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Message-Id: <1479147965-29662-10-git-send-email-rob.rice@broadcom.com>
Date: Mon, 14 Nov 2016 13:26:03 -0500
From: Rob Rice <rob.rice@...adcom.com>
To: Jassi Brar <jassisinghbrar@...il.com>
Cc: bcm-kernel-feedback-list@...adcom.com,
linux-kernel@...r.kernel.org, Steve Lin <steven.lin1@...adcom.com>,
Rob Rice <rob.rice@...adcom.com>
Subject: [PATCH 09/11] mailbox: bcm-pdc: Performance improvements
Three changes to improve performance in the PDC driver:
- disable and reenable interrupts while the interrupt handler is
running
- update rxin and txin descriptor indexes more efficiently
- group receive descriptor context into a structure and keep
context in a single array rather than five to improve locality
of reference
Signed-off-by: Rob Rice <rob.rice@...adcom.com>
Reviewed-by: Andy Gospodarek <gospo@...adcom.com>
---
drivers/mailbox/bcm-pdc-mailbox.c | 85 ++++++++++++++++++++++-----------------
1 file changed, 49 insertions(+), 36 deletions(-)
diff --git a/drivers/mailbox/bcm-pdc-mailbox.c b/drivers/mailbox/bcm-pdc-mailbox.c
index e7dc1a2..8c2aa7c 100644
--- a/drivers/mailbox/bcm-pdc-mailbox.c
+++ b/drivers/mailbox/bcm-pdc-mailbox.c
@@ -260,6 +260,27 @@ struct pdc_ring_alloc {
u32 size; /* ring allocation size in bytes */
};
+/*
+ * context associated with a receive descriptor.
+ * @rxp_ctx: opaque context associated with frame that starts at each
+ * rx ring index.
+ * @dst_sg: Scatterlist used to form reply frames beginning at a given ring
+ * index. Retained in order to unmap each sg after reply is processed.
+ * @rxin_numd: Number of rx descriptors associated with the message that starts
+ * at a descriptor index. Not set for every index. For example,
+ * if descriptor index i points to a scatterlist with 4 entries,
+ * then the next three descriptor indexes don't have a value set.
+ * @resp_hdr: Virtual address of buffer used to catch DMA rx status
+ * @resp_hdr_daddr: physical address of DMA rx status buffer
+ */
+struct pdc_rx_ctx {
+ void *rxp_ctx;
+ struct scatterlist *dst_sg;
+ u32 rxin_numd;
+ void *resp_hdr;
+ dma_addr_t resp_hdr_daddr;
+};
+
/* PDC state structure */
struct pdc_state {
/* Index of the PDC whose state is in this structure instance */
@@ -377,11 +398,7 @@ struct pdc_state {
/* Index of next rx descriptor to post. */
u32 rxout;
- /*
- * opaque context associated with frame that starts at each
- * rx ring index.
- */
- void *rxp_ctx[PDC_RING_ENTRIES];
+ struct pdc_rx_ctx rx_ctx[PDC_RING_ENTRIES];
/*
* Scatterlists used to form request and reply frames beginning at a
@@ -389,18 +406,6 @@ struct pdc_state {
* is processed
*/
struct scatterlist *src_sg[PDC_RING_ENTRIES];
- struct scatterlist *dst_sg[PDC_RING_ENTRIES];
-
- /*
- * Number of rx descriptors associated with the message that starts
- * at this descriptor index. Not set for every index. For example,
- * if descriptor index i points to a scatterlist with 4 entries, then
- * the next three descriptor indexes don't have a value set.
- */
- u32 rxin_numd[PDC_RING_ENTRIES];
-
- void *resp_hdr[PDC_RING_ENTRIES];
- dma_addr_t resp_hdr_daddr[PDC_RING_ENTRIES];
struct dentry *debugfs_stats; /* debug FS stats file for this PDC */
@@ -591,11 +596,11 @@ pdc_receive_one(struct pdc_state *pdcs)
struct brcm_message mssg;
u32 len, rx_status;
u32 num_frags;
- int i;
u8 *resp_hdr; /* virtual addr of start of resp message DMA header */
u32 frags_rdy; /* number of fragments ready to read */
u32 rx_idx; /* ring index of start of receive frame */
dma_addr_t resp_hdr_daddr;
+ struct pdc_rx_ctx *rx_ctx;
mbc = &pdcs->mbc;
chan = &mbc->chans[0];
@@ -607,7 +612,8 @@ pdc_receive_one(struct pdc_state *pdcs)
* to read.
*/
frags_rdy = NRXDACTIVE(pdcs->rxin, pdcs->last_rx_curr, pdcs->nrxpost);
- if ((frags_rdy == 0) || (frags_rdy < pdcs->rxin_numd[pdcs->rxin]))
+ if ((frags_rdy == 0) ||
+ (frags_rdy < pdcs->rx_ctx[pdcs->rxin].rxin_numd))
/* No response ready */
return -EAGAIN;
@@ -617,24 +623,23 @@ pdc_receive_one(struct pdc_state *pdcs)
dma_unmap_sg(dev, pdcs->src_sg[pdcs->txin],
sg_nents(pdcs->src_sg[pdcs->txin]), DMA_TO_DEVICE);
- for (i = 0; i < num_frags; i++)
- pdcs->txin = NEXTTXD(pdcs->txin, pdcs->ntxpost);
+ pdcs->txin = (pdcs->txin + num_frags) & pdcs->ntxpost;
dev_dbg(dev, "PDC %u reclaimed %d tx descriptors",
pdcs->pdc_idx, num_frags);
rx_idx = pdcs->rxin;
- num_frags = pdcs->rxin_numd[rx_idx];
+ rx_ctx = &pdcs->rx_ctx[rx_idx];
+ num_frags = rx_ctx->rxin_numd;
/* Return opaque context with result */
- mssg.ctx = pdcs->rxp_ctx[rx_idx];
- pdcs->rxp_ctx[rx_idx] = NULL;
- resp_hdr = pdcs->resp_hdr[rx_idx];
- resp_hdr_daddr = pdcs->resp_hdr_daddr[rx_idx];
- dma_unmap_sg(dev, pdcs->dst_sg[rx_idx],
- sg_nents(pdcs->dst_sg[rx_idx]), DMA_FROM_DEVICE);
+ mssg.ctx = rx_ctx->rxp_ctx;
+ rx_ctx->rxp_ctx = NULL;
+ resp_hdr = rx_ctx->resp_hdr;
+ resp_hdr_daddr = rx_ctx->resp_hdr_daddr;
+ dma_unmap_sg(dev, rx_ctx->dst_sg, sg_nents(rx_ctx->dst_sg),
+ DMA_FROM_DEVICE);
- for (i = 0; i < num_frags; i++)
- pdcs->rxin = NEXTRXD(pdcs->rxin, pdcs->nrxpost);
+ pdcs->rxin = (pdcs->rxin + num_frags) & pdcs->nrxpost;
dev_dbg(dev, "PDC %u reclaimed %d rx descriptors",
pdcs->pdc_idx, num_frags);
@@ -826,6 +831,7 @@ static int pdc_rx_list_init(struct pdc_state *pdcs, struct scatterlist *dst_sg,
u32 rx_pkt_cnt = 1; /* Adding a single rx buffer */
dma_addr_t daddr;
void *vaddr;
+ struct pdc_rx_ctx *rx_ctx;
rx_avail = pdcs->nrxpost - NRXDACTIVE(pdcs->rxin, pdcs->rxout,
pdcs->nrxpost);
@@ -849,15 +855,16 @@ static int pdc_rx_list_init(struct pdc_state *pdcs, struct scatterlist *dst_sg,
/* This is always the first descriptor in the receive sequence */
flags = D64_CTRL1_SOF;
- pdcs->rxin_numd[pdcs->rx_msg_start] = 1;
+ pdcs->rx_ctx[pdcs->rx_msg_start].rxin_numd = 1;
if (unlikely(pdcs->rxout == (pdcs->nrxd - 1)))
flags |= D64_CTRL1_EOT;
- pdcs->rxp_ctx[pdcs->rxout] = ctx;
- pdcs->dst_sg[pdcs->rxout] = dst_sg;
- pdcs->resp_hdr[pdcs->rxout] = vaddr;
- pdcs->resp_hdr_daddr[pdcs->rxout] = daddr;
+ rx_ctx = &pdcs->rx_ctx[pdcs->rxout];
+ rx_ctx->rxp_ctx = ctx;
+ rx_ctx->dst_sg = dst_sg;
+ rx_ctx->resp_hdr = vaddr;
+ rx_ctx->resp_hdr_daddr = daddr;
pdc_build_rxd(pdcs, daddr, pdcs->pdc_resp_hdr_len, flags);
return PDC_SUCCESS;
}
@@ -925,7 +932,7 @@ static int pdc_rx_list_sg_add(struct pdc_state *pdcs, struct scatterlist *sg)
desc_w++;
sg = sg_next(sg);
}
- pdcs->rxin_numd[pdcs->rx_msg_start] += desc_w;
+ pdcs->rx_ctx[pdcs->rx_msg_start].rxin_numd += desc_w;
return PDC_SUCCESS;
}
@@ -954,6 +961,9 @@ static irqreturn_t pdc_irq_handler(int irq, void *data)
/* Clear interrupt flags in device */
iowrite32(intstatus, pdcs->pdc_reg_vbase + PDC_INTSTATUS_OFFSET);
+ /* Disable interrupts until soft handler runs */
+ iowrite32(0, pdcs->pdc_reg_vbase + PDC_INTMASK_OFFSET);
+
/* Wakeup IRQ thread */
if (likely(pdcs && (irq == pdcs->pdc_irq) &&
(intstatus & PDC_INTMASK))) {
@@ -971,6 +981,9 @@ static void pdc_tasklet_cb(unsigned long data)
rx_int = test_and_clear_bit(PDC_RCVINT_0, &pdcs->intstatus);
if (likely(pdcs && rx_int))
pdc_receive(pdcs);
+
+ /* reenable interrupts */
+ iowrite32(PDC_INTMASK, pdcs->pdc_reg_vbase + PDC_INTMASK_OFFSET);
}
/**
--
2.1.0
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