASK, dpriv->timv);
+       rate = clk_get_rate(aclk) / 1000UL;
+       if (rate == dpriv->timv)
+               return;
+
+       dev_info(&dpriv->pdev->dev, "Update CCC/DevSlp timer for Fapp %lu MHz\n",
+                rate / 1000UL);
+       dpriv->timv = FIELD_PREP(AHCI_DWC_HOST_TIMV_MASK, rate);
+       writel(dpriv->timv, hpriv->mmio + AHCI_DWC_HOST_TIMER1MS);
+}
+
+static int ahci_dwc_init_dmacr(struct ahci_host_priv *hpriv)
+{
+       struct ahci_dwc_host_priv *dpriv = hpriv->plat_data;
+       struct device_node *child;
+       void __iomem *port_mmio;
+       u32 port, dmacr, ts;
+
+       /*
+        * Update the DMA Tx/Rx transaction sizes in accordance with the
+        * platform setup. Note values exceeding maximal or minimal limits will
+        * be automatically clamped. Also note the register isn't affected by
+        * the HBA global reset so we can freely initialize it once until the
+        * next system reset.
+        */
+       for_each_child_of_node(dpriv->pdev->dev.of_node, child) {
+               if (!of_device_is_available(child))
+                       continue;
+
+               if (of_property_read_u32(child, "reg", &port)) {
+                       of_node_put(child);
+                       return -EINVAL;
+               }
+
+               port_mmio = __ahci_port_base(hpriv, port);
+               dmacr = readl(port_mmio + AHCI_DWC_PORT_DMACR);
+
+               if (!of_property_read_u32(child, "snps,tx-ts-max", &ts)) {
+                       ts = ilog2(ts);
+                       dmacr &= ~AHCI_DWC_PORT_TXTS_MASK;
+                       dmacr |= FIELD_PREP(AHCI_DWC_PORT_TXTS_MASK, ts);
+               }
+
+               if (!of_property_read_u32(child, "snps,rx-ts-max", &ts)) {
+                       ts = ilog2(ts);
+                       dmacr &= ~AHCI_DWC_PORT_RXTS_MASK;
+                       dmacr |= FIELD_PREP(AHCI_DWC_PORT_RXTS_MASK, ts);
+               }
+
+               writel(dmacr, port_mmio + AHCI_DWC_PORT_DMACR);
+               dpriv->dmacr[port] = dmacr;
+       }
+
+       return 0;
+}
+
+static int ahci_dwc_init_host(struct ahci_host_priv *hpriv)
+{
+       int rc;
+
+       rc = ahci_platform_enable_resources(hpriv);
+       if (rc)
+               return rc;
+
+       ahci_dwc_check_cap(hpriv);
+
+       ahci_dwc_init_timer(hpriv);
+
+       rc = ahci_dwc_init_dmacr(hpriv);
+       if (rc)
+               goto err_disable_resources;
+
+       return 0;
+
+err_disable_resources:
+       ahci_platform_disable_resources(hpriv);
+
+       return rc;
+}
+
+static int ahci_dwc_reinit_host(struct ahci_host_priv *hpriv)
+{
+       struct ahci_dwc_host_priv *dpriv = hpriv->plat_data;
+       unsigned long port_map = hpriv->port_map;
+       void __iomem *port_mmio;
+       int i, rc;
+
+       rc = ahci_platform_enable_resources(hpriv);
+       if (rc)
+               return rc;
+
+       writel(dpriv->timv, hpriv->mmio + AHCI_DWC_HOST_TIMER1MS);
+
+       for_each_set_bit(i, &port_map, AHCI_MAX_PORTS) {
+               port_mmio = __ahci_port_base(hpriv, i);
+               writel(dpriv->dmacr[i], port_mmio + AHCI_DWC_PORT_DMACR);
+       }
+
+       return 0;
+}
+
+static void ahci_dwc_clear_host(struct ahci_host_priv *hpriv)
+{
+       ahci_platform_disable_resources(hpriv);
+}
+
+static void ahci_dwc_stop_host(struct ata_host *host)
+{
+       struct ahci_host_priv *hpriv = host->private_data;
+
+       ahci_dwc_clear_host(hpriv);
+}
+
+static struct ata_port_operations ahci_dwc_port_ops = {
+       .inherits       = &ahci_platform_ops,
+       .host_stop      = ahci_dwc_stop_host,
+};
+
+static const struct ata_port_info ahci_dwc_port_info = {
+       .flags          = AHCI_FLAG_COMMON,
+       .pio_mask       = ATA_PIO4,
+       .udma_mask      = ATA_UDMA6,
+       .port_ops       = &ahci_dwc_port_ops,
+};
+
+static struct scsi_host_template ahci_dwc_scsi_info = {
+       AHCI_SHT(DRV_NAME),
+};
+
+static int ahci_dwc_probe(struct platform_device *pdev)
+{
+       struct ahci_host_priv *hpriv;
+       int rc;
+
+       hpriv = ahci_dwc_get_resources(pdev);
+       if (IS_ERR(hpriv))
+               return PTR_ERR(hpriv);
+
+       rc = ahci_dwc_init_host(hpriv);
+       if (rc)
+               return rc;
+
+       rc = ahci_platform_init_host(pdev, hpriv, &ahci_dwc_port_info,
+                                    &ahci_dwc_scsi_info);
+       if (rc)
+               goto err_clear_host;
+
+       return 0;
+
+err_clear_host:
+       ahci_dwc_clear_host(hpriv);
+
+       return rc;
+}
+
+static int ahci_dwc_suspend(struct device *dev)
+{
+       struct ata_host *host = dev_get_drvdata(dev);
+       struct ahci_host_priv *hpriv = host->private_data;
+       int rc;
+
+       rc = ahci_platform_suspend_host(dev);
+       if (rc)
+               return rc;
+
+       ahci_dwc_clear_host(hpriv);
+
+       return 0;
+}
+
+static int ahci_dwc_resume(struct device *dev)
+{
+       struct ata_host *host = dev_get_drvdata(dev);
+       struct ahci_host_priv *hpriv = host->private_data;
+       int rc;
+
+       rc = ahci_dwc_reinit_host(hpriv);
+       if (rc)
+               return rc;
+
+       return ahci_platform_resume_host(dev);
+}
+
+static DEFINE_SIMPLE_DEV_PM_OPS(ahci_dwc_pm_ops, ahci_dwc_suspend,
+                               ahci_dwc_resume);
+
+static const struct of_device_id ahci_dwc_of_match[] = {
+       { .compatible = "snps,dwc-ahci", },
+       { .compatible = "snps,spear-ahci", },
+       {},
+};
+MODULE_DEVICE_TABLE(of, ahci_dwc_of_match);
+
+static struct platform_driver ahci_dwc_driver = {
+       .probe = ahci_dwc_probe,
+       .remove = ata_platform_remove_one,
+       .shutdown = ahci_platform_shutdown,
+       .driver = {
+               .name = DRV_NAME,
+               .of_match_table = ahci_dwc_of_match,
+               .pm = &ahci_dwc_pm_ops,
+       },
+};
+module_platform_driver(ahci_dwc_driver);
+
+MODULE_DESCRIPTION("DWC AHCI SATA platform driver");
+MODULE_AUTHOR("Serge Semin <Sergey.Semin@baikalelectronics.ru>");
+MODULE_LICENSE("GPL");