[PATCH RFC 08/10] mmc: core: Add halt support

Ritesh Harjani
2016-06-15T13:03:03Z

From: Asutosh Das <asutoshd@codeaurora.org>

Halt is a controller feature that can change the controller mode
from command-queue to legacy. This feature is very helpful in
error cases.

Signed-off-by: Asutosh Das <asutoshd@codeaurora.org>
Signed-off-by: Venkat Gopalakrishnan <venkatg@codeaurora.org>
[riteshh@codeaurora.org: fixed merge conflicts]
Signed-off-by: Ritesh Harjani <riteshh@codeaurora.org>
---
drivers/mmc/card/queue.c | 1 +
drivers/mmc/core/core.c | 33 +++++++++++++++++++++++++++++++++
include/linux/mmc/core.h | 1 +
include/linux/mmc/host.h | 17 +++++++++++++++++
4 files changed, 52 insertions(+)

diff --git a/drivers/mmc/card/queue.c b/drivers/mmc/card/queue.c
index 32f9726..37423ab 100644
--- a/drivers/mmc/card/queue.c
+++ b/drivers/mmc/card/queue.c
@@ -50,6 +50,7 @@ static inline bool mmc_cmdq_should_pull_reqs(struct mmc_host *host,
struct mmc_cmdq_context_info *ctx)
{
if (test_bit(CMDQ_STATE_DCMD_ACTIVE, &ctx->curr_state) ||
+ mmc_host_halt(host) ||
test_bit(CMDQ_STATE_ERR, &ctx->curr_state)) {
pr_debug("%s: %s: skip pulling reqs: state: %lu\n",
mmc_hostname(host), __func__, ctx->curr_state);
diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c
index ce5e303..6f97841 100644
--- a/drivers/mmc/core/core.c
+++ b/drivers/mmc/core/core.c
@@ -596,6 +596,39 @@ void mmc_cmdq_post_req(struct mmc_host *host, struct mmc_request *mrq, int err)
}
EXPORT_SYMBOL(mmc_cmdq_post_req);

+/**
+ * mmc_cmdq_halt - halt/un-halt the command queue engine
+ * @host: host instance
+ * @halt: true - halt, un-halt otherwise
+ *
+ * Host halts the command queue engine. It should complete
+ * the ongoing transfer and release the bus.
+ * All legacy commands can be sent upon successful
+ * completion of this function.
+ * Returns 0 on success, negative otherwise
+ */
+int mmc_cmdq_halt(struct mmc_host *host, bool halt)
+{
+ int err = 0;
+
+ if ((halt && mmc_host_halt(host)) ||
+ (!halt && !mmc_host_halt(host)))
+ return -EINVAL;
+
+ if (host->cmdq_ops->halt) {
+ err = host->cmdq_ops->halt(host, halt);
+ if (!err && halt)
+ mmc_host_set_halt(host);
+ else if (!err && !halt)
+ mmc_host_clr_halt(host);
+ } else {
+ err = -ENOSYS;
+ }
+
+ return err;
+}
+EXPORT_SYMBOL(mmc_cmdq_halt);
+
int mmc_cmdq_start_req(struct mmc_host *host, struct mmc_cmdq_req *cmdq_req)
{
struct mmc_request *mrq = &cmdq_req->mrq;
diff --git a/include/linux/mmc/core.h b/include/linux/mmc/core.h
index 7b3a60c..92aa8cc 100644
--- a/include/linux/mmc/core.h
+++ b/include/linux/mmc/core.h
@@ -143,6 +143,7 @@ struct mmc_card;
struct mmc_async_req;
struct mmc_cmdq_req;

+extern int mmc_cmdq_halt(struct mmc_host *host, bool enable);
extern void mmc_cmdq_post_req(struct mmc_host *host, struct mmc_request *mrq,
int err);
extern int mmc_cmdq_start_req(struct mmc_host *host,
diff --git a/include/linux/mmc/host.h b/include/linux/mmc/host.h
index 135a83e..f2fb79a 100644
--- a/include/linux/mmc/host.h
+++ b/include/linux/mmc/host.h
@@ -85,6 +85,7 @@ struct mmc_cmdq_host_ops {
int (*request)(struct mmc_host *host, struct mmc_request *mrq);
void (*post_req)(struct mmc_host *host, struct mmc_request *mrq,
int err);
+ int (*halt)(struct mmc_host *host, bool halt);
};

struct mmc_host_ops {
@@ -216,6 +217,7 @@ struct mmc_cmdq_context_info {
unsigned long curr_state;
#define CMDQ_STATE_ERR 0
#define CMDQ_STATE_DCMD_ACTIVE 1
+#define CMDQ_STATE_HALT 2
/* no free tag available */
unsigned long req_starved;
};
@@ -534,6 +536,21 @@ static inline int mmc_host_packed_wr(struct mmc_host *host)
return host->caps2 & MMC_CAP2_PACKED_WR;
}

+static inline void mmc_host_set_halt(struct mmc_host *host)
+{
+ set_bit(CMDQ_STATE_HALT, &host->cmdq_ctx.curr_state);
+}
+
+static inline void mmc_host_clr_halt(struct mmc_host *host)
+{
+ clear_bit(CMDQ_STATE_HALT, &host->cmdq_ctx.curr_state);
+}
+
+static inline int mmc_host_halt(struct mmc_host *host)
+{
+ return test_bit(CMDQ_STATE_HALT, &host->cmdq_ctx.curr_state);
+}
+
static inline int mmc_card_hs(struct mmc_card *card)
{
return card->host->ios.timing == MMC_TIMING_SD_HS ||