* Added support for translating the SGLs associated with incoming
commands either to IEE SGL or NVMe PRPs for NVMe devices.
* The hardware translation of IEEE SGL to NVMe PRPs has limitation
and if a command cannot be translated by hardware then it will go
to firmware and the firmware needs to translate it. And this will
have a performance reduction. To avoid that driver proactively
checks whether the translation will be done in hardware or not,
if not then driver try to translate inside the driver.
Signed-off-by: Chaitra P B
Signed-off-by: Suganath Prabu S
---
drivers/scsi/mpt3sas/mpt3sas_base.c | 668 +-
drivers/scsi/mpt3sas/mpt3sas_base.h | 44 ++-
drivers/scsi/mpt3sas/mpt3sas_ctl.c |1 +
drivers/scsi/mpt3sas/mpt3sas_scsih.c | 14 +-
drivers/scsi/mpt3sas/mpt3sas_warpdrive.c |2 +-
5 files changed, 713 insertions(+), 16 deletions(-)
diff --git a/drivers/scsi/mpt3sas/mpt3sas_base.c
b/drivers/scsi/mpt3sas/mpt3sas_base.c
index 18039bb..d48f176 100644
--- a/drivers/scsi/mpt3sas/mpt3sas_base.c
+++ b/drivers/scsi/mpt3sas/mpt3sas_base.c
@@ -59,6 +59,7 @@
#include
#include
#include
+#include /* To get host page size per arch */
#include
@@ -1347,6 +1348,547 @@ _base_build_sg(struct MPT3SAS_ADAPTER *ioc, void *psge,
/* IEEE format sgls */
/**
+ * _base_build_nvme_prp - This function is called for NVMe end devices to build
+ * a native SGL (NVMe PRP). The native SGL is built starting in the first PRP
+ * entry of the NVMe message (PRP1). If the data buffer is small enough to be
+ * described entirely using PRP1, then PRP2 is not used. If needed, PRP2 is
+ * used to describe a larger data buffer. If the data buffer is too large to
+ * describe using the two PRP entriess inside the NVMe message, then PRP1
+ * describes the first data memory segment, and PRP2 contains a pointer to a
PRP
+ * list located elsewhere in memory to describe the remaining data memory
+ * segments. The PRP list will be contiguous.
+
+ * The native SGL for NVMe devices is a Physical Region Page (PRP). A PRP
+ * consists of a list of PRP entries to describe a number of noncontigous
+ * physical memory segments as a single memory buffer, just as a SGL does.
Note
+ * however, that this function is only used by the IOCTL call, so the memory
+ * given will be guaranteed to be contiguous. There is no need to translate
+ * non-contiguous SGL into a PRP in this case. All PRPs will describe
+ * contiguous space that is one page size each.
+ *
+ * Each NVMe message contains two PRP entries. The first (PRP1) either
contains
+ * a PRP list pointer or a PRP element, depending upon the command. PRP2
+ * contains the second PRP element if the memory being described fits within 2
+ * PRP entries, or a PRP list pointer if the PRP spans more than two entries.
+ *
+ * A PRP list pointer contains the address of a PRP list, structured as a
linear
+ * array of PRP entries. Each PRP entry in this list describes a segment of
+ * physical memory.
+ *
+ * Each 64-bit PRP entry comprises an address and an offset field. The address
+ * always points at the beginning of a 4KB physical memory page, and the offset
+ * describes where within that 4KB page the memory segment begins. Only the
+ * first element in a PRP list may contain a non-zero offest, implying that all
+ * memory segments following the first begin at the start of a 4KB page.
+ *
+ * Each PRP element normally describes 4KB of physical memory, with exceptions
+ * for the first and last elements in the list. If the memory being described
+ * by the list begins at a non-zero offset within the first 4KB page, then the
+ * first PRP element will contain a non-zero offset indicating where the region
+ * begins within the 4KB page. The last memory segment may end before the end
+ * of the 4KB segment, depending upon the overall size of the memory being
+ * described by the PRP list.
+ *
+ * Since PRP entries lack any indication of size, the overall data buffer
length
+ * is used to determine where the end of the data memory buffer is located, and
+ * how many PRP entries are required to describe it.
+ *
+ * @ioc: per adapter object
+ * @smid: system request message index for getting asscociated SGL
+ * @nvme_encap_request: the NVMe request msg frame pointer
+ * @data_out_dma: physical address for WRITES
+ * @data_out_sz: data xfer size for WRITES
+ * @data_in_dma: physical address for READS
+ * @data_in_sz: data xfer size for READS
+ *
+ * Returns nothing.
+ */
+static void
+_base_build_nvme_prp(struct MPT3SAS_ADAPTER *ioc, u16 smid,
+ Mpi26NVMeEncapsulatedRequest_t *nvme_encap_request,
+ dma_addr_t data_out_dma, size_t data_out_sz, dma_addr_t data_in_dma,
+ size_t data_in_sz)
+{
+ int prp_size = NVME_PRP_SIZE;
+ u64 *prp_entry, *prp1_entry, *prp2_entry, *prp_entry_phys;
+ u64 *prp_page, *prp_page_phys;
+ u32 offset