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| author | Dustin L. Howett <dustin@howett.net> | 2022-02-17 19:59:30 +0300 |
|---|---|---|
| committer | Tzung-Bi Shih <tzungbi@kernel.org> | 2022-05-03 08:43:21 +0300 |
| commit | c9bc1a0ef9f613a7bc1adfff4c67dc5e5d7d1709 (patch) | |
| tree | c408119dc280f4c9001bd1dda97d7ab967403170 /drivers/platform | |
| parent | 6a5d778edaa39dfa07a61d487a70f2deb1017c0f (diff) | |
| download | linux-c9bc1a0ef9f613a7bc1adfff4c67dc5e5d7d1709.tar.xz | |
platform/chrome: cros_ec_lpcs: reserve the MEC LPC I/O ports first
Some ChromeOS EC devices (such as the Framework Laptop) only map I/O
ports 0x800-0x807. Making the larger reservation required by the non-MEC
LPC (the 0xFF ports for the memory map, and the 0xFF ports for the
parameter region) is non-viable on these devices.
Since we probe the MEC EC first, we can get away with a smaller
reservation that covers the MEC EC ports. If we fall back to classic
LPC, we can grow the reservation to cover the memory map and the
parameter region.
cros_ec_lpc_probe also interacted with I/O ports 0x800-0x807 without a
reservation. Restructuring the code to request the MEC LPC region first
obviates the need to do so.
Signed-off-by: Dustin L. Howett <dustin@howett.net>
Signed-off-by: Tzung-Bi Shih <tzungbi@kernel.org>
Link: https://lore.kernel.org/r/20220217165930.15081-3-dustin@howett.net
Diffstat (limited to 'drivers/platform')
| -rw-r--r-- | drivers/platform/chrome/cros_ec_lpc.c | 39 |
1 files changed, 26 insertions, 13 deletions
diff --git a/drivers/platform/chrome/cros_ec_lpc.c b/drivers/platform/chrome/cros_ec_lpc.c index 1ec12d19c779..8eeef85a96b1 100644 --- a/drivers/platform/chrome/cros_ec_lpc.c +++ b/drivers/platform/chrome/cros_ec_lpc.c @@ -341,9 +341,14 @@ static int cros_ec_lpc_probe(struct platform_device *pdev) u8 buf[2]; int irq, ret; - if (!devm_request_region(dev, EC_LPC_ADDR_MEMMAP, EC_MEMMAP_SIZE, - dev_name(dev))) { - dev_err(dev, "couldn't reserve memmap region\n"); + /* + * The Framework Laptop (and possibly other non-ChromeOS devices) + * only exposes the eight I/O ports that are required for the Microchip EC. + * Requesting a larger reservation will fail. + */ + if (!devm_request_region(dev, EC_HOST_CMD_REGION0, + EC_HOST_CMD_MEC_REGION_SIZE, dev_name(dev))) { + dev_err(dev, "couldn't reserve MEC region\n"); return -EBUSY; } @@ -357,6 +362,12 @@ static int cros_ec_lpc_probe(struct platform_device *pdev) cros_ec_lpc_ops.write = cros_ec_lpc_mec_write_bytes; cros_ec_lpc_ops.read(EC_LPC_ADDR_MEMMAP + EC_MEMMAP_ID, 2, buf); if (buf[0] != 'E' || buf[1] != 'C') { + if (!devm_request_region(dev, EC_LPC_ADDR_MEMMAP, EC_MEMMAP_SIZE, + dev_name(dev))) { + dev_err(dev, "couldn't reserve memmap region\n"); + return -EBUSY; + } + /* Re-assign read/write operations for the non MEC variant */ cros_ec_lpc_ops.read = cros_ec_lpc_read_bytes; cros_ec_lpc_ops.write = cros_ec_lpc_write_bytes; @@ -366,17 +377,19 @@ static int cros_ec_lpc_probe(struct platform_device *pdev) dev_err(dev, "EC ID not detected\n"); return -ENODEV; } - } - if (!devm_request_region(dev, EC_HOST_CMD_REGION0, - EC_HOST_CMD_REGION_SIZE, dev_name(dev))) { - dev_err(dev, "couldn't reserve region0\n"); - return -EBUSY; - } - if (!devm_request_region(dev, EC_HOST_CMD_REGION1, - EC_HOST_CMD_REGION_SIZE, dev_name(dev))) { - dev_err(dev, "couldn't reserve region1\n"); - return -EBUSY; + /* Reserve the remaining I/O ports required by the non-MEC protocol. */ + if (!devm_request_region(dev, EC_HOST_CMD_REGION0 + EC_HOST_CMD_MEC_REGION_SIZE, + EC_HOST_CMD_REGION_SIZE - EC_HOST_CMD_MEC_REGION_SIZE, + dev_name(dev))) { + dev_err(dev, "couldn't reserve remainder of region0\n"); + return -EBUSY; + } + if (!devm_request_region(dev, EC_HOST_CMD_REGION1, + EC_HOST_CMD_REGION_SIZE, dev_name(dev))) { + dev_err(dev, "couldn't reserve region1\n"); + return -EBUSY; + } } ec_dev = devm_kzalloc(dev, sizeof(*ec_dev), GFP_KERNEL); |