fcfa060468
Enabling write-combining may also enable read reordering. The BIU is only guaranteed to read from a 128-bit CSR or 64-bit SRAM word when the host reads from its lowest address; otherwise the BIU may use the latched value. Therefore we need to reinstate the read memory barriers after the first read operation for each CSR or SRAM word. Signed-off-by; Ben Hutchings <bhutchings@solarflare.com>
300 lines
9.8 KiB
C
300 lines
9.8 KiB
C
/****************************************************************************
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* Driver for Solarflare Solarstorm network controllers and boards
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* Copyright 2005-2006 Fen Systems Ltd.
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* Copyright 2006-2010 Solarflare Communications Inc.
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License version 2 as published
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* by the Free Software Foundation, incorporated herein by reference.
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*/
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#ifndef EFX_IO_H
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#define EFX_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:
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*
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* Most CSRs are 128-bit (oword) and therefore cannot be read or
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* written atomically. Access from the host is buffered by the Bus
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* Interface Unit (BIU). Whenever the host reads from the lowest
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* address of such a register, or from the address of a different such
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* register, the BIU latches the register's value. Subsequent reads
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* from higher addresses of the same register will read the latched
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* value. Whenever the host writes part of such a register, the BIU
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* collects the written value and does not write to the underlying
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* register until all 4 dwords have been written. A similar buffering
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* scheme applies to host access to the NIC's 64-bit SRAM.
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*
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* Access to different CSRs and 64-bit SRAM words must be serialised,
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* since interleaved access can result in lost writes or lost
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* information from read-to-clear fields. We use efx_nic::biu_lock
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* for this. (We could use separate locks for read and write, but
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* this is not normally a performance bottleneck.)
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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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#if BITS_PER_LONG == 64
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#define EFX_USE_QWORD_IO 1
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#endif
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#ifdef EFX_USE_QWORD_IO
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static inline void _efx_writeq(struct efx_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 _efx_readq(struct efx_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 _efx_writed(struct efx_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 _efx_readd(struct efx_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 efx_writeo(struct efx_nic *efx, efx_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 " EFX_OWORD_FMT "\n", reg,
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EFX_OWORD_VAL(*value));
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spin_lock_irqsave(&efx->biu_lock, flags);
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#ifdef EFX_USE_QWORD_IO
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_efx_writeq(efx, value->u64[0], reg + 0);
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_efx_writeq(efx, value->u64[1], reg + 8);
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#else
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_efx_writed(efx, value->u32[0], reg + 0);
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_efx_writed(efx, value->u32[1], reg + 4);
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_efx_writed(efx, value->u32[2], reg + 8);
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_efx_writed(efx, value->u32[3], reg + 12);
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#endif
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wmb();
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mmiowb();
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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 efx_sram_writeq(struct efx_nic *efx, void __iomem *membase,
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efx_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 " EFX_QWORD_FMT "\n",
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addr, EFX_QWORD_VAL(*value));
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spin_lock_irqsave(&efx->biu_lock, flags);
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#ifdef EFX_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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wmb();
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mmiowb();
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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 efx_writed(struct efx_nic *efx, efx_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 "EFX_DWORD_FMT"\n",
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reg, EFX_DWORD_VAL(*value));
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/* No lock required */
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_efx_writed(efx, value->u32[0], reg);
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wmb();
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}
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/* Read a 128-bit CSR, locking as appropriate. */
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static inline void efx_reado(struct efx_nic *efx, efx_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] = _efx_readd(efx, reg + 0);
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rmb();
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value->u32[1] = _efx_readd(efx, reg + 4);
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value->u32[2] = _efx_readd(efx, reg + 8);
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value->u32[3] = _efx_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 " EFX_OWORD_FMT "\n", reg,
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EFX_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 efx_sram_readq(struct efx_nic *efx, void __iomem *membase,
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efx_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 EFX_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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rmb();
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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 "EFX_QWORD_FMT"\n",
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addr, EFX_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 efx_readd(struct efx_nic *efx, efx_dword_t *value,
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unsigned int reg)
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{
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value->u32[0] = _efx_readd(efx, reg);
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netif_vdbg(efx, hw, efx->net_dev,
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"read from register %x, got "EFX_DWORD_FMT"\n",
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reg, EFX_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 efx_writeo_table(struct efx_nic *efx, efx_oword_t *value,
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unsigned int reg, unsigned int index)
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{
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efx_writeo(efx, value, reg + index * sizeof(efx_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 efx_reado_table(struct efx_nic *efx, efx_oword_t *value,
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unsigned int reg, unsigned int index)
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{
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efx_reado(efx, value, reg + index * sizeof(efx_oword_t));
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}
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/* Write a 32-bit CSR forming part of a table, or 32-bit SRAM */
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static inline void efx_writed_table(struct efx_nic *efx, efx_dword_t *value,
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unsigned int reg, unsigned int index)
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{
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efx_writed(efx, value, reg + index * sizeof(efx_oword_t));
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}
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/* Read a 32-bit CSR forming part of a table, or 32-bit SRAM */
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static inline void efx_readd_table(struct efx_nic *efx, efx_dword_t *value,
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unsigned int reg, unsigned int index)
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{
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efx_readd(efx, value, reg + index * sizeof(efx_dword_t));
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}
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/* Page-mapped register block size */
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#define EFX_PAGE_BLOCK_SIZE 0x2000
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/* Calculate offset to page-mapped register block */
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#define EFX_PAGED_REG(page, reg) \
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((page) * EFX_PAGE_BLOCK_SIZE + (reg))
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/* Write the whole of RX_DESC_UPD or TX_DESC_UPD */
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static inline void _efx_writeo_page(struct efx_nic *efx, efx_oword_t *value,
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unsigned int reg, unsigned int page)
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{
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reg = EFX_PAGED_REG(page, reg);
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netif_vdbg(efx, hw, efx->net_dev,
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"writing register %x with " EFX_OWORD_FMT "\n", reg,
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EFX_OWORD_VAL(*value));
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#ifdef EFX_USE_QWORD_IO
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_efx_writeq(efx, value->u64[0], reg + 0);
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_efx_writeq(efx, value->u64[1], reg + 8);
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#else
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_efx_writed(efx, value->u32[0], reg + 0);
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_efx_writed(efx, value->u32[1], reg + 4);
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_efx_writed(efx, value->u32[2], reg + 8);
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_efx_writed(efx, value->u32[3], reg + 12);
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#endif
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wmb();
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}
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#define efx_writeo_page(efx, value, reg, page) \
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_efx_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 or the high bits of
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* RX_DESC_UPD or TX_DESC_UPD)
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*/
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static inline void _efx_writed_page(struct efx_nic *efx, efx_dword_t *value,
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unsigned int reg, unsigned int page)
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{
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efx_writed(efx, value, EFX_PAGED_REG(page, reg));
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}
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#define efx_writed_page(efx, value, reg, page) \
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_efx_writed_page(efx, value, \
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reg + \
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BUILD_BUG_ON_ZERO((reg) != 0x400 && (reg) != 0x83c \
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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 _efx_writed_page_locked(struct efx_nic *efx,
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efx_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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efx_writed(efx, value, EFX_PAGED_REG(page, reg));
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spin_unlock_irqrestore(&efx->biu_lock, flags);
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} else {
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efx_writed(efx, value, EFX_PAGED_REG(page, reg));
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}
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}
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#define efx_writed_page_locked(efx, value, reg, page) \
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_efx_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 /* EFX_IO_H */
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