/* SPDX-License-Identifier: GPL-2.0-only */
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/****************************************************************************
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* Driver for Solarflare network controllers and boards
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* Copyright 2005-2006 Fen Systems Ltd.
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* Copyright 2006-2013 Solarflare Communications Inc.
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*/
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#ifndef EF4_IO_H
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#define EF4_IO_H
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#include <linux/io.h>
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#include <linux/spinlock.h>
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/**************************************************************************
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*
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* NIC register I/O
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*
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**************************************************************************
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*
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* Notes on locking strategy for the Falcon architecture:
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*
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* Many CSRs are very wide and cannot be read or written atomically.
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* Writes from the host are buffered by the Bus Interface Unit (BIU)
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* up to 128 bits. Whenever the host writes part of such a register,
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* the BIU collects the written value and does not write to the
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* underlying register until all 4 dwords have been written. A
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* similar buffering scheme applies to host access to the NIC's 64-bit
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* SRAM.
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*
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* Writes to different CSRs and 64-bit SRAM words must be serialised,
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* since interleaved access can result in lost writes. We use
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* ef4_nic::biu_lock for this.
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*
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* We also serialise reads from 128-bit CSRs and SRAM with the same
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* spinlock. This may not be necessary, but it doesn't really matter
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* as there are no such reads on the fast path.
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*
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* The DMA descriptor pointers (RX_DESC_UPD and TX_DESC_UPD) are
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* 128-bit but are special-cased in the BIU to avoid the need for
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* locking in the host:
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*
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* - They are write-only.
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* - The semantics of writing to these registers are such that
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* replacing the low 96 bits with zero does not affect functionality.
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* - If the host writes to the last dword address of such a register
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* (i.e. the high 32 bits) the underlying register will always be
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* written. If the collector and the current write together do not
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* provide values for all 128 bits of the register, the low 96 bits
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* will be written as zero.
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* - If the host writes to the address of any other part of such a
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* register while the collector already holds values for some other
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* register, the write is discarded and the collector maintains its
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* current state.
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*
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* The EF10 architecture exposes very few registers to the host and
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* most of them are only 32 bits wide. The only exceptions are the MC
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* doorbell register pair, which has its own latching, and
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* TX_DESC_UPD, which works in a similar way to the Falcon
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* architecture.
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*/
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#if BITS_PER_LONG == 64
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#define EF4_USE_QWORD_IO 1
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#endif
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#ifdef EF4_USE_QWORD_IO
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static inline void _ef4_writeq(struct ef4_nic *efx, __le64 value,
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unsigned int reg)
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{
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__raw_writeq((__force u64)value, efx->membase + reg);
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}
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static inline __le64 _ef4_readq(struct ef4_nic *efx, unsigned int reg)
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{
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return (__force __le64)__raw_readq(efx->membase + reg);
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}
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#endif
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static inline void _ef4_writed(struct ef4_nic *efx, __le32 value,
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unsigned int reg)
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{
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__raw_writel((__force u32)value, efx->membase + reg);
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}
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static inline __le32 _ef4_readd(struct ef4_nic *efx, unsigned int reg)
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{
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return (__force __le32)__raw_readl(efx->membase + reg);
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}
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/* Write a normal 128-bit CSR, locking as appropriate. */
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static inline void ef4_writeo(struct ef4_nic *efx, const ef4_oword_t *value,
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unsigned int reg)
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{
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unsigned long flags __attribute__ ((unused));
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netif_vdbg(efx, hw, efx->net_dev,
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"writing register %x with " EF4_OWORD_FMT "\n", reg,
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EF4_OWORD_VAL(*value));
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spin_lock_irqsave(&efx->biu_lock, flags);
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#ifdef EF4_USE_QWORD_IO
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_ef4_writeq(efx, value->u64[0], reg + 0);
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_ef4_writeq(efx, value->u64[1], reg + 8);
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#else
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_ef4_writed(efx, value->u32[0], reg + 0);
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_ef4_writed(efx, value->u32[1], reg + 4);
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_ef4_writed(efx, value->u32[2], reg + 8);
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_ef4_writed(efx, value->u32[3], reg + 12);
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#endif
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spin_unlock_irqrestore(&efx->biu_lock, flags);
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}
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/* Write 64-bit SRAM through the supplied mapping, locking as appropriate. */
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static inline void ef4_sram_writeq(struct ef4_nic *efx, void __iomem *membase,
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const ef4_qword_t *value, unsigned int index)
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{
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unsigned int addr = index * sizeof(*value);
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unsigned long flags __attribute__ ((unused));
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netif_vdbg(efx, hw, efx->net_dev,
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"writing SRAM address %x with " EF4_QWORD_FMT "\n",
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addr, EF4_QWORD_VAL(*value));
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spin_lock_irqsave(&efx->biu_lock, flags);
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#ifdef EF4_USE_QWORD_IO
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__raw_writeq((__force u64)value->u64[0], membase + addr);
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#else
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__raw_writel((__force u32)value->u32[0], membase + addr);
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__raw_writel((__force u32)value->u32[1], membase + addr + 4);
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#endif
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spin_unlock_irqrestore(&efx->biu_lock, flags);
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}
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/* Write a 32-bit CSR or the last dword of a special 128-bit CSR */
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static inline void ef4_writed(struct ef4_nic *efx, const ef4_dword_t *value,
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unsigned int reg)
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{
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netif_vdbg(efx, hw, efx->net_dev,
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"writing register %x with "EF4_DWORD_FMT"\n",
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reg, EF4_DWORD_VAL(*value));
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/* No lock required */
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_ef4_writed(efx, value->u32[0], reg);
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}
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/* Read a 128-bit CSR, locking as appropriate. */
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static inline void ef4_reado(struct ef4_nic *efx, ef4_oword_t *value,
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unsigned int reg)
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{
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unsigned long flags __attribute__ ((unused));
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spin_lock_irqsave(&efx->biu_lock, flags);
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value->u32[0] = _ef4_readd(efx, reg + 0);
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value->u32[1] = _ef4_readd(efx, reg + 4);
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value->u32[2] = _ef4_readd(efx, reg + 8);
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value->u32[3] = _ef4_readd(efx, reg + 12);
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spin_unlock_irqrestore(&efx->biu_lock, flags);
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netif_vdbg(efx, hw, efx->net_dev,
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"read from register %x, got " EF4_OWORD_FMT "\n", reg,
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EF4_OWORD_VAL(*value));
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}
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/* Read 64-bit SRAM through the supplied mapping, locking as appropriate. */
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static inline void ef4_sram_readq(struct ef4_nic *efx, void __iomem *membase,
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ef4_qword_t *value, unsigned int index)
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{
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unsigned int addr = index * sizeof(*value);
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unsigned long flags __attribute__ ((unused));
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spin_lock_irqsave(&efx->biu_lock, flags);
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#ifdef EF4_USE_QWORD_IO
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value->u64[0] = (__force __le64)__raw_readq(membase + addr);
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#else
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value->u32[0] = (__force __le32)__raw_readl(membase + addr);
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value->u32[1] = (__force __le32)__raw_readl(membase + addr + 4);
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#endif
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spin_unlock_irqrestore(&efx->biu_lock, flags);
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netif_vdbg(efx, hw, efx->net_dev,
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"read from SRAM address %x, got "EF4_QWORD_FMT"\n",
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addr, EF4_QWORD_VAL(*value));
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}
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/* Read a 32-bit CSR or SRAM */
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static inline void ef4_readd(struct ef4_nic *efx, ef4_dword_t *value,
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unsigned int reg)
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{
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value->u32[0] = _ef4_readd(efx, reg);
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netif_vdbg(efx, hw, efx->net_dev,
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"read from register %x, got "EF4_DWORD_FMT"\n",
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reg, EF4_DWORD_VAL(*value));
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}
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/* Write a 128-bit CSR forming part of a table */
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static inline void
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ef4_writeo_table(struct ef4_nic *efx, const ef4_oword_t *value,
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unsigned int reg, unsigned int index)
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{
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ef4_writeo(efx, value, reg + index * sizeof(ef4_oword_t));
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}
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/* Read a 128-bit CSR forming part of a table */
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static inline void ef4_reado_table(struct ef4_nic *efx, ef4_oword_t *value,
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unsigned int reg, unsigned int index)
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{
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ef4_reado(efx, value, reg + index * sizeof(ef4_oword_t));
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}
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/* Page size used as step between per-VI registers */
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#define EF4_VI_PAGE_SIZE 0x2000
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/* Calculate offset to page-mapped register */
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#define EF4_PAGED_REG(page, reg) \
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((page) * EF4_VI_PAGE_SIZE + (reg))
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/* Write the whole of RX_DESC_UPD or TX_DESC_UPD */
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static inline void _ef4_writeo_page(struct ef4_nic *efx, ef4_oword_t *value,
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unsigned int reg, unsigned int page)
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{
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reg = EF4_PAGED_REG(page, reg);
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netif_vdbg(efx, hw, efx->net_dev,
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"writing register %x with " EF4_OWORD_FMT "\n", reg,
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EF4_OWORD_VAL(*value));
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#ifdef EF4_USE_QWORD_IO
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_ef4_writeq(efx, value->u64[0], reg + 0);
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_ef4_writeq(efx, value->u64[1], reg + 8);
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#else
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_ef4_writed(efx, value->u32[0], reg + 0);
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_ef4_writed(efx, value->u32[1], reg + 4);
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_ef4_writed(efx, value->u32[2], reg + 8);
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_ef4_writed(efx, value->u32[3], reg + 12);
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#endif
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}
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#define ef4_writeo_page(efx, value, reg, page) \
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_ef4_writeo_page(efx, value, \
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reg + \
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BUILD_BUG_ON_ZERO((reg) != 0x830 && (reg) != 0xa10), \
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page)
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/* Write a page-mapped 32-bit CSR (EVQ_RPTR, EVQ_TMR (EF10), or the
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* high bits of RX_DESC_UPD or TX_DESC_UPD)
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*/
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static inline void
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_ef4_writed_page(struct ef4_nic *efx, const ef4_dword_t *value,
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unsigned int reg, unsigned int page)
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{
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ef4_writed(efx, value, EF4_PAGED_REG(page, reg));
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}
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#define ef4_writed_page(efx, value, reg, page) \
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_ef4_writed_page(efx, value, \
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reg + \
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BUILD_BUG_ON_ZERO((reg) != 0x400 && \
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(reg) != 0x420 && \
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(reg) != 0x830 && \
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(reg) != 0x83c && \
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(reg) != 0xa18 && \
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(reg) != 0xa1c), \
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page)
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/* Write TIMER_COMMAND. This is a page-mapped 32-bit CSR, but a bug
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* in the BIU means that writes to TIMER_COMMAND[0] invalidate the
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* collector register.
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*/
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static inline void _ef4_writed_page_locked(struct ef4_nic *efx,
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const ef4_dword_t *value,
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unsigned int reg,
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unsigned int page)
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{
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unsigned long flags __attribute__ ((unused));
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if (page == 0) {
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spin_lock_irqsave(&efx->biu_lock, flags);
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ef4_writed(efx, value, EF4_PAGED_REG(page, reg));
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spin_unlock_irqrestore(&efx->biu_lock, flags);
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} else {
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ef4_writed(efx, value, EF4_PAGED_REG(page, reg));
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}
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}
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#define ef4_writed_page_locked(efx, value, reg, page) \
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_ef4_writed_page_locked(efx, value, \
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reg + BUILD_BUG_ON_ZERO((reg) != 0x420), \
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page)
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#endif /* EF4_IO_H */
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