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linux_dsm_epyc7002/include/linux/mmc/dw_mmc.h
Doug Anderson f8c58c1136 mmc: dw_mmc: Protect read-modify-write of INTMASK with a lock 
We're running into cases where our enabling of the SDIO interrupt in
dw_mmc doesn't actually take effect.  Specifically, adding patch like
this:

 +++ b/drivers/mmc/host/dw_mmc.c
 @@ -1076,6 +1076,9 @@ static void dw_mci_enable_sdio_irq(struct mmc_host *mmc, int enb)

      mci_writel(host, INTMASK,
           (int_mask | SDMMC_INT_SDIO(slot->id)));
 +    int_mask = mci_readl(host, INTMASK);
 +    if (!(int_mask & SDMMC_INT_SDIO(slot->id)))
 +      dev_err(&mmc->class_dev, "failed to enable sdio irq\n");
    } else {

...actually triggers the error message.  That's because the
dw_mci_enable_sdio_irq() unsafely does a read-modify-write of the
INTMASK register.

We can't just use the standard host->lock since that lock is not irq
safe and mmc_signal_sdio_irq() (called from interrupt context) calls
dw_mci_enable_sdio_irq().  Add a new irq-safe lock to protect INTMASK.

An alternate solution to this is to punt mmc_signal_sdio_irq() to the
tasklet and then protect INTMASK modifications by the standard host
lock.  This seemed like a bit more of a high-latency change.

Reported-by: Bing Zhao <bzhao@marvell.com>
Signed-off-by: Doug Anderson <dianders@chromium.org>
Reviewed-by: James Hogan <james.hogan@imgtec.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
2015-01-19 09:56:05 +01:00

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/*
* Synopsys DesignWare Multimedia Card Interface driver
* (Based on NXP driver for lpc 31xx)
*
* Copyright (C) 2009 NXP Semiconductors
* Copyright (C) 2009, 2010 Imagination Technologies Ltd.
*
* 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.
*/
#ifndef LINUX_MMC_DW_MMC_H
#define LINUX_MMC_DW_MMC_H
#include <linux/scatterlist.h>
#include <linux/mmc/core.h>
#define MAX_MCI_SLOTS 2
enum dw_mci_state {
STATE_IDLE = 0,
STATE_SENDING_CMD,
STATE_SENDING_DATA,
STATE_DATA_BUSY,
STATE_SENDING_STOP,
STATE_DATA_ERROR,
STATE_SENDING_CMD11,
STATE_WAITING_CMD11_DONE,
};
enum {
EVENT_CMD_COMPLETE = 0,
EVENT_XFER_COMPLETE,
EVENT_DATA_COMPLETE,
EVENT_DATA_ERROR,
EVENT_XFER_ERROR
};
struct mmc_data;
/**
* struct dw_mci - MMC controller state shared between all slots
* @lock: Spinlock protecting the queue and associated data.
* @regs: Pointer to MMIO registers.
* @sg: Scatterlist entry currently being processed by PIO code, if any.
* @sg_miter: PIO mapping scatterlist iterator.
* @cur_slot: The slot which is currently using the controller.
* @mrq: The request currently being processed on @cur_slot,
* or NULL if the controller is idle.
* @cmd: The command currently being sent to the card, or NULL.
* @data: The data currently being transferred, or NULL if no data
* transfer is in progress.
* @use_dma: Whether DMA channel is initialized or not.
* @using_dma: Whether DMA is in use for the current transfer.
* @dma_64bit_address: Whether DMA supports 64-bit address mode or not.
* @sg_dma: Bus address of DMA buffer.
* @sg_cpu: Virtual address of DMA buffer.
* @dma_ops: Pointer to platform-specific DMA callbacks.
* @cmd_status: Snapshot of SR taken upon completion of the current
* command. Only valid when EVENT_CMD_COMPLETE is pending.
* @data_status: Snapshot of SR taken upon completion of the current
* data transfer. Only valid when EVENT_DATA_COMPLETE or
* EVENT_DATA_ERROR is pending.
* @stop_cmdr: Value to be loaded into CMDR when the stop command is
* to be sent.
* @dir_status: Direction of current transfer.
* @tasklet: Tasklet running the request state machine.
* @card_tasklet: Tasklet handling card detect.
* @pending_events: Bitmask of events flagged by the interrupt handler
* to be processed by the tasklet.
* @completed_events: Bitmask of events which the state machine has
* processed.
* @state: Tasklet state.
* @queue: List of slots waiting for access to the controller.
* @bus_hz: The rate of @mck in Hz. This forms the basis for MMC bus
* rate and timeout calculations.
* @current_speed: Configured rate of the controller.
* @num_slots: Number of slots available.
* @verid: Denote Version ID.
* @data_offset: Set the offset of DATA register according to VERID.
* @dev: Device associated with the MMC controller.
* @pdata: Platform data associated with the MMC controller.
* @drv_data: Driver specific data for identified variant of the controller
* @priv: Implementation defined private data.
* @biu_clk: Pointer to bus interface unit clock instance.
* @ciu_clk: Pointer to card interface unit clock instance.
* @slot: Slots sharing this MMC controller.
* @fifo_depth: depth of FIFO.
* @data_shift: log2 of FIFO item size.
* @part_buf_start: Start index in part_buf.
* @part_buf_count: Bytes of partial data in part_buf.
* @part_buf: Simple buffer for partial fifo reads/writes.
* @push_data: Pointer to FIFO push function.
* @pull_data: Pointer to FIFO pull function.
* @quirks: Set of quirks that apply to specific versions of the IP.
* @irq_flags: The flags to be passed to request_irq.
* @irq: The irq value to be passed to request_irq.
* @sdio_id0: Number of slot0 in the SDIO interrupt registers.
*
* Locking
* =======
*
* @lock is a softirq-safe spinlock protecting @queue as well as
* @cur_slot, @mrq and @state. These must always be updated
* at the same time while holding @lock.
*
* @irq_lock is an irq-safe spinlock protecting the INTMASK register
* to allow the interrupt handler to modify it directly. Held for only long
* enough to read-modify-write INTMASK and no other locks are grabbed when
* holding this one.
*
* The @mrq field of struct dw_mci_slot is also protected by @lock,
* and must always be written at the same time as the slot is added to
* @queue.
*
* @pending_events and @completed_events are accessed using atomic bit
* operations, so they don't need any locking.
*
* None of the fields touched by the interrupt handler need any
* locking. However, ordering is important: Before EVENT_DATA_ERROR or
* EVENT_DATA_COMPLETE is set in @pending_events, all data-related
* interrupts must be disabled and @data_status updated with a
* snapshot of SR. Similarly, before EVENT_CMD_COMPLETE is set, the
* CMDRDY interrupt must be disabled and @cmd_status updated with a
* snapshot of SR, and before EVENT_XFER_COMPLETE can be set, the
* bytes_xfered field of @data must be written. This is ensured by
* using barriers.
*/
struct dw_mci {
spinlock_t lock;
spinlock_t irq_lock;
void __iomem *regs;
struct scatterlist *sg;
struct sg_mapping_iter sg_miter;
struct dw_mci_slot *cur_slot;
struct mmc_request *mrq;
struct mmc_command *cmd;
struct mmc_data *data;
struct mmc_command stop_abort;
unsigned int prev_blksz;
unsigned char timing;
/* DMA interface members*/
int use_dma;
int using_dma;
int dma_64bit_address;
dma_addr_t sg_dma;
void *sg_cpu;
const struct dw_mci_dma_ops *dma_ops;
#ifdef CONFIG_MMC_DW_IDMAC
unsigned int ring_size;
#else
struct dw_mci_dma_data *dma_data;
#endif
u32 cmd_status;
u32 data_status;
u32 stop_cmdr;
u32 dir_status;
struct tasklet_struct tasklet;
unsigned long pending_events;
unsigned long completed_events;
enum dw_mci_state state;
struct list_head queue;
u32 bus_hz;
u32 current_speed;
u32 num_slots;
u32 fifoth_val;
u16 verid;
u16 data_offset;
struct device *dev;
struct dw_mci_board *pdata;
const struct dw_mci_drv_data *drv_data;
void *priv;
struct clk *biu_clk;
struct clk *ciu_clk;
struct dw_mci_slot *slot[MAX_MCI_SLOTS];
/* FIFO push and pull */
int fifo_depth;
int data_shift;
u8 part_buf_start;
u8 part_buf_count;
union {
u16 part_buf16;
u32 part_buf32;
u64 part_buf;
};
void (*push_data)(struct dw_mci *host, void *buf, int cnt);
void (*pull_data)(struct dw_mci *host, void *buf, int cnt);
/* Workaround flags */
u32 quirks;
bool vqmmc_enabled;
unsigned long irq_flags; /* IRQ flags */
int irq;
int sdio_id0;
};
/* DMA ops for Internal/External DMAC interface */
struct dw_mci_dma_ops {
/* DMA Ops */
int (*init)(struct dw_mci *host);
void (*start)(struct dw_mci *host, unsigned int sg_len);
void (*complete)(struct dw_mci *host);
void (*stop)(struct dw_mci *host);
void (*cleanup)(struct dw_mci *host);
void (*exit)(struct dw_mci *host);
};
/* IP Quirks/flags. */
/* DTO fix for command transmission with IDMAC configured */
#define DW_MCI_QUIRK_IDMAC_DTO BIT(0)
/* delay needed between retries on some 2.11a implementations */
#define DW_MCI_QUIRK_RETRY_DELAY BIT(1)
/* High Speed Capable - Supports HS cards (up to 50MHz) */
#define DW_MCI_QUIRK_HIGHSPEED BIT(2)
/* Unreliable card detection */
#define DW_MCI_QUIRK_BROKEN_CARD_DETECTION BIT(3)
/* No write protect */
#define DW_MCI_QUIRK_NO_WRITE_PROTECT BIT(4)
/* Slot level quirks */
/* This slot has no write protect */
#define DW_MCI_SLOT_QUIRK_NO_WRITE_PROTECT BIT(0)
struct dma_pdata;
struct block_settings {
unsigned short max_segs; /* see blk_queue_max_segments */
unsigned int max_blk_size; /* maximum size of one mmc block */
unsigned int max_blk_count; /* maximum number of blocks in one req*/
unsigned int max_req_size; /* maximum number of bytes in one req*/
unsigned int max_seg_size; /* see blk_queue_max_segment_size */
};
/* Board platform data */
struct dw_mci_board {
u32 num_slots;
u32 quirks; /* Workaround / Quirk flags */
unsigned int bus_hz; /* Clock speed at the cclk_in pad */
u32 caps; /* Capabilities */
u32 caps2; /* More capabilities */
u32 pm_caps; /* PM capabilities */
/*
* Override fifo depth. If 0, autodetect it from the FIFOTH register,
* but note that this may not be reliable after a bootloader has used
* it.
*/
unsigned int fifo_depth;
/* delay in mS before detecting cards after interrupt */
u32 detect_delay_ms;
struct dw_mci_dma_ops *dma_ops;
struct dma_pdata *data;
struct block_settings *blk_settings;
};
#endif /* LINUX_MMC_DW_MMC_H */
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