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In some circumstances the current implementation of the SPI memory operations may occasionally fail even though they are executed in the atomic context. This may happen if the system bus is relatively slow in comparison to the SPI bus frequency, or there is a concurrent access to it, which makes the MMIO-operations occasionally stalling before push-pulling data from the DW APB SPI FIFOs. These two problems we've discovered on the Baikal-T1 SoC. In order to fix them we have no choice but to set an artificial limitation on the SPI bus speed. Note currently this limitation will be only applicable for the memory operations, since the standard SPI core interface is implemented with an assumption that there is no problem with the automatic CS toggling. Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru> Link: https://lore.kernel.org/r/20201007235511.4935-19-Sergey.Semin@baikalelectronics.ru Signed-off-by: Mark Brown <broonie@kernel.org>
298 lines
7.5 KiB
C
298 lines
7.5 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef DW_SPI_HEADER_H
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#define DW_SPI_HEADER_H
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#include <linux/bits.h>
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#include <linux/completion.h>
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#include <linux/debugfs.h>
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#include <linux/irqreturn.h>
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#include <linux/io.h>
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#include <linux/scatterlist.h>
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#include <linux/spi/spi-mem.h>
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/* Register offsets */
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#define DW_SPI_CTRLR0 0x00
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#define DW_SPI_CTRLR1 0x04
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#define DW_SPI_SSIENR 0x08
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#define DW_SPI_MWCR 0x0c
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#define DW_SPI_SER 0x10
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#define DW_SPI_BAUDR 0x14
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#define DW_SPI_TXFTLR 0x18
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#define DW_SPI_RXFTLR 0x1c
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#define DW_SPI_TXFLR 0x20
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#define DW_SPI_RXFLR 0x24
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#define DW_SPI_SR 0x28
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#define DW_SPI_IMR 0x2c
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#define DW_SPI_ISR 0x30
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#define DW_SPI_RISR 0x34
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#define DW_SPI_TXOICR 0x38
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#define DW_SPI_RXOICR 0x3c
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#define DW_SPI_RXUICR 0x40
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#define DW_SPI_MSTICR 0x44
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#define DW_SPI_ICR 0x48
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#define DW_SPI_DMACR 0x4c
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#define DW_SPI_DMATDLR 0x50
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#define DW_SPI_DMARDLR 0x54
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#define DW_SPI_IDR 0x58
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#define DW_SPI_VERSION 0x5c
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#define DW_SPI_DR 0x60
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#define DW_SPI_RX_SAMPLE_DLY 0xf0
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#define DW_SPI_CS_OVERRIDE 0xf4
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/* Bit fields in CTRLR0 */
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#define SPI_DFS_OFFSET 0
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#define SPI_FRF_OFFSET 4
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#define SPI_FRF_SPI 0x0
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#define SPI_FRF_SSP 0x1
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#define SPI_FRF_MICROWIRE 0x2
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#define SPI_FRF_RESV 0x3
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#define SPI_MODE_OFFSET 6
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#define SPI_SCPH_OFFSET 6
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#define SPI_SCOL_OFFSET 7
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#define SPI_TMOD_OFFSET 8
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#define SPI_TMOD_MASK (0x3 << SPI_TMOD_OFFSET)
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#define SPI_TMOD_TR 0x0 /* xmit & recv */
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#define SPI_TMOD_TO 0x1 /* xmit only */
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#define SPI_TMOD_RO 0x2 /* recv only */
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#define SPI_TMOD_EPROMREAD 0x3 /* eeprom read mode */
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#define SPI_SLVOE_OFFSET 10
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#define SPI_SRL_OFFSET 11
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#define SPI_CFS_OFFSET 12
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/* Bit fields in CTRLR0 based on DWC_ssi_databook.pdf v1.01a */
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#define DWC_SSI_CTRLR0_SRL_OFFSET 13
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#define DWC_SSI_CTRLR0_TMOD_OFFSET 10
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#define DWC_SSI_CTRLR0_TMOD_MASK GENMASK(11, 10)
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#define DWC_SSI_CTRLR0_SCPOL_OFFSET 9
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#define DWC_SSI_CTRLR0_SCPH_OFFSET 8
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#define DWC_SSI_CTRLR0_FRF_OFFSET 6
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#define DWC_SSI_CTRLR0_DFS_OFFSET 0
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/*
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* For Keem Bay, CTRLR0[31] is used to select controller mode.
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* 0: SSI is slave
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* 1: SSI is master
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*/
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#define DWC_SSI_CTRLR0_KEEMBAY_MST BIT(31)
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/* Bit fields in CTRLR1 */
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#define SPI_NDF_MASK GENMASK(15, 0)
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/* Bit fields in SR, 7 bits */
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#define SR_MASK 0x7f /* cover 7 bits */
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#define SR_BUSY (1 << 0)
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#define SR_TF_NOT_FULL (1 << 1)
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#define SR_TF_EMPT (1 << 2)
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#define SR_RF_NOT_EMPT (1 << 3)
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#define SR_RF_FULL (1 << 4)
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#define SR_TX_ERR (1 << 5)
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#define SR_DCOL (1 << 6)
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/* Bit fields in ISR, IMR, RISR, 7 bits */
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#define SPI_INT_TXEI (1 << 0)
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#define SPI_INT_TXOI (1 << 1)
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#define SPI_INT_RXUI (1 << 2)
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#define SPI_INT_RXOI (1 << 3)
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#define SPI_INT_RXFI (1 << 4)
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#define SPI_INT_MSTI (1 << 5)
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/* Bit fields in DMACR */
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#define SPI_DMA_RDMAE (1 << 0)
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#define SPI_DMA_TDMAE (1 << 1)
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#define SPI_WAIT_RETRIES 5
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#define SPI_BUF_SIZE \
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(sizeof_field(struct spi_mem_op, cmd.opcode) + \
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sizeof_field(struct spi_mem_op, addr.val) + 256)
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#define SPI_GET_BYTE(_val, _idx) \
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((_val) >> (BITS_PER_BYTE * (_idx)) & 0xff)
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enum dw_ssi_type {
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SSI_MOTO_SPI = 0,
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SSI_TI_SSP,
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SSI_NS_MICROWIRE,
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};
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/* DW SPI capabilities */
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#define DW_SPI_CAP_CS_OVERRIDE BIT(0)
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#define DW_SPI_CAP_KEEMBAY_MST BIT(1)
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#define DW_SPI_CAP_DWC_SSI BIT(2)
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/* Slave spi_transfer/spi_mem_op related */
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struct dw_spi_cfg {
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u8 tmode;
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u8 dfs;
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u32 ndf;
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u32 freq;
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};
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struct dw_spi;
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struct dw_spi_dma_ops {
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int (*dma_init)(struct device *dev, struct dw_spi *dws);
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void (*dma_exit)(struct dw_spi *dws);
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int (*dma_setup)(struct dw_spi *dws, struct spi_transfer *xfer);
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bool (*can_dma)(struct spi_controller *master, struct spi_device *spi,
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struct spi_transfer *xfer);
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int (*dma_transfer)(struct dw_spi *dws, struct spi_transfer *xfer);
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void (*dma_stop)(struct dw_spi *dws);
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};
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struct dw_spi {
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struct spi_controller *master;
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void __iomem *regs;
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unsigned long paddr;
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int irq;
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u32 fifo_len; /* depth of the FIFO buffer */
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u32 max_mem_freq; /* max mem-ops bus freq */
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u32 max_freq; /* max bus freq supported */
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u32 caps; /* DW SPI capabilities */
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u32 reg_io_width; /* DR I/O width in bytes */
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u16 bus_num;
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u16 num_cs; /* supported slave numbers */
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void (*set_cs)(struct spi_device *spi, bool enable);
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/* Current message transfer state info */
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void *tx;
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unsigned int tx_len;
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void *rx;
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unsigned int rx_len;
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u8 buf[SPI_BUF_SIZE];
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int dma_mapped;
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u8 n_bytes; /* current is a 1/2 bytes op */
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irqreturn_t (*transfer_handler)(struct dw_spi *dws);
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u32 current_freq; /* frequency in hz */
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u32 cur_rx_sample_dly;
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u32 def_rx_sample_dly_ns;
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/* Custom memory operations */
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struct spi_controller_mem_ops mem_ops;
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/* DMA info */
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struct dma_chan *txchan;
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u32 txburst;
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struct dma_chan *rxchan;
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u32 rxburst;
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u32 dma_sg_burst;
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unsigned long dma_chan_busy;
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dma_addr_t dma_addr; /* phy address of the Data register */
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const struct dw_spi_dma_ops *dma_ops;
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struct completion dma_completion;
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#ifdef CONFIG_DEBUG_FS
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struct dentry *debugfs;
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struct debugfs_regset32 regset;
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#endif
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};
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static inline u32 dw_readl(struct dw_spi *dws, u32 offset)
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{
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return __raw_readl(dws->regs + offset);
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}
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static inline void dw_writel(struct dw_spi *dws, u32 offset, u32 val)
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{
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__raw_writel(val, dws->regs + offset);
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}
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static inline u32 dw_read_io_reg(struct dw_spi *dws, u32 offset)
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{
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switch (dws->reg_io_width) {
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case 2:
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return readw_relaxed(dws->regs + offset);
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case 4:
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default:
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return readl_relaxed(dws->regs + offset);
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}
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}
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static inline void dw_write_io_reg(struct dw_spi *dws, u32 offset, u32 val)
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{
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switch (dws->reg_io_width) {
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case 2:
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writew_relaxed(val, dws->regs + offset);
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break;
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case 4:
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default:
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writel_relaxed(val, dws->regs + offset);
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break;
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}
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}
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static inline void spi_enable_chip(struct dw_spi *dws, int enable)
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{
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dw_writel(dws, DW_SPI_SSIENR, (enable ? 1 : 0));
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}
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static inline void spi_set_clk(struct dw_spi *dws, u16 div)
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{
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dw_writel(dws, DW_SPI_BAUDR, div);
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}
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/* Disable IRQ bits */
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static inline void spi_mask_intr(struct dw_spi *dws, u32 mask)
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{
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u32 new_mask;
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new_mask = dw_readl(dws, DW_SPI_IMR) & ~mask;
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dw_writel(dws, DW_SPI_IMR, new_mask);
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}
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/* Enable IRQ bits */
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static inline void spi_umask_intr(struct dw_spi *dws, u32 mask)
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{
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u32 new_mask;
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new_mask = dw_readl(dws, DW_SPI_IMR) | mask;
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dw_writel(dws, DW_SPI_IMR, new_mask);
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}
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/*
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* This disables the SPI controller, interrupts, clears the interrupts status
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* and CS, then re-enables the controller back. Transmit and receive FIFO
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* buffers are cleared when the device is disabled.
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*/
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static inline void spi_reset_chip(struct dw_spi *dws)
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{
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spi_enable_chip(dws, 0);
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spi_mask_intr(dws, 0xff);
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dw_readl(dws, DW_SPI_ICR);
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dw_writel(dws, DW_SPI_SER, 0);
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spi_enable_chip(dws, 1);
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}
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static inline void spi_shutdown_chip(struct dw_spi *dws)
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{
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spi_enable_chip(dws, 0);
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spi_set_clk(dws, 0);
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}
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extern void dw_spi_set_cs(struct spi_device *spi, bool enable);
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extern void dw_spi_update_config(struct dw_spi *dws, struct spi_device *spi,
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struct dw_spi_cfg *cfg);
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extern int dw_spi_check_status(struct dw_spi *dws, bool raw);
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extern int dw_spi_add_host(struct device *dev, struct dw_spi *dws);
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extern void dw_spi_remove_host(struct dw_spi *dws);
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extern int dw_spi_suspend_host(struct dw_spi *dws);
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extern int dw_spi_resume_host(struct dw_spi *dws);
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#ifdef CONFIG_SPI_DW_DMA
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extern void dw_spi_dma_setup_mfld(struct dw_spi *dws);
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extern void dw_spi_dma_setup_generic(struct dw_spi *dws);
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#else
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static inline void dw_spi_dma_setup_mfld(struct dw_spi *dws) {}
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static inline void dw_spi_dma_setup_generic(struct dw_spi *dws) {}
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#endif /* !CONFIG_SPI_DW_DMA */
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#endif /* DW_SPI_HEADER_H */
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