@@ -496,19 +496,21 @@ static void xhci_enable_max_dev_slots(struct xhci_hcd *xhci)
static void xhci_set_cmd_ring_deq(struct xhci_hcd *xhci)
{
- u64 val_64;
+ dma_addr_t deq_dma;
+ u64 crcr;
- /* step 2: initialize command ring buffer */
- val_64 = xhci_read_64(xhci, &xhci->op_regs->cmd_ring);
- val_64 = (val_64 & (u64) CMD_RING_RSVD_BITS) |
- (xhci_trb_virt_to_dma(xhci->cmd_ring->deq_seg,
- xhci->cmd_ring->dequeue) &
- (u64) ~CMD_RING_RSVD_BITS) |
- xhci->cmd_ring->cycle_state;
- xhci_dbg_trace(xhci, trace_xhci_dbg_init,
- "// Setting command ring address to 0x%llx",
- (unsigned long long) val_64);
- xhci_write_64(xhci, val_64, &xhci->op_regs->cmd_ring);
+ deq_dma = xhci_trb_virt_to_dma(xhci->cmd_ring->deq_seg, xhci->cmd_ring->dequeue);
+ deq_dma &= CMD_RING_PTR_MASK;
+
+ crcr = xhci_read_64(xhci, &xhci->op_regs->cmd_ring);
+ crcr &= ~CMD_RING_PTR_MASK;
+ crcr |= deq_dma;
+
+ crcr &= ~CMD_RING_CYCLE;
+ crcr |= xhci->cmd_ring->cycle_state;
+
+ xhci_dbg_trace(xhci, trace_xhci_dbg_init, "Setting command ring address to 0x%llx", crcr);
+ xhci_write_64(xhci, crcr, &xhci->op_regs->cmd_ring);
}
/*
@@ -191,16 +191,16 @@ struct xhci_op_regs {
#define DEV_NOTE_FWAKE ENABLE_DEV_NOTE(1)
/* CRCR - Command Ring Control Register - cmd_ring bitmasks */
-/* bit 0 is the command ring cycle state */
+/* bit 0 - Cycle bit indicates the ownership of the command ring */
+#define CMD_RING_CYCLE (1 << 0)
/* stop ring operation after completion of the currently executing command */
#define CMD_RING_PAUSE (1 << 1)
/* stop ring immediately - abort the currently executing command */
#define CMD_RING_ABORT (1 << 2)
/* true: command ring is running */
#define CMD_RING_RUNNING (1 << 3)
-/* bits 4:5 reserved and should be preserved */
-/* Command Ring pointer - bit mask for the lower 32 bits. */
-#define CMD_RING_RSVD_BITS (0x3f)
+/* bits 63:6 - Command Ring pointer */
+#define CMD_RING_PTR_MASK GENMASK_ULL(63, 6)
/* CONFIG - Configure Register - config_reg bitmasks */
/* bits 0:7 - maximum number of device slots enabled (NumSlotsEn) */
Refactor xhci_set_cmd_ring_deq() making the code more understandable by using more descriptive constants and separating operations logically. - Remove 'CMD_RING_RSVD_BITS' the macro is misleading, the reserved bits are 5:4, yet the mask is for bits 5:0. - Introduce masks 'CMD_RING_PTR_MASK' and 'CMD_RING_CYCLE' to clearly define the bits for the Command Ring pointer and Command Ring Cycle. - Simplifying the process of setting the command ring address by separating the DMA address calculation and the Command Ring Control register (crcr) updates. - Remove the "// " prefix from trace messages, as it is unnecessary and distracting. Note: In the current implementation, the cycle bit is not cleared before applying the OR operation. Although this hasn't caused issues so far because the bit is '0' before reaching this function, the bit is now cleared before being set to prevent potential future problems and simplify the process. Signed-off-by: Niklas Neronin <niklas.neronin@linux.intel.com> --- drivers/usb/host/xhci.c | 26 ++++++++++++++------------ drivers/usb/host/xhci.h | 8 ++++---- 2 files changed, 18 insertions(+), 16 deletions(-)