Merge tag 'net-next-6.3' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-nextgrafted

Pull networking updates from Jakub Kicinski:
 "Core:

   - Add dedicated kmem_cache for typical/small skb->head, avoid having
     to access struct page at kfree time, and improve memory use.

   - Introduce sysctl to set default RPS configuration for new netdevs.

   - Define Netlink protocol specification format which can be used to
     describe messages used by each family and auto-generate parsers.
     Add tools for generating kernel data structures and uAPI headers.

   - Expose all net/core sysctls inside netns.

   - Remove 4s sleep in netpoll if carrier is instantly detected on
     boot.

   - Add configurable limit of MDB entries per port, and port-vlan.

   - Continue populating drop reasons throughout the stack.

   - Retire a handful of legacy Qdiscs and classifiers.

  Protocols:

   - Support IPv4 big TCP (TSO frames larger than 64kB).

   - Add IP_LOCAL_PORT_RANGE socket option, to control local port range
     on socket by socket basis.

   - Track and report in procfs number of MPTCP sockets used.

   - Support mixing IPv4 and IPv6 flows in the in-kernel MPTCP path
     manager.

   - IPv6: don't check net.ipv6.route.max_size and rely on garbage
     collection to free memory (similarly to IPv4).

   - Support Penultimate Segment Pop (PSP) flavor in SRv6 (RFC8986).

   - ICMP: add per-rate limit counters.

   - Add support for user scanning requests in ieee802154.

   - Remove static WEP support.

   - Support minimal Wi-Fi 7 Extremely High Throughput (EHT) rate
     reporting.

   - WiFi 7 EHT channel puncturing support (client & AP).

  BPF:

   - Add a rbtree data structure following the "next-gen data structure"
     precedent set by recently added linked list, that is, by using
     kfunc + kptr instead of adding a new BPF map type.

   - Expose XDP hints via kfuncs with initial support for RX hash and
     timestamp metadata.

   - Add BPF_F_NO_TUNNEL_KEY extension to bpf_skb_set_tunnel_key to
     better support decap on GRE tunnel devices not operating in collect
     metadata.

   - Improve x86 JIT's codegen for PROBE_MEM runtime error checks.

   - Remove the need for trace_printk_lock for bpf_trace_printk and
     bpf_trace_vprintk helpers.

   - Extend libbpf's bpf_tracing.h support for tracing arguments of
     kprobes/uprobes and syscall as a special case.

   - Significantly reduce the search time for module symbols by
     livepatch and BPF.

   - Enable cpumasks to be used as kptrs, which is useful for tracing
     programs tracking which tasks end up running on which CPUs in
     different time intervals.

   - Add support for BPF trampoline on s390x and riscv64.

   - Add capability to export the XDP features supported by the NIC.

   - Add __bpf_kfunc tag for marking kernel functions as kfuncs.

   - Add cgroup.memory=nobpf kernel parameter option to disable BPF
     memory accounting for container environments.

  Netfilter:

   - Remove the CLUSTERIP target. It has been marked as obsolete for
     years, and we still have WARN splats wrt races of the out-of-band
     /proc interface installed by this target.

   - Add 'destroy' commands to nf_tables. They are identical to the
     existing 'delete' commands, but do not return an error if the
     referenced object (set, chain, rule...) did not exist.

  Driver API:

   - Improve cpumask_local_spread() locality to help NICs set the right
     IRQ affinity on AMD platforms.

   - Separate C22 and C45 MDIO bus transactions more clearly.

   - Introduce new DCB table to control DSCP rewrite on egress.

   - Support configuration of Physical Layer Collision Avoidance (PLCA)
     Reconciliation Sublayer (RS) (802.3cg-2019). Modern version of
     shared medium Ethernet.

   - Support for MAC Merge layer (IEEE 802.3-2018 clause 99). Allowing
     preemption of low priority frames by high priority frames.

   - Add support for controlling MACSec offload using netlink SET.

   - Rework devlink instance refcounts to allow registration and
     de-registration under the instance lock. Split the code into
     multiple files, drop some of the unnecessarily granular locks and
     factor out common parts of netlink operation handling.

   - Add TX frame aggregation parameters (for USB drivers).

   - Add a new attr TCA_EXT_WARN_MSG to report TC (offload) warning
     messages with notifications for debug.

   - Allow offloading of UDP NEW connections via act_ct.

   - Add support for per action HW stats in TC.

   - Support hardware miss to TC action (continue processing in SW from
     a specific point in the action chain).

   - Warn if old Wireless Extension user space interface is used with
     modern cfg80211/mac80211 drivers. Do not support Wireless
     Extensions for Wi-Fi 7 devices at all. Everyone should switch to
     using nl80211 interface instead.

   - Improve the CAN bit timing configuration. Use extack to return
     error messages directly to user space, update the SJW handling,
     including the definition of a new default value that will benefit
     CAN-FD controllers, by increasing their oscillator tolerance.

  New hardware / drivers:

   - Ethernet:
      - nVidia BlueField-3 support (control traffic driver)
      - Ethernet support for imx93 SoCs
      - Motorcomm yt8531 gigabit Ethernet PHY
      - onsemi NCN26000 10BASE-T1S PHY (with support for PLCA)
      - Microchip LAN8841 PHY (incl. cable diagnostics and PTP)
      - Amlogic gxl MDIO mux

   - WiFi:
      - RealTek RTL8188EU (rtl8xxxu)
      - Qualcomm Wi-Fi 7 devices (ath12k)

   - CAN:
      - Renesas R-Car V4H

  Drivers:

   - Bluetooth:
      - Set Per Platform Antenna Gain (PPAG) for Intel controllers.

   - Ethernet NICs:
      - Intel (1G, igc):
         - support TSN / Qbv / packet scheduling features of i226 model
      - Intel (100G, ice):
         - use GNSS subsystem instead of TTY
         - multi-buffer XDP support
         - extend support for GPIO pins to E823 devices
      - nVidia/Mellanox:
         - update the shared buffer configuration on PFC commands
         - implement PTP adjphase function for HW offset control
         - TC support for Geneve and GRE with VF tunnel offload
         - more efficient crypto key management method
         - multi-port eswitch support
      - Netronome/Corigine:
         - add DCB IEEE support
         - support IPsec offloading for NFP3800
      - Freescale/NXP (enetc):
         - support XDP_REDIRECT for XDP non-linear buffers
         - improve reconfig, avoid link flap and waiting for idle
         - support MAC Merge layer
      - Other NICs:
         - sfc/ef100: add basic devlink support for ef100
         - ionic: rx_push mode operation (writing descriptors via MMIO)
         - bnxt: use the auxiliary bus abstraction for RDMA
         - r8169: disable ASPM and reset bus in case of tx timeout
         - cpsw: support QSGMII mode for J721e CPSW9G
         - cpts: support pulse-per-second output
         - ngbe: add an mdio bus driver
         - usbnet: optimize usbnet_bh() by avoiding unnecessary queuing
         - r8152: handle devices with FW with NCM support
         - amd-xgbe: support 10Mbps, 2.5GbE speeds and rx-adaptation
         - virtio-net: support multi buffer XDP
         - virtio/vsock: replace virtio_vsock_pkt with sk_buff
         - tsnep: XDP support

   - Ethernet high-speed switches:
      - nVidia/Mellanox (mlxsw):
         - add support for latency TLV (in FW control messages)
      - Microchip (sparx5):
         - separate explicit and implicit traffic forwarding rules, make
           the implicit rules always active
         - add support for egress DSCP rewrite
         - IS0 VCAP support (Ingress Classification)
         - IS2 VCAP filters (protos, L3 addrs, L4 ports, flags, ToS
           etc.)
         - ES2 VCAP support (Egress Access Control)
         - support for Per-Stream Filtering and Policing (802.1Q,
           8.6.5.1)

   - Ethernet embedded switches:
      - Marvell (mv88e6xxx):
         - add MAB (port auth) offload support
         - enable PTP receive for mv88e6390
      - NXP (ocelot):
         - support MAC Merge layer
         - support for the the vsc7512 internal copper phys
      - Microchip:
         - lan9303: convert to PHYLINK
         - lan966x: support TC flower filter statistics
         - lan937x: PTP support for KSZ9563/KSZ8563 and LAN937x
         - lan937x: support Credit Based Shaper configuration
         - ksz9477: support Energy Efficient Ethernet
      - other:
         - qca8k: convert to regmap read/write API, use bulk operations
         - rswitch: Improve TX timestamp accuracy

   - Intel WiFi (iwlwifi):
      - EHT (Wi-Fi 7) rate reporting
      - STEP equalizer support: transfer some STEP (connection to radio
        on platforms with integrated wifi) related parameters from the
        BIOS to the firmware.

   - Qualcomm 802.11ax WiFi (ath11k):
      - IPQ5018 support
      - Fine Timing Measurement (FTM) responder role support
      - channel 177 support

   - MediaTek WiFi (mt76):
      - per-PHY LED support
      - mt7996: EHT (Wi-Fi 7) support
      - Wireless Ethernet Dispatch (WED) reset support
      - switch to using page pool allocator

   - RealTek WiFi (rtw89):
      - support new version of Bluetooth co-existance

   - Mobile:
      - rmnet: support TX aggregation"

* tag 'net-next-6.3' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next: (1872 commits)
  page_pool: add a comment explaining the fragment counter usage
  net: ethtool: fix __ethtool_dev_mm_supported() implementation
  ethtool: pse-pd: Fix double word in comments
  xsk: add linux/vmalloc.h to xsk.c
  sefltests: netdevsim: wait for devlink instance after netns removal
  selftest: fib_tests: Always cleanup before exit
  net/mlx5e: Align IPsec ASO result memory to be as required by hardware
  net/mlx5e: TC, Set CT miss to the specific ct action instance
  net/mlx5e: Rename CHAIN_TO_REG to MAPPED_OBJ_TO_REG
  net/mlx5: Refactor tc miss handling to a single function
  net/mlx5: Kconfig: Make tc offload depend on tc skb extension
  net/sched: flower: Support hardware miss to tc action
  net/sched: flower: Move filter handle initialization earlier
  net/sched: cls_api: Support hardware miss to tc action
  net/sched: Rename user cookie and act cookie
  sfc: fix builds without CONFIG_RTC_LIB
  sfc: clean up some inconsistent indentings
  net/mlx4_en: Introduce flexible array to silence overflow warning
  net: lan966x: Fix possible deadlock inside PTP
  net/ulp: Remove redundant ->clone() test in inet_clone_ulp().
  ...

1 files changed, 662 insertions, 0 deletions

diff --git a/drivers/mmc/host/litex_mmc.c b/drivers/mmc/host/litex_mmc.c
new file mode 100644
index 000000000..39c6707fd
--- /dev/null
+++ b/drivers/mmc/host/litex_mmc.c
@@ -0,0 +1,662 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * LiteX LiteSDCard driver
+ *
+ * Copyright (C) 2019-2020 Antmicro <contact@antmicro.com>
+ * Copyright (C) 2019-2020 Kamil Rakoczy <krakoczy@antmicro.com>
+ * Copyright (C) 2019-2020 Maciej Dudek <mdudek@internships.antmicro.com>
+ * Copyright (C) 2020 Paul Mackerras <paulus@ozlabs.org>
+ * Copyright (C) 2020-2022 Gabriel Somlo <gsomlo@gmail.com>
+ */
+
+#include <linux/bits.h>
+#include <linux/clk.h>
+#include <linux/delay.h>
+#include <linux/dma-mapping.h>
+#include <linux/interrupt.h>
+#include <linux/iopoll.h>
+#include <linux/litex.h>
+#include <linux/mod_devicetable.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+
+#include <linux/mmc/host.h>
+#include <linux/mmc/mmc.h>
+#include <linux/mmc/sd.h>
+
+#define LITEX_PHY_CARDDETECT  0x00
+#define LITEX_PHY_CLOCKERDIV  0x04
+#define LITEX_PHY_INITIALIZE  0x08
+#define LITEX_PHY_WRITESTATUS 0x0C
+#define LITEX_CORE_CMDARG     0x00
+#define LITEX_CORE_CMDCMD     0x04
+#define LITEX_CORE_CMDSND     0x08
+#define LITEX_CORE_CMDRSP     0x0C
+#define LITEX_CORE_CMDEVT     0x1C
+#define LITEX_CORE_DATEVT     0x20
+#define LITEX_CORE_BLKLEN     0x24
+#define LITEX_CORE_BLKCNT     0x28
+#define LITEX_BLK2MEM_BASE    0x00
+#define LITEX_BLK2MEM_LEN     0x08
+#define LITEX_BLK2MEM_ENA     0x0C
+#define LITEX_BLK2MEM_DONE    0x10
+#define LITEX_BLK2MEM_LOOP    0x14
+#define LITEX_MEM2BLK_BASE    0x00
+#define LITEX_MEM2BLK_LEN     0x08
+#define LITEX_MEM2BLK_ENA     0x0C
+#define LITEX_MEM2BLK_DONE    0x10
+#define LITEX_MEM2BLK_LOOP    0x14
+#define LITEX_MEM2BLK         0x18
+#define LITEX_IRQ_STATUS      0x00
+#define LITEX_IRQ_PENDING     0x04
+#define LITEX_IRQ_ENABLE      0x08
+
+#define SD_CTL_DATA_XFER_NONE  0
+#define SD_CTL_DATA_XFER_READ  1
+#define SD_CTL_DATA_XFER_WRITE 2
+
+#define SD_CTL_RESP_NONE       0
+#define SD_CTL_RESP_SHORT      1
+#define SD_CTL_RESP_LONG       2
+#define SD_CTL_RESP_SHORT_BUSY 3
+
+#define SD_BIT_DONE    BIT(0)
+#define SD_BIT_WR_ERR  BIT(1)
+#define SD_BIT_TIMEOUT BIT(2)
+#define SD_BIT_CRC_ERR BIT(3)
+
+#define SD_SLEEP_US       5
+#define SD_TIMEOUT_US 20000
+
+#define SDIRQ_CARD_DETECT    1
+#define SDIRQ_SD_TO_MEM_DONE 2
+#define SDIRQ_MEM_TO_SD_DONE 4
+#define SDIRQ_CMD_DONE       8
+
+struct litex_mmc_host {
+	struct mmc_host *mmc;
+
+	void __iomem *sdphy;
+	void __iomem *sdcore;
+	void __iomem *sdreader;
+	void __iomem *sdwriter;
+	void __iomem *sdirq;
+
+	void *buffer;
+	size_t buf_size;
+	dma_addr_t dma;
+
+	struct completion cmd_done;
+	int irq;
+
+	unsigned int ref_clk;
+	unsigned int sd_clk;
+
+	u32 resp[4];
+	u16 rca;
+
+	bool is_bus_width_set;
+	bool app_cmd;
+};
+
+static int litex_mmc_sdcard_wait_done(void __iomem *reg, struct device *dev)
+{
+	u8 evt;
+	int ret;
+
+	ret = readx_poll_timeout(litex_read8, reg, evt, evt & SD_BIT_DONE,
+				 SD_SLEEP_US, SD_TIMEOUT_US);
+	if (ret)
+		return ret;
+	if (evt == SD_BIT_DONE)
+		return 0;
+	if (evt & SD_BIT_WR_ERR)
+		return -EIO;
+	if (evt & SD_BIT_TIMEOUT)
+		return -ETIMEDOUT;
+	if (evt & SD_BIT_CRC_ERR)
+		return -EILSEQ;
+	dev_err(dev, "%s: unknown error (evt=%x)\n", __func__, evt);
+	return -EINVAL;
+}
+
+static int litex_mmc_send_cmd(struct litex_mmc_host *host,
+			      u8 cmd, u32 arg, u8 response_len, u8 transfer)
+{
+	struct device *dev = mmc_dev(host->mmc);
+	void __iomem *reg;
+	int ret;
+	u8 evt;
+
+	litex_write32(host->sdcore + LITEX_CORE_CMDARG, arg);
+	litex_write32(host->sdcore + LITEX_CORE_CMDCMD,
+		      cmd << 8 | transfer << 5 | response_len);
+	litex_write8(host->sdcore + LITEX_CORE_CMDSND, 1);
+
+	/*
+	 * Wait for an interrupt if we have an interrupt and either there is
+	 * data to be transferred, or if the card can report busy via DAT0.
+	 */
+	if (host->irq > 0 &&
+	    (transfer != SD_CTL_DATA_XFER_NONE ||
+	     response_len == SD_CTL_RESP_SHORT_BUSY)) {
+		reinit_completion(&host->cmd_done);
+		litex_write32(host->sdirq + LITEX_IRQ_ENABLE,
+			      SDIRQ_CMD_DONE | SDIRQ_CARD_DETECT);
+		wait_for_completion(&host->cmd_done);
+	}
+
+	ret = litex_mmc_sdcard_wait_done(host->sdcore + LITEX_CORE_CMDEVT, dev);
+	if (ret) {
+		dev_err(dev, "Command (cmd %d) error, status %d\n", cmd, ret);
+		return ret;
+	}
+
+	if (response_len != SD_CTL_RESP_NONE) {
+		/*
+		 * NOTE: this matches the semantics of litex_read32()
+		 * regardless of underlying arch endianness!
+		 */
+		memcpy_fromio(host->resp,
+			      host->sdcore + LITEX_CORE_CMDRSP, 0x10);
+	}
+
+	if (!host->app_cmd && cmd == SD_SEND_RELATIVE_ADDR)
+		host->rca = (host->resp[3] >> 16);
+
+	host->app_cmd = (cmd == MMC_APP_CMD);
+
+	if (transfer == SD_CTL_DATA_XFER_NONE)
+		return ret; /* OK from prior litex_mmc_sdcard_wait_done() */
+
+	ret = litex_mmc_sdcard_wait_done(host->sdcore + LITEX_CORE_DATEVT, dev);
+	if (ret) {
+		dev_err(dev, "Data xfer (cmd %d) error, status %d\n", cmd, ret);
+		return ret;
+	}
+
+	/* Wait for completion of (read or write) DMA transfer */
+	reg = (transfer == SD_CTL_DATA_XFER_READ) ?
+		host->sdreader + LITEX_BLK2MEM_DONE :
+		host->sdwriter + LITEX_MEM2BLK_DONE;
+	ret = readx_poll_timeout(litex_read8, reg, evt, evt & SD_BIT_DONE,
+				 SD_SLEEP_US, SD_TIMEOUT_US);
+	if (ret)
+		dev_err(dev, "DMA timeout (cmd %d)\n", cmd);
+
+	return ret;
+}
+
+static int litex_mmc_send_app_cmd(struct litex_mmc_host *host)
+{
+	return litex_mmc_send_cmd(host, MMC_APP_CMD, host->rca << 16,
+				  SD_CTL_RESP_SHORT, SD_CTL_DATA_XFER_NONE);
+}
+
+static int litex_mmc_send_set_bus_w_cmd(struct litex_mmc_host *host, u32 width)
+{
+	return litex_mmc_send_cmd(host, SD_APP_SET_BUS_WIDTH, width,
+				  SD_CTL_RESP_SHORT, SD_CTL_DATA_XFER_NONE);
+}
+
+static int litex_mmc_set_bus_width(struct litex_mmc_host *host)
+{
+	bool app_cmd_sent;
+	int ret;
+
+	if (host->is_bus_width_set)
+		return 0;
+
+	/* Ensure 'app_cmd' precedes 'app_set_bus_width_cmd' */
+	app_cmd_sent = host->app_cmd; /* was preceding command app_cmd? */
+	if (!app_cmd_sent) {
+		ret = litex_mmc_send_app_cmd(host);
+		if (ret)
+			return ret;
+	}
+
+	/* LiteSDCard only supports 4-bit bus width */
+	ret = litex_mmc_send_set_bus_w_cmd(host, MMC_BUS_WIDTH_4);
+	if (ret)
+		return ret;
+
+	/* Re-send 'app_cmd' if necessary */
+	if (app_cmd_sent) {
+		ret = litex_mmc_send_app_cmd(host);
+		if (ret)
+			return ret;
+	}
+
+	host->is_bus_width_set = true;
+
+	return 0;
+}
+
+static int litex_mmc_get_cd(struct mmc_host *mmc)
+{
+	struct litex_mmc_host *host = mmc_priv(mmc);
+	int ret;
+
+	if (!mmc_card_is_removable(mmc))
+		return 1;
+
+	ret = !litex_read8(host->sdphy + LITEX_PHY_CARDDETECT);
+	if (ret)
+		return ret;
+
+	/* Ensure bus width will be set (again) upon card (re)insertion */
+	host->is_bus_width_set = false;
+
+	return 0;
+}
+
+static irqreturn_t litex_mmc_interrupt(int irq, void *arg)
+{
+	struct mmc_host *mmc = arg;
+	struct litex_mmc_host *host = mmc_priv(mmc);
+	u32 pending = litex_read32(host->sdirq + LITEX_IRQ_PENDING);
+	irqreturn_t ret = IRQ_NONE;
+
+	/* Check for card change interrupt */
+	if (pending & SDIRQ_CARD_DETECT) {
+		litex_write32(host->sdirq + LITEX_IRQ_PENDING,
+			      SDIRQ_CARD_DETECT);
+		mmc_detect_change(mmc, msecs_to_jiffies(10));
+		ret = IRQ_HANDLED;
+	}
+
+	/* Check for command completed */
+	if (pending & SDIRQ_CMD_DONE) {
+		/* Disable it so it doesn't keep interrupting */
+		litex_write32(host->sdirq + LITEX_IRQ_ENABLE,
+			      SDIRQ_CARD_DETECT);
+		complete(&host->cmd_done);
+		ret = IRQ_HANDLED;
+	}
+
+	return ret;
+}
+
+static u32 litex_mmc_response_len(struct mmc_command *cmd)
+{
+	if (cmd->flags & MMC_RSP_136)
+		return SD_CTL_RESP_LONG;
+	if (!(cmd->flags & MMC_RSP_PRESENT))
+		return SD_CTL_RESP_NONE;
+	if (cmd->flags & MMC_RSP_BUSY)
+		return SD_CTL_RESP_SHORT_BUSY;
+	return SD_CTL_RESP_SHORT;
+}
+
+static void litex_mmc_do_dma(struct litex_mmc_host *host, struct mmc_data *data,
+			     unsigned int *len, bool *direct, u8 *transfer)
+{
+	struct device *dev = mmc_dev(host->mmc);
+	dma_addr_t dma;
+	int sg_count;
+
+	/*
+	 * Try to DMA directly to/from the data buffer.
+	 * We can do that if the buffer can be mapped for DMA
+	 * in one contiguous chunk.
+	 */
+	dma = host->dma;
+	*len = data->blksz * data->blocks;
+	sg_count = dma_map_sg(dev, data->sg, data->sg_len,
+			      mmc_get_dma_dir(data));
+	if (sg_count == 1) {
+		dma = sg_dma_address(data->sg);
+		*len = sg_dma_len(data->sg);
+		*direct = true;
+	} else if (*len > host->buf_size)
+		*len = host->buf_size;
+
+	if (data->flags & MMC_DATA_READ) {
+		litex_write8(host->sdreader + LITEX_BLK2MEM_ENA, 0);
+		litex_write64(host->sdreader + LITEX_BLK2MEM_BASE, dma);
+		litex_write32(host->sdreader + LITEX_BLK2MEM_LEN, *len);
+		litex_write8(host->sdreader + LITEX_BLK2MEM_ENA, 1);
+		*transfer = SD_CTL_DATA_XFER_READ;
+	} else if (data->flags & MMC_DATA_WRITE) {
+		if (!*direct)
+			sg_copy_to_buffer(data->sg, data->sg_len,
+					  host->buffer, *len);
+		litex_write8(host->sdwriter + LITEX_MEM2BLK_ENA, 0);
+		litex_write64(host->sdwriter + LITEX_MEM2BLK_BASE, dma);
+		litex_write32(host->sdwriter + LITEX_MEM2BLK_LEN, *len);
+		litex_write8(host->sdwriter + LITEX_MEM2BLK_ENA, 1);
+		*transfer = SD_CTL_DATA_XFER_WRITE;
+	} else {
+		dev_warn(dev, "Data present w/o read or write flag.\n");
+		/* Continue: set cmd status, mark req done */
+	}
+
+	litex_write16(host->sdcore + LITEX_CORE_BLKLEN, data->blksz);
+	litex_write32(host->sdcore + LITEX_CORE_BLKCNT, data->blocks);
+}
+
+static void litex_mmc_request(struct mmc_host *mmc, struct mmc_request *mrq)
+{
+	struct litex_mmc_host *host = mmc_priv(mmc);
+	struct device *dev = mmc_dev(mmc);
+	struct mmc_command *cmd = mrq->cmd;
+	struct mmc_command *sbc = mrq->sbc;
+	struct mmc_data *data = mrq->data;
+	struct mmc_command *stop = mrq->stop;
+	unsigned int retries = cmd->retries;
+	unsigned int len = 0;
+	bool direct = false;
+	u32 response_len = litex_mmc_response_len(cmd);
+	u8 transfer = SD_CTL_DATA_XFER_NONE;
+
+	/* First check that the card is still there */
+	if (!litex_mmc_get_cd(mmc)) {
+		cmd->error = -ENOMEDIUM;
+		mmc_request_done(mmc, mrq);
+		return;
+	}
+
+	/* Send set-block-count command if needed */
+	if (sbc) {
+		sbc->error = litex_mmc_send_cmd(host, sbc->opcode, sbc->arg,
+						litex_mmc_response_len(sbc),
+						SD_CTL_DATA_XFER_NONE);
+		if (sbc->error) {
+			host->is_bus_width_set = false;
+			mmc_request_done(mmc, mrq);
+			return;
+		}
+	}
+
+	if (data) {
+		/*
+		 * LiteSDCard only supports 4-bit bus width; therefore, we MUST
+		 * inject a SET_BUS_WIDTH (acmd6) before the very first data
+		 * transfer, earlier than when the mmc subsystem would normally
+		 * get around to it!
+		 */
+		cmd->error = litex_mmc_set_bus_width(host);
+		if (cmd->error) {
+			dev_err(dev, "Can't set bus width!\n");
+			mmc_request_done(mmc, mrq);
+			return;
+		}
+
+		litex_mmc_do_dma(host, data, &len, &direct, &transfer);
+	}
+
+	do {
+		cmd->error = litex_mmc_send_cmd(host, cmd->opcode, cmd->arg,
+						response_len, transfer);
+	} while (cmd->error && retries-- > 0);
+
+	if (cmd->error) {
+		/* Card may be gone; don't assume bus width is still set */
+		host->is_bus_width_set = false;
+	}
+
+	if (response_len == SD_CTL_RESP_SHORT) {
+		/* Pull short response fields from appropriate host registers */
+		cmd->resp[0] = host->resp[3];
+		cmd->resp[1] = host->resp[2] & 0xFF;
+	} else if (response_len == SD_CTL_RESP_LONG) {
+		cmd->resp[0] = host->resp[0];
+		cmd->resp[1] = host->resp[1];
+		cmd->resp[2] = host->resp[2];
+		cmd->resp[3] = host->resp[3];
+	}
+
+	/* Send stop-transmission command if required */
+	if (stop && (cmd->error || !sbc)) {
+		stop->error = litex_mmc_send_cmd(host, stop->opcode, stop->arg,
+						 litex_mmc_response_len(stop),
+						 SD_CTL_DATA_XFER_NONE);
+		if (stop->error)
+			host->is_bus_width_set = false;
+	}
+
+	if (data) {
+		dma_unmap_sg(dev, data->sg, data->sg_len,
+			     mmc_get_dma_dir(data));
+	}
+
+	if (!cmd->error && transfer != SD_CTL_DATA_XFER_NONE) {
+		data->bytes_xfered = min(len, mmc->max_req_size);
+		if (transfer == SD_CTL_DATA_XFER_READ && !direct) {
+			sg_copy_from_buffer(data->sg, sg_nents(data->sg),
+					    host->buffer, data->bytes_xfered);
+		}
+	}
+
+	mmc_request_done(mmc, mrq);
+}
+
+static void litex_mmc_setclk(struct litex_mmc_host *host, unsigned int freq)
+{
+	struct device *dev = mmc_dev(host->mmc);
+	u32 div;
+
+	div = freq ? host->ref_clk / freq : 256U;
+	div = roundup_pow_of_two(div);
+	div = clamp(div, 2U, 256U);
+	dev_dbg(dev, "sd_clk_freq=%d: set to %d via div=%d\n",
+		freq, host->ref_clk / div, div);
+	litex_write16(host->sdphy + LITEX_PHY_CLOCKERDIV, div);
+	host->sd_clk = freq;
+}
+
+static void litex_mmc_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)
+{
+	struct litex_mmc_host *host = mmc_priv(mmc);
+
+	/*
+	 * NOTE: Ignore any ios->bus_width updates; they occur right after
+	 * the mmc core sends its own acmd6 bus-width change notification,
+	 * which is redundant since we snoop on the command flow and inject
+	 * an early acmd6 before the first data transfer command is sent!
+	 */
+
+	/* Update sd_clk */
+	if (ios->clock != host->sd_clk)
+		litex_mmc_setclk(host, ios->clock);
+}
+
+static const struct mmc_host_ops litex_mmc_ops = {
+	.get_cd = litex_mmc_get_cd,
+	.request = litex_mmc_request,
+	.set_ios = litex_mmc_set_ios,
+};
+
+static int litex_mmc_irq_init(struct platform_device *pdev,
+			      struct litex_mmc_host *host)
+{
+	struct device *dev = mmc_dev(host->mmc);
+	int ret;
+
+	ret = platform_get_irq_optional(pdev, 0);
+	if (ret < 0 && ret != -ENXIO)
+		return ret;
+	if (ret > 0)
+		host->irq = ret;
+	else {
+		dev_warn(dev, "Failed to get IRQ, using polling\n");
+		goto use_polling;
+	}
+
+	host->sdirq = devm_platform_ioremap_resource_byname(pdev, "irq");
+	if (IS_ERR(host->sdirq))
+		return PTR_ERR(host->sdirq);
+
+	ret = devm_request_irq(dev, host->irq, litex_mmc_interrupt, 0,
+			       "litex-mmc", host->mmc);
+	if (ret < 0) {
+		dev_warn(dev, "IRQ request error %d, using polling\n", ret);
+		goto use_polling;
+	}
+
+	/* Clear & enable card-change interrupts */
+	litex_write32(host->sdirq + LITEX_IRQ_PENDING, SDIRQ_CARD_DETECT);
+	litex_write32(host->sdirq + LITEX_IRQ_ENABLE, SDIRQ_CARD_DETECT);
+
+	return 0;
+
+use_polling:
+	host->mmc->caps |= MMC_CAP_NEEDS_POLL;
+	host->irq = 0;
+	return 0;
+}
+
+static void litex_mmc_free_host_wrapper(void *mmc)
+{
+	mmc_free_host(mmc);
+}
+
+static int litex_mmc_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct litex_mmc_host *host;
+	struct mmc_host *mmc;
+	struct clk *clk;
+	int ret;
+
+	/*
+	 * NOTE: defaults to max_[req,seg]_size=PAGE_SIZE, max_blk_size=512,
+	 * and max_blk_count accordingly set to 8;
+	 * If for some reason we need to modify max_blk_count, we must also
+	 * re-calculate `max_[req,seg]_size = max_blk_size * max_blk_count;`
+	 */
+	mmc = mmc_alloc_host(sizeof(struct litex_mmc_host), dev);
+	if (!mmc)
+		return -ENOMEM;
+
+	ret = devm_add_action_or_reset(dev, litex_mmc_free_host_wrapper, mmc);
+	if (ret)
+		return dev_err_probe(dev, ret,
+				     "Can't register mmc_free_host action\n");
+
+	host = mmc_priv(mmc);
+	host->mmc = mmc;
+
+	/* Initialize clock source */
+	clk = devm_clk_get(dev, NULL);
+	if (IS_ERR(clk))
+		return dev_err_probe(dev, PTR_ERR(clk), "can't get clock\n");
+	host->ref_clk = clk_get_rate(clk);
+	host->sd_clk = 0;
+
+	/*
+	 * LiteSDCard only supports 4-bit bus width; therefore, we MUST inject
+	 * a SET_BUS_WIDTH (acmd6) before the very first data transfer, earlier
+	 * than when the mmc subsystem would normally get around to it!
+	 */
+	host->is_bus_width_set = false;
+	host->app_cmd = false;
+
+	/* LiteSDCard can support 64-bit DMA addressing */
+	ret = dma_set_mask_and_coherent(dev, DMA_BIT_MASK(64));
+	if (ret)
+		return ret;
+
+	host->buf_size = mmc->max_req_size * 2;
+	host->buffer = dmam_alloc_coherent(dev, host->buf_size,
+					   &host->dma, GFP_KERNEL);
+	if (host->buffer == NULL)
+		return -ENOMEM;
+
+	host->sdphy = devm_platform_ioremap_resource_byname(pdev, "phy");
+	if (IS_ERR(host->sdphy))
+		return PTR_ERR(host->sdphy);
+
+	host->sdcore = devm_platform_ioremap_resource_byname(pdev, "core");
+	if (IS_ERR(host->sdcore))
+		return PTR_ERR(host->sdcore);
+
+	host->sdreader = devm_platform_ioremap_resource_byname(pdev, "reader");
+	if (IS_ERR(host->sdreader))
+		return PTR_ERR(host->sdreader);
+
+	host->sdwriter = devm_platform_ioremap_resource_byname(pdev, "writer");
+	if (IS_ERR(host->sdwriter))
+		return PTR_ERR(host->sdwriter);
+
+	/* Ensure DMA bus masters are disabled */
+	litex_write8(host->sdreader + LITEX_BLK2MEM_ENA, 0);
+	litex_write8(host->sdwriter + LITEX_MEM2BLK_ENA, 0);
+
+	init_completion(&host->cmd_done);
+	ret = litex_mmc_irq_init(pdev, host);
+	if (ret)
+		return ret;
+
+	mmc->ops = &litex_mmc_ops;
+
+	ret = mmc_regulator_get_supply(mmc);
+	if (ret || mmc->ocr_avail == 0) {
+		dev_warn(dev, "can't get voltage, defaulting to 3.3V\n");
+		mmc->ocr_avail = MMC_VDD_32_33 | MMC_VDD_33_34;
+	}
+
+	/*
+	 * Set default sd_clk frequency range based on empirical observations
+	 * of LiteSDCard gateware behavior on typical SDCard media
+	 */
+	mmc->f_min = 12.5e6;
+	mmc->f_max = 50e6;
+
+	ret = mmc_of_parse(mmc);
+	if (ret)
+		return ret;
+
+	/* Force 4-bit bus_width (only width supported by hardware) */
+	mmc->caps &= ~MMC_CAP_8_BIT_DATA;
+	mmc->caps |= MMC_CAP_4_BIT_DATA;
+
+	/* Set default capabilities */
+	mmc->caps |= MMC_CAP_WAIT_WHILE_BUSY |
+		     MMC_CAP_DRIVER_TYPE_D |
+		     MMC_CAP_CMD23;
+	mmc->caps2 |= MMC_CAP2_NO_WRITE_PROTECT |
+		      MMC_CAP2_NO_SDIO |
+		      MMC_CAP2_NO_MMC;
+
+	platform_set_drvdata(pdev, host);
+
+	ret = mmc_add_host(mmc);
+	if (ret)
+		return ret;
+
+	dev_info(dev, "LiteX MMC controller initialized.\n");
+	return 0;
+}
+
+static int litex_mmc_remove(struct platform_device *pdev)
+{
+	struct litex_mmc_host *host = platform_get_drvdata(pdev);
+
+	mmc_remove_host(host->mmc);
+	return 0;
+}
+
+static const struct of_device_id litex_match[] = {
+	{ .compatible = "litex,mmc" },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, litex_match);
+
+static struct platform_driver litex_mmc_driver = {
+	.probe = litex_mmc_probe,
+	.remove = litex_mmc_remove,
+	.driver = {
+		.name = "litex-mmc",
+		.of_match_table = litex_match,
+	},
+};
+module_platform_driver(litex_mmc_driver);
+
+MODULE_DESCRIPTION("LiteX SDCard driver");
+MODULE_AUTHOR("Antmicro <contact@antmicro.com>");
+MODULE_AUTHOR("Kamil Rakoczy <krakoczy@antmicro.com>");
+MODULE_AUTHOR("Maciej Dudek <mdudek@internships.antmicro.com>");
+MODULE_AUTHOR("Paul Mackerras <paulus@ozlabs.org>");
+MODULE_AUTHOR("Gabriel Somlo <gsomlo@gmail.com>");
+MODULE_LICENSE("GPL v2");