Re: [PATCH v3 1/2] interconnect: qcom: Add sdm845 interconnect provider driver

From: Evan Green
Date: Mon Oct 01 2018 - 14:46:18 EST


Hi David. Apologies for my late review, this fell under the rug for a
little while.

On Thu, Aug 23, 2018 at 6:57 PM David Dai <daidavid1@xxxxxxxxxxxxxx> wrote:
>
> Introduce Qualcomm SDM845 specific provider driver using the
> interconnect framework.
>
> Change-Id: I716b39068b4a211b8203b2a52d3037a5b84594ea
> Signed-off-by: David Dai <daidavid1@xxxxxxxxxxxxxx>
> ---
> .../bindings/interconnect/qcom-sdm845.txt | 22 +
> drivers/interconnect/qcom/Kconfig | 8 +
> drivers/interconnect/qcom/Makefile | 1 +
> drivers/interconnect/qcom/sdm845.c | 844 +++++++++++++++++++++
> include/dt-bindings/interconnect/qcom.h | 110 ++-
> 5 files changed, 984 insertions(+), 1 deletion(-)
> create mode 100644 Documentation/devicetree/bindings/interconnect/qcom-sdm845.txt
> create mode 100644 drivers/interconnect/qcom/sdm845.c
>
...
> diff --git a/drivers/interconnect/qcom/sdm845.c b/drivers/interconnect/qcom/sdm845.c
> new file mode 100644
> index 0000000..57aba8a
> --- /dev/null
> +++ b/drivers/interconnect/qcom/sdm845.c
> @@ -0,0 +1,844 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +/*
> + * Copyright (c) 2018, The Linux Foundation. All rights reserved.
> + *
> + */
> +
> +#include <linux/device.h>
> +#include <linux/io.h>
> +#include <linux/interconnect.h>

Nit: alphabetization here (io > in)

> +#include <linux/interconnect-provider.h>
> +#include <dt-bindings/interconnect/qcom.h>
> +#include <linux/module.h>
> +#include <linux/of_device.h>
> +#include <linux/of_platform.h>
> +#include <linux/platform_device.h>
> +#include <linux/slab.h>

slab.h is not needed is it?

> +#include <linux/sort.h>
> +
> +#include <soc/qcom/cmd-db.h>
> +#include <soc/qcom/rpmh.h>
> +#include <soc/qcom/tcs.h>
> +
> +#define BCM_TCS_CMD_COMMIT_SHFT 30
> +#define BCM_TCS_CMD_COMMIT_MASK 0x40000000
> +#define BCM_TCS_CMD_VALID_SHFT 29
> +#define BCM_TCS_CMD_VALID_MASK 0x200010000

Did you mean to have that 0x10000 in there? In BCM_TCS_CMD you just
shift by 29, which would make that 0x10000 always zero.

> +#define BCM_TCS_CMD_VOTE_X_SHFT 14
> +#define BCM_TCS_CMD_VOTE_MASK 0x3fff
> +#define BCM_TCS_CMD_VOTE_Y_SHFT 0
> +#define BCM_TCS_CMD_VOTE_Y_MASK 0xfffc000

This VOTE_Y_MASK isn't used. Also, given that the shift is 0, it
doesn't look right.

> +
> +#define BCM_TCS_CMD(commit, valid, vote_x, vote_y) \
> + ((commit << BCM_TCS_CMD_COMMIT_SHFT) |\
> + (valid << BCM_TCS_CMD_VALID_SHFT) |\
> + ((cpu_to_le32(vote_x) &\
> + BCM_TCS_CMD_VOTE_MASK) << BCM_TCS_CMD_VOTE_X_SHFT) |\
> + ((cpu_to_le32(vote_y) &\
> + BCM_TCS_CMD_VOTE_MASK) << BCM_TCS_CMD_VOTE_Y_SHFT))
> +
> +#define to_qcom_provider(_provider) \
> + container_of(_provider, struct qcom_icc_provider, provider)
> +
> +#define DEFINE_QNODE(_name, _id, _channels, _buswidth, \
> + _numlinks, ...) \
> + static struct qcom_icc_node _name = { \
> + .id = _id, \
> + .name = #_name, \
> + .channels = _channels, \
> + .buswidth = _buswidth, \
> + .num_links = _numlinks, \
> + .links = { __VA_ARGS__ }, \
> + }
> +
> +#define DEFINE_QBCM(_name, _bcmname, _keepalive, _numnodes, ...) \
> + static struct qcom_icc_bcm _name = { \
> + .name = _bcmname, \
> + .keepalive = _keepalive, \
> + .num_nodes = _numnodes, \
> + .nodes = { __VA_ARGS__ }, \
> + }
> +
> +struct qcom_icc_provider {
> + struct icc_provider provider;
> + void __iomem *base;
> + struct device *dev;
> + struct qcom_icc_bcm **bcms;
> + size_t num_bcms;
> +};
> +
> +/**
> + * struct bcm_db - Auxiliary data pertaining to each Bus Clock Manager(BCM)
> + * @unit: bcm threshold values are in magnitudes of this

I'm having a little trouble understanding this comment, I think it
could be crispened up. So this is a divisor that applies when
converting a bytes/second bandwidth value to an RPMh message. Yes?

> + * @width: prototype width

So this is a multiplier that's applied when converting a bytes/second
bandwidth into an RPMh message?

> + * @vcd: virtual clock domain that this bcm belongs to
> + */
> +
> +struct bcm_db {
> + u32 unit;
> + u16 width;
> + u8 vcd;
> + u8 reserved;
> +};
> +
> +#define SDM845_MAX_LINKS 43
> +#define SDM845_MAX_BCMS 30
> +#define SDM845_MAX_BCM_PER_NODE 2
> +#define SDM845_MAX_VCD 10
> +
> +/**
> + * struct qcom_icc_node - Qualcomm specific interconnect nodes
> + * @name: the node name used in debugfs
> + * @links: an array of nodes where we can go next while traversing
> + * @id: a unique node identifier
> + * @num_links: the total number of @links
> + * @channels: num of channels at this node
> + * @buswidth: width of the interconnect between a node and the bus
> + * @sum_avg: current sum aggregate value of all avg bw requests
> + * @max_peak: current max aggregate value of all peak bw requests
> + * @bcms: list of bcms associated with this logical node
> + * @num_bcm: num of @bcms
> + */
> +struct qcom_icc_node {
> + const char *name;
> + u16 links[SDM845_MAX_LINKS];
> + u16 id;
> + u16 num_links;
> + u16 channels;
> + u16 buswidth;
> + u64 sum_avg;
> + u64 max_peak;
> + struct qcom_icc_bcm *bcms[SDM845_MAX_BCM_PER_NODE];
> + size_t num_bcms;
> +};
> +
> +/**
> + * struct qcom_icc_bcm - Qualcomm specific hardware accelerator nodes
> + * known as Bus Clock Manager(BCM)
> + * @name: the bcm node name used to fetch BCM data from command db
> + * @type: latency or bandwidth bcm
> + * @addr: address offsets used when voting to RPMH
> + * @vote_x: aggregated threshold values, represents sum_bw when @type is bw bcm
> + * @vote_y: aggregated threshold values, represents peak_bw when @type is bw bcm
> + * @dirty: flag used to indicate whether or bcm needs to be committed
> + * @aux_data: auxiliary data used when calculating threshold values and
> + * communicating with RPMh
> + * @list: used to link to other bcms when compiling lists for commit
> + * @num_nodes: total number of @num_nodes
> + * @nodes: list of qcom_icc_nodes that this BCM encapsulates
> + */
> +
> +struct qcom_icc_bcm {
> + const char *name;
> + u32 type;
> + u32 addr;
> + u64 vote_x;
> + u64 vote_y;
> + bool dirty;
> + bool keepalive;
> + struct bcm_db aux_data;
> + struct list_head list;
> + size_t num_nodes;
> + struct qcom_icc_node *nodes[];
> +};
> +
> +struct qcom_icc_fabric {
> + struct qcom_icc_node **nodes;
> + size_t num_nodes;
> + u32 base_offset;
> + u32 qos_offset;
> +};
> +
> +struct qcom_icc_desc {
> + struct qcom_icc_node **nodes;
> + size_t num_nodes;
> + struct qcom_icc_bcm **bcms;
> + size_t num_bcms;
> +};
> +
...
> +
> +static int qcom_tcs_cmd_gen(struct tcs_cmd *cmd, u64 vote_x,
> + u64 vote_y, u32 addr, bool commit)
> +{
> + int ret = 0;
> + bool valid = true;
> +
> + if (!cmd)
> + return ret;
> +
> + if (vote_x == 0 && vote_y == 0)
> + valid = false;
> +
> + if (vote_x > BCM_TCS_CMD_VOTE_MASK)
> + vote_x = BCM_TCS_CMD_VOTE_MASK;
> +
> + if (vote_y > BCM_TCS_CMD_VOTE_MASK)
> + vote_y = BCM_TCS_CMD_VOTE_MASK;
> +
> + cmd->addr = addr;
> + cmd->data = BCM_TCS_CMD(commit, valid, vote_x, vote_y);
> +
> + /*
> + * Set the wait for completion flag on commands that have the commit
> + * set, in order to indicate to the RSC to not release the TCS slot
> + * until hardware has acknowledged that this transaction has completed.
> + */
> + if (commit)
> + cmd->wait = true;
> +
> + return ret;

This function appears never to be able to fail. Perhaps remove ret and
change return type to void.

> +}
> +
> +static void qcom_tcs_list_gen(struct list_head *bcm_list,
> + struct tcs_cmd *tcs_list, int *n)
> +{
> + struct qcom_icc_bcm *bcm;
> + bool commit;
> + size_t idx = 0, batch = 0, cur_vcd_size = 0;
> +
> + memset(n, 0, sizeof(int) * SDM845_MAX_VCD);
> +
> + list_for_each_entry(bcm, bcm_list, list) {
> + commit = false;
> + cur_vcd_size++;
> + if ((list_is_last(&bcm->list, bcm_list)) ||
> + bcm->aux_data.vcd !=
> + list_is_last(&bcm->list, bcm_list)) {

Whoa, I think this fixup got scrozzed. The old logic was...
+ if ((bcm->aux_data.vcd !=
+ list_next_entry(bcm, list)->aux_data.vcd) ||
+ list_is_last(&bcm->list, bcm_list)) {
...and I think all you were trying to do was reverse the order of the
two conditionals so list_is_last happened first. Something happened
along the way.

> + commit = true;
> + cur_vcd_size = 0;
> + }
> + qcom_tcs_cmd_gen(&tcs_list[idx], bcm->vote_x, bcm->vote_y,
> + bcm->addr, commit);
> + idx++;
> + n[batch]++;
> + /*
> + * Batch the BCMs in such a way that we do not split them in
> + * multiple payloads when they are under the same VCD. This is
> + * to ensure that every BCM is committed since we only set the
> + * commit bit on the last BCM request of every VCD.
> + */
> + if (n[batch] >= MAX_RPMH_PAYLOAD) {
> + if (!commit) {
> + n[batch] -= cur_vcd_size;
> + n[batch+1] = cur_vcd_size;
> + }
> + batch++;
> + }
> + }
> +}
> +
> +static void qcom_icc_bcm_aggregate(struct qcom_icc_bcm *bcm)
> +{
> + size_t i;
> + u64 agg_avg = 0;
> + u64 agg_peak = 0;
> +
> + for (i = 0; i < bcm->num_nodes; i++) {
> + agg_avg = max(agg_avg,
> + bcm->nodes[i]->sum_avg * bcm->aux_data.width /
> + (bcm->nodes[i]->buswidth * bcm->nodes[i]->channels));
> + agg_peak = max(agg_peak,
> + bcm->nodes[i]->max_peak * bcm->aux_data.width /
> + bcm->nodes[i]->buswidth);
> + }
> +
> + bcm->vote_x = (u64)(agg_avg * 1000ULL / bcm->aux_data.unit);
> + bcm->vote_y = (u64)(agg_peak * 1000ULL / bcm->aux_data.unit);
> +
> + if (bcm->keepalive && bcm->vote_x == 0 && bcm->vote_y == 0) {
> + bcm->vote_x = 1;
> + bcm->vote_y = 1;
> + }
> +
> + bcm->dirty = false;
> +}
> +
> +static int qcom_icc_aggregate(struct icc_node *node, u32 avg_bw,
> + u32 peak_bw, u32 *agg_avg, u32 *agg_peak)
> +{
> + size_t i;
> + struct qcom_icc_node *qn;
> +
> + qn = node->data;
> +
> + *agg_avg += avg_bw;
> + *agg_peak = max_t(u64, agg_peak, peak_bw);

This should be u32 instead of u64. My compiler complains about this.

> +
> + qn->sum_avg = *agg_avg;
> + qn->max_peak = *agg_peak;
> +
> + for (i = 0; i < qn->num_bcms; i++)
> + qn->bcms[i]->dirty = true;
> +
> + return 0;
> +}
> +
> +static int qcom_icc_set(struct icc_node *src, struct icc_node *dst)
...