STRUCT RSC_DRV(9)

💅 struct rsc_drv(9) — from the Kernel API Manual, bestie

okay so picture this: it's a page from the Kernel API Manual, the headline act is struct rsc_drv(9), and it's literally the whole personality of the Direct Resource Voter (DRV) — that's the DRV of the Resource State Coordinator controller (RSC). yes the acronyms are unhinged, no we're not changing them, they're iconic 💅

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✨ SYNOPSIS ✨

here's the whole glow-up, copied exactly, no notes:

       struct rsc_drv {
           const char *name;
           void __iomem *base;
           void __iomem *tcs_base;
           int id;
           int num_tcs;
           struct notifier_block rsc_pm;
           struct notifier_block genpd_nb;
           atomic_t cpus_in_pm;
           struct tcs_group tcs[TCS_TYPE_NR];
           unsigned long tcs_in_use[BITS_TO_LONGS( MAX_TCS_NR)];
           spinlock_t lock;
           wait_queue_head_t tcs_wait;
           struct rpmh_ctrlr client;
           struct device *dev;
           struct rsc_ver ver;
           u32 *regs;
        };

she's got range, she's got fields, she's got BITS_TO_LONGS( MAX_TCS_NR) with that little space in there — we keep the space, that's canon 🎀

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🫶 Members (the cast, in order, no skips)

• name — the controller's identifier. her name, her whole identity, main character energy.
• base — start address of the DRV registers in this controller. where the DRV stuff lives ✨
• tcs_base — start address of the TCS registers in this controller. same vibe, TCS edition.
• id — instance id in the controller (Direct Resource Voter). yes it's the id and the DRV, both at once, we contain multitudes.
• num_tcs — how many TCSes are in this DRV. headcount 🧮
• rsc_pm — CPU PM notifier for controller. used when solver mode is not present. so it's the fallback bestie 🥺
• genpd_nb — PM Domain notifier for cluster genpd notifications. she's on the notify list, literally.
• cpus_in_pm — number of CPUs not in idle power collapse. used when solver mode and "power-domains" are not present. lowkey the "nobody showed up to the party" counter 🙈
• tcs — TCS groups. plural, a whole friend group.
• tcs_in_use — the S/W state of the TCS 🦋 only set for ACTIVE_ONLY transfers — but heads up, it might show a sleep/wake TCS in use if it was borrowed for an active_only transfer. and the big rule:

you must hold the lock in this struct (AKA drv->lock) in order to update this. not optional, no cap, do not touch it without the lock 💀

• lock — synchronizes the state of the controller. and here's the lock-ordering tea: if RPMH's cache lock will also be held, the order is: drv->lock then cache_lock. get the order wrong and that's not slay, that's a deadlock 👑
• tcs_wait — wait queue used to wait for tcs_in_use to free up a slot. she's the queue where you sit patiently until a slot opens, like waiting for your friend to finally text back 😭
• client — handle to the DRV's client. the plus-one 🫶
• dev — the RSC device. the actual hardware boo.

so quick thing: ver and regs are right there in the struct, but this page gives them no blurb of their own. not me making up lore for them — we simply do not invent facts on this account 🙈 they're in the struct, that's what we're saying, periodt.

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🌈 SEE ALSO

• Kernel file ./drivers/soc/qcom/rpmh-internal.h — struct tcs_group(9), struct rpmh_request(9), struct rpmh_ctrlr(9)

go read those next, iykyk 🔥

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🌸 okay that's the page!! big kiss to ./drivers/soc/qcom for shipping it with an October 2026 date, and the whole thing is filed under struct rsc_drv(9) in the Kernel API Manual — the way that footer ate, honestly. byeee 💜🎀