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https://git.kernel.org/pub/scm/linux/kernel/git/chenhuacai/linux-loongson
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5378bdf6a6
Define a new, optional, callback that allows the driver to specify how the return data buffer is allocated. If that callback is set, mailbox/pcc.c is now responsible for reading from and writing to the PCC shared buffer. This also allows for proper checks of the Commnand complete flag between the PCC sender and receiver. For Type 4 channels, initialize the command complete flag prior to accepting messages. Since the mailbox does not know what memory allocation scheme to use for response messages, the client now has an optional callback that allows it to allocate the buffer for a response message. When an outbound message is written to the buffer, the mailbox checks for the flag indicating the client wants an tx complete notification via IRQ. Upon receipt of the interrupt It will pair it with the outgoing message. The expected use is to free the kernel memory buffer for the previous outgoing message. Signed-off-by: Adam Young <admiyo@os.amperecomputing.com> Signed-off-by: Jassi Brar <jassisinghbrar@gmail.com>
79 lines
2.2 KiB
C
79 lines
2.2 KiB
C
/* SPDX-License-Identifier: GPL-2.0-only */
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/*
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* PCC (Platform Communications Channel) methods
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*/
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#ifndef _PCC_H
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#define _PCC_H
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#include <linux/mailbox_controller.h>
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#include <linux/mailbox_client.h>
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struct pcc_mbox_chan {
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struct mbox_chan *mchan;
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u64 shmem_base_addr;
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void __iomem *shmem;
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u64 shmem_size;
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u32 latency;
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u32 max_access_rate;
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u16 min_turnaround_time;
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/* Set to true to indicate that the mailbox should manage
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* writing the dat to the shared buffer. This differs from
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* the case where the drivesr are writing to the buffer and
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* using send_data only to ring the doorbell. If this flag
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* is set, then the void * data parameter of send_data must
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* point to a kernel-memory buffer formatted in accordance with
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* the PCC specification.
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*
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* The active buffer management will include reading the
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* notify_on_completion flag, and will then
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* call mbox_chan_txdone when the acknowledgment interrupt is
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* received.
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*/
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bool manage_writes;
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/* Optional callback that allows the driver
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* to allocate the memory used for receiving
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* messages. The return value is the location
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* inside the buffer where the mailbox should write the data.
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*/
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void *(*rx_alloc)(struct mbox_client *cl, int size);
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};
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struct pcc_header {
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u32 signature;
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u32 flags;
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u32 length;
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u32 command;
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};
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/* Generic Communications Channel Shared Memory Region */
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#define PCC_SIGNATURE 0x50434300
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/* Generic Communications Channel Command Field */
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#define PCC_CMD_GENERATE_DB_INTR BIT(15)
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/* Generic Communications Channel Status Field */
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#define PCC_STATUS_CMD_COMPLETE BIT(0)
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#define PCC_STATUS_SCI_DOORBELL BIT(1)
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#define PCC_STATUS_ERROR BIT(2)
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#define PCC_STATUS_PLATFORM_NOTIFY BIT(3)
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/* Initiator Responder Communications Channel Flags */
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#define PCC_CMD_COMPLETION_NOTIFY BIT(0)
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#define MAX_PCC_SUBSPACES 256
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#ifdef CONFIG_PCC
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extern struct pcc_mbox_chan *
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pcc_mbox_request_channel(struct mbox_client *cl, int subspace_id);
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extern void pcc_mbox_free_channel(struct pcc_mbox_chan *chan);
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#else
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static inline struct pcc_mbox_chan *
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pcc_mbox_request_channel(struct mbox_client *cl, int subspace_id)
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{
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return ERR_PTR(-ENODEV);
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}
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static inline void pcc_mbox_free_channel(struct pcc_mbox_chan *chan) { }
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#endif
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#endif /* _PCC_H */
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